#drepanosauridae

[vulturescale]

Drepanosaurus with a pigment mutation. I won't be finishing this, but i wanted to share the general idea anyways :p

Originally it was supposed to be an average Drepanosaurus (but then i started using alot more pink than a jungle animal should have), so i'm not sure what mutation this could be classified as... Either xanthism or erythrism. Maybe even a mutation that doesn't appear in modern animals?

[makairodonx]

Breaking news! A newly-described European relative of the bizarre early Triassic reptile Longisquama just dropped:

Triassic diapsid shows early diversification of skin appendages in reptiles - Nature

A Middle Triassic diapsid is presented that has a distinctive crest consisting of integumentary appendages that are structurally distinct fr

[alphynix]

Drepanosaurs were a weird little group of tree-climbing Triassic reptiles with prehensile claw-tipped tails, chameleon-like bodies, humped backs, grasping feet, long necks, and somewhat bird-like skulls that may have been tipped with toothless beaks in some species.

Recently some of them have been recognized as also having adaptations for digging and ripping into insect nests, similar to modern anteaters, with highly specialized forelimb bones and a massively enlarged hoked claw on each hand.

And now we have another one of these digging drepanosaurs: Unguinychus onyx, whose name delightfully translates to "claw claw claw"!

Living in what is now New Mexico, USA during the late Triassic, around 215-208 million years ago, Unguinychus is only known from its enlarged hand claws but was probably similar in size to some of its close relatives, likely around 40cm long (~1'4").

Based on skin impressions from the early drepanosaur Kyrgyzsaurus it also would have been covered in small scales, possibly with a skin crest and a chameleon-like throat sac.

Drepanosaurs' evolutionary relationships are rather unclear, with various studies classifying them as an early branch of diapsid reptiles, as close relatives of the gliding kuehneosaurids, or as protorosaurian archosauromorphs. But recently another idea has been proposed, instead placing them slightly further up the archosauromorph evolutionary tree in the allokotosaur lineage close to trilophosaurids – and notably making them very closely related to fellow Triassic bird-headed weirdo Teraterpeton.

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References:

Alifanov, V. R., and E. N. Kurochkin. "Kyrgyzsaurus bukhanchenkoi gen. et sp. nov., a new reptile from the Triassic of southwestern Kyrgyzstan." Paleontological Journal 45 (2011): 639-647. https://www.researchgate.net/publication/257843064_Kyrgyzsaurus_bukhanchenkoi_gen_et_sp_nov_a_New_Reptile_from_the_Triassic_of_Southwestern_Kyrgyzstan

Buffa, Valentin, et al. "‘Birds’ of two feathers: Avicranium renestoi and the paraphyly of bird-headed reptiles (Diapsida:‘Avicephala’)." Zoological Journal of the Linnean Society (2024): zlae050. https://doi.org/10.1093/zoolinnean/zlae050

Jenkins, Xavier A., et al. "Using manual ungual morphology to predict substrate use in the Drepanosauromorpha and the description of a new species." Journal of Vertebrate Paleontology 40.5 (2020): e1810058. https://www.researchgate.net/publication/344545876_Using_Manual_Ungual_Morphology_to_Predict_Substrate_Use_in_the_Drepanosauromorpha_and_the_Description_of_a_New_Species

Pugh, Isaac, et al. "A new drepanosauromorph (Diapsida) from East–Central New Mexico and diversity of drepanosaur morphology and ecology at the Upper Triassic Homestead Site at Garita Creek (Triassic: mid-Norian)." Journal of Vertebrate Paleontology (2024): e2363202. https://doi.org/10.1080/02724634.2024.2363202

[alphynix]

Drepanosaurs were already some extremely weird animals, even among all the other weirdos of the Triassic period.

These strange little tree-climbing reptiles had chameleon-like bodies, humped backs, long necks, and oddly bird-like skulls with toothless beaks – and then some of them also had bizarre forelimb anatomy with a single enormous claw on the second finger of each hand, along with a claw on the tip of their prehensile tail.

But new discoveries are showing that some members of this bizarre group were doing something different.

Ancistronychus paradoxus here lived during the late Triassic, about 227 million years ago, in what is now the southwestern United States. Measuring around 50cm long (1'8"), its enormous hand claws were unusual compared to its close relatives, with a distinctly wide and hooked shovel-like shape.

Along with another recently-discovered species, Skybalonyx skapter, and the weird burly arms of Drepanosaurus, this suggests that instead of tree-climbing some drepanosaurs were instead much more specialized for digging. They may have been Triassic equivalents to modern anteaters or pangolins, using their enlarged claws to excavate burrows and rip their way into insect nests.

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