#torvoneustes

[arminreindl]

Fossil Crocs of 2023

2023 has been a year with its ups and downs, but one consistent thing has been its fossil crocs at least, giving us another interesting variety of species and genera not known before. Like last year, I'll go down each of them (including phytosaurs) and give you some key notes. And since I've done my best to make individual posts for them I'll link those when available. I'll also try to give translations where possible, but do note that sometimes I might switch around a word due to it just sounding awkward otherwise.

Scolotosuchus

Starting us off is Scolotosuchus basileus ("royal scythian crocodile"), a basal, rauisuchian-like animal from the early stages of the Triassic. An animal roughly 3 meters long, it is primarily known from vertebrae and some other material, which however does have interesting implications. Based on the anatomy of the vertebrae, it has been speculated that Scolotosuchus performed a lot of rapid movement of the neck, presumably while hunting. Furthermore, it might be that Scolotosuchus lacked osteoderms, instead having developed a bracing system for its body much more like that of dinosaurs and mammals. Artwork by @knuppitalism-with-ue (he'll pop up quite a lot)

Colossosuchus

Fast forward to the Late Triassic, the hayday of early Pseudosuchians, and we find our first phytosaur of the list. Colossosuchus techniensis ("colossal crocodile of the Indian Institute of Technology") was an enormous animal from India's Tiki Formation. This one is known from undisputably better material, perhaps some of the best on this list as we have an entire bone bed of these guys, possibly representing a mass death site. Size estimates of the large specimens generally range from 6 to 9 meters in length, also making it the largest animal of this list, with the authors favoring an estimated 8 meters for the largest individual. Of course this is all subject to change, as we don't know the precise proportions (the downside of a bone bed is that all the bones are kinda jumbled together and god knows what belongs to what). Artwork by Joschua Knüppe again, a female being courted by an overconfident and confused Volcanosuchus (told you so)

Kryphioparma

Ok I won't bother you with this one too much. Kryphioparma caerula ("blue mysterious shield") is an aetosaur from the Late Triassic Chinle Formation of Arizona. Now aetosaurs are cool of course, but the thing is that Kryphioparma is known from exclusively osteoderms, their large armour plates. While thats valid, its also not really exciting (as you could have guessed from the absolute lack of artwork). Best I can say is that it coexisted with a bunch of other aetosaurs, which surely would have been a sight to see back in the day.

Venkatasuchus

Now Venkatasuchus armatum ("Venkata's armoured crocodile") is in a similar boat. This Indian aetosaur too is only known from osteoderms, tho at least a lot more of them that were found together, meaning we got a much better idea of its shape. There are some interesting implications it has on paleogeography and how different animal groups spread across Pangea, but that's probably beyond the scope of this post. There is at least some art of it tho, including one piece by Joschua featuring Jaklapallisaurus, an early sauropodomorph.

Mystriosuchus alleroq

Now we got our first new species of a preexisting genus. While I did my best to make posts on new genera, which typically went hand in hand with their respective wikipedia pages, species are a different matter since they'd require me to overhaul and research the whole genus. Which for Mystriosuchus would go all the way back to 1896.

Anyhow, Mystriosuchus alleroq ("jawbone spoon crocodile") is the newest in a long line of Mystriosuchus species and has been recovered from western Greenland of all places. Like Colossosuchus it is known from multiple individuals, at least four in fact, And like Venkatasuchus, it appears to have wideraning implications for the spread of archosaurs during the Triassic. Oh look its Josch's art again, neat.

Jupijkam

The final phytosaur and the final Triassic taxon of the year, Jupijkam paleofluvialis ("horned serpent of ancient rivers") was recovered from Nova Scotia Canada and represents one of the northernmost phytosaurs (alongside obviously our friend Mystriosuchus alleroq above). It is far less complete than the other phytosaurs I covered so far, but still nothing to scoff at. It's also one of the youngest known phytosaurs, possibly having lived during the last stage of the Triassic. There's no art but here's an image of its snout from the original paper.

Turnersuchus

And with this we have reached the Jurassic and somewhat of a double feature. Ordering these via chronology makes this almost like storytelling. Turnersuchus hingleyae ("Hingley's and Turner's crocodile") is the oldest and basalmost named thalattosuchian, a group of crocodylomorphs that took to the seas. As such it shows a mosaic of features, already having begun to reduce its limbs, having a moderately long snout and still bearing osteoderms, which some of its descendents would come to lose. Turnersuchus dates to the Pliensbachian, a stage of the early Jurassic, tho the paper mentions how its not likely to hold its title as oldest member of its group for long as even older material has been discovered and is awaiting publication. Artwork by Júlia d’Oliveira and Joschua Knüppe

Torvoneustes jurensis

While Turnersuchus gives us a glimpse at what the earliest thalattosuchians were like, Torvoneustes jurensis ("savage swimmer of the Jura Mountains") represents them at one of their most derived. At 4 meters long, it must have been an impressive creature, entirely smooth and lacking osteoderms, highly reduced arms and a tail fluke to boot. There are some interesting features, as unlike other species of Torvoneustes, this one does not appear to have been as durophagous, instead appearing to be more of a generalist. It's the last Jurassic croc of the year and practically lived at the opposite end of this time period relative to our previous thalattosuchian, during the Kimmeridgian. Artwork by Sophie De Sousa Oliveira, not to be confused with Jùlia who drew Turnersuchus.

Comahuesuchus bonapartei

From marine to terrestrial, Comahuesuchus bonapartei is a member of the Notosuchia, land-dwelling cousins to the Neosuchia. This new species is known from the Cretaceous of Argentina and was described on the basis of a lower jaw, which differs from the previously described species of Comahuesuchus by the fact that the teeth are situated in individual sockets. Its jaws were short and wide, being described as U-shaped, giving it a somewhat pug-nosed appearance. In case you're wondering why I don't have the translation of the name thats because I can't access Bonaparte's first paper, so all I can say is that the new species is named after famed Argentinian paleontologist Jóse Fernando Bonaparte. Artwork by I mean you probably guessed it, its Josch again.

Aphaurosuchus kaiju

I have some mixed feelings on Aphaurosuchus kaiju ("powerless kaiju crocodile"), not just because I have to rewrite its genus wikipedia page that I am no longer happy with. No, Aphaurosuchus is a great genus in my opinion, given the complete nature of the holotype. But I do think that the species name of this second form is a bit of an exaggeration, seeing as it is to my knowledge not that exceptionally big. So why name it kaiju other than to sound cool? I also think it just kinda becoms funny when you consider the meaning of the genus name. Anyhow, it does look pretty mean, but thats to be expected from a baurusuchid. It lived during the Late Cretaceous in Brazil and the phylogenetic analysis that accompanied its description had some interesting implications that I'm curious to see tackled in the future. Other than that it's just another baurusuchid from a place crawling with baurusuchids, which tbh is pretty cool itself but doesn't really help make it stand out. Arwork by Paula Zeinner

Dentaneosuchus

It is the middle Eocene. France is entirely occupied by mammals. Well, not entirely... One indomitable reptile still holds out against the invaders. Yes, I am of course talking about Dentaneosuchus ("frightfull crocodile"), the titan of the Eocene, the terror of the jungle. Easily among the most exciting finds, this animal was an enormous sebecid previously thought to be a member of the genus Iberosuchus, but recent research not only shows its distinct but enormous. With a lower jaw around 90 cm long, it rivals even the famed Barinasuchus of Miocene South America. The total body lenght is of course a matter of debate given how little we know about sebecid proportions, with the paper lowballing it at 3 to 4 meters and I personally recovering something more akin to 5 meters. Regardless of the specifics, this would make it easily one of the top predators of its time, tho sadly this was not meant to last. It was among the last non-mammalian apex predators of Europe, before climate change and competition from mammals eventually drove them to extinction. Arwork by Joschua Knüppe and @mariolanzas

Baru iylwenpeny

Our last three entries were all members of the Notosuchia, the terrestrial crocodiles that existed from the Jurassic to the Miocene, so lets jump to the other major group of the time, the Neosuchians, specifically their most recent branch, the Crocodilians. Yes finally we are getting to crocs in the stricter sense.

Baru iylwenpeny ("divine crocodile thats good at hunting") is an animal we also knew for a while under the informal name Alcoota Baru based on where it was found. This year I spent a lot of time writing in the Mekosuchinae, Australasian crocodiles of the Cenozoic and just when I had finished the page for Baru, this guy got published. It's the largest, most robust and most recent member of the genus. Good at hunting is a good choice for the species name, as this animal was over 4 meters long with a head commonly likened to a cleaver and a hunting style speculated to consist of inflicting a lot of trauma on its prey with its massive teeth. I could gush about Baru for ages, but thats the important parts. It lived in central Australia during the Miocene only 8 million years ago. Artwork by the incredible @manusuchus

Antecrocodylus

Now for the last crocodilian described this year and one I remised to make a dedicated post for due to time constraints (I had a busy few months). Antecrocodylus chiangmuanensis ("before Crocodylus from Chiang Muan") is a close relative of the modern dwarf and true crocodiles from the Miocene of Thailand. It is only known from the back of the skull and an associated lower jaw, but it serves to highlight how little we know about the crocodiless of eastern Asia during the Miocene, which is a shame given that this region is crucial to deciphering where true crocodiles originated.

Alligator munensis

And our final taxon is Alligator munensis ("Mun river alligator"), which, obviously, is a member of the modern genus Alligator and thus most closely related to the still extant Chinese and American Alligator. Likely having been split from its Chinese relatives when the Tibetan plateau was lifted up, this species lived during the middle Pleistocene in Thailand and may have survived until the Holocene. It's head was short and robust and its teeth globular, which could indicate that it fed on hard-shelled prey like clams and snails. It was also small, likely not much bigger than 1.5 meters. Artwork by Joschua Knüppe

And that should be all of them, all new species and genera of Pseudosuchians described this past year. It's once again been fun to look back and I hope that you find them just as interesting as I do. Lets hope that 2024 will bring equally fascinating discoveries.

[knuppitalism-with-ue]

Results from the #paleostream Cratochelone, Madygenerpeton, Igai and Torvoneustes.

(I hope you all realize what happens in the Igai piece)

[saritapaleo]

Archovember 2024 Day 14 - Cuspicephalus scarfi

Cuspicephalus scarfi was a wukongopterid pterosaur from Late Jurassic England. It’s name comes from the Latin cuspis for “point” and the Greek κεφαλή for “head”, and its species name is a reference to Gerald Scarfe who was known for caricatures with very pointy noses (including Margaret Thatcher as the “Torydactyl), and who was also the production designer for Disney’s Hercules. Cuspicephalus scarfi basically means “pointed head which could have been designed by Gerald Scarfe.” Looking at this animal you can probably see the resemblance! Cuspicephalus had a very long, angled skull, most of which was occupied by the air pockets in its fenestra. A low bony crest is present, which was likely the base of a much higher soft tissue crest. Like most other Jurassic pterosaurs, it had sharp interlocking teeth, and likely also had a long ornamented tail. Due to its small size and lightly built skull, it probably fed on small land animals like arthropods and worms.

Cuspicephalus scarfi was found in the Kimmeridge Clay Formation. This was a seaside environment and is known for its many fish, turtle, plesiosaur, and icthyosaur fossils. Other pterosaurs have been found here as well, but from later ages than Cuspicephalus. Other archosaurs would have included the stegosaur Dacentrurus, the iguanodontian Cumnoria, the megalosaurid Torvosaurus, and the thalattosuchians Bathysuchus, Cricosaurus, Dakosaurus, Metriorhynchus, Plesiosuchus, and Torvoneustes.

This art may be used for educational purposes, with credit, but please contact me first for permission before using my art. I would like to know where and how it is being used. If you don’t have something to add that was not already addressed in this caption, please do not repost this art. Thank you!

[greenfrog04]

Description and phylogenetic relationships of a new species of Torvoneustes (Crocodylomorpha, Thalattosuchia) from the Kimmeridgian of Switzerland

Published 19th July 2023

A new metriorhynchid from the Kimmeridgian of Porrentruyi Switzerland based on a relatively complete disarticulated skeleton, Torvoneustes jurensis.

Torvoneustes jurensis holotype

Artist illustration of jaw and mandible

Torvoneustes jurensis teeth

Artist reconstruction of Torvoneustes jurensis, by SDSO.

Source:

[arminreindl]

Torvoneustes jurensis

I did mention that new croc taxa were numerous this week. After covering both Triassic forms, here's the newest crocodyliform from the Jurassic. Torvoneustes jurensis, a large (4 meter) metriorhynchid.

Artwork by SDSO, figure from Girard et al. 2023

Now the genus Torvoneustes itself isn't a new one. The genus itself has been knocking around since 2010 whereas one species has been known since 1910. Fossils of this genus have previously been found in the UK, Czech Republic and even Mexico. This species tho is brand new tho, found in the Jura Mountains of Switzerland in 2008. The fossils date to the Kimmeridgian, the second to last stage of the Jurassic.

Like its relatives, Torvoneustes jurensis was an animal well adapted for life in the open ocean. The eyes faced sideways, the limbs were converted into flippers (with especially short arms), the tail had a fin more like that of a shark than the paddle of a crocodile. And it was smooth, lacking the osteoderm armor we so often associate with pseudosuchians. It reached a length of up to 4 meters, which puts it among the larger metriorhynchids alongside Suchodus (4.1), Dakosaurus andiniensis (4.3) and Torvoneustes carpenteri (4-4.7).

Artwork below by Dmitry Bogdanov

Being recovered as one of the most derived members of its genus, Torvoneustes jurensis is interesting as it allows to further observe the evolutionary trends undergone by this lineage. For example, the skull bones appear to have become increasingly smoother, possibly to be more hydrodynamic or because basking becomes less important. The oldest species also lacks the pseudoziphodont teeth seen in all others, but its possible that this was just lost in one form and retained by all others. There's also some straight up contradictions presented by T. jurensis relative to other species. For example, previously it was thought that species in the genus became increasingly durophagous, taking on harder shelled prey and thus developing less curved, more robust teeth. This does however not seem to be the case for this new species, which could have been more of a generalist. It also retains more teeth than other derived species of Torvoneustes, another trend seemingly debunked by this new find (tho toothcount was so far limited by available material, so this may change still if we find better fossils of the other species).

Overall its another really interesting find and while not a new genus, its still nice to see further exploration of the species diversity among crocodyliforms

[arminreindl]

Two more croc-line archosaurs to dig into with this one and both are super fascinating.

Obviously the star of this piece is our friend in the foreground, Plesiosuchus manselii, the largest of the fully marine metriorhynchids (the skull of which being the first one shown in the image to the right, taken from Young et al. 2012)

More broadly speaking, metriorhynchids are a fascinating group of early croc-relatives that stand out for having returned completely back into the water, developing a fluked tail, tiny little reduced forelimps, flipper like hindlimbs and smooth skin entirely lacking in the osteoderm armour we so strongly associate with pseudosuchians.

Plesiosuchus specifically is the largest of them. Close to 7 meters in length, it's basically in the same range as Liopleurodon (although smaller than several of the pliosaurs we know from the Kimmeridge Clay like that very decorative skeleton). Plesiosuchus actually wasn't the only metriorhynchid from the formation either. We also know of the small Cricosaurus, the name-giving Metriorhynchus and most interestingly the large-bodied Dakosaurus and Torvoneustes, which were likely to reach lengths of 4.5 to 4.7 meters respectively. At least with metriorhynchids this diversity can be explained in the different animals having very different preferences. Torvoneustes is interpreted as a durophage, feeding on hard-shelled prey. Dakosaurus is characterized by slicing dentition, potentially able to cut apart large prey with tooth wear possibly suggesting sharks or suction feeding habits. Plesiosaurus meanwhile would be able to take on large prey simply due to its great size and large gape but may have been limited by the size of its own head.

The other marine "croc" in the image is Bathysuchus, which may be described as a cousin to the metriorhynchids.

Remember Machimosaurus from the Guimarota locality that Josch drew a few weeks back? Yeah its related to that one. A teleosauroid to be precise, which are the sister group to metriorhynchoids and appear much more croc-like in their appearance despite still being a long way off from crocodiles in the strict sense. Teleosauroids may appear like what you'd think of as basal to metriorhynchoids, but they simply did their own thing after diverging, thus retaining this more ancestral bauplan with more developed limbs, more croc-like skulls and maintaining their armour plating (keep that in mind).

Bathysuchus is kind of a weird one tho. Why? Because from what we can tell Bathysuchus seems to have tried to become more like its metriorhynchoid cousins. It's known from deeper waters, its osteoderms were much more reduced and if the closely related Aelodon is anything to go from then its quite likely that this guy also started reducing the size of its forelimbs. In short, adaptations to a more pelagic lifestyle that moves away from the coastal habitat other teleosauroids seem to have preferred. Who knows, maybe its possible that in some other timeline these guys might have become something akin to metriorhynchoids like what happened with mosasaurs.

Unlike metriorhynchoids, teleosauroids were way less common in the Kimmeridge Clay, hell, to my knowledge Bathysuchus is the only one of them, a pretender among the other pelagic pseudosuchians.

Result from the Kimmeridge Clay #paleostream!

We were only able to scratch the surface, but I think you get the idea ;)