PERMIAN
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PERMIAN
298.9 - 251.9 mya
The Permian is the sixth and final period from the Paleozoic era that spanned about 47 million years, beginning after the end of the Carboniferous and ending before the beginning of the Triassic period. It was a period that began within the aftermath of the Carboniferous rainforest collapse, which left behind vast regions of desert and arid lands across the continental interior.
The term Permian was introduced in geology by Sir Roderick Impey Murchison, president of the Geological Society of London, in the 1840s, collaborating with Russian geologists, naming it after the Russian region of Perm, which takes its name from the medieval kingdom of Permia, which occupied the region centuries before. Between 1853 and 1867, Jules Marcou recognised Permian strata in a large area of North America from the Mississippi River to the Colorado River and proposed the name Dyassic, from Dyas and Trias, though Murchison rejected this in 1871.
For most of the period's history of definition, it was divided in two parts, Early and Late Permian, but Glenister and colleagues, in 1992, proposed a tripartite scheme, advocating that the Roadian-Capitanian (274.4 - 259.5 mya) was distinct from the rest of the Late Permian, and should be regarded as a separate epoch. The Cisuralian series, also known as Early Permian (298.9 - 274.4 mya), was proposed by J. B. Waterhouse in 1982 to comprise the Asselian (298.9 - 293.5 mya), Sakmarian (293.5 - 290.1 mya), and Artinskian (290.1 - 283.3 mya) stages, with the Kungurian (283.3 - 274.4 mya) being only later added to the roster. The GSSP for the base of the Asselian is located in the Aidaralash River valley near Aqtöbe, Kazakhstan, which was ratified in 1996. The GSSP for the base of the Sakmarian is located at the Usolka section in the southern Urals, which was ratified in 2018. The base of the Artinskian is proposed to be defined by the first appearance of the conodont Sweetognathus aff. S. whitei. The Kungurian takes its name after Kungur, a city in Perm Krai. The stage was introduced by Alexandr Antonovich Stukenberg in 1890. The Guadalupian series, also known as Middle Permian (274.4 - 259.5 mya), starts with the Roadian (274.4 - 266.9 mya), having been named in 1968 in reference to the Road Canyon Member of the Word Formation in Texas. The other two stages of the Middle Permian are the Wordian (266.9 - 264.2 mya) and the Capitanian (264.2 - 259.5 mya), this last one being named after the Capitan Reef in the Guadalupe Mountains of Texas, named by George Burr Richardson in 1904, and first used in a chronostratigraphic sense by Glenister and Furnish in 1961 as a substage of the Guadalupian stage. The Lopingian series, or Late Permian (259.5 - 251.9 mya), was adopted by the Subcommission on Permian Stratigraphy of the ICS after a vote in 1995 as an international standard chronostratigraphic unit. It begins with the Wuchiapingian (259.5 - 254.1 mya), whose GSSP for its base is located at Penglaitan, Guangxi, China and was ratified in 2004. The Changhsingian (254.1 - 251.9 mya) has a GSSP for its base located 88 centimeters above the base of the Changxing Limestone in the Meishan D section, Zhejiang, China and was ratified in 2005, with the boundary being defined by the first appearance of the conodont species Clarkina wangi. The GSSP for the base of the Triassic is located at the base of Bed 27c at the Meishan D section, and was ratified in 2001. The Permian is divided in its own distinct stages in some regions, however; for example, in New Zealand, the Pre-Telfordian (c. 298.9 - 283.3 mya) is roughly equivalent to the Asselian, Sakmarian and Artinskian stages, the D'Urville (c. 283.3 - 259.5 mya) is roughly equivalent to the Kungurian stage and Guadalupian series, and the Aparima (c. 259.5 - 251.9 mya) is roughly equivalent to the Lopingian series.
During the Permian, most of the continental landmasses were joined in a supercontinent named Pangaea, with microcontinental terranes forming the separated Cathaysia to the east. Pangaea crossed the equator and the poles, being surrounding by a single gigantic ocean, Panthalassa (meaning "universal sea") and the Palaeo-Tethys ocean, separating Asia from Gondwana. The Central Pangean Mountains, forming when Laurasia and Gondwana collided in the Carboniferous, reached their maximum height during the early Permian around 295 mya, comparable to the modern Himalayas, but heavily eroded as the period progressed. It was teeming with dry conditions for the proliferation of gymnosperm plants, which had seeds enclosed in a protective cover to avoid drying out, unlike most other plants, like ferns, that typically disperse spores in a wetter environment. Sea levels dropped slightly during the earliest Permian, in the Asselian stage. The sea level was stable at several tens of metres above present during the Early Permian, but there was a sharp drop beginning during the Roadian, culminating in the lowest sea level of the entire Paleozoic at around present sea level during the Wuchiapingian, followed by a slight rise during the Changhsingian.
At the end of the Carboniferous and the beginning of the Permian, the climate became warmer and drier. Glaciers were less abundant than they were in the Carboniferous, with some upland glaciers remaining in South Africa during the final stages of the Early Permian, and in a few other localities. In the late Kungurian, however, a cooling trend is observed, resulting in a cool glacial interval that lasted until the early Capitanian, though temperatures remained higher than they were at the start of the Permian. Another cool period occured in the middle Capitanian. The Capitanian ended with the Emeishan Traps, a flood basalt volcanic eruption, that gave entry to the Wuchiapingian, where global temperatures declined as the carbon dioxide emitted by the eruptions was weathered out of the atmosphere by the large igneous province's emplaced basalts. Then, by the end of the Changhsingian, the eruption of the much larger Siberian Traps caused a vast and quick release of greenhouse gases into the atmosphere, ushering in an extreme hothouse condition that caused the Permian-Triassic mass extinction event and lasted for millions of years into the Triassic period. The Permian climate was also extremely seasonal and characterised by megamonsoons, which produced high aridity and extreme seasonality in Pangaea's interiors. Precipitation along the western margins of the Palaeo-Tethys Ocean was very high. The increasing equatorial aridity of Pangaea was likely driven by the development and intensification of this Pangaean megamonsoon.
The productidans were the dominant group of Permian brachiopods, forming about half of all Permian brachiopod genera. Among ammonoids, the goniatites were a major group in the early-mid Permian, but declined in the late Permian. Only three families of trilobite are known from the Permian, Proetidae, Brachymetopidae and Phillipsiidae. Around the middle Permian there was a major transition in terrestrial vegetation. Rich forests were present in many areas, with a diverse mix of plant groups. The Permian is when the ginkgoaleans and cycadophytes first appear in the fossil record. Insects were very diverse in the period, but they suffered a sharp drop in origination and extinction rates towards the end of the Permian, denouncing a decline. The Holometabola clade, the largest group of insects in our timeline's today, was diversifying greatly during this period, however. The terrestrial fossil record of the Permian is quite patchy and temporally discontinuous. During the Early Permian, terrestrial faunas were dominated by primitive "pelycosaur" synapsids, such as the herbivorous edaphosaurids and the carnivorous sphenacodontids, being accompanied by other tetrapods like diadectids and amphibians. Predator-prey interactions among terrestrial synapsids became more dynamic as the period progressed. The Middle Permian faunas of South Africa and Russia are dominated by therapsids, most abundantly by the diverse Dinocephalia. The archosauromorphs, the group of reptiles that includes the Triassic originated pseudosuchians, pterosaurs and dinosaurs, first appeared in the Middle Permian and diversified during the Late Permian, with the Archosauriformes clade first appearing in the fossil record during the Late Permian. Cynodonts, the group that includes the mammals that would evolve in later periods, first appear in the fossil record of the Late Permian, gaining worldwide distribution already before the end of the period. Temnospondyls reached a peak of diversity in the Early Permian, with a substantial decline during the Mid-Late Permian following Olson's extinction (273 mya), with the family diversity dropping below Carboniferous levels. The embolomeres, a group of aquatic crocodile-like vertebrates that are likely basal reptiliomorphs, are found in the fossil record of most of the period. The dominant group of bony fish during the Permian were the paraphyletic "palaeoniscoids", a group of unrelated primitive ray-finned fish that sit outside the Neopterygii clade. Cartilaginous fish of the Holocephali clade (which contain our timeline's modern chimaeras) reached their apex of diversity during the Carboniferous and Permian periods, with some famous representatives like Helicoprion, nicknamed the "buzz-saw shark" for its spiral-shaped tooth whorl on the lower jaw. Hybodonts, a group of shark-like cartilaginous fish were widespread and abundant in marine and freshwater areas throughout the Permian. The oldest known fossils definitively assignable to cycadophytes appear in the Permian. In the isolated Cathaysia, the Cathaysian Wuda Tuff flora from the earliest Asselian existed, containing a coal swamp community, with an upper canopy consisting of the lycopsid tree Sigillaria, with a lower canopy consisting of marattialean tree ferns, and the progymnosperm Noeggerathiales clade. In low latitudes, however, the increased aridity prompted conifers to spread and diversify and become dominant floral components. The lyginopterids, a group of seed ferns with a patchy fossil record that had declined in the late Carboniferous, are known to have survived into the end of the Permian in Cathaysia and equatorial east Gondwana.
The Permian ends with the Permian-Triassic extinction event, an event so drastic that writes the end for long lasting lineages, with trilobites, for instance, ceasing their fossil presence near the end of the Permian. Several hypothesis have been proposed to explain the reasons behind this extinction, such as ocean venting of hydrogen sulfide gas. If enough hydrogen sulfide, produced by anaerobic bacteria, accumulates in an anoxic zone, the gas can rise into the atmosphere, and although oxidizing gases in the atmosphere would destroy the toxic gas, the hydrogen sulfide would soon consume all of the atmospheric gas available. Another hypothesis builds on the flood basalt eruption theory, where vast emmissions of CO2 produced by the Siberian Traps, coupled with the release of methane from frozen marine deposits, contributed mostly to the extinction, being majorly responsible for the drastic increase in global temperature.
main source: Wikipedia
A Earth map reconstruction, some 275 mya
SUGGESTED SUBMISSIONS
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Species (singular species submissions)
Species (singular species submissions)
Name: "Potamocarcinus" vorax
Creator: pinguino77epico
Size: 55 centimeters long
Location: Equatorial Pangaea, in southern Europe and northern Africa
Time period: 290 mya
Clade: Tetrapoda, Amphibia, Rhachitomi, Dvinosauria, Trimerorhachidae
It was a small agile animal, described to have a snout to vent length of 40 centimeters and a short 15 centimeter long tail. It lived in rivers and lakes with clear, well oxygenated water, inhabiting beds with abundant aquatic vegetation and hiding spots among logs. "Potamocarcinus" vorax was a temnospondyl highly specialized for the predation of hard-shelled aquatic arthropods, mainly some of the later freshwater eurypterids (Adelophthalmus spp.) and large crustaceans. Its skull was low and broad, with large, dorsally-oriented eyes to locate prey from below. The most distinctive synapomorphy was its dentition: it possessed numerous conical and sharp teeth along the jaw margin to capture prey, but it had developed a pair of enlarged, blunt "molar teeth" on the palate, ideal for crushing and piercing the chitinous exoskeleton of its victims. Its body was anguilliform (eel-like) and its limbs were reduced, making it a slow swimmer but one with explosive acceleration, propelled mainly by its powerful tail. It ambushed among the vegetation or bottom detritus, launching itself in rapid strikes.
It became extinct long before the Permian-Triassic event, as its prey declined and with climate changes that made aquatic environments more stressful.
Name: Pseudosuchocephalus parahippoides
Creator: SocietalNarrator
Size: 1.2 meters long
Location: Unknown
Time period: 254.1 - 251.9 mya
Clade: Chordata, Olfactores, Vertebrata, Placodermi, Eugnathostomata, Osteichthyes, Sarcopterygii, Rhipidistia, Tetrapodomorpha, Choanata, Eotetrapodiformes, Elpistostegalia, Stegocephali, Tetrapoda, Reptiliomorpha, Romeriida, Amniota, Synapsida, Pelycosauria, Eupelycosauria, Metopophora, Haptodontiformes, Sphenacomorpha, Sphenacodontia, Pantherapsida, Sphenacodontoidea, Therapsida, Eutherapsida, Neotherapsida, Theriodontia, Eutheriodontia, Therocephalia, Cynodontia, Procynosuchidae
Pseudosuchocephalus parahippoides was a species of procynosuchid cynodont that survived to the Permian-Triassic mass extinction. Although Pseudosuchocephalus, the last member of its family, is known to mean "false crocodile-head," the species name, when added, would have resulted in "parallel horse-like false crocodile-head," but it had no relation to crocodiles, and the name is a valid genus.
Information about this species is limited to the skull and tail, but it is definitely known that the species was carnivorous and fed on fish and other aquatic animals in its surroundings.
Its unclear what caused the extinction of the species, with no definitive conclusion to explain it; however, it is thought that they became extinct due to environmental changes and the arrival of competitors that were successful at feeding on the fish.
Clades (multiple related species submissions; 2 - 3 species)
Clades (multiple related species submissions; 2 - 3 species)
To be added
Ecosystems (2-6 species that live in one shared real or fictional ecosystem)
Ecosystems (2-6 species that live in one shared real or fictional ecosystem)
To be added
SUGGESTED EXTINCTIONS
(clades that are suggested to go extinct in this time period)
SUGGESTED EXTINCTIONS
(clades that are suggested to go extinct in this time period)
Procynosuchidae (†251.9 mya): - Pseudosuchocephalus is the last member of its family that survived to the Permian-Triassic mass extinction. Its unclear what caused the extinction of the species, with no definitive conclusion to explain it; however, it is thought that they became extinct due to environmental changes and the arrival of competitors that were successful at feeding on the fish. (SocietalNarrator)
SUGGESTED ECOSYSTEMS
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SUGGESTED ECOSYSTEMS
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To be added
CANON
CANON
OFFICIAL
(ultimate canonical compilation of submissions; official submissions, extinctions and ecosystems can only fall in this category after the deadline is over and proper judging can occur; I will have authority to canonize my own submissions before the deadline, however, and that information can be used by other people to build over the canon in anticipation)
OFFICIAL
(ultimate canonical compilation of submissions; official submissions, extinctions and ecosystems can only fall in this category after the deadline is over and proper judging can occur; I will have authority to canonize my own submissions before the deadline, however, and that information can be used by other people to build over the canon in anticipation)
SPECIES
Name: Policeratosuchus apsis
Creator: TheTiger773
Size: 2.7 meters long
Location: Southeastern Pangaea (modern North Africa)
Time period: 265 mya
Clade: Chordata, Olfactores, Vertebrata, Placodermi, Eugnathostomata, Osteichthyes, Sarcopterygii, Rhipidistia, Tetrapodomorpha, Choanata, Eotetrapodiformes, Elpistostegalia, Stegocephali, Tetrapoda, Reptiliomorpha, Romeriida, Amniota, Synapsida, Pelycosauria, Eupelycosauria, Metopophora, Haptodontiformes, Sphenacomorpha, Sphenacodontia, Pantherapsida, Sphenacodontoidea, Therapsida, Eutherapsida, Dinocephalia, Tapinocephalia, Tapinocephalidae
Policeratosuchus apsis was a large herbivorous dinocephalian from the Tapinocephalidae family. Its exact phylogenetic position is unclear, though they appear to be somewhat basal. At the first glance, this animal looks like many other large synapsids of its family, like Moschops or Tapinocephalus. Its head, however, was adorned by ten bony protrusions, vaguely reminiscent to that of the unrelated Estemmenosuchus. Additionally, spinous processes of its thoracic vertebrae are greatly elongated, although not nearly as much as in earlier edaphosaurids. A minor sexual dimorphism was present among individuals, distinguished by the generally larger size of males and their higher intensity of colors on their backs. Their reproductive period precedes the period of increased rainfall brought by megamonsoons that allow for short-term vegetation growth. This is when these usually solitary animals congregate into large groups called leks. Females make their choice by seeking out the largest males, who fight among themselves for the right to mate. Some time after that, females seek a place to lay their eggs, where they dig up a shallow hole in which they can deposit up to 40 leathery eggs. However, due to high mortality caused by predation and environmental conditions, only one or two individuals on average may survive to adulthood. After that, however, they are almost immune to predation. Only some of the largest anteosaurs can take on adults, but even then they'll mostly avoid them due to their aggressive demeanor.
Name: Parosaurus antarcticus
Creator: YellowPanda2001
Size: 60 - 70 centimeters long
Location: Antarctica
Time period: 265 mya
Clade: Afrothyra, Elliotsmithiini, Parosaurina
In the Wordian stage of the middle Permian, life was flourishing in the aftermath of the Olson's extinction, a supposed biotic overhaul that dramatically changed the composition of Permian fauna. One of the most talked changes between the earlier Permian fauna and the middle Permian one is the general absence of non-therapsid synapsids, the traditional "pelycosaurs". However, we know from the fossil record that "pelycosaurs" still flourished in the middle Permian, namely the caseids and the varanopids. Though they were still dwarfed by the dominant therapsid megafauna, they existed in smaller size ranges, typically, often having lower and more reptilian-like metabolisms. Parosaurus antarcticus is an example of a varanopid that lived in Antarctica in the Wordian stage, 265 mya. It is a close relative of the south african fossil genus Elliotsmithia. Because Antarctica is, nowadays, covered in thick ice and snow, its understandable that no fossils of this reptile-like synapsid were found. Back in the middle Permian, Parosaurus lived in a temperate glossopterid forest, where it fed on small animals, like insects, arachnids and small tetrapods.
This may not appear like a particularly striking species. It does share the scaly skin and varanid-looking bauplan of other related varanopids. This animal was a semi-arboreal predator, like their relatives. However, one intriguing aspect of this species is that it lived in groups. This may not be entirely unique, as evidence of social lifestyles and even parental care are known from other varanopids known from the fossil record, but this however reinforces the idea that varanopids were more invested on social interactions and parental care than often considered. In fact they may be one of the most primitive groups of synapsids to display parental care, a universal trait in our timeline's modern mammals, indicating a very ancient adoption of this trait. But perhaps the most striking characteristic of Parosaurus is that, in opposition to what would be expected for such a basal synapsid, it actually does not lay eggs, but gives birth to live young, like our timeline's therian mammals. It is a fact that synapsids (indeed mammals themselves) were ancestrally egg-layers, but our knowledge of the reproductive habits of Permian synapsids is very sparse. It is to no wonder that extinct synapsid lineages might have developed different reproductive strategies independently. As varanopids increasingly complexified their social and parental caring specializations, the loss of oviparity followed, allowing them to give birth to a smaller number of larger well developed offspring. This paralels the evolution of the Solomon Islands skink of our timeline's today, which has a similar method of reproduction and social lifestyle. Parosaurus, therefore, is one of the earliest examples of a viviparous tetrapod to evolve, predicting a growing trend in the evolution of viviparous amniotes, in the future.
Name: Aerochimaera incredibilis
Creator: YellowPanda2001
Size: 1.4 meters of wingspan
Location: Eastern Panthalassa
Time period: 257 mya
Clade: Holocephali, Chimaeriformes
After the end Capitanian extinction event, life on Earth was slowly recovering after the cataclism, in both the land and the sea. The shallow seas were particularly affected by the Emeishan traps, forcing several species adapted to those environments to adapt to new ones. That was the case of the strange chimaeriform Aerochimaera incredibilis which inhabits eastern Panthalassa in the early Wuchiapingian. This is a large-finned open water glider, not dissimilar to the Cenozoic manta rays and the Mesozoic Aquilolamna, granting the Paleozoic with its own strange example of a large gliding marine chondrichthyan.
This strange chimaeriform shares a lot of characteristics with its known related counterparts, using its pectoral fins to aid in moving in the water column, as well as having the characteristic fin spines and strange serrations and claspers on their head to aid in mating. It is however not a filter feeder like the manta rays and aquilolamnids it so resembles, having what appears to be a strange protrusable beak that can suck up hard-shelled swimmers, like crustaceans, nautiloids and ammonoids, and crush their hard shells. The open oceans were comparatively less affected by the extinction, granting this chimaera relative with a different and unexplored environment to adapt to. Unfortunetly, the open ocean conditions of the late Permian were changeable and didn't last very long, so its presence in Earth's history was too short lived and poorly localized to ensure fossilization of this weird taxon.
Name: Longirostrotherium hemisphaerium
Creator: AlDodo
Size: 2.9 meters long, 1.67 meters tall and 1.36 tonnes
Location: Northeastern North America
Time period: 254 - 251.9 mya
Clade: Animalia, Eumetazoa, ParaHoxozoa, Planulozoa, Bilateria, Nephrozoa, Deuterostomia, Chordata, Olfactores, Vertebrata, Placodermi, Eugnathostomata, Osteichthyes, Sarcopterygii, Rhipidistia, Tetrapodomorpha, Choanata, Eotetrapodiformes, Elpistostegalia, Stegocephali, Tetrapoda, Reptiliomorpha, Romeriida, Amniota, Synapsida, Pelycosauria, Eupelycosauria, Metopophora, Haptodontiformes, Sphenacomorpha, Sphenacodontia, Pantherapsida, Sphenacodontoidea, Therapsida, Eutherapsida, Dinocephalia, Tapinocephalia, Styracocephalidae
The Permian period is the last period of the Paleozoic era, being mostly characterized by a rise in diversity of land tetrapods and their adaptations into large sizes (both in herbivorous and predatory niches) and various specializations for a fully terrestrial lifestyle in a dry context in response to the general trend of aridification and increasing warm temperatures which occured from the start to the very end of the period.
However, its also observed an increasing in intensity of those changing climatic traits over the period and, as a result, also induced declines in biodiversity, decrease in available habitat suitable for large animals and forcing increasing specializations for organisms, both plants and animals, into a more and more harsh climate. This would ultimatly reach its peak at the end of the period and lead to a famous extinction event, the Great Dying, which would kill most life, both on land and sea, on Earth.
The Permian witnessed two minor extinction events roughly dividing the Early, Middle and Late parts of it, those being the Olson’s extinction, at 273 mya, and the Capitanian mass extinction 262-259.5 mya ago.
The dominant cast of animals during the whole Permian are the synapsids, a line of reptiliomorphs which split from the reptile lineage, and eventually would one day lead to typical mammals, with much of the Permian representatives representing a transition between reptile-like and mammal-like amniotes. Within the different types of synapsids that lived during the period, some evolved more and more mammalian traits and behaviors.
They were composed by the "pelycosaurs", most usually regarded as an informal group of early synapsids that dominated the Early Permian, which were reptile/lizard-like animals in broad anatomy and appearance, often with a sprawling gait posture, which includes the edaphosaurs, ophiacodonts, caseids, eothyridids, palaeohatteriids and sphenacodontids (which includes Dimetrodon) most of this diversity dying out during the Olson’s extinction; then the therapsids, a subgroup of synapsids which would dominate the rest of the period, including the dinocephalians that ruled during the Middle Permian, some having more erect gaits and larger sizes, with fossil evidence suggesting that they died shortly after the Capitanian extinction; and finally gorgonopsians and therocephalians, such as cynodonts, which flourished during the Late Permian. These last ones lived alongside the dicynodonts during the Middle and/or Late Permian, these often forming more subordinate herbivorous roles.
However, one very interesting animal is found by the Late Permian revealing a holdover of the Middle Permian, this being Longirostrotherium hemisphaerium, meaning "domed long-snouted beast".
This animal is remarkable in the fact that it was a surviving, very late dinocephalian, of the herbivore lineage of the tapinocephalians, with some animals belonging to this group, in broad strokes, being visually similar to the famous genus Moschops.
And like it, Longirostrotherium was a rather classic looking member of its group.
Its body was deep and capacious, allowing the presence of an important herbivorous gut. The shoulders are very high, more so than the pelvic region, so that the back slopes, in giraffe fashion, from neck to tail. The limbs are heavy, with sturdy forelegs that sprawled out to the sides, while the longer hind legs were placed directly under the hips, while the feet are broad and short.
It was a very derived species of its group, as shown by the traits of its skull, ubiquitous in many members within its group, but very amplified in this species.
The skull is massively constructed and long-snouted, with the forehead being elevated into a thick dome made up of a huge mass of bone (pachyostosis). This clearly indicates these animals engaged in intraspecific head-butting behavior, presumably for territory or mates.
While it may appear unclear over whether the various tapinocephalians were terrestrial or semi-aquatic (or both, depending on the species), this youngest member of the group was definitively semi-aquatic. Living much like a moose or a hippo in shallow waters systems, it used its long snout to grasp efficiently, and with low effort, soft aquatic vegetation and using its dome to fight congeners.
It lived in small herds held by a single dominant male, which repelled other males for mating rights. Being a large sized animal, it was one of the most dominant megafauna of its habitat.
It isn’t known how the ancestor of these animals survived the Capitanian extinction, which killed off most other dinocephalians, but it is thought this lineage was survived by a small species, going against the common trend of this animals for gigantism, and survived as semi-aquatic animals, able to find its food there.
This lineage then radiated in the Late Permian and grew to sizes akin to its relatives and endured competition from newly arosed synapsid groups by sticking to this amphibious specialization.
Longirostrotherium is found mostly in swamps and coastline habitats, of the northeastern region of North America, hence why its fossils weren’t found as these biomes weren't favourable positioned for fossilization. And as the continent was isolated from the rest of Pangaea by the Central Pangaean mountains, it is thought this served as a refugium for this dinocephalian stock, with it dealing with less competition and living in a more stable ecosystem.
Its placement within Tapinocephalia, and its affiliations with the rest of the group, may be unclear, with affiliations with Tapinocephalidae or Titanosuchidae capable of being drawn, given its head characteristics were vaguely common and quite widespread within much of the dinocephalian group (even with the anteosaurs, from the predatory lineage Anteosauria, which also had vaguely dome-shaped skulls, perhaps for head-butting).
Differents lineages of dinocephalians also independently evolved long snouts or developed domes as well.
However, this animal may more likely belong to the Styracocephalidae, and descending from an animal akin to Styracocephalus, as these animals were generally smaller and less common than their relatives, and would have survived better and taken some benefits of the aftermath of the Capitanian extinction.
However, Longirostrotherium was the last tapinocephalian and dinocephalian to ever live, with its dying, at the Great Dying even, putting an end to a ghost lineage of almost 9 million years.
CLADES
Name: "Crassigasterinae"
Creator: MrBlueShark
Location: Russia
Clade: Anomodontia, Venyukovioidea, Venyukoviidae
No clade description given.
Name: Arborovenator minimus
Size: 30 centimeters long
Location: Russia
Time period: 259 - 251.9 mya
These strange therapsids are part of a radiation of late Permian arboreal anomodonts of the infraorder Venyukovioidea, likely being closest to Suminia. This particular genus is most unusual for having abandoned the herbivorous specializations of its group, evolving instead to take advantage of the various insects found up amongst the branches using an incredible jumping ability to leap amongst branches and trunks of trees at night. Their large forward facing eyes can pin-point nighttime insects grabbing them with their forelimbs and tearing them apart with their jaws. They are only around 30 centimeters in length, half of which is tail. It may be inferred that the rebound of late Permian insect diversity, as a response to global warming and plant rediversification after the end Capitanian extinction, promoted the reduced size and insect-eating lifestyles to avoid competition with other arboreal anomodonts. It however still includes plant matter in its diet, using its powerful jaws and teeth to proccess plant material, despite repurposing them for processing insect-based meals.
Name: Crassigaster gigas
Size: 60 centimeters long
Location: Russia
Time period: 259 - 251.9 mya
This larger sympatric species is much like Suminia, a herbivore feeding on the leaves, cones and even bark from trees and other plants. They are lethargic and possess a slower metabolism, conserving energy for long periods. They are capable of loud vocalisations to communicate with one another as they travel in spread out troops, having a large throat pouch that makes their calls loud and guttural. At 60 centimeters they are amongst the larger, if not the largest, arboreal animals of its time.
ECOSYSTEMS
EXTINCTIONS
Tapinocephalidae (†256.9 mya): - The end Capitanian extinction is most famous for marking the end of the dinocephalian domain. But in reality, some dinocephalians appear to have survived after the extinction boundary. Some have made it to the fossil record, as shown by the survival of a few taxa into the lowermost Poortjie Member of the Teekloof Formation in South Africa. However, they would have survived even further in localized refugia. The tapinocephalids, well known for composing herbivorous taxa with large domed heads for head-butting, survived for at least 2.5 million years in an isolated region corresponding to modern Australia. These were the very last survivors, related to Criocephalosaurus, having disappeared quietly as a dead clade walking. (YellowPanda2001)
Charassognathidae (†254.1 mya): - In the late Permian, one of the lesser represented groups of synapsids are the cynodonts. Cynodonts seem to have diverged from therocephalians, as evidenced by one of the most basal offshoots of this group, the charassognathids. Charassognathids were very small cynodonts, having a few features characteristic of therocephalians. Charassognathids share other features believed to have been ancestral to the more traditional Permian cynodonts, such as a small size and burrowing specializations, which might have given them the edge in surviving the later Permian-Triassic extinction event. However, charassognathids seem to have gone extinct at the end of the Wuchiapingian over 2 million years before the extinction event. These small primitive cynodonts seem to have been quite restricted to southern Africa, at least based on the fossil record, and the transition from the Wuchiapingian to the following Changshingian was marked by a global warming trend. Volcanic activity would have led to the end of the Late Paleozoic Ice Age, terminating glacial deposits on Earth by the late Wuchiapingian, and the ongoing global warming caused changes in global ecosystems even earlier than the Great Dying itself. So, by the end of the Wuchiapingian, even small and generalistic synapsids, like the charassognathids, saw their end, as biomes changed locally. (YellowPanda2001)
Dinocephalia (†251.9 mya): - Longirostrotherium was the last tapinocephalian and dinocephalian to ever live, with its dying, at the Great Dying even, putting an end to a ghost lineage of almost 9 million years. (AlDodo)
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