#archosauriforms

Archosauriform Erythrosuchus africanus, of Early to Middle Triassic, South Africa!

Before the large pseudosuchians took over the Late Triassic of South Africa, a different kind of archosauromorph ruled the Karoo. This was the big-headed Erythrosuchus africanus, a true giant of its time, at around 4.75–5 m (15.6–16.4 ft) long, including a 1 m (3.3 ft) long head. It walked on all fours and had limbs positioned semivertically under its body, unlike the sprawling gait of most other early reptiles. This apex predator was the largest of its own family, the erythrosuchids. It was not an archosaur, but is thought to be closely related to the last common ancestor of all archosaurs.

Erythrosuchus africanus has been found in the Cynognathus Assemblage Zone of the Burgersdorp Formation. Erythrosuchus was highly successful, its 5 million year rule spanning from the early to middle Triassic, and it would have seen the rise and extinction of multiple species. Its main prey were likely dicynodont synapsids, such as Kannemeyeria and Kombuisia, cynodont synapsids like Bolotridon, Cricodon, Cynognathus, Diademodon, and Lumkuia, and therocephalian synapsids like Bauria and Microgomphodon. It could have also preyed on other reptiles, rhynchosaurs like Eohyosaurus, Howesia, and Mesosuchus, procolophonids like Myocephalus, Teratophon, Theledectes, Thelephon, and Thelerpeton, and others like Euparkeria. Erythrosuchus likely wasn’t picky, and may have also fed on the wealth of large temnospondyl amphibians here, such as Batrachosuchus, Jammerbergia, Laidleria, Microposaurus, Vanastega, and Xenotosuchus.

Whelp we’ve got about a week and a half til November (aaaaaah), so I guess I’ll post this year’s Archovember list now!

It’s a bit dinosaur-heavy this time, but there are a lot of species I’d really like to try my hand at! Also, we have two leptoceratopsians and two Araripesuchus species. I thought it would be interesting to compare and contrast these species within the same month, so I hope it doesn’t get /too/ repetitive!

For new folks: this is my “Draw Dinovember” list that I expanded out to include other archosauriforms. I started doing this a few years ago to challenge myself to draw species I’ve never drawn before and/or ones that don’t get a lot of attention. Feel free to join in! You can do the whole list, just the dinosaurs, just the pterosaurs, just the pseudosuchians, just your favorites, just ones you’ve never drawn before, roll a D20 and a D10 and draw the sum of whichever numbers you get, etc. Just make sure they’re posted on or after their specific day so I remember to share them on my blog! You can use #Archovember or #Archovember2023, as those are the tags I follow. (Note that I and the whole Archovember event are usually a lot more active on Instagram so if you have an IG I encourage you to join in there!)

Anyway, here is the list in case the graphic is hard to read:

Belatedly finished @saritawolff 's Archovember

#Archovember Day 9 - Doswellia kaltenbachi

Hailing from Late Triassic North America, Doswellia was an archosauriform relative of the crocodile-like Proterochampsids. Together with the proterochampsids, Doswelliids formed an ancient group outside of Archosauria and, unlike the Archosaurs, have no living representatives to this day.

From neck to tail, Doswellia was heavily armored in rows of bony scutes (which make it just SO fun to draw /sarcasm). Unlike crocodiles, which have a strong bite force but a much weaker ability to open their jaws, Doswellia had strong jaw muscles for both closing and opening their jaws in a scissor-like motion. It’s sharp teeth and upward-pointing eyes seem to suggest that Doswellia was at least a semi-aquatic predator. It may have hunted on land as well, partially burrowing itself with only its armoured back exposed for defense. Possible food sources include small reptiles, crustaceans, mollusks, or even large insects.

Doswellia kaltenbachi would have shared its environment with other Late Triassic North American animals, such as cynodonts, crocodyliformes, temnospondyl amphibians, Redfieldiid fish, and the freshwater shark Lissodus.

Bonus:

(Image by Smokeybjb.)

Vancleavea was not a close relative of crocodilians.  It actually belonged to the Archosauriformes, a group of reptiles that predated true archosaurs (although it did coexist with the archosaurs).  However, as an aquatic reptile that coexisted with the pseudosuchians - and just as a super-strange animal - I feel the need to include it.

It had a number of unusual features for a reptile.  It had multiple types of teeth - mostly small, sharp teeth, along with several pairs of fang-like teeth.  It also bore a tail fin that was made up of elongated osteoderms rather than bony spines or skin - a unique feature among all known animals.  Its finned tail, high-mounted nostrils, and tiny limbs indicate that it spent most, if not all, of its time in the water.

yo yo yo! sorry bout da hiatus but when the goin gets tuff, the tuff get off tumblr fo a little while. Anywayz, im back and with me is this lil rascal, Vancleavea Campi. These guys were non-archosaurian archisauriforms, which besides soundin like it dont make no sense, what I gather from it is dat these were very early ancestors of what today is now crocodiles and certain birds. Vancleavea never got too big, averagin about 1.2 m (ruffly 4 ft) and lived during the late Triassic.

However, these lil rascals were a bit different. They differed from otha archosauriforms and tetrapods in that they tails had scale like things (called osteoderms) extending from them rather than tall neural spines. Their long fin like tail and their short limbs suggest they were semiaquatic lil ragamuffins, but I'd lean more to the aquatic side just because look at those arms.... tiny (do some curls or some'in).