TRIASSIC
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TRIASSIC
251.9 - 201.4 mya
The Triassic is a geological period that spans about 50.5 million years, starting from the end of the Permian period, 251.9 mya, and ending at the start of the Jurassic period, 201.4 mya. During this time, the world was dominated by the supercontinent Pangaea, but by the last stage of the Triassic, in the Rhaetian, it began to rift, which would gradually lead to the future continents of Laurasia (in the north) and Gondwana (in the south); the period is divided in the Early Triassic, or Scythian (251.9 - 246.7 mya), including two stages, Induan (251.9 - 249.9 mya) and Olenekian (249.9 - 246.7 mya), the Middle Triassic (246.7 - 237 mya), including two stages, Anisian (246.7 - 241.4 mya) and Ladinian (241.4 - 237 mya), and finally the Late Triassic (237 - 201.4 mya), including three stages, Carnian (237 - 227.3 mya), Norian (227.3 - 205.7 mya) and Rhaetian (205.7 - 201.4 mya).
The Triassic was composed of three major oceanic bodies, the northern Paleo-Tethys, the southern Neo-Tethys (these two in the arc of the Pangaea supercontinent), and the gigantic superocean Panthalassa (surrounding Pangaea). The northern part of Pangaea, called Laurussia, was characterized for having major deltaic systems during the first half of the Triassic, such as the Triassic Boreal Ocean delta plain, which advanced across the shallow Arctic Ocean during the Carnian stage. Major extensional tectonic movements, that began in the late Permian, continued across Laurussia from North/Central Europe in the east to eastern Canada in the west, with north-south trending graben systems developing across Europe, including further subsidence in the northern and southern Permian basins. Corsica, Sardinia, Calabria, and the Balearic terranes were attached to Europe, whilst Apulia, Adria, and the terranes of southern Turkey remained attached to the African plate. In southern Pangaea, the region called Gondwana, northeast-southwest trending rifting along the eastern edge of Africa between Madagascar (Indian plate) and eastern Africa (Somalian plate) continued from the Late Carboniferous into the Triassic, with substantial mountains rising along the edge of the rift and the formation of a series of pull-apart basins. The Paleo-Tethys ocean remained since the formation of Pangaea in the late Paleozoic, but it was beginning to close. To its south were the Cimmerian terranes (Central Iran, Qiangtang(north Tibet), Lhasa (south Tibet), and Sibumasu (eastern Myanmar, Thailand, Malay peninsula and Sumatra)), which gradually moved north during the period until it collided with Pangaea through the lands corresponding to northern China around the middle-late Triassic. The segment of the Paleo-Tethys between North China and Qiangtang may never have fully closed, but was filled with Permo-Triassic turbidites preserved in the West Kunlun and Bayanhar belts of the Central China orogenic belt. Late Triassic deformation across the Eastern Mediterranean area and much of the Middle East was complex, with regional scale strike-slip faulting and continued subduction below the Iranian margin. At this time, the Moroccan basins were the equivalent of Nova Scotian basins, and the Iberian the equivalent of the Newfoundland basins, predicting the future north Atlantic rift, which had commenced in the late Triassic. The period of rifting came to an end with the emplacement of the Central Atlantic Magmatic Province (CAMP) over 201 mya. The resulting magmatism produced dense dyke swarms, with individual dykes up to 800 km long, massive sill complexes, and lava fields that covered several hundred kilometres. This resulted in long-term climate warming and ocean acidification, causing end end Triassic mass extinction. Panthalassa is thought to have been divided in three major tectonic plates: Farallon, Izanagi and Phoenix. Sea level rise accelerated in the Ladinian, culminating with a sea level up to 50 metres above present-day levels during the Carnian. Sea levels however dropped a lot after that, with this condition persisting into the earliest Jurassic. It has generally been assumed that the cause for this sea level drop was changes in volume of the global ocean basin due to variations in oceanic volcanism, with largest volumes occurring in volcanism's absence when the ocean basins were subsiding.
During the Triassic, the poles were free of glaciation, and were instead moist and temperate, providing a climate suitable for forests and several land vertebrates, including reptiles. The Early Triassic was the hottest point in the entire Phanerozoic eon, as it was living with the aftermath of the titanic volumes of greenhouse gases emitted during the Permian-Triassic extinction. At the beginning of the Carnian, global temperatures were getting cooler. There was a short period of global warming, the Mid-Carnian Warm Interval (MCWI), occuring some 234 - 227 mya, triggering the Carnian Pluvial Event (CPE). There was also a later Mid-Norian Warm Interval (MNWI), some 217 - 209 mya, which was briefly interrupted, 214 mya, by a cooling spike, possibly caused by the Manicouagan meteorite impact. At the very end of the Triassic there was an extreme warming event, the End-Triassic Thermal Event (ETTE), which triggered the Triassic-Jurassic extinction event.
Coal deposits are not known from the start of the Triassic period, being known as the Early Triassic coal gap. In the ocean, secondary endosymbiotic algae became the most important form of plankton.
New types of corals evolved in the Triassic, forming successful modest reef patches, though they sometimes suffered some declines, such as during the end of the Carnian, where we observe a reef crisis in South China. In the immediate aftermath of the Permian-Triassic extinction, fish diversity was relatively uniform, with a lot of families and genera exhibiting a cosmopolitan distribution. Amphibians, once abundant in both terrestrial and aquatic environments in the Permian, were mostly just represented by aquatic species instead in the Triassic, with most terrestrial ones dying out in the end Permian extinction. Some amphibian lineages flourished briefly in the early Triassic, such as the trematosauroids, while others became successful throughout the whole period, such as capitosaurs, while others became more successful during the late Triassic, such as plagiosaurs and metoposaurs. Non-amniote reptiliomorphs mostly disappeared at the end of the Permian, with only the aquatic chroniosuchians being known to have survived, at least, until the end of the Triassic. On land, complex food web structures and communities took about 30 million years to reestablish since the end Permian extinction. By the early Triassic, several archosauromorph groups have appeared. Characteristic of the Triassic were the tanystropheids, a family of tanysaurs where some members had immensely elongated necks, much longer than its body, such as Tanystropheus. During the Triassic, other archosauromorphs were trending more to dedicated stocky herbivores with specialized jaw structures, such as rhynchosaurs and allokotosaurs. Allokotosaurs included mostly iguana-like reptiles, such as the three-crowned toothed Trilophosaurus, the long-snouted Teraterpeton, and the giant horned Shringasaurus. One group of archosauromorphs, the archosauriforms, was characterized for mostly having a more active predatory lifestyle, with serrated teeth and a more upright limb posture. In this group were the erythrosuchids, large-headed carnivores that were dominant predators in the early Triassic. The phytosaurs were more aquatic, and with their long toothed snouts, greatly resemble our timeline's modern crocodilians, but this similarity is a result of convergent evolution. Another group of archosauriforms of the Triassic were the dinosaurs, which first originated during this time, most of them being, then, small, often common, carnivores, such as Coelophysis. Another Triassic group were the armored aetosaurs, with most being herbivorous eaters of low-lying plants, though a few did eat meat. During the early-mid Triassic, marine reptiles rapidly radiated, such as ichthyopterygians and thalattosuchians, such as Askeptosaurus. In the Triassic, the only parareptiles known are the procolophonids, an important group of mostly lizard-like herbivores. Three therapsid groups are known to have made it to the Triassic: the dicynodonts, the eutherocephalians and the cynodonts. Eutherocephalians were consisted of predators, such as Moschorhinus, and herbivores, such as bauriids, but the group disappears from the fossil record in the Middle Triassic. Ecteniniid cynodonts play a role of large cursorial predators during the late Triassic. In this period, however, archosaurs overthrew the therapsids as the most dominant and prollific terrestrial animals.
The Guiyang biota, in China, and the Paris biota, Idaho, USA, are the two oldest Mesozoic lagerstätten, hailing from the early Triassic, providing an insight into the biotic recovery after the Permian-Triassic extinction event. The Monte San Giorgio lagerstätte in Italy preserves a lagoonal reef environment from the Middle Triassic under anoxic conditions, where little turbulence and scavenging occured, so to preserve its extraordinary fossils.
The end Triassic extinction event was a very severe event that nearly wiped out conodonts, and caused extinctions of many marine reptiles, with only ichthyosaurs and plesiosaurs being known to have survived into the Jurassic. The causes of this extinction have been historically debated, with an extraterrestrial impact, like the Manicouagan impact, being hypothesized as possible candidates, however that impact specifically occured 13 million years before the extinction. Accurate dating of the Triassic-Jurassic boundary puts it at 201.4 million years ago, far too late for it to be caused by this meteor impact. It was hypothesized that there were a number of extinction events across the Late Triassic, but there is evidence that partially refutes this idea. For instance, in the Petrified Forest, in Arizona, sediments dating to the Carnian-Norian boundary show no signs of paleoenvironmental change, implying that there was no extinction event between the two stages. The end Triassic extinction event, however, became the opening to the true Age of Dinosaurs, where the dinosaurs now ruled as the dominant terrestrial animals across the following Jurassic and Cretaceous periods.
main source: Wikipedia
A Earth map reconstruction, some 235 mya.
SUGGESTED SUBMISSIONS
(this space will be reserved to catalogue submissions done for this contest, simply for people to get a sense of what other people are working on)
Species (singular species submissions)
Species (singular species submissions)
Name: Postcyonosaurus triassicus
Creator: AlDodo
Size: 1.7 to 2.5 centimeters long
Location: South and Central Africa
Time period: 235 - 234 mya
Clade: Synapsida, Pelycosauria, Eupelycosauria, Metopophora, Haptodontiformes, Sphenacomorpha, Sphenacodontia, Pantherapsida, Sphenacodontoidea, Therapsida, Eutherapsida, Neotherapsida, Theriodontia, Gorgonopsia, African clade, Cyonosauridae
The end of the Permian was particulary tough for Earth’s organisms as a whole, for both plants and animals, as it ended with what is essentially agreed to have been the worst mass extinction event to have ever occured in the planet’s long past history. To a point when life itself is sometimes said to have been almost erased from existence, warranting it the nickname of "The Great Dying".
This extinction event caused extreme aridity, induced mostly by important warming climate trends that reached an unsuitable point for global ecosystem stability, with much of its part being induced by volcanic activity, causes that started back at the end of the Middle Permian with the end-Capitanian extinction event (one could imagine it basically starting the Great Dying but taking time to reach its peak until the end of the Late Permian).
The results were a great reset of the ecosystems which took time and most of the Early Triassic, the following period, to recover. And as the cast of surviving organisms were often small and enduring organisms, usually few in numbers, they underwent a massive adaptive radiation to fill these again. Many clades that evolved during the Permian ended up becoming subordinates to the fauna that became the new dominant groups after these.
Among the groups that dominated the Permian and lost their place as dominant animals were the gorgonopsians, which were the dominant apex predators during much of the later parts of the Permian period, and one of the three major groups of theriodont therapsids of the synapsid group (that is mammal-line vertebrates) alongside the traditional therocephalians and the cynodonts. These three groups were the lineages that especially evolved lot of the many mammalian traits that modern mammals (descendants of cynodonts) would inherit.
While much of the group went extinct at the end of the Permian, as it would appear from our fossil record, these animals, in reality, did manage to miraculously survive into the Triassic.
Surviving under a representative of the African clade of the group, and supposed to be closed to the genus Cyonosaurus (debatably could be part of this genus itself), it resided in South Africa and endured the mass extinction.
While the exact reasons of its survival are unknown, its small size of up to only 60 to 110 centimeters, gracile built and supposedly more generalistic nature, were definitively contributive to it, allowing the group to pass the boundary and managing survival.
That said, gorgonopsians didn’t seem to have radiated again and weren’t able to recover enough fast to regain their niches before the other surviving clades filled them for themselves. As an effect, the group once dominant remained as subordinates to the new established cast of dominant Triassic fauna. Such dominant fauna was made up of various sauropsid reptiles, such as archosaur reptiles, including the earliest dinosaurs, and large dicynodonts, as well as diverse cynodonts. They retained, seemingly, a low diversity, low number of new genera, and generalistic nature, which seem to support their conditions as a group now living in the fringes of their ecosystems. This placed quite an important competitive pressure on the gorgons, especially against their cynodont relatives.
Among the species descending from this surviving lineage of gorgons, and among the very latest before their disappearance from the remaining Triassic, is Postcyonosaurus triassicus. This member of the groups is quite revealing about the survival of gorgonopsians into this period.
This animal was very much like Cyonosaurus in every point, both physically and in term of behaviors, being a small, nimble animal which seems to have been an opportunistic omnivore in its ecosystems, found in both South and Central Africa. It was very likely a crepuscular to nocturnal animal, being active at night and hunting small game. It made its life as a mesopredator, and low in the food chain. Potentially akin to a fox or coyote in niche, these animals seem to have been a nest raider of dicynodonts and reptile eggs, taking their offspring as well, during breeding seasons. Postcyonosaurus also seem to have been both a flexible animal in its resting habits, taking advantage of dens and burrows that it made or using ones made by others animals, as well as a climber of trees and other elevated platforms to hide and rest from larger predators.
Postcyonosaurus lived during the early Carnian stage and is recorded right before the Carnian pluvial episode (CPE), which lasted 234–232 mya, seemingly becoming extinc during this turnover and minor extinction event induced by important flooding and rain events which lasted for some millions years. With such changes and too much flooding contexts it ultimately became too much for this animal to handle.
Name: Fossorivenator alloi
Creator: Chickadeesarecool
Size: 4.5 meters long
Location: Grenade Formation - Central Pangaea, between what is now Africa and Americas
Time period: 231 mya
Clade: Sphenacodontoidea, Therapsida
Similarly to the rauisuchians of our timeline, Fossorivenator lived in the Grenade Formation during the Triassic.
It has comically small legs to make room for a 4.5 meter long body (including the tail), with the huge arms not only being used to dig prey out but also for pinning and dragging them. These prey are, of course, the Vermisuchus. This reptilian-looking creature is of the same order as Vermisuchus, but it fills a different niche. It would be comparable to the difference between the closely related hyraxes and elephants. The tail and underbelly are armoured, as it has to be dragged around to move.
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)
To be added
SUGGESTED ECOSYSTEMS
(real or fictional ecosystems suggested by the community for other people to build into)
SUGGESTED ECOSYSTEMS
(real or fictional ecosystems suggested by the community for other people to build into)
Grenade Formation / Central Pangaea, between what is now Africa and Americas (231 mya) - During the Triassic period, the landmasses were all mostly joined together via a massive supercontinent known as Pangaea. These uniform landmass allowed several groups of organisms to achieve cosmopolitan distribution, leaving little room for hidden terrestrial lineages to exist anywhere in the globe. But some places are completely gone from the fossil record. Most notably, with the future separation of the Americas from Africa, a massive corridor of central pangaean ecosystems has lost much of its record, preserving life that existed in secluded valleys and mountain ranges around this region. The Grenade Formation preserves a strange mountainous environment of weird inhabitants, some of them hailing from a very ancient time. It dates to about 231 million years ago, in the Carnian stage of the late Triassic, set shortly after the Carnian pluvial episode, and its present day location is now well under the Caribbean sea. Here high altitude forests create a unique environment for endemic inhabitants of this strange and bizarre new world. (YellowPanda2001)
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: Ingluvorax terriblis
Creator: TheTiger773
Size: 1.7 meters long
Location: Panthalassa (cosmopolitan)
Time period: 220 mya
Clade: Chordata, Olfactores, Vertebrata, Agnatha, Conodonta, Conodonti, Prionodontida, Ozarkodinida, Ozarkodinina, Polygnathacea, Anchignathodontidae
Ingluvorax terriblis is a strange species of extremelly large, carnivorous conodont. It appears to be a late surviving member of the Anchignathodontidae, perhaps a close relative or direct descendant of Hindeodus. This particular species usually lives in between the mesopelagic and bathypelagic zones of the open ocean, which corresponds to an average of 500 to 1100 meters below sea level. The presence of Ingluvorax outside this range is uncommon, both due to increased competition and predation above and crushing pressure below. Their red coloration makes them near invisible at the depths they reside. This is important, as they are predators. However, due to the lack of resources in the environment in which they live, they cannot afford active pursuit, so their metabolism is rather slow. Instead, they patiently wait for prey to swim next to them. To attract potential prey, they have developed their most distinctive feature, namely skin spots along the lateral line filled with symbiotic, bioluminescent bacteria. Thanks to muscle contractions, these spots flicker in a wave-like motion from the tail to the mouth. The same flashes are also used for intraspecific communication. When a female is ready to reproduce, she begins to release hormones into the water that attract males. After fertilization, which occurs internally, the female will lay up to 40 eggs on the seabed. It can take up to 6 months for them to fully mature. This immensely slow growth rate (for conodonts, that is) is most surely an adaptation adopted over tens of millions of years of life in the abyssal regions. This allowed Ingluvorax to grow to gigantic sizes and develop iteroparity, that is, unlike most conodonts, they don't die after they reproduce, allowing them to live for years and reproduce multiple times throughout their lifetime. Despite their relatively large size, they often fall prey to large fish and ichthyosaurs at all stages of their life.
Name: Hadronychia fundata
Creator: MrBlueshark (art) and Vincent (Im not Italian) (writing)
Size: 4 to 5 meters long
Location: Northern Eurasia
Time period: 220-218 mya
Clade: Drepanosauromorpha, Elyurosauria, Hadronychidae
Hadronychidae is a weird family of basal Drepanosauromorpha. Having originated before the Carnian Pluvial Event, during a more arid time of the Triassic, this family's ancestors quickly became more terrestrial over time. It is suspected that hadronychids are very closely related to drepanosaurids, due to sharing several anatomical features with them. They likely evolved in the isolated Amuria island, which was isolated through much of the first half of the Triassic, before it collided with the mainland during the late Triassic. By the late Triassic this family was already massively changed from its ancestors bodyplan. The largest of this family is the type genus Hadronychia, which also shows the shared traits of the family. They possess a large, wide beak at the front of their mouths with a large number of teeth in the back. This makes it a sort of giant "plant vacuum", for it is oddly adapted for herbivory. Another one of their diagnotic traits are their weird forelimbs. Their forelimbs have become unguligrade with them walking on two of their nails for better movement on the ground. This makes them in a way look like the forelimbs of derived hadrosaurs. A large claw was possibly present in Hadronychia as a vestigial remnant of its arboreal lifestyle, but a similar claw could also possibly be present in a sort of archosaur instead. They are known from various localities across northern Eurasia in a short period of time during the late Adamanian faunachron and may have been seasonally migratory. Having evolved in an insular environment first, where they could achieve megafaunal forms on land without the competition of more dominant mainland clades, hadronychids successfully established on the mainland during the early-mid Norian stage in a short fluke of success, before they swiftly decline, barely missing preservation in the fossil record.
Name: Megalogomphodon antarcticus
Creator: YellowPanda2001
Size: 4 meters long
Location: Antarctica
Time period: 201.5 mya
Clade: Traversodontidae, Gomphodontosuchinae
The transition from the Triassic to the Jurassic is often argued to have been a more gradual proccess, and that several staple Triassic clades went extinct well before the very end of the period. However, much of this notion comes from a relatively poor understanding of what was life like during the Rhaetian stage of the late Triassic, the very last stage of the period. In more recent fossil discoveries, Lisowicia extended the temporal range of dicynodonts and it even demonstrated that these ancient synapsids kept diversifying despite their steady decline. Even more recently, aetosaurs were revealed to have lasted even closer to the Triassic-Jurassic boundary. This provides a new idea that Triassic life kept on going until a catastrophic end at the very end of the period where a mass extinction led way to the Jurassic and to an ecosystem ruled by dinosaurs. In other parts of the world, traditional Triassic groups continued to diversify until the very end, such as this strange beast called Megalogomphodon antarcticus.
Hailing from Antarctica, any fossil remains of this giant can't easily be accessed by our timeline's modern paleontologists, so its existence is completely unknown to humans. This is actually a gigantic herbivorous gomphodontosuchine cynodont, related to Exaeretodon and Gomphodontosuchus. These were already very large cynodonts, spread across Gondwana, with the most recent fossil representative being Scalenodontoides, known from the Rhaetian of South Africa, already probably the largest non-mammalian cynodont known from fossils. By the very end of the Rhaetian, gomphodontosuchines continued to grow larger and larger, paralelling the evolution of Lisowicia in the north, by being huge and robust erect-limbed synapsids, culminating in this monstrosity. Megalogomphodon weighed somewhere between 1 and 3 tonnes, already making it one of the largest non-mammalian synapsids in existence, and larger than any other non-mammalian cynodont known. Its enormous size allows it to be immune to most predators that inhabit these antarctic temperate biomes. Its enormous head has a series of teeth adapted for chewing and grinding tough plant material, which sets it apart substantially from the various sauropodomorphs that it coexists with. Its quite the strange image to see a giant mammalian-like creature coexisting in a very dinosaur-centered ecosystem, but the Triassic was just like that, up until its very end. This rotund vegetarian is, however, not that gentle, having enormous fangs that can inflict tremendous damage to any creature that dares to question its might.
CLADES
ECOSYSTEMS
Name: Grenade Formation
Creator: YellowPanda2001
Time period: 231 mya
Location: Central Pangaea, between what is now Africa and Americas
During the Triassic period, the landmasses were all mostly joined together via a massive supercontinent known as Pangaea. These uniform landmass allowed several groups of organisms to achieve cosmopolitan distribution, leaving little room for hidden terrestrial lineages to exist anywhere in the globe. But some places are completely gone from the fossil record. Most notably, with the future separation of the Americas from Africa, a massive corridor of central pangaean ecosystems has lost much of its record, preserving life that existed in secluded valleys and mountain ranges around this region. The Grenade Formation preserves a strange mountainous environment of weird inhabitants, some of them hailing from a very ancient time. It dates to about 231 million years ago, in the Carnian stage of the late Triassic, set shortly after the Carnian pluvial episode, and its present day location is now well under the Caribbean sea. Here high altitude forests create a unique environment for endemic inhabitants of this strange and bizarre new world.
Name: Therizinotitan mortalis
Size: 20 centimeters long
Clade: Titanoptera, Gigatitanidae
In the alpine forests, trees and shrubs abound, creating a great environment for arboreal creatures. Because of Pangaea, groups of successful animals found in one side of the world could feasibly be found almost everywhere else that matches their habitat. This is the case of the titanopterans, often surprisingly large insects of the orthopteran lineage. In the Grenade Formation, just like in some other places of the world during the late Triassic, large carnivorous titanopterans exist, such as the endemic Therizinotitan mortalis. It is large and can't jump, in fact it can't even fly, moving only through walking, climbing and gliding. It moves mostly in the trees, but it can move on the ground if needed, and hunt prey in both mediums. Its most distinctive feature is the absolutely enormous scythe-like growths it has on its forelimbs, crucial to subdue small prey. It is however bold enough to go after prey larger than itself.
Name: Vermisuchus triassicus
Size: 40 to 50 centimeters long
Clade: Nikkasauridae, Vermisuchinae
Quickly the most mind-blowing inhabitant of the Grenade Formation is this strange naked fossorial creature, named Vermisuchus triassicus. It resembles the mole lizards of our timeline's today, but it is not a lizard, in fact its not even a reptile. This is, in fact, a synapsid. Lacking back limbs and instead using its enormously robust clawed forelimbs to dig, this is a toothless insectivore that moves underground, feeding mostly on grubs and worms. Phylogenetically, it is totally unrelated to any other synapsid group previously known to have survived into the Triassic. This is in fact a late surviving biarmosuchian. Forming a ghost lineage of almost 30 million years, it is a member of the diminute nikkasaurids of the middle Permian. Nikkasaurids were small insectivores thought to have gone extinct, perhaps, with the Emeishan Traps, but they did survive relictually, perhaps specializing in a fossorial lifestyle. To a dramatic degree, these fossorial diminute biarmosuchians survived in the secluded central pangaean mountains, surviving the cataclismic Permian-Triassic extinction and enduring up until, at least, the late Triassic. This odd distant relative of mammals is cold-blooded and oviparous. It spends nearly all its life underground, rarely coming out to the surface. It moves quite like a mole lizard, with its front limbs to dig and move about, undulating sideways like a snake.
EXTINCTIONS
Gorgonopsia (†234 mya): - Among the species descending from a Permian surviving lineage of gorgons, and among the very latest before their disappearance from the remaining Triassic, existed 234 million years ago. This member of the group reveals quite some traits about the survival of gorgonopsians into this period, especially a smaller size and more generalized diet. Living during the early Carnian stage its recorded right before the Carnian pluvial episode (CPE), which lasted 234–232 mya, seemingly becoming extinct during this turnover and minor extinction event, induced by important flooding and rain events which lasted for some millions years. With such changes and too much flooding contexts it ultimately became too much for this animal to handle, resulting in a forgotten extinction. (AlDodo)
Varanopidae (†221 mya): - Although the fossils tell us that only three major groups of synapsids survived the Permian-Triassic extinction (dicynodonts, eutherocephalians and cynodonts), the reality is that more lineages did survive, and for a very long time, afterwards, but simply remained relictual while the rest flourished globally. One of the strangest survivors are the varanopids. Once abundant in the early and middle Permian, these primitive lizard-like scaly synapsids disappear from the fossil record before the end Capitanian mass extinction, but actually their simple morphology allowed them to survive in an isolated insular context in the Paleo-Tethys. These insular varanopids adapted profoundly in this isolated context to the point that they even survived the Permian-Triassic extinction event. Unfortunetly, as the Paleo-Tethys began to close, their island refugia became threatened. By the early Norian, some 221 million years ago, the last varanopids died out as the islands they lived in either submerged or were merged with other landmasses, not resisting the invading fauna. (YellowPanda2001)
Placodermi (†210 mya): - Without the knowledge of paleontologists, placoderms, shockingly, survived after the Devonian and into the Mesozoic era. Placoderms are known for being dominant armored fish mostly known from the Devonian, that disappear in the fossil record by the very end of the period. But they did survive in secret for almost 150 million years afterwards. The last placoderms were ptyctodonts, a group of bottom dwelling placoderms that were already known for having reduced armor. It turns out the very last group of placoderms to survive have lost their armor entirely and dedicated to life in abyssal environments, allowing them to stay undetected from the fossil record, allowing them to survive the massive extinctions of the late Devonian and Permian periods. Their extinction by the Norian stage in the late Triassic can be explained by the fact that this group was extremelly weakened by the mid-late Permian extinctions, and gradually declined with the ongoing effects of the Mesozoic Marine Revolution (MMR) as well as the replacement of brachiopod dominated environments with bivalve dominated ones. As ptyctodonts tend to be durophages, the increase in competition with new durophage species and the establishment of totally new hard-shelled fauna meant that the relictual deep sea ptyctodonts had their days counted. (YellowPanda2001)
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