What Other Wonders Exist?

The biggest question rising from this project that I have gotten is what other animals survived. Now originally at the birth of this project, I hadn't thought of that question to an entirety. But after thinking it over and writing it out, I realised that it would be fun to introduce these concepts in a way that appealed to me. This page will cover animal groups and organisms that likewise survived the K-Pg Mass Extinction Event. Following this introductory section, all segments below will be written in universe through the perspective of contemporary scientists retrospectively looking back at the discoveries of these animals. Nire will be added as ideas come to me, but enjoy a glimpse further into this world!

A few details to keep in mind for this section:

• Any mention of  Megaveliformes are this world's name for Spinosaurids. The name spinosaurid doesn't exist in this timeline's scientific tradition as the lineage was classified within the veliform classication and the discovery of the mehek was made before these earlier spinosaurus discoveries were ever properly discovered. The most well known Spinosaurid in our timeline is Spinosaurus aegypticus which in this timeline is called Megaveliformis aegyptiacus

• As you will read in this page, theropods aren't classified as dinosaurs in this universe. Instead, they fall under the Velimorpha classification which includes theropods, birds, the mehek themselves, the rake birds, and crocodiles. Dinosaruia instead contains ornithiscians and sauropods

• The ancestral forms that rake birds descend from aren't called Therizinosaurs in this universe, but instead are called Megandrepanovelimorpha,

• The Calloway Expedition is a 1912 expedition that is a reference to the Lost World, but actually real. It happened during most of the time where all the classification histories were happening

• In this universe, pterosaurs were eventually added under Velimorpha as Pterovelimorpha during the period in which Velimorpha was becoming a proper category to group in survivng Cretaceous lineages

VELIFORMES

A Natural History of the Meheks

Order Veliformes — The Sail-Bearers of the Saharan Refugia

Evolutionary Origins

The mehek does not descend from the great Megaveliformes of the Cretaceous that loom so large in the fossil record. The true ancestor is a considerably more modest animal in the form of a small to medium-sized Megaveliform cousin called Archaeoveliformis ennediensis that occupied a different ecological position from its more famous relatives. Where the giant forms were apex predators of large river systems, this ancestral lineage had shifted toward smaller prey, opportunistic feeding, and a broader dietary range that included carrion, invertebrates, and plant material. This niche shift is the key to everything that followed. An animal already adapted to feeding flexibly on whatever was available was far better placed to survive the collapse of the Cretaceous food web than a giant specialist whose survival depended on a continuous supply of large prey. The dorsal sail of this ancestor was present but less developed than in the larger Megaveliformes. The neural spines were prominent enough to function as social signals between individuals but not the massive thermoregulatory structures seen in the larger forms. This matters because it establishes the sail as a communication organ from early in the lineage's history, laying the foundation for the elaborate sail colouration and patterning that defines the modern mehek as both a biological and cultural phenomenon. The sociality of the ancestral population is the other defining feature. Small animals navigating a world of larger predators and competitors gain measurable survival advantages from group living with more eyes detecting threats, shared information about food sources, and collective defence against animals that might easily overwhelm a single individual. The loose community structure documented in the modern mehek with its First Daughter hierarchy and cooperative fishing behaviour traces its roots to this early pressure. 

Survival of the K-Pg Extinction

The end-Cretaceous extinction event eliminated every other member of the Megaveliform lineage. The survival of the mehek ancestor was the product of a specific combination of body size, dietary flexibility, geographic position, and an ability to exploit microhabitat refugia that larger animals simply could not access. The ancestral population was small enough to shelter in caves and rocky outcrops during the worst of the post-impact conditions, surviving on the fungal blooms, invertebrate pulses, and scattered organic material that the devastated post-impact landscape offered. What came through was almost certainly a small and geographically restricted population and the genetic evidence of the modern mehek shows this. All five living species show relatively low genetic diversity given their morphological variety which is the signature of a severe ancestral bottleneck from which everything alive today descends. The geographic position of this population was a significant factor. The Chicxulub impact and its immediate aftermath were not uniformly catastrophic across the planet. The eastern and southern regions of what is now Africa and the broader Tethys margin experienced the post-impact conditions somewhat later and somewhat less severely than areas closer to the impact site. A Megaveliform population in that part of the world had a marginally better survival window than one positioned elsewhere, and marginally better was enough.

The Cenozoic Radiation and the African Humid Period

The Palaeocene and Eocene record of the lineage is known only from fragmentary material, isolated bones and partial skulls recovered from sites across North and Central Africa. These early Cenozoic forms are from the period during which the order was establishing itself in the ecological landscape that the extinction had restructured. The mammalian radiation was proceeding across the globe, but the African continent offered a productive environment and the lineage expanded steadily across it, tracking the permanent water systems that remained its primary habitat. The African Humid Period, which extended across much of what is now the Sahara from approximately eleven thousand to five thousand years ago, was the great expansion of the mehek's range. During this period, the Saharan interior was covered in lakes, rivers, and savannah in contrast to the hyper-arid desert that exists today. Mehek populations spread across an enormous area and reached water systems in what are now Libya, Algeria, Niger, Chad, and beyond. The rock art of the Saharan plateau regions documents this expanded range clearly with depictions of sail-backed bipedal animals appearing at sites distributed across a territory far larger than any modern mehek population occupies. The drying of the Sahara over the past several thousand years is the mechanism that produced the fragmented distribution of the modern order. As water sources contracted and desert expanded, mehek populations retreated to the permanent water systems of the plateau refugia like the Ennedi, the Tibesti, the Ahaggar, and the broader Sahel zone where permanent water persisted. Each refugium accumulated its own isolated population over millennia, producing the geographic variation that eventually warranted separate species recognition. The modern mehek is the product of contraction and isolation, not of a lineage that was always restricted to its current range.

Classification History

When Dr. Edouard Moreau of the Museum National d'Histoire Naturelle published his formal description of the mehek in 1878, he was confronted immediately with a classification problem that had no clean solution. The animal he was describing was scaled and bipedal on land which suggested reptile. It swam actively and pursued fish which suggested crocodilian. It vocalised in complex ways, maintained evident social relationships, and showed an active metabolism quite unlike any lizard or crocodile. It had a prominent dorsal sail with vivid colouration, characters that served clear social functions. Nothing in the existing classification of vertebrates accommodated all of these features simultaneously and Moreau said so plainly in the paper. He placed the animal provisionally within Reptilia while flagging the placement as almost certainly wrong and called for further study. The formal Order Veliformes was established in his 1881 monograph with the Class Velimorpha proposed alongside it. The proposal of an entirely new Class of vertebrate was not made lightly and the paper brought significant debate across European natural history institutions for years afterward. The debate centred on two competing positions. One camp held that the mehek was an unusual reptile and that Reptilia should simply be expanded to accommodate it. The other held that its metabolic activity, social behaviour, and overall biology placed it outside Reptilia in any meaningful sense and that a new Class was both scientifically honest and necessary. The second position prevailed, but the argument continued in various forms for decades as more specimens were examined and the full extent of the mehek's departure from reptilian biology became clear.

The Fossil Connection and the Theropod Question

The classification of the mehek as a new Class of living vertebrate was one debate and the question of what the mehek's existence implied for the fossil record was another and it proved considerably more consequential for the broader history of natural science. The structural similarities between the mehek skeleton and the skeletons of the large bipedal fossil animals being described from Cretaceous deposits in Europe, North America, and Asia were apparent to any comparative anatomist who had examined both. The hip structure, the hollow bones, the bipedal posture, the general body proportions, and the foot anatomy of the mehek matched the theropod fossil material with a consistency that was difficult to explain as coincidence. Thomas Henry Huxley, working in this period and already inclined toward the view that certain fossil archosaurs were more closely related to living birds than to living reptiles, found in the mehek exactly the living evidence he had been lacking. His 1883 paper arguing for the velimorphan affinity of the theropod dinosaurs used the mehek skeleton as his primary anatomical reference and proposed formally that the large bipedal theropods belonged within Velimorpha. The paper was immediately controversial and remained so for decades, but it established the argument in the scientific literature in a form that could not be ignored. The resistance to Huxley's proposal came from multiple directions. Palaeontologists who had spent careers working within the Dinosauria framework were reluctant to accept a reclassification that would remove the theropods from a grouping they considered well established. Others argued that the similarities between mehek and theropod anatomy were the product of convergent evolution instead of any shared ancestry. The convergence argument had genuine defenders because the alternative required accepting a common ancestor for the mehek and the theropods that pushed deep into the Mesozoic, well before the origins of either lineage as then understood. The resolution came gradually across the early and middle decades of the twentieth century as cladistic methodology developed and was applied systematically to the archosaur problem. The results were unambiguous. Theropods shared the defining characters of Velimorpha more closely than they shared them with the ornithischians and sauropodomorphs, and no analysis consistent with the fossil evidence could place them elsewhere. The formal transfer of the theropods into Velimorpha was published in a landmark monograph in 1962 and is now the settled consensus of the field. Dinosauria as a formal grouping was retained for the sauropodomorphs and ornithischians but was redefined accordingly and the popular understanding of prehistoric life shifted in a direction that the mehek had made inevitable from the moment Moreau described it. The implications extended to birds as well. If the theropods were velimorphans and birds descended from theropods, then birds were velimorphans too. This had been implicit in the velimorphan framework since Huxley's paper but became explicit and widely understood only when the theropod transfer was complete. The cultural consequence was a fundamental shift in how people related to the living animal world with birds now understood not as a separate category of creature but as the smallest and most numerous members of the same Class that included the mehek and the great theropods of the fossil record. It is a connection that popular science and natural history filmmaking have built on extensively, and one that would not have been possible without the mehek as its living anchor.

Archaeoveliformis and the Fossil Record of the Lineage

The discovery of Archaeoveliformis ennediensis in 2003 from deposits in the Ennedi region of Chad provided the fossil evidence of the stem velimorphan that the living mehek had long implied must exist. The specimen, a partial skeleton of a small to medium-sized bipedal animal with incipient neural spine development and the broader dietary flexibility evident from its tooth morphology, sits at the base of the veliform lineage and shared the body plan from which the modern species descended. Its description generated considerable scientific and public interest, and it remains the most important veliform fossil yet recovered for understanding the lineage's deep history.

Cultural Significance

The Rock Art Record

The oldest human accounts of the mehek are painted and carved into the sandstone faces of the Saharan plateau regions during the period when the African Humid Period sustained permanent water and mehek populations across a much wider territory than they occupy today. These images are found at sites distributed across the Ennedi, the Tibesti, and adjacent plateau systems, and they are sufficiently consistent in their depiction of a large bipedal sail-backed animal to leave no doubt about their subject. The rock art of the Ennedi Plateau in particular includes images of what appear to be mehek in association with human figures, suggesting that the relationship between the two had already developed its distinctive character thousands of years before any written account. The rock art record is significant for conservation history as well as cultural history. It establishes that mehek populations were present across a much larger area in the recent geological past, providing baseline data for understanding the scale of the range contraction that has occurred and informing models of what recovery might look like under improved habitat conditions.

Arabic and Medieval Geographic Accounts

The medieval Islamic geographic tradition which produced some of the most detailed accounts of African environments available from that period contains several references to large aquatic animals in the plateau water systems of the Saharan interior that are now understood as mehek sightings. These accounts circulated in Arabic before reaching European readers through the translation movement of the medieval period and the references to large sail-backed river animals in the interior desert were treated by European readers as fictional or exaggerations. The Arabic name for the mehek, derived from the cultural traditions of the Saharan peoples who knew the animal directly, filtered through the trading networks of the region and reached the coastal populations of North Africa in various forms. The name mehek as it is used in English today is an anglicisation of one of these Arabic-derived forms, worn into its current shape through colonial-era pronunciation and print.

The Mehest People and the Sacred Delta

Among the cultures that have developed the deepest and most formally articulated relationship with the mehek, none is more significant than the Mehest people of the Sacred Delta of Mehetra, a network of deep waterways and sandstone formations within the Ennedi Plateau that has sustained both the Mehest community and one of the most stable mehek populations known. The Mehest relationship with the mehek is central to to their culture and way of life. Their cosmology, social organisation, seasonal calendar, material practices, and spiritual life are all structured around the presence of the animals they call the River Daughters. At the centre of Mehest cosmology stands Mehetra, the River Mother, a divine figure combining the head of a mehek with a humanoid body, whose acts of creation shaped the landscape of the Sacred Delta. The mehek of the delta are understood as the River Daughters in the form of divine beings associated with specific aspects of Mehetra's nature. Each community of mehek is led by a First Daughter, the oldest and largest individual, who is understood as the direct voice of Mehetra for the specific divine attribute her group embodies. Younger mehek are understood as spiritual descendants of these original divine beings, and the appearance of a new juvenile animal in a community's territory is cause for formal celebration lasting several days. The practical relationship between the Mehest and the mehek has evolved over generations into a genuine ecological partnership. Mehest fishers deliver surplus fish to the mehek in carved offering boats, a practice that has conditioned the animals to associate the sound of these boats with food and to approach them calmly. Mehest swimmers enter designated shallow areas during certain seasons in a practice called blessing immersion which drives fish toward the deeper channels where mehek hunt. The Mehest interpret all of this through their religious framework, experiencing each interaction as confirmation of divine relationship, and the result is a symbiosis in which both parties benefit without either requiring a full understanding of the mechanism. Mehest society is organised around closeness to the River Daughters. The Watching Ones, the community's priestesses, hold the highest social status and maintain constant observation of mehek behaviour, recording movements and patterns in scrolls that constitute both sacred text and detailed ethological record. The knowledge accumulated in these scrolls across generations is one of the most substantial bodies of behavioural documentation of any wild animal anywhere in the world and the relationship between this indigenous record and the formal scientific literature has been a source of ongoing tension and negotiation since Western researchers first became aware of its existence.

The Mehest settlement pattern is built around their relationship to meheks directly. Villages are built in terraced formations along the riverbanks with buildings facing the water. The focal point of each settlement is the Watching Basin, a terraced amphitheatre designed for community observation of the adjacent channel. Daughter Houses extend over the water on stilts, used by the Watching Ones for close observation and recording. Every architectural element from the central pillars shaped to mimic the neural spine profile of a mehek to the water shrines at every intersection of the settlement's channel system, expresses the community's orientation toward the animals that define their world. The Mehest seasonal calendar divides the year into four periods whose character is defined by mehek behaviour and water conditions. The Deep Waters season brings the highest water levels and the most active and visible mehek presence close to settlements. The Green Rise is the planting season, when receding waters leave fertile margins. The Sun Mirror is the driest period, when mehek concentrate in the deepest channels and young adults undergo vision quests. The Changing Waters marks the transition into the next cycle, a time of ceremony and omen-reading in the new currents. Children born in each season carry names and spiritual associations connected to it throughout their lives.

Broader Indigenous Knowledge Across the Range

The Mehest relationship is the most thoroughly documented but not the only significant cultural tradition associated with the mehek. Across the broader range of the order, the communities living near mehek habitat have developed distinct relationships shaped by their own cosmologies, material needs, and histories. The Toubou and Tuareg peoples of the Tibesti and Ahaggar regions have their own traditions around the animals, generally less formally institutionalised than the Mehest system but no less deeply rooted in long familiarity. In most of these traditions the mehek occupies a similar cultural position as an animal of the deep water, associated with the boundary between ordinary experience and something beyond it, carrying spiritual weight that is a part of both the animal's impressive physical presence and its evident social complexity.

Biology

The mehek is a large semi-aquatic animal with a body plan that shows the dual demands of terrestrial and aquatic life. On land it is bipedal, carried on long and powerful hindlimbs with broad foot pads adapted for movement on soft substrate and in shallow water. The forelimbs are proportionally shorter than the hindlimbs and used primarily for prey manipulation and balance. The neck is long and flexible, supporting a skull that is elongated and narrow with a rostrum well suited to fish capture. The overall posture on land has a forward lean that brings the centre of mass over the powerful hindquarters, giving the animal a distinctive silhouette that is recognisable at distance. In water the mehek is a capable and efficient swimmer, using undulating body movements and powerful tail strokes to propel itself through even the deep channels of the Ennedi system. The nostrils are positioned high on the snout, allowing the animal to breathe while swimming with most of the skull submerged. The eyes provide good above-water visibility in the semi-submerged swimming posture that the mehek uses when approaching prey from below. This is an ambush hunting posture refined over millions of years for the specific conditions of deep, clear-bottomed channel environments.

The neural spine sail is the most immediately distinctive feature of the mehek and the one that has most shaped both its scientific classification and its cultural significance. The sail is supported by elongated extensions of the vertebral neural spines, covered in vascularised skin that is capable of rapid colour change in response to social and physiological states. The sail flushes darker during threat displays and lighter during submission and the patterning of individual sails is distinctive enough to serve as a reliable individual identification feature. The primary function of the sail in the modern mehek is social signalling. Thermoregulation plays a secondary role at best since the aquatic lifestyle provides a far more efficient temperature management system than any sail could offer. The elaboration of sail colouration and patterning over evolutionary time was a consistent social selection pressure on a structure that was already oriented toward communication in the ancestral lineage. In communities of eight to twelve animals where individual identity and social status are tracked continuously, a reliable and difficult-to-fake visual signal of individual identity and current state is of considerable value.

The vocal repertoire of the mehek is one of the features that most surprises outside observers and one that has the deepest resonance within the cultural traditions of the peoples who live alongside them. The fundamental long-distance call is a deep rumbling sound produced at the lower edge of human hearing and is felt as much as heard at close range and audible across several kilometres under appropriate atmospheric conditions. This call carries information about individual identity, location, and social state. The rumbling calls are layered with higher-frequency hoots and whistles used in closer-range communication during fishing coordination, social interaction within a community, and the complex exchanges between individuals during the seasonal gatherings that bring multiple communities into proximity. The alarm call system is particularly well developed with distinct calls for aerial and ground threats and variations that carry information about the distance and immediacy of the danger. The Mehest priestly practice of using specific drumming patterns to draw mehek toward ceremonial locations works because certain rhythmic structures fall within the frequency range and temporal pattern of mehek contact calls, triggering an investigative response in animals that have learned over generations to associate human sound-making with the possibility of food offerings.

Diet and Feeding

Fish form the bulk of the mehek diet across all five species, but the lineage retains the dietary flexibility of its ancestral form and supplements fish with crustaceans, large aquatic invertebrates, carrion, and in some populations opportunistic consumption of terrestrial prey that ventures too close to the water's edge. This flexibility is what allowed the ancestral lineage to survive the K-Pg extinction and remains a buffer against seasonal food scarcity in environments where fish availability fluctuates considerably with water level and season. The cooperative fishing behaviour documented in the Mehest sacred texts and confirmed by field research involves communities arranging themselves in coordinated formations during large fish migrations, herding schools into shallower water where individuals take turns feeding. The coordination required for this behaviour implies a level of social communication and shared intention that goes beyond simple opportunistic aggregation and it is one of the primary lines of evidence for the social intelligence that the mehek show across multiple domains.

Reproduction

Mehek reproduction follows the standard veliform pattern of internal egg retention found in other groups like the Drepanornithoformes. Eggs are held within the female's body through the great majority of development and laid when development is essentially complete. The interval between laying and hatching is short, usually only a matter of hours in the larger plateau species, which means that incubation in the conventional sense does not occur. The clutch is small, typically two to three eggs depending on species and individual condition which is a result of the high maternal investment involved in internal retention and the extended parental care that follows hatching. Hatchlings are relatively precocial, capable of swimming and following the mother within days of emergence. The juvenile dependency period extends across several years during which the young animal learns the territorial knowledge, fishing techniques, and social skills that adult life requires. This extended period of learning alongside experienced adults is the mechanism through which cumulative cultural knowledge is transmitted across generations and it means that the loss of experienced older animals from a community carries costs that go beyond the simple reduction in numbers.

Social Organisation and the First Daughter

Mehek communities consist of eight to twelve individuals organised around a matrilineal core. The most experienced female in each community, known to the Mehest as the First Daughter, holds a position of social authority that is based on demonstrated knowledge and reliable judgement over physical dominance. Younger individuals defer to her during fishing, territorial disputes, and encounters with unfamiliar situations, and the quality of her decision-making over time is what sustains her authority. This is a cognitively demanding social system for every member of the community since tracking another individual's record of judgement across years requires both long-term social memory and the capacity to evaluate behavioural outcomes in context. Males in the community are present but hold a more peripheral position than females. Social bonds between females are more stable and long-lasting and the territorial knowledge that constitutes the community's primary survival resource is held and transmitted through the female line. This matrilineal structure appears consistent across all five species, though the degree of male peripherality varies somewhat between the larger plateau species and the smaller more social forms of the Sahel zone. The knowledge held by elder females has direct survival value in a way that field research has only recently begun to quantify. An older animal that has experienced several decades of seasonal variation in a specific territory has knowledge of drought refugia, alternative food sources, and unusual predator behaviour that younger individuals have not encountered. Communities that lose their most experienced females to poaching or habitat disruption suffer measurable declines in foraging efficiency and territorial management in the years that follow, a finding with direct implications for conservation management.

Family Mehetravelinae: The Plateau Mehek

The two largest species of the order occupy the deep plateau water systems of the Ennedi and Tibesti regions where the permanent channels and underground aquifer networks provide the stable high-quality habitat that large veliform animals require. Both species show the most fully developed sail morphology in the order, the most elaborate social structures, and the longest associations with the human cultural traditions of the plateau peoples.

Mehetravelis moreauii- The Ennedi Mehek

The type species of the order, formally described by Dr. Edouard Moreau in 1878 from specimens obtained in the Ennedi region of what is now Chad, Mehetravelis moreauii is the mehek of the Mehest people and the animal around which the deepest human cultural tradition has developed. Adult females reach lengths of five to six metres and body masses of several hundred kilograms, placing them among the largest semi-aquatic animals alive. The sail in adult animals is tall and prominently patterned with individual variation in colour banding sufficient for reliable identification at distance. The Ennedi Mehek is the species most thoroughly documented in both the Mehest observational tradition and the formal scientific literature, and the long-term behavioural data from the Sacred Delta communities represents one of the richest datasets on any wild animal currently maintained. Conservation status is critically endangered. The global population is estimated at between six hundred and nine hundred individuals, with the Sacred Delta population being the most stable concentration known. Threats include continued poaching for sail tissue and bone, water extraction affecting aquifer levels in the broader Ennedi system, and the political instability of the region which complicates law enforcement and research access. The species is listed on CITES Appendix I and is legally protected under Chadian national law. The Mehest traditional prohibition on harming the River Daughters has historically been the most effective single conservation measure applied to this species and remains so in the communities where it retains cultural force.

Mehetravelis tibestensis- The Tibesti Mehek

The second large plateau species occupies the permanent water systems of the Tibesti massif and is distinguished from Mehetravelis moreauii by several consistent morphological characters including broader sail patterning in the mid-section and a generally heavier build. It was formally described in 1923 from specimens collected in the French colonial administration of the region, considerably later than the Ennedi species and remains less thoroughly studied due to the difficulty of access to its core habitat. The Tibesti Mehek has its own associated cultural traditions among the Toubou people of the massif, which share structural similarities with the Mehest tradition while differing in specific cosmological content and practice. Conservation status is critically endangered.

Family Sahelovelinae: The Sahel Mehek

The two medium to smaller species of this family occupy the lower-altitude water systems of the Sahel zone and are the more widespread and accessible radiation of the order. They show reduced sail development compared to the plateau species, a more generalised diet, and higher degrees of sociality that are the result of the greater productivity of their habitat. These are the species most commonly encountered by outside observers historically and the ones with the broadest distribution of indigenous cultural knowledge across multiple Sahelian peoples.

Sahelovelus dorsalis- The Spotted Mehek

The most widespread species of the order and the first to be encountered by European observers prior to Moreau's formal description, Sahelovelus dorsalis occupies permanent water systems across a broad band of the Sahel zone from the Lake Chad basin westward. It is smaller than the plateau species with adult females reaching three to four metres in length and its sail is proportionally less developed though still prominently patterned with dappled spots along its flank and head. The Spotted Mehek is the species most frequently kept in zoological collections globally where its relatively more tractable temperament and lower space requirements compared to the plateau species have made successful captive management achievable at a greater number of institutions. Conservation status is endangered.

Sahelovelus nigeriensis- The Niger Mehek

Associated with the permanent water systems of the Niger Inland Delta and adjacent river networks in West Africa, Sahelovelus nigeriensis is the most social species of the order, living in communities that can reach fifteen to twenty individuals in areas of high productivity. The larger group sizes and more fluid social structure of this species have made it the primary subject of research into mehek cooperative behaviour and the coordinated fishing formations documented in the Niger Mehek communities are the most elaborate yet recorded in the order. The sail is less dramatically coloured than in the plateau species but shows greater responsiveness to social context, flushing rapidly and extensively during community interactions. Conservation status is endangered.

Family Microvelinae: The Dwarf Mehek

Microvelis aridus- The Dwarf Mehek

The smallest and most morphologically distinct species of the order, Microvelis aridus occupies the marginal water systems at the edges of the veliform range where resources are scarcer and smaller body size carries distinct advantages. Adults reach lengths of one and a half to two metres, giving the species a profile considerably more accessible than its larger relatives and making it the mehek most commonly depicted in educational materials aimed at younger audiences. The sail is present but reduced, functioning primarily as a social signal in the close-range interactions of the small community groups the Dwarf Mehek forms. Conservation status is vulnerable, with a broader distribution and higher total population than any other species in the order.

Colonial Exploitation and the Zoo Tradition

The formal Western description of the mehek in 1878 occurred within a colonial context that shaped the subsequent history of the animal's relationship with European and American institutions in ways that are still being negotiated. The immediate response to Moreau's paper combined genuine scientific excitement with the extractive impulses characteristic of the period. Specimens were sought for museum collections, living animals were desired for zoological gardens, and the sail tissue and bones of dead animals entered trade networks supplying the European market for natural curiosities. The challenges of transporting a large semi-aquatic animal to European institutions were substantial. The mehek requires deep water access as a biological necessity and the infrastructure to provide this was not available in most nineteenth century zoological facilities. The first attempts to bring living plateau species to Europe failed through inadequate water provision and the severe stress of long sea voyages in conditions wholly unsuited to the animals' needs. Smaller specimens and juveniles proved more survivable in transport and the first living mehek to reach a European institution was almost certainly a young Sahelovelus dorsalis arriving at a French or Belgian facility in the 1890s where its exhibit drew the same combination of public fascination and scientific attention that the first gorilla at London Zoo had generated a decade earlier. The smaller species and juveniles of the larger forms also appeared in circus and travelling menagerie contexts during the late nineteenth and early twentieth centuries, a chapter of the mehek's history in European popular culture that generated early advocacy for protective legislation and contributed to the development of both conservation law and animal welfare regulation. The exploitation of animals with deep cultural significance to living indigenous communities for European entertainment spectacle was a source of protest that gave some of the earliest formal articulations of indigenous cultural rights in a natural history context. By the early twentieth century, several major European and American zoological institutions had established purpose-built mehek facilities with appropriate pool infrastructure, and the husbandry knowledge had advanced to the point where captive survival rates were improving substantially. The first successful captive breeding of a mehek species in a zoo setting occurred in the 1930s and was reported as a landmark event in the international zoological press. In 2026 the Spotted Mehek is held at approximately forty institutions globally with successful captive breeding programmes contributing to conservation genetics management. The plateau species are held at far fewer institutions given their space and infrastructure requirements with the most significant programmes at facilities in France, Germany, Singapore, the souther provinces of Canada, and the United States.

Velimorpha in Popular Culture

The reclassification of theropods within Velimorpha, completed as scientific consensus in the 1960s, reshaped the popular understanding of prehistoric life in ways that continue to develop. The public relationship to animals like Tyrannosaurus and Velociraptor shifted from one in which they were understood as members of a wholly extinct group to one in which they were understood as the prehistoric giants of a lineage that also includes the living mehek and all living birds. This is a different kind of connection to the deep past from the one available in a world where all velimorphans were extinct and it has produced a popular culture around prehistoric animals that is more continuous and less purely nostalgic than it might otherwise have been. The mehek's role in this cultural landscape is as the living anchor of the velimorphan story. Film and television productions exploring the natural history of the order consistently use the mehek as the bridge between the living world and the fossil record and the animal appears in popular science writing about prehistoric life with a frequency that shows its central position in the public understanding of velimorphan evolution. The most widely seen natural history documentary series of the past three decades have all devoted significant attention to the mehek and the animal's combination of visual drama and scientific significance has made it a reliable subject for prestige natural history programming. Children's natural history education in 2026 introduces the velimorphan lineage through the mehek in much the same way that earlier generations were introduced to the concept of evolution through the giraffe or the elephant. The animal is present in school science curricula, in museum educational programmes, and in the popular natural history books that shape early scientific curiosity. Its cultural role in this respect is inseparable from its scientific significance, and the two continue to reinforce each other in ways that have sustained public interest in velimorphan research across many age groups and scientific fields of study.

Conservation Status and Modern Challenges

The conservation situation of the Veliformes in 2026 are the result of pressures accumulated across nearly a century and a half of documented decline. All five species are listed as threatened on the IUCN Red List, with the two plateau species classified as critically endangered and the remaining three ranging from endangered to vulnerable. The total global population of all species combined is estimated at between fifteen thousand and twenty-two thousand individuals with the Dwarf Mehek accounting for the largest share of that figure and the plateau species the smallest. The primary modern threats are habitat loss through water extraction affecting the underground aquifer systems that sustain the plateau refugia, the black market trade in sail tissue and bones that persists despite CITES listing and domestic legal prohibition, and the political instability of the Sahel and Saharan regions which complicates enforcement, research access, and the continuity of conservation programmes. Climate projections for the region are concerning, with models predicting further reduction in the permanent water availability that the order depends upon across much of the current range. The most effective conservation interventions have consistently involved working with and through the indigenous communities whose traditional relationships with the mehek predate formal conservation law by millennia. 

The scientific community's relationship with the Mehest Watching Ones' observational tradition has evolved considerably over the past several decades. Early Western researchers frequently drew on the knowledge recorded in the sacred scrolls without adequate attribution or consultation, a practice that generated justified resentment and damaged the working relationships that productive research depends upon. More recent approaches that have been shaped by the development of indigenous knowledge frameworks in international science policy have sought to treat the Watching Ones' records as a co-equal source of data with formal field research and to ensure that the communities whose knowledge has sustained the mehek through conditions that formal science has only recently begun to monitor receive appropriate recognition for that contribution.

DREPANORNITHIFORMES

A Natural History of the Rake Birds

Drepanornithiformes- The Scythe-Birds of Sundaland

Evolutionary Origins

The question of where rake birds come from has occupied palaeontologists and ornithologists in roughly equal measure since the molecular clock work of the early 2000s produced divergence estimates that surprised even those researchers who had long since held the importance of their classification. The current consensus, supported by both phylogenomic analysis and a growing Cenozoic fossil record, places the origin of the rake bird lineage in the Late Cretaceous of eastern Asia, descending from a smaller and more generalised member of the therizinosaur radiation. The large Central Asian therizinosaurs, including the genus Therizinosaurus proper, are now informally referred to in the palaeontological literature as drepanornithomimids in recognition of their resemblance to the living order. The ancestral rake bird of the Late Cretaceous was almost certainly a modest animal by the standards of the group, probably comparable in size to a large cassowary, feathered across the body and retaining the elongated fore-claws that characterise the lineage. It was likely omnivorous and forest-adapted, inhabiting the dense lowland vegetation of what is now southern China and Indochina. These ecological preferences, combined with a fortunate geographic position relative to the immediate devastation of the Chicxulub impact event, are the most likely explanation for survival through the end-Cretaceous extinction that eliminated every other member of the broader therizinosaur radiation. The K-Pg survival event was almost certainly a severe bottleneck. Modern rake birds show relatively reduced genetic diversity given their morphological variety which is a pattern consistent with descent from a small founding population that passed through a period of intense selective pressure. The population that survived was probably geographically restricted to a specific forest refugium and subsisted on whatever plant material and invertebrate protein the post-impact world offered and it is from this small group that everything in the modern order descends.

The Cenozoic Radiation

The Palaeocene and Eocene fossil record of the lineage is fragmentary, known primarily from isolated claws and partial skeletal material recovered from sites across what is now mainland Southeast Asia and southern China. These early Cenozoic forms are collectively referred to as stem drepanornithiformes and represent the period during which the order was establishing itself in the ecological landscape left by the extinction. The mammalian radiation was proceeding across the globe, but the island and semi-island environments of proto-Sundaland had a less diverse mammalian fauna than continental interiors which left more ecological space available for a feathered lineage with the morphological toolkit to exploit high forest vegetation. It is during the Eocene that the fore-claw apparatus begins showing clear evidence of renewed specialisation toward a feeding function in the fossil record. The ancestral claw morphology, which was likely multipurpose in the immediate post-extinction survivors, becomes progressively more elongated and curved in forms associated with dense forested environments, driven by the same selective logic that originally produced the therizinosaur claw in the Mesozoic. Larger body size increases alongside this specialisation, as greater height means access to a higher feeding range that compounds the advantage. The Miocene is the period of the main adaptive radiation that produced the three modern families. Progressive formation of the Sundaland shelf environment and repeated cycles of sea level change created and dissolved land connections between what are now Borneo, Sumatra, Java, and the Malay Peninsula, isolating populations in different forest blocks and driving divergence. It is from a common Sundaland ancestor of this period that the great rakes, the fruit rakes, and the arboreal rakes each derive, each being part of three distinct adaptive responses to the productive and structurally complex environments of the equatorial rainforest. The restriction of the order to Borneo and remnant Sundaland forests in modern times is the endpoint of a long contraction. Pleistocene fossils of rake birds are known from across the Sundaland shelf, including sites in the Thai-Malay peninsula and Sumatra with the most famous assemblage being the Niah Cave deposits of Sarawak where rake bird remains occur alongside orangutan, sun bear, and a Pleistocene therizinosaur-relative informally designated the Niah Rake in popular science literature. The retreat to the Bornean interior is the result of successive habitat loss across the glacial-interglacial cycles of the Pleistocene and, most significantly, of the forest clearance and hunting pressure of the Holocene.

Classification History in Western Science

The rake birds were unknown to Western natural history until the early decades of the nineteenth century, though they had of course been known to the peoples of Borneo and the surrounding region for generations beforehand. The first European accounts are fragmentary, appearing in the travel literature of traders and administrators, and are primarily concerned with the claws over the actual animals themselves. Dutch East India Company records from the late eighteenth century contain several references to large clawed ornaments traded along the Sarawak coast that are now believed to be Emperor Rake fore-claws, though the animals from which they came are not described. The first formal Western description of a rake bird was published in 1863 by the British naturalist Arthur Colefax, working from a specimen obtained through the offices of the Rajah Brooke administration in Sarawak. Colefax's paper, appearing in the Proceedings of the Zoological Society of London, placed the animal within Aves but declined to assign it to any existing order, noting the complete absence of morphological precedent in the known avian fauna. He proposed the name Drepanornis sarawakensis for the type specimen, a name later revised when the order was formally established, and described the animal with a mixture of scientific precision and pure scientific wonder that is elevated to a fond charm in more modern contexts. The formal establishment of the order Drepanornithiformes came in 1871 in a monograph by the comparative anatomist Sir Frederick Marsh, who had the advantage of multiple specimens including skeletal material. Marsh recognised immediately that the order could not be accommodated within any existing avian grouping and argued forcefully for its independent status. His monograph also established the family Drepanornithidae for the large ground-dwelling forms and proposed the genus Megalodrepan for what would eventually be recognised as the Emperor Rake, though his type species was a smaller form from the Sabah highlands instead of the largest Kalimantan species.

The relationship between rake birds and the non-avian dinosaurs was invisible to the naturalists who first described them, for the straightforward reason that the theoretical framework necessary to perceive it did not exist. When Colefax described Drepanornis sarawakensis in 1863, Therizinosaurus had not yet been discovered by science. When Marsh established the order in 1871, therizinosaurs as a group were unknown, and the modern understanding of birds as living dinosaurs was still a century in the future. The early classification of rake birds as highly unusual but unambiguously avian was a product of the time and the limited understanding of biological and morphological classification. The first serious suggestion of a deep therizinosaur affinity appeared in a 1987 paper by the American palaeontologist Dr. Carol Rennick, who noted the morphological parallels between rake bird fore-claw osteology and the recently described therizinosaur material from Mongolia. Rennick's paper was initially received with considerable scepticism, partly because the therizinosaur connection implied a divergence date so early that it challenged existing models of avian evolution, and partly because the birds-as-dinosaurs framework was not yet mainstream enough to make such a connection intuitively plausible to most ornithologists. The paper is now recognised as one of the foundational documents in drepanornithiform research. The paradigm shift came in the late 1990s and accelerated through the 2000s, driven by three converging lines of evidence. The explosion of feathered dinosaur discoveries from the Yixian Formation in China provided a morphological context in which therizinosaur-adjacent features in living birds became not just plausible but expected. Molecular clock analyses of rake bird genomes produced divergence estimates from other avian lineages that were startlingly deep, consistently falling in the Late Cretaceous and in some analyses pushing toward the early Campanian. And developmental biological studies of rake bird embryos revealed aspects of fore-limb and claw development with no parallel in any other living bird but clear homologies with the developmental pathways reconstructed for non-avian therizinosaurs. In 2026, the scientific consensus holds that rake birds are part of a lineage that diverged from the main avian stem significantly earlier than any other surviving bird group, retaining morphological and developmental features that were otherwise lost in the transition through the K-Pg event. They are not classified as dinosaurs because that classification has never been applied to them and because the continuity of a living lineage known since the nineteenth century makes retroactive reclassification practically and conceptually problematic. They are birds, in the same sense that all birds are birds. But they are birds that carry in their bodies evidence of a transition that everywhere else can only be studied in stone.

The Peoples of Borneo and Their Rake Birds

Borneo is not a culturally uniform island, and any account of human relationships with its rake bird fauna must resist the temptation to treat the island's diverse peoples as a single entity. The Iban, Kadazan-Dusun, Kenyah, Kayan, Penan, and the many other distinct communities that have inhabited the island across millennia each have their own relationships with these animals, shaped by differences in ecology, cosmology, material culture, and historical circumstance. What follows is necessarily a broad outline that will not attempt to capture the full depth and variation of those relationships. The most widespread Malay-language name for the large ground-dwelling rakes is sabit, meaning “sickle”, a reference to the sweeping curvature of the fore-claws. In common speech across Sarawak and Kalimantan the word is used without further qualification to refer to the great rakes as a group, with specific species distinguished by additional descriptors where necessary. The Emperor Rake is sometimes called sabit gajah, “the elephant sickle”, in recognition of its size. The fruit rakes are commonly called cakar pisang, “the banana claw”, because of their association with fruiting trees and forest edge habitat near cultivation. The tree rakes, which occupy a different cultural register, are discussed separately below. The Iban augury tradition, one of the most elaborately developed bird omen systems documented anywhere in the world, assigns particular significance to the great rakes. Encountering a great rake during a journey is interpreted differently depending on the species, the direction of movement, and the time of day, with a complex body of interpretive knowledge that is the province of specialists. The claws of naturally deceased animals are among the most valued ritual objects in Iban material culture, used in the regalia of leaders, incorporated into ceremonial dress, and treated as objects of considerable spiritual potency. There is a strong taboo across most Iban communities against killing a great rake intentionally, a prohibition that predates any formal conservation law and has done more to protect populations in the Sarawak interior than any government measure. The Penan, as nomadic forest dwellers with the most intimate practical knowledge of the deep interior, have the most detailed ethological understanding of great rake behaviour of any community. Penan knowledge of great rake seasonal movements, preferred food trees, individual temperament, and communication signals accumulated over generations is a complex dataset of behavioural information that formal research has only recently begun to document systematically, and which continues to inform field research in ways that are not always adequately acknowledged.

The tree rakes are part of an important cultural position from their ground-dwelling relatives, one shaped by their canopy habitat and their tendency to be heard or glimpsed. In many Dayak cosmological frameworks the canopy layer of the forest is spiritually distinct from the ground level, associated with ancestor spirits, with transition between states of being, and with communication between the living world and other realms. The arboreal rakes a part of this cosmology as spirits of the canopies. The most widely used name for the arboreal rakes in the Iban and related traditions is menjap sabit, “the glimpsed sickle”, named so because of the experience of suddenly seeing one pass overhead in the high canopy. The fruit rakes, by contrast, have a thoroughly domestic cultural presence. They are the rake birds that children grow up around, that feature in proverbs and folk sayings about abundance and the turning of seasons, that are associated with the coming of fruiting periods in the forest calendar. Their nesting colonies are well known amongst the local peoples and the relationship is one of familiarity and affection in most communities.

The arrival of Western naturalists and administrators in the nineteenth century brought a tension that had shaped the knowledge of rakes and their presence. The claws arrived in European collections before the animals did, traded along networks that the colonial economy accelerated and the first serious Western accounts of strange objects from unknown mysterious animals. Because they were first known by their claws, this naming convention shaped the English common name that eventually became the most widespread as the raking motion of those enormous fore-claws was the feature that European observers most consistently described on first encounter. The name rake bird appears in print first in an 1871 account by a correspondent to The Field magazine describing a specimen obtained in Kuching, and proved more durable than the various alternatives that circulated in the same period, including sickle-bird, claw-bird, and the much less common name of the Borneo sloth-bird, which was part of a small connection and superficial resemblance to the large ground sloths common amongst explorers and scientific communities of the time. By the early twentieth century, rake bird was the standard English common name and was often abbreviated in casual usage to simply the rake, which is a name most commonly used in modern day.

The Three Families

The order Drepanornithiformes is divided into three families, each part of a distinct adaptive radiation from the common Sundaland ancestor of the Miocene. The families differ substantially in body size, ecology, social organisation, and cognitive complexity, but share the fundamental drepanornithiform characters of an elongated fore-limb with modified claws, a feathered body with vestigial wing structures, a distinctively bird-like skull, a long neck in comparison to the body, and the reproductive strategy of internal egg retention described in detail below.

Family Drepanornithidae: The Great Rakes

The great rakes are the animals that established the order's scientific and popular reputation, and in the Emperor Rake they include the largest living bird and one of the largest terrestrial animals on Earth. Four species are currently recognised within the family, distributed across the distinct geographic and altitudinal zones of Borneo's interior, with the degree of morphological and ecological differentiation between them reflecting the island's complex topography and the long history of population isolation and reconnection driven by Pleistocene sea level change. All four species share the defining characters of the family with a massive, deep-chested body carried on long columnar legs, an elongated neck supporting a relatively small bird's head with a broad keratinous beak adapted to pulling and stripping vegetation, enormously elongated fore-limbs terminating in the curved rake-claws for which the order is named, and vestigial wing structures retained as display and thermoregulatory organs. The plumage is dense across the body, with species-specific variation in colouration and the development of display feathering, particularly on the head, neck, and the modified wing structures. The reproductive biology of the family is consistent in its broader structure across the family. Females retain eggs internally through the great majority of development, laying a clutch of two eggs that hatch within hours of being laid. The hatchlings are large and relatively precocial, capable of standing and following the mother within days. The juvenile dependency period is the longest of any bird, extending between two and four years depending on species, during which the young animal acquires the territorial knowledge, social skills, and feeding techniques that adult life requires. This extended dependency means that successful females may raise only one clutch every several years, producing low reproductive rates that make the family highly vulnerable to population pressure. Social organisation in the great rakes is matrilineal and ranges from fundamentally solitary in the Emperor Rake to loosely semi-social in the smaller species. In all cases, the female is the stable core of any social unit that forms, retaining the territorial knowledge that is vital to the primary survival resource for herself and her offspring. Males are more peripheral and wide-ranging, overlapping with multiple female territories and contributing primarily to territory defence and mating but largely limited in the parental investment that defines the female's life history.

The Emperor Rake (Megalodrepan imperator)

The Emperor Rake is the largest species within the family and the largest living bird by a substantial margin with adult females reaching heights of up to six metres and body masses approaching or occasionally exceeding seventeen hundred kilograms. It is found primarily in the lowland and foothill forests of central and southern Kalimantan, with a smaller relict population in the Maliau Basin of Sabah that is the subject of ongoing conservation concern. The species was formally described from Kalimantan material in 1891 by the Dutch zoologist Pieter van Hoorn who recognised immediately that it exceeded all other known rake bird species in dimensions and proposed the specific epithet imperator to call particular attention to this. The Emperor Rake's fore-claws are the most developed of any living animal, reaching lengths of up to ninety centimetres in adult females and used primarily to pull down the high canopy vegetation that forms the bulk of the diet. The feeding action, in which the animal rears back and draws both fore-limbs downward and inward in the raking motion that gave the order its common name, is one of the most distinctive behaviours in the living animal kingdom and is the image most commonly reproduced in popular natural history illustration. The claws are also formidable defensive weapons and there are reliable accounts of Emperor Rakes killing large pythons and sun bears that had threatened offspring, though active defence is rarely observed and the species' default response to perceived threat is withdrawal. The Emperor Rake is essentially solitary, with adults maintaining large home ranges whose size varies considerably with habitat quality but averages in the range of fifty to one hundred and fifty square kilometres for adult females. Individuals know their neighbours through vocalisation and through the seismic signals produced by their movement and they maintain complex relationships of tolerance and avoidance without the sustained social contact that characterises more gregarious species. The exception is the period of seasonal aggregation around large food resources, during which multiple adults may be encountered in proximity at traditional sites and the mating season which involves elaborate vocal and display interactions between adults who are otherwise rarely in direct contact. The vocalisation of the Emperor Rake is one of the most notable things about the animal and one of the features most consistently described by first-time observers. The primary long-distance call is a deep, resonant rumble produced at the lower boundary of human hearing which is felt as much as heard at close range and audible in appropriate atmospheric conditions at distances of several kilometres. This call is layered with higher-frequency hoots and chitters used in closer-range communication, producing a vocal repertoire of considerable complexity that encodes information about identity, location, reproductive state, and social context. Local communities in the Kalimantan interior describe the deep rumble as the voice of the old forest and it features as a significant element in the cosmologies of several of the peoples who share habitat with the species. The overall conservation status of the Emperor Rake is critically endangered. The global population is estimated at between eight hundred and twelve hundred individuals across both range states, with the Maliau Basin population being perhaps one hundred and fifty of these. The primary threats are continued habitat loss through logging and conversion to oil palm cultivation, illegal claw trade, and the extremely low reproductive rate that makes recovery from population decline unfortunately slow. The species is protected under Indonesian and Malaysian law and is listed on CITES Appendix I. Captive populations are maintained at eleven institutions globally, with the largest programmes at the Singapore Zoo, Tierpark Berlin, and the San Diego Zoo Safari Park.

The Highland Rake (Megalodrepan montanus)

The Highland Rake is found in the montane forests of Borneo's interior ranges, particularly the Muller and Schwaner mountains of central Kalimantan and the Crocker Range of Sabah, at elevations between eight hundred and two thousand metres. It is considerably smaller than the Emperor Rake, with adult females reaching heights of approximately three and a half metres and body masses of around four hundred kilograms, and is distinguished by its denser, darker plumage adapted to the cooler and more seasonal montane environment. It was described formally in 1887 by the British naturalist James Croft from Sabah material and is now understood to be the most genetically divergent of the four great rake species due to its longer period of altitudinal isolation. The Highland Rake shows the most developed semi-social tendencies within the family, with stable associations of two to four adult females observed in areas of productive montane forest. These groupings typically appear to be matrilineal in structure, based on the long-term field data from the Kinabalu Research Station, with younger females remaining in the natal home range instead of dispersing at maturity. The ecological basis for this greater sociality is the more seasonal and patchily distributed food resources of the montane environment, which reward social information sharing in ways that the more uniformly productive lowland forests of the Emperor Rake's range do not. The Highland Rake is also notable for the traditional seasonal aggregations that occur at several known sites in the Crocker Range during the peak fruiting season, when up to twenty individuals may be present within a relatively small area. These gatherings are among the most spectacular wildlife events in Borneo and have been recorded in local ceremonial calendars and featuring in the annual festivals of several Kadazan-Dusun communities as markers of seasonal abundance. Their conservation status has been classified as endangered.

The Sarawak Rake (Drepanornis sarawakensis)

Drepanornis sarawakensis, the type species of the order's original genus and the first rake bird formally described by Western science, is a medium-sized species found in the lowland and peat swamp forests of Sarawak and the adjacent areas of West Kalimantan. It is notably smaller than the Emperor Rake with adult females reaching heights of approximately two and a half metres, and is the great rake species most often encountered by human observers given the historically more accessible nature of much of its habitat. The peat swamp adaptation is distinctive within the family and has produced several morphological differences from the highland species, including broader foot pad development for locomotion on soft substrate and dietary flexibility that encompasses the aquatic vegetation of swamp margins. The Sarawak Rake has the longest and most detailed history of Western observation of any great rake species, and the species' interactions with the Iban and other Sarawak communities have been more extensively documented than those of any other member of the family. It is the species around which the most substantial body of indigenous ethological knowledge has been recorded, and the primary focus of the long-term Batang Ai Drepanornithiform Project, which has been running continuously since 1978 and has produced some of the most important field data on great rake behaviour and ecology in the literature. Conservation status: Vulnerable.

The Kalimantan Forest Rake (Drepanornis borneensis)

The smallest of the great rakes, reaching adult female heights of approximately two metres, the Kalimantan Forest Rake occupies the dipterocarp forests of east and central Kalimantan and is the least studied of the four species. Its relatively modest size and dense forest habitat have made systematic population assessment difficult, and the species' conservation status is currently listed as endangered and is based on modelled habitat loss data as much as direct observation. It is distinguished from the Sarawak Rake by several osteological characters like a generally more rufous plumage colouration and a vocal repertoire that field researchers describe as considerably more complex and variable than that of its Sarawak relative, though systematic bioacoustic study of the species remains limited. It’s conservation status is also listed as endangered.

Family Brachidrepanidae: The Fruit Rakes

The fruit rakes are the smallest and most numerous members of the order, comprising two described species that together have the widest distribution and largest total population of any drepanornithiform family. They are compact, active animals, generally between sixty and ninety centimetres in height with proportionally more prominent wing structures than the great rakes and fore-claws that are reduced in length and less strongly curved which is consistent in the shift from the high-browsing feeding strategy of the ancestral lineage toward a frugivorous and gleaning ecology. Their social organisation is the most complex of the ground-dwelling families, centred on traditional communal nesting grounds used across generations and on fluid group associations that form and dissolve around fruiting resources. The cakar pisang, as the fruit rakes are collectively known in Malay, are the rake birds with the most intimate relationship to human communities. Their tolerance of secondary forest and forest edge habitat has allowed them to persist in areas where great rake populations have long since collapsed and they are familiar animals to communities across Borneo's forest margins in a way that the more cryptic and interior-dwelling species are not. They feature extensively in the folk literature and proverb traditions of Iban, Kadazan-Dusun, and Malay communities, associated primarily with fruiting seasons and the rhythms of the forest year. Communal nesting in the fruit rakes involves the synchronised laying of multiple females at traditional sites typically in areas of open ground near fruiting trees with good visibility for predator detection. The internally retained eggs of multiple females hatch within a brief window and produce a predator-swamping effect in which the availability of large numbers of hatchlings exceeds the local predator population's capacity to exploit them. Post-hatching, the colonial structure relaxes into smaller family units that aggregate and disperse fluidly around resource availability, with individuals maintaining established relationships across a community of known animals. Conservation status for both species ranges from near threatened to vulnerable as a result of primarily habitat loss.

Family Dendrodrepanidae: The Tree Rakes

The tree rakes are the most morphologically and behaviourally derived members of the order, being part of an adaptive transition into the high canopy that has produced a suite of characters with no parallel in the other two families. They are medium-sized animals, generally between one and one and a half metres in height, with a proportionally longer tail that functions as a counterbalancing organ during arboreal locomotion, fore-claws that have been substantially reorganised from the ancestral feeding apparatus into gripping and climbing structures, and wing surface development that enables controlled gliding between trees. The family currently contains two described species, of which the Red-throated Tree Rake is considerably the better known and studied. The arboreal lifestyle has driven cognitive development in the tree rakes to a degree that has made them the most scientifically discussed members of the order and, by many assessments, the most cognitively complex birds currently known. The demands of three-dimensional canopy navigation, cooperative breeding within stable social groups, cumulative cultural transmission, and the physical reasoning required for glide trajectory calculation have produced an intelligence that researchers in comparative cognition now regard as warranting comparison with the great apes and cetaceans. This assessment remains somewhat contested in its stronger formulations, but the specific cognitive capacities shown in laboratory and field settings leave little doubt that the tree rakes are a substantial outlier in avian intelligence.

The Red-throated Tree Rake (Arboridrepan wilfredi)

The Red-throated Tree Rake was formally described in 1938 from specimens collected during the Calloway Expedition of 1936 by Dr. Lloyd J. Wilfred, the expedition's zoologist, after whom the species is named. Wilfred's original description noted the distinctive rufous-red colouration of the bare skin on the throat and upper chest which is particularly vivid in adult males during the breeding season and provides the basis for the common name, as well as the elongated tail and the modified fore-claw morphology that distinguishes the family from its ground-dwelling relatives. The genus name Arboridrepan, combining the Latin arbori (of the trees) with the established drepan root of the order, was proposed by Wilfred in the same paper and has been retained through subsequent taxonomic revision. Arboridrepan wilfredi is distributed across the old-growth dipterocarp forests of central and northern Borneo, with the densest known populations in the Danum Valley Conservation Area of Sabah and the Maliau Basin. It is an obligate old-growth canopy species, unable to persist in logged or degraded forest due to its dependence on the structural complexity and fruiting tree diversity of primary forest, and this ecological specificity makes it acutely vulnerable to the continued loss and degradation of Bornean forest cover.

The social organisation of the Red-throated Tree Rake centres on stable cooperative units of three to six adults sharing a defined canopy territory of between two and five hectares. These units are matrilineal in structure, with adult females forming the permanent core and males moving between groups with greater frequency. Cooperative breeding within the unit involves collective vigilance, communal warming of eggs and newly hatched young, and social facilitation of foraging in which experienced adults share information about food locations with younger or less experienced group members. The degree of behavioural coordination within units and the long-term stability of the social bonds involved places the species among the handful of birds known to practise genuine cooperative breeding in the fullest sense of that term. The cognitive profile of Arboridrepan wilfredi has been the subject of intensive research since the mid-1990s, when a series of studies at the Danum Valley Field Centre produced the first systematic evidence of the capacities that have since made the species scientifically remarkable. Reliable demonstrations of mirror self-recognition, individual-specific vocal repertoires, spontaneous tool-assisted foraging including height-calibrated food dropping for access to protected food items, causal reasoning about the behavioural consequences of environmental disturbance, and long-term social memory extending across years have all been documented in peer-reviewed literature. The species passes the mirror test at a rate comparable to chimpanzees and consistently outperforms all other tested bird species on tasks requiring prospective physical reasoning. Perhaps most significantly, the species shows robust evidence of cumulative cultural transmission with distinct behavioural traditions documented between geographically separate populations that cannot be explained by genetic or environmental differences alone. Populations in the Danum Valley use a specific technique for accessing the seed interior of a locally common fruit that involves a two-stage process not observed in any other population and which naive individuals from other areas do not develop independently even when given extended access to the same fruit. The technique is transmitted socially within the Danum population from experienced adults to younger animals during the extended juvenile dependency period, and has been documented persisting across at least four generations of observed individuals. This finding, published in 2019, is now widely cited in discussions of cumulative culture outside the primate lineage. Vocal complexity in the species is high, with a described repertoire of over sixty distinct call types used in combination to communicate information about predator identity, location, and threat level, food availability, social relationships, and individual identity. Regional variation in call structure between geographically isolated populations has been documented, and there is preliminary evidence that this variation is maintained by social learning over genetic differentiation, qualifying as vocal dialect in the same sense the term is applied to cetaceans and some passerine birds. Full acoustic description of the species' repertoire and the social mechanisms by which it is transmitted remains an active area of research.

The conservation status of the Red-throated Tree Rake is endangered, with the global population estimated at between four thousand and seven thousand individuals. The species is listed on CITES Appendix I and is protected under both Malaysian and Indonesian law. The captive population is maintained at fourteen institutions globally, but captive breeding has proved more challenging than for the great rakes given the species' requirements for complex social environments and extensive cognitive stimulation. The most successful captive programme is at the Sepilok Rehabilitation and Research Centre in Sabah, where a semi-wild managed population in forested enclosures has produced consistent breeding results and serves as the primary source population for reintroduction trials in restored forest patches.

Reproductive Biology

The reproductive strategy of the Drepanornithiformes is unique among living birds and is one of the most discussed aspects of the order's biology in both scientific and popular literature. All members of the order share the ancestral drepanornithiform trait of internal egg retention, in which the developing egg is held within the female's body through the great majority of embryonic development and laid only when development is essentially complete. The interval between laying and hatching varies between species from a few hours in the great rakes to near-simultaneous laying and hatching in the fruit rakes, but in no species does incubation in the conventional sense occur. The egg, once laid, is at or very close to the point of hatching. The evolutionary origin of this strategy almost certainly lies in the predator pressure experienced by the lineage during the Palaeocene and Eocene, when small to medium-sized rake bird ancestors were establishing themselves in environments with diverse and active predator guilds. A fixed nest containing eggs is a static and highly vulnerable target. Internal retention transforms the incubation period from a period of immobility and exposure into a period of normal maternal mobility, with the developing embryos protected by the mother's locomotor capacity. The selective advantage of even partial internal retention in such environments is substantial, and the progressive extension of the retention period over evolutionary time has produced the near-complete internalisation observed in modern forms. Clutch size varies across the order, from two eggs in the great rakes to three in the fruit rakes, with the arboreal family reduced to one or at most two eggs in recognition of the locomotor constraints imposed by internal retention during canopy life. Post-hatching parental investment is intensive across all families, with the extended juvenile dependency period of the great rakes being the most extreme documented in any bird. The relationship between the long juvenile period, the low reproductive rate, and the intensive transmission of ecological and social knowledge during that period is central to understanding both the life history of the order and its vulnerability to population pressure.

Conservation

The conservation situation of the Drepanornithiformes in 2026 is the product of historical processes stretching back to the earliest colonial contact with the order and continuing through the present day. The broad outline is one of severe but not irreversible decline, with the great rakes most critically affected and the fruit rakes retaining the largest and most geographically distributed populations. All seven described species are listed as threatened on the IUCN Red List, ranging from Vulnerable to Critically Endangered. The nineteenth and early twentieth centuries were the period of most severe direct hunting pressure. European trophy hunting created a demand for dead specimens that, combined with the commercial claw trade supplying both European curiosity markets and existing regional trade networks, placed intense pressure on great rake populations across their range during the period of maximum colonial access and minimum conservation regulation. The scientific case for protection was articulated early and forcefully, with Frederick Marsh among the first to argue publicly for the legal protection of rake birds, but meaningful regulatory response came slowly and inconsistently. The formal protection of the great rakes in Sarawak in 1929, and in British North Borneo in 1934, was the first substantial legal protection, predating equivalent measures in Dutch Borneo by several decades. The post-colonial period has brought new pressures to replace the old. Habitat loss through logging and the expansion of oil palm agriculture has been the dominant driver of population decline since independence, and continues to be the primary threat to all rake bird species in both Malaysian and Indonesian Borneo. The fragmentation of continuous forest into isolated patches has particular consequences for the great rakes, which require large contiguous home ranges and can’t persist in degraded or secondary forest. Climate change adds a further layer of uncertainty with modelled projections showing a reduced contraction of suitable high-quality forest habitat across the Bornean interior by mid-century. The illegal wildlife trade in rake bird parts, especially with the fore-claws and feathers, persists as a significant conservation problem despite CITES listing and domestic legal protection. Demand comes from a combination of traditional ceremonial use, luxury collector markets, and an online trade that has proved difficult for authorities in both range states to monitor effectively. The cultural complexity of the claw trade is a particular challenge for conservation advocacy, given that traditional community relationships with rake birds predate and exist independently of Western conservation frameworks and cannot be addressed through enforcement alone. Community-based conservation approaches in partnership with indigenous land managers across the Bornean interior have produced the most consistently positive outcomes of any conservation intervention applied to the order. In areas where traditional prohibitions on killing great rakes remain culturally strong and where communities have secure land tenure over their forest territories, rake bird populations have shown greater stability than in areas dependent on state enforcement alone. The Iban taboo on intentional killing of great rakes in Sarawak's Batang Ai region is often cited as the single most effective conservation measure in the history of the order's protection, having maintained a viable population in an area where habitat conditions alone would not have been sufficient.

THE CALLOWAY EXPEDITION OF 1912

Origins, Discoveries, and Scientific Legacy of the First Western Exploration of the Tepui Auyana Plateau

Published in the Archives of Natural History and Exploration, Volume 53, Issue 2, 2026

The Expedition That Changed Everything

The Calloway Expedition of 1912, led by British naturalist Dr. Horace M. Calloway under the auspices of the Royal Geographical Society, was the first formal Western scientific exploration of the isolated tepui plateau now known in the scientific literature as the Calloway Plateau which is situated within the Guiana Highlands of Venezuela. Originally commissioned to investigate reports of unusual aerial fauna observed in local waterways, the expedition expanded into a comprehensive multi-month survey of the plateau's flora and fauna between June and October of that year. The discoveries made during the expedition's tenure proved to be among the most significant in the history of natural science, encompassing novel species of carnivorous plants, megafauna of extraordinary biological interest, and fauna whose subsequent reclassification over the following decades fundamentally altered the scientific understanding of vertebrate evolution. This article examines the expedition's origins and composition, provides biographical sketches of its principal members, surveys the major discoveries and their scientific legacy, and traces the post-expedition history of the plateau through to the present day.

I. Origins of the Expedition

The Calloway Expedition did not begin as the ambitious undertaking it became. Its origins lay in a modest commission issued through the administrative channels of the British colonial presence in coastal Venezuela, where reports had been accumulating since approximately 1909 of unusual flying creatures whose bodies had been found in local waterways, streams, and on village shores in the broader Guiana region. The animals were described by local communities and the occasional colonial administrator as rat-like in body but possessed of wing structures unlike any known bat, and the carcasses that had been examined suggested something considerably stranger than any familiar species. The reports were passed eventually to the Royal Geographical Society in London, where they reached Calloway through his established relationship with the Society's zoological correspondence committee.¹

Calloway's initial plan was characteristically modest. He intended to travel to the Venezuelan coast with two trusted colleagues, Dr. Pierre Moreau of the Muséum National d'Histoire Naturelle in Paris and Dr. Lloyd J. Wilfred, an independent American field naturalist of growing reputation, and to conduct a survey sufficient to identify the source of the reports and determine whether they warranted formal scientific attention. The three men had worked together on previous expeditions to South America and West Africa and constituted a collegial working unit whose combined expertise in taxonomy, botany, and field zoology was well suited to the task as originally conceived. It was the accumulation of additional intelligence, gathered in the months before the expedition's departure, that transformed this modest survey into something considerably larger.

Reports had been reaching European natural history circles through a variety of sources, including Venezuelan geological survey correspondence and the accounts of missionaries and traders in the interior, of a plateau in the Guiana Highlands of anomalous biological character. The tepui formations of that region had long been known to Venezuelan and indigenous communities as places of unusual ecology, but the specific plateau that became the expedition's ultimate destination had not been formally described in any Western scientific publication. The accounts that reached Calloway described a table-mountain environment largely isolated from the surrounding lowland jungle by sheer cliff faces, with internal ecosystems that bore little relationship to the flora and fauna of the surrounding region. Several correspondents noted fauna of unusual size and character, and one letter from a Capuchin friar stationed near the plateau's western approach described, in language that mixed sincere wonder with evident theological distress, animals and plants that he felt defied the natural order as he understood it.² Calloway, whose appetite for the genuinely anomalous was considerable, recognised an opportunity of potential significance. He expanded the expedition, recruited additional members with specialist expertise, and secured supplementary funding through the RGS and through his own personal resources, the latter being considerable given the fortune inherited from his father, the explorer and naturalist Sir Edmund Calloway. The expedition that departed from Caracas in May of 1912 comprised eleven members.

II. The Principal Members

Dr. Horace M. Calloway (1878–1951) served as expedition leader and chief taxonomist. Born in Bristol to Sir Edmund Calloway and educated at University College London, where he read natural sciences, Calloway had by 1912 already established a reputation as a careful and ambitious field naturalist through expeditions to West Africa and the Argentine interior. He possessed a temperament well suited to the leadership of a large scientific party in difficult terrain: methodical, fair-minded, and capable of the kind of diplomatic patience that prevents talented and opinionated colleagues from coming to blows over classification disputes. His published field reports from the 1912 expedition, which appeared in the Transactions of the South American Botanical and Zoological Survey between 1912 and 1914, established the tone that the expedition's published record maintained throughout, authoritative in scientific content while preserving the human texture of discovery in the field. Calloway continued working in natural history for the remainder of his career, leading several further expeditions to South America and Africa, and in 1934 described Tikomimus callowayi, a new species of mimic dolo encountered during a Mediterranean survey, a discovery that earned him a second wave of scientific attention late in his career.³

Dr. Pierre Moreau (1876–1944) served as expedition botanist and naturalist. A Frenchman attached to the Muséum National d'Histoire Naturelle, Moreau came from a family with a distinguished tradition in natural history. His grandfather, Dr. Edouard Moreau, had formally described the first known species of mehek in 1878, a discovery that had made the Moreau name synonymous with the description of anomalous and scientifically transformative fauna. Pierre Moreau had absorbed something of this heritage into his own sensibility, approaching the natural world with a combination of precise botanical training and a reflective, almost literary quality of attention that distinguished his field writing from that of his colleagues. His published reports from the 1912 expedition are among the most widely anthologised in the history of natural history journalism, valued as much for their observational depth as for their scientific content. The relationship between Moreau and Dr. McBride, which developed during the expedition and persisted for the remainder of both men's lives, was a defining personal dimension of the expedition's human history. Their correspondence, examined by scholars in the decades following their deaths, suggests a closeness that went considerably beyond professional collegiality, a bond that neither man fully articulated in writing given the period's constraints on such expression, but whose warmth is evident in even the most formally worded of their surviving letters. Moreau returned to the Calloway Plateau in 1916 as part of the Johnston Expedition, a smaller party that succeeded in collecting physical specimens of several flora discovered in 1912, including preserved Devil's Lantern material and samples of the Strangler's Vein, as well as preserved specimens of several smaller faunal species. These collections, deposited at the Muséum National d'Histoire Naturelle and the Natural History Museum in London, formed the primary physical basis for the taxonomic work that followed in subsequent decades.

Dr. Lloyd J. Wilfred (1878–1963) served as field zoologist. An American by birth, Wilfred had been orphaned with his younger brother Jonathan in childhood and had come to natural history by a circuitous route that included several years of manual labour before Calloway's patronage secured both brothers places at University College London, where Wilfred completed his degree in zoological sciences. By 1912 he had developed a reputation as a field naturalist of exceptional range and, it must be said, exceptional recklessness, having accumulated a catalogue of injuries from animal encounters on three continents that would have retired a less constitutionally robust man many years earlier. His published reports from the 1912 expedition are distinguished by a voice of irrepressible personal engagement that sits somewhat awkwardly with the conventions of scientific reportage but has endeared them to general readers for over a century. Jonathan Wilfred, who accompanied the expedition as an illustrator and assistant naturalist, produced a body of field sketches whose quality has been consistently praised in subsequent assessments of the expedition's published record. Lloyd Wilfred's most significant scientific contribution came not in 1912 but twenty-four years later, when as lead naturalist on a second Calloway Plateau expedition he formally described Arboridrepan wilfredi, the Red-throated Tree Rake, a species of drepanornithiform veliform whose discovery in the Bornean interior added substantially to the understanding of that remarkable order. The species epithet honours him directly, and it is by the association of his name with that discovery, as much as by his 1912 reports, that Wilfred is chiefly remembered in the scientific literature today.⁴

Sir Arnold Dotkins (1866–1938), zoologist and taxonomist, represented the institutional presence of the Zoological Society of London on the expedition, his participation having been arranged through the Society's formal relationship with Calloway's RGS-backed project. A man of considerable professional experience and equally considerable professional vanity, Dotkins proved simultaneously the expedition's most formally accomplished taxonomist and the member whose published reports most entertainingly documented the experience of having one's taxonomic certainties repeatedly overturned by the plateau's biological novelties. His eventual formal classification of the Rooted Maw gastropods, published in the Transactions in 1913, is considered a landmark paper in invertebrate zoology despite the months of initial misidentification that preceded it. Dr. Calvin McBride (1875–1948) served as medical specialist and zoological observer. A Scots physician who had met Moreau through shared scientific circles in Paris the previous year, McBride brought to the expedition both the practical medical expertise essential for a party operating in a remote tropical environment and a dry observational intelligence that expressed itself in field reports of considerable acuity. The friendship between McBride and Moreau that developed during the expedition produced, in the Ironthorn Tree and Snarecap Fungus reports of October 1912, some of the most quietly personal writing in the expedition's published record. The remaining members, including Dr. Cornelius Rowland, Dr. Phillipe Vanderson, Sir Llewellyn, Dr. Edward Burke, Dr. Hadal Lewis, and Sir Richard Dotkins, each contributed to the expedition's published record and its scientific work, though it is the five principal members whose contributions have received the most sustained attention in subsequent scholarship.

III. Geographic Setting and Indigenous Context

The plateau that became known to Western science as the Calloway Plateau occupies a position within the broader tepui landscape of the Guiana Highlands, that extraordinary geological formation of ancient sandstone table-mountains that rises from the surrounding Gran Sabana and lowland jungle of southern Venezuela. The tepui formations are among the oldest exposed rock surfaces on Earth, their isolation from the surrounding lowlands having produced the conditions for the independent biological evolution that characterises tepui ecosystems generally and the Calloway Plateau specifically. The indigenous Pemón communities of the region, whose oral traditions extend back far beyond any Western record of the plateau, know it by the name Aurantepui, a compound broadly translatable as the place of ancient things or the plateau of old presences, a designation that the 2026 scientific literature has adopted in parallel with the Western common name.⁵ The relationship between the Pemón and the plateau's fauna predates the Calloway Expedition by an unknown number of generations, and the expedition members' field reports contain several passages indicating that Pemón guides were aware of the plateau's most remarkable inhabitants without finding them remarkable, a disparity in response that itself constitutes data of anthropological significance. The colonial administrative framework within which the expedition operated did not systematically document indigenous knowledge of the plateau's biology, a failure that subsequent scholarship has addressed only partially through oral history projects conducted from the 1970s onwards.

The plateau's isolation is maintained by cliff faces of varying height that present a formidable barrier to access from the surrounding lowland jungle. The 1912 expedition reached the plateau's interior through a route identified with Pemón assistance via a gradual approach along a river valley to the north-east, ascending the final section over several days of climbing. The interior proved to contain a network of distinct habitat zones including dense highland rainforest, open rocky terrain with endemic grass and heath communities, several substantial water bodies, and areas of swamp and transitional vegetation whose biological character differed substantially from anything the expedition members had previously encountered. The First World War delayed any systematic follow-up to the 1912 reports, and it was not until the Johnston Expedition of 1916, a smaller party led by Sir George Johnston of the Natural History Museum and including Moreau and McBride among its members, that physical specimens were successfully removed from the plateau for study in European institutions. The Johnston Expedition collected preserved material of several carnivorous plant species, smaller invertebrate and vertebrate fauna, and botanical samples that formed the basis for the taxonomic work published through the 1920s and 1930s. Access to the plateau remained difficult and episodic throughout the colonial period, with the result that several of the most significant faunal discoveries of 1912 were not formally described in the scientific literature until decades after the expedition's return.

IV. Botanical Discoveries

The botanical discoveries of the Calloway Expedition were among the first to receive formal scientific treatment, in part because Moreau's field expertise allowed for provisional classification in the field and in part because plant material, being more readily preserved than large fauna, could be brought back in usable form by the Johnston Expedition of 1916. Three discoveries in particular have retained their significance in the botanical literature. The Corpsefruit Tree, formally described as Terrabryophyton vorax by Calloway in 1912 and subsequently examined in greater detail from Johnston Expedition specimens, represents an extraordinary elaboration of the carnivorous plant strategy. A member of the Lentibulariaceae that has diverged radically from the bladderwort habit of its closest relatives, Terrabryophyton vorax employs large pendulous trap structures capable of digesting prey of vertebrate size, a scale of carnivory without precedent in documented plant biology. The tree's ecology within the plateau's waterside environments was documented in Calloway's initial report and has been confirmed and elaborated by subsequent field studies. The Devil's Lantern, placed within the genus Florabryophyton by Wilfred and subsequently confirmed as a distinct species from Johnston Expedition material, represents a convergent carnivorous strategy of equal novelty, employing bioluminescent lures to attract prey to snap-trap flowers of a scale and speed without documented parallel in plant physiology. Moreau's report of the Strangler's Vein, a parasitic vine of the genus Florabryophyton that siphons nutrients from host trees through filamentous vascular penetration rather than direct competition for light or water, completed a trilogy of botanical discoveries that collectively established the Calloway Plateau as a site of exceptional significance for the understanding of carnivorous plant evolution. The Snarecap Fungus, documented by McBride, is not strictly a plant but has been consistently treated alongside the botanical discoveries in the literature and represents a similarly anomalous development of adhesive carnivorous strategy in a fungal lineage. The Ironthorn Tree, described by Moreau as the ecological anchor of the plateau's highland forest community and the primary resource around which several faunal species organise their activity, is the botanical discovery of longest-lasting ecological significance, its role in the plateau's food web having been traced in considerable detail by subsequent researchers.⁶

V. Faunal Discoveries and Their Subsequent Classification

The Rooted Maw

The organism eventually classified as Fauciradicis maximus by Dotkins in his October 1912 report, and placed within the new suborder Phytogastropoda of the class Gastropoda, represents one of the most extraordinary cases of convergent evolution documented in the invertebrate record. The Rooted Maw and its related variants, Fauciradicis arborius and Fauciradicis mobilis, are gastropod molluscs that have independently evolved a suite of adaptations rendering them superficially indistinguishable from carnivorous plants during the greater part of their life cycle. The mineralised tube structure serves the function of a gastropod shell while mimicking the root and stem architecture of aquatic vegetation. The modified appendages hosting symbiotic algae replicate the photosynthetic structures of the surrounding plant life while serving as a secondary nutritional system for the animal. The snap-trap mechanism, though functionally analogous to that of Dionaea muscipula, is operated by specialised muscle tissue rather than the hydraulic turgor mechanism of the Venus flytrap, and closes at speeds incompatible with plant physiology. Dotkins's initial misidentification of these organisms as carnivorous plants, sustained through the first several months of the expedition's botanical phase, is understandable given that the combination of photosymbiosis, sessile lifestyle, and plant-mimicking morphology is without parallel in documented gastropod evolution. The Rooted Maw complex continues to generate research interest, primarily in the fields of evolutionary biology and symbiosis studies.⁷

The Gigamyrmex and Tonitrunykus

The Gigamyrmex, formally described by Calloway from field observations in the September 1912 reports and placed within the order Gigamyrmeciformes on the basis of skeletal characters examined in Johnston Expedition specimens, represents an independent experiment in mammalian gigantism within a lineage of anteater-adjacent insectivores. The extreme sexual dimorphism, with fully grown females reaching heights of three and a half to four metres at the shoulder, the whip-tongue predatory mechanism with its three-tended serrated tip, and the matriarchal social structure organised around dominant females whose courtship selectivity controls male access to the breeding group, collectively establish the Gigamyrmex as one of the most biologically anomalous mammals described from any source. Its presence on the plateau is best understood as the product of the same long-term isolation that characterises the tepui ecosystem generally: a lineage that entered a productive but enclosed environment and radiated under reduced competitive pressure into a body size and ecological role that would be unsustainable in a more open landscape. The Johnston Expedition collected specimens of juvenile Gigamyrmex, and the skeletal material deposited at the Natural History Museum in London formed the basis for the formal anatomical description published by Johnston and Moreau in 1919. The Tonitrunykus, described by Calloway in the same series of reports and named for the thunderous call used in its sentinel role, was initially a source of considerable classification debate. Its feathered body and general veliform body plan led it to be provisionally classified as an avian species by Calloway and subsequently as a possible drepanornithiform relative in the 1960s literature, an identification that was overturned by molecular analysis in the 1990s, which established it as a distinct South American veliform lineage descended from a small theropod ancestor that had survived on the plateau through the same K-Pg refugium conditions that preserved the plateau's other relict fauna. It is now placed in the order Tonitrunyciformes, a South American endemic veliform group without close relatives elsewhere. The mutualistic relationship between the Tonitrunykus and the Gigamyrmex, in which the former provides sentinel services and parasite removal in exchange for food access and nest security within the herd's territory, remains one of the most fully documented inter-order symbioses in the zoological literature.⁸

The Seraphim King

The Seraphim King, named by Rowland in response to its extraordinary cephalic ornamentation and first formally examined from Johnston Expedition material, was eventually placed within the order Neoceratopsiformes as Seraphiceratops callowayensis, a surviving member of the ceratopsian lineage that had persisted in the tepui refugium while the broader group went extinct at the end of the Cretaceous. This identification, proposed tentatively in the 1940s and confirmed by molecular analysis in the 1980s, established the Calloway Plateau as the site of a surviving dinosaurian lineage in the restricted modern sense of that term, a discovery whose significance was not diminished by the contemporaneous confirmation of veliform fauna on the same plateau. As an ornithischian and thus a true dinosaur rather than a veliform, the Seraphim King occupied a genuinely different evolutionary position from the Tonitrunykus and the Enigma Birds, and its presence on the plateau raised questions about the mechanisms by which multiple lineages had independently found refuge in the tepui environment across the K-Pg boundary. Its role as an apex browser and opportunistic scavenger, documented in the 1912 reports and confirmed by subsequent field study, makes it the ecological equivalent of the large omnivorous ursid guild in other southern hemisphere ecosystems.

The Mammavi

The Mammavi, whose fatal reproductive biology was documented with a combination of scientific precision and evident awe in Calloway's July 1912 reports, was formally placed within the order Rodentia following anatomical examination of Johnston Expedition specimens, the family Mammaviidae being established to accommodate a wing structure unlike anything previously documented in rodent evolution. The digitopatagium, with its three independently articulating digit-supported membrane spans and secondary foot membranes, is a convergent flight solution that shares no homologous structures with the wing of any bat, representing an entirely independent evolutionary pathway to powered flight within Mammalia. The suicidal reproductive biology, in which adrenal overdrive during mating display produces cardiac failure in males following copulation, was confirmed by dissection as a genuine physiological mechanism rather than an exaggerated field observation, and has generated an extensive theoretical literature on the evolutionary stability of sexually selected traits that impose lethal costs on their bearers. The Mammavi remains the most striking example of terminal sexual selection known from any vertebrate.

The Enigma Birds

The creatures identified by Wilfred as Monster Toucans and renamed Enigma Birds by Dotkins are the discovery of the 1912 expedition that has generated the greatest volume of subsequent scientific attention and the most sustained public interest. Their classification in 1912 was genuinely impossible to resolve with the available evidence and frameworks, and the published debate between the mammal hypothesis advanced by the Wilfreds and Dotkins, the avian hypothesis favoured by Moreau and Rowland, the monotreme hypothesis proposed by Calloway and McBride, and Vanderson's pterosaur hypothesis, which was treated with general derision at the time, constitutes a remarkable document of taxonomic bewilderment in the face of genuinely novel biology. It was Vanderson who came closest to the truth. The Enigma Birds are pterovelimorpha, specifically azhdarchid-lineage velimorphans that have undergone secondary flightlessness and extensive adaptation to an arboreal, fruit-eating, socially complex lifestyle over the sixty-five million years since the plateau first provided refugium conditions for their ancestors. The confirmation of their pterosaur affinity came in 2001 from molecular analysis conducted by a joint Venezuelan and British team, and their formal placement within Pterovelimorpha was published in 2003, the same year as the description of Archaeoveliformis ennediensis from the Ennedi Plateau, in a conjunction that generated considerable excitement in the veliform research community.⁹ The discovery that the Calloway Plateau hosts not merely a single pterovelimorph lineage but multiple surviving pterosaur-derived groups, including the crested Craniopteriformes and the smaller Microrandiformes observed but not formally described in the 1912 reports, has made the plateau the most significant site for pterovelimorph biology in the world. The Enigma Birds themselves, formally described as a new genus and species pending ongoing taxonomic discussion at the time of writing, have been the primary focus of the Long-Term Plateau Behavioural Study which has been running continuously since 1988 and has produced the most detailed longitudinal dataset on cognitive complexity in any non-mammalian vertebrate. Their intelligence, which encompasses individual recognition, spatial reasoning of extraordinary sophistication, cumulative cultural transmission, and social dynamics of a complexity that has prompted serious scholarly discussion of sapience in the philosophical sense, places them in a category that the comparative cognition literature is still developing adequate frameworks to describe. The journal theft incident documented in Wilfred's October 1912 report, long treated as an entertaining anecdote, is now routinely cited in the research literature as an early field observation of theory of mind and deliberate social manipulation.¹⁰

VI. Scientific Legacy and the Plateau in 2026

The Calloway Expedition's legacy in the scientific literature is multidimensional in a way that few single expeditions can claim. Its botanical contributions established new parameters for carnivorous plant evolution and introduced to science organisms whose biological novelty has not diminished with familiarity. Its faunal discoveries collectively established the Tepui Auyana Plateau as a biological refugium of global significance, a site where the accident of extreme isolation has preserved lineages that were eliminated everywhere else by the pressures of the Cenozoic. And its most significant discovery, the Enigma Birds, contributed directly to the veliform classification revolution of the mid-twentieth century by providing the first confirmed evidence of living pterovelimorpha at a time when the theoretical framework for understanding such animals was still being constructed. The expedition's published reports have never gone out of print. Their combination of scientific substance and personal voice has sustained a general readership that extends well beyond the specialist literature, and several of the expedition members, particularly Wilfred and Moreau, have become figures of broader cultural recognition whose work is anthologised and taught in natural history curricula at secondary and university level. The plateau itself, designated as part of the Tepui Auyana National Reserve in 1971 and accorded World Heritage status in 1994, is subject to strictly managed research access, with the Pemón communities of the region holding formal co-management authority over the terms of that access. The Long-Term Plateau Behavioural Study, the ongoing palaeobiological survey programme, and the plateau's botanical research station together constitute one of the most productive field research environments in the southern hemisphere, generating on average some forty peer-reviewed publications per year across multiple disciplines. The fauna that Calloway and his colleagues encountered with such evident astonishment in 1912 are today the subjects of research programmes of a sophistication those men could not have imagined, yet the quality of their original observations remains a genuine contribution to scientific knowledge more than a century after it was made. That is a measure of the expedition's enduring significance that no quantity of subsequent institutional recognition quite captures.

Endnotes

1. The original commission documentation is held in the RGS archive, London. The relevant correspondence is catalogued under the South American Survey files, 1909–1912. Several of the animal reports forwarded to the Society describe body dimensions consistent with the Mammavi species subsequently described by Calloway (1912), and it is now understood that the Mammavi's Great Feast reproductive cycle, which results in large numbers of male carcasses washing into regional waterways, was the primary source of the unusual sightings that prompted the commission.

2. The letter from Father Augusto Ribeiro de Sousa, dated March 1911, is preserved in the archive of the Capuchin mission at Puerto Ayacucho. An English translation appears in Hernandez-Vega, C. and Blackwood, A., "Primary Sources for the Pre-Calloway History of the Tepui Auyana Plateau," Journal of the History of Biology, Vol. 44, 2018, pp. 112–145.

3. The Mediterranean mimic dolo discovery is documented in Calloway, H.M., "A New Species of Tikomimus from the Western Mediterranean Basin," Proceedings of the Zoological Society of London, Vol. 104, 1934, pp. 287–301. The species, Tikomimus callowayi, is characterised by a more robust body plan and distinct colouration pattern from the Atlantic populations previously described.

4. The formal description of Arboridrepan wilfredi appears in Wilfred, L.J., "A New Drepanornithiform from the Interior of British North Borneo," Transactions of the South American Zoological Survey, supplementary series, Vol. 12, 1938, pp. 1–34. The paper, submitted two years after the 1936 discovery expedition, is notable for its relatively restrained tone compared to Wilfred's 1912 reports, a restraint that several biographers have attributed to the influence of Jonathan Wilfred, who edited the manuscript before submission.

5. The etymology and cultural significance of the Pemón name Aurantepui is discussed in Salazar-Rojas, M., "Tepui Toponymy and Indigenous Ecological Knowledge in the Guiana Highlands," Journal of Ethnobiology and Ethnomedicine, Vol. 18, 2022, pp. 44–61. The author notes that Aurantepui appears in Pemón oral tradition as a site of particular spiritual significance associated with beings that are neither fully animal nor fully spirit, a characterisation whose biological resonance with the plateau's fauna is not lost on the author.

6. The comprehensive botanical survey of the Calloway Plateau, incorporating data from the Johnston Expedition specimens and subsequent field collections, is presented in Greenbaum, F. and Moreau, C., "Carnivorous Flora of the Tepui Auyana: A Systematic Review," Botanical Journal of the Linnean Society, Vol. 67, 1921, pp. 1–89. The paper remains the foundational reference for plateau botanical taxonomy despite its age, updated primarily by molecular phylogenetic work published since 2000.

7. The most comprehensive recent treatment of Fauciradicis biology is Nakamura, T., Osei, K., and Williams, R., "Photosymbiosis, Mineralisation, and Predation in the Plateau Gastropods: An Integrated Review," Journal of Molluscan Studies, Vol. 88, 2024, pp. 201–239.

8. The formal anatomical description of Tonitrunykus callowayi is Johnston, G. and Moreau, P., "Anatomical Notes on the Plateau Saurian Tonitrunykus," Proceedings of the Zoological Society of London, Vol. 89, 1919, pp. 447–478. The molecular confirmation of its veliform affinities appears in Ramirez-Costa, A. et al., "Phylogenetic Placement of the South American Plateau Veliform Fauna," Molecular Phylogenetics and Evolution, Vol. 28, 2003, pp. 112–129.

9. The molecular analysis confirming pterovelimorph affinity for the Enigma Birds is Okonkwo, B., St. Claire, M., and Vasquez, J., "Pterovelimorph Survival in the Guiana Highlands: Molecular Evidence for Azhdarchid Ancestry in the Calloway Plateau Arboreal Fauna," Nature, Vol. 413, 2001, pp. 814–819. The subsequent formal placement within Pterovelimorpha and the description of two additional pterovelimorph lineages on the plateau appear in the same authors' follow-up paper, Journal of Veliform Biology, Vol. 1, 2003, pp. 1–44.

10. The Wilfred journal theft incident as an early observation of cognitive complexity is discussed in Petrov, A. and Ngozi, C., "Historical Field Accounts as Primary Data in Comparative Cognition: The Calloway Plateau Enigma Bird Reports Reconsidered," Animal Cognition, Vol. 26, 2023, pp. 889–904. The authors analyse sixteen specific incidents described across the 1912 reports and classify each according to contemporary cognitive ethology frameworks, finding evidence of theory of mind, causal reasoning, and deliberate social manipulation in eleven of the sixteen cases