#pattisaura

Well, well well, look who comes crawling out of the woodwork again after having failed to live up to any promise I made earlier last year.

In my defense, tho my love for crocs continue, I suffered several hits to my motivation not to mention plenty of work both at my job and private life including a complete revision of the clade Itasuchidae on Wikipedia (currently 8 out of 13 pages in).

But I'm taking a brief moment to try and bring back at least a summary of all the new taxa we got last year.

Taihangosuchus Our chronologically oldest animal on this little list is Taihangosuchus from the Anisian (Middle Triassic ) Ermaying Formation. Fittingly this little is also part of one of the most ancient pseudosuchian linages, the gracilisuchids, small, erect-limbed quadrupeds, which it feels have been getting a lot more attention as of late. Two specimens are known, one smaller preserving the head and neck, one larger that exclusively preserves postcrania. The larger furthermore shows at least parts of the animals last meal in the form of several osteoderms in the gut, indicating that this animal was not just predatory but seemingly fed on other archosaurs. Which one is unclear. Shansisuchus had no osteoderms, Halazhaisuchus is from the lower parts of the formation, Fenhosuchus is a candidate, as most osteoderms from Ermaying have historically been referred to it but its just as possible that the victim was a smaller individual of Taihangosuchus.

Tainrakuasuchus Poposauroids keep on winning as of late, at least as far as basal forms are concerned. Tainrakuasuchus bellator (roughly meaning "pointed tooth warrior crocodile") may be one of the most basal poposauroids, having been recovered as a close relative of Mandasuchus and more derived than either Benggwigwishingasuchus or Mambawakale. At a size of roughly 2.4 meters (give or take) and specimens estimated at 3 meters it would have been a sizable predator of the Dinodontosaurus AZ, which is well known for an already diverse croc fauna. Size alone demands it to fill a different nische from behemoths like Prestosuchus, but also as a poposauroid the neck vertebrae weren't built to deal with the same immense stresses anyways, so one way or another different prey was required.

Telkaralura From a poposauroid back to another gracilisuchid, this time from the Carnian of South America. Telkaralura is one of those taxa that have a surprisingly long history for something only really described recently. It was first discovered by famed paleontologist José F. Bonaparte in 1980 in the same rock layers as Gracilisuchus and both were for a time regarded to be early dinosaurs. It was briefly regarded as a juvenile Luperosuchus in 2009, split off in 2017 and finally given a name in 2025.

Telkaralura is notable for being the largest gracilisuchid known today, some 20 to 25% larger than the next largest members of the group including the recently named Parvosuchus, twice the size of Gracilisuchus and five times the size of Maehary (previously thought to be basal to pterosaurs, fun fact). But even that wasn't enough to make it top predator, which is an honor that goes to the proterochampsid Gualosuchus.

Olkasuchus AN AETOSAUR KNOWN FROM MORE THAN JUST A HANDFULL OF ISOLATED OSTEODERMS?! Yes, Olkasuchus was a pleasent surprise, which makes me all the more disappointed in myself that I have yet to find the time to write about it on wikipedia. So this will need to suffice for the time being (I mean sooner or later I gotta give that whole clade an overhaul anyways, no?) Olkasuchus is known from the Late Triassic (Norian) Los Colorados Formation, famous for its enormous "prosauropods" and titanic rauisuchian Fasolasuchus. This basal desmatosuchine is however not nearly as big, for reference the scalebar in the image below is 20 centimeters.

Pattisaura Early pseudosuchians sure loved the small and gracile morphotype, but we're not dealing with a gracilisuchid this time. Pattisaura is an early crocodylomorph, part of the grade frequently referred to as "sphenosuchians".

As an inhabitant of the Cooper Canyon Formation Pattisaura lived around many other famous stem-crocs including Postosuchus, Shuvosaurus and Desmatosuchus. And with a fauna like that you can nicely see just how diverse early pseudosuchians were, covering large predators, gracile bipeds, armored quadrupeds and of course smaller, almost dog-like forms like Pattisaura.

Kuttysuchus Now that's more like what I'm used to with aetosaurs: OSTEODERMS AND NOTHING ELSE. Perhaps the most shocking developement of having had to deal with these over the past few years is that I'm getting scarily comfortable with how these isolated bony plates are described, but I won't make you suffer through that.

So I'll keep this one at the key points. Kuttysuchus is a new typothoracine from the Norian to Rhaetian of India. It coexisted with mystriosuchine phytosaurs, early sauropodomorphs and two other aetosaurs, an as of yet unnamed desmatosuchine and Venkatasuchus, which you might remember (or not, I won't blame you). Excuse me for being a little glib, but with so many crocs its hard to really sell something thats known from a handfull of bony plates without giving info thats super generalized to the group as a whole.

And with that we finish the Triassic and actually jump straight to the Cretaceous. Yup, no Jurassic taxa for you.

Paarthurnax Yes, like the dragon from Skyrim. While this 4 meter animal from the middle Cretaceous appears similar to modern crocodiles, its actually part of the older family Goniopholididae, and one that actually proves to be quite informative at that.

The thing with Goniopholidids is that they were most successfull during the Late Jurassic and Early Cretaceous, filling the crocodilian nische throughout North America, Europe and Asia prior to Eusuchians making it big. But we knew even before 2025 that goniopholidids didn't go out without a fight and in fact made it until the Maastrichtian in the form of Denazinosuchus. This of course left a massive gap in time we didn't quite know how to fill. But the discovery of Paarthurnax allowed Platt and co to create a neat line from early Cretaceous European goniopholidids like Anteophthalmosuchus all the way to Denazinosuchus in America, briding the gap with Paarthurnax, Paluxysuchus and Deltasuchus. Will this hypothesis hold? Only time will tell.

Sissokosuchus Remember me mentioning itasuchids at the beginning? Well in 2025 we got two of those. The first I want to talk about is the one that I am still relatively satisfied with as far as the Wikipedia page goes.

Sissokosuchus maliensis (Famory Sissoko's crocodile from Mali) is known from multiple specimens, none of which especially complete sadly, found within the poorly defined Continental intercalaire of Mali, which date to the Aptian and Albian. At that point in time Mali cotained part of what was once an enormous ancient river system, the  Paleo-Tegama, perfect for anything that loved freshwater.

This included Sissokosuchus, which, despite looking suspiciously like a normal crocodile, was actually part of an off-shoot of the otherwise famously terrestrial notosuchians. Itasuchids in general are quite a fascinating group in that regard, ranging from more robust types like Barreirosuchus to slender-snouted animals such as Stolokrosuchus. But more on that some other time.

Thikarisuchus Now for something entirely different, Thikarisuchus xenodens (strange-toothed sheath crocodile). Small, terrestrial, long and slender limbs and actually closer to modern crocodiles than either of our previous two newcommers.

This adorable little guy from the Cenomanian Blackleaf Formation is a wannchampsid, close kin to the similarily gracile and terrestrial atoposaurids. What makes Thikarisuchus interesting is the fact that it had three different tooth types (hence the name), ranging from pointed and conical to mediolaterally flat and very low-crowned. This likely reflects a broad diet that could have included insects, small animals and even plants. The front teeth would be used to grab food items, the cheek teeth served to slice.

Thilastikosuchus Staying with the nimble, terrestrial genre of crocodylomorphs for a bit takes us across the sea into South America to meet Thilastikosuchus scutorectangularis (Mammal crocodile with rectangular osteoderms), a notosuchian of the family Candidodontidae.

Candidodontids are perhaps the most obscure family of notosuchian to an outsider, perhaps even more obscure than itasuchids, and similarily its partially because we're still only just beginning to understand them (fun fact, Malawisuchus, another candidodontid, was actually among the first two taxa assigned to Itasuchidae alongside Itasuchus itself, tho the family has changed drastically since then).

Like Thikarisuchus, Thilastikosuchus is noted for its teeth. Two types of teeth are known from this animal, subconical incisors in the front of the jaw and molariform teeth in the back, but no canines, despite the fact that they are present in other notosuchians incleading some fellow candidodontids. But while the posterior teeth of Thikarisuchus are also different, Thilastikosuchus goes a step beyond, its teeth being and well mammal-like.

Ibirasuchus Oh boy....well, this is our second itasuchid of 2025 and its beyond the shadow of a doubt worse than Sissokosuchus. I'll be honest I'm not gonna spend a lot of time on it. It was named in a broader paper describing various fossils and the only things known of Ibirasuchus are admittedly most of a parietal and supraoccipital and a tiny corner of a squamosal... yeah its not even half a skull table. The paper does propose a possible length of four meters, but problematically itasuchid postcrania are barely described and my current plans are to start reconstructing them once I've got the writing down. Will this animals Wikipedia page get another overhaul beyond my initial script, yes, will it be significantly better, well, theres only so much I can work with.

Wadisuchus Moving on to something a lot more pleasent, we have Wadisuchus kassabi (Kassab's Valley Crocodile), known from two fairly complete skulls that were found in the sediments of the Campanian Quseir Formation.

The animal, which may have grown as long as 4 meters, is among the oldest known dyrosaurids, a group closely related to pholidosaurids like Sarcosuchus and that held out until the Eocene. Given its basal position its unsurprising that Wadisuchus displays a mix of derived dyrosaurid and more basal pholidosaurid features. For example pholidosaurids have a famously hooked snout tip, which is absent in dyrosaurids. Well in Wadisuchus we see a mix, with the first teeth strongly downturned and the rest positioned normally, which may be related to the way the lower jaw grew longer throughout this groups evolutionary history.

Kostensuchus A Kostensuchus, how excited I was when you dropped. And rightfully so, its not every day you get a 3 meter terrestrial behemoth of a notosuchian known from a complete skull and almost the entire vertebral collumn up to the hip. What makes this animal even more fascinating is the fact that tho superficially similar to baurusuchids, its actually a peirosaur.

The fact that there is a whole distinct clade of robust peirosaurids actually lead to an interesting hypothesis. Novas and colleagues speculate that South America may have been split into two distinct predator faunal zones. In the northern parts, i.e. Brazil's Bauru Group, the top predators were abelisaurs and baurusuchids, while the south their rolle may have been filled by megaraptorans and peirosaurids. Here's hoping we find more to support this idea because I for one love it.

Animation by PALEOGDY

Tewkensuchus Tewkensuchus in some aspects is not all that different from Kostensuchus. The "forehead crocodile", tho known from rather limited material, was likely a robust, terrestrial animal that stalked what is now Argentina during the earliest days of the Paleogene.

And that's where things get interesting. With an estimated weight of 300 kg this sebecoid is exceptionally large for its time, which has prompted researchers to question how that came to be. The two main explanations are as follows. 1. Sebecoids have been as large as this since before the meteor whiped out the dinosaurs and underwent a brief aquatic phase that allowed them to stay in this range without being annihilated as the purely terrestrial fauna was (a method employed by the ancestors of our modern crocs) 2. These guys were small prior to the impact and, somehow, got absolutely fucking jacked the second theropods were out of the picture.

A final note, despite being from almost southernmost South America, Tewkensuchus appears to have actually been more closely related to Eocene European sebecoids like Bergisuchus and Dentaneosuchus rather than the geographically closer proper sebecids. This whole paleogeography continues to be a headache let me tell you that.

Paleoart by Michael Tripoli

Pseudogavialis Pseudogavialis is a classic case of authors trying to make sense of something thats been an issue we've had for hundreds of years. In this case the fact that Oligocene to Miocene Pakistani gavialoids are a mess. Several species were coined in the 1800s and have repeatedly been lumped, split, lumped again. Courville and colleagues published an extensive paper on some of them, including "Gavialis" curvirostris. Their conclusion: the animal is clearly distinct and it was given the new name Pseudogavialis. It was probably close to todays Indian gharial, may have featured a similar soft tissue bulb on its snout and grew to a length of 6 to 7 meters.

Rhamphosuchus brevirostris Ok one could argue this ones a bit of a cheat because obviously Rhamphosuchus has been well established for over a hundred years and the species is similarily old. However, given that we weren't even sure brevirostris was legit and its now been redescribed and pretty firmly placed in the genus Rhamphosuchus I'll include it here.

The same paper I just mentioned in regards to Pseudogavialis also touched on "Gavialis" pachyrhynchus. Unlike Pseudogavialis it was not separated on a genus level, but instead sunk into Rhamphosuchus as you already know.

Now Rhamphosuchus pachyrhynchus is notably more robust than Pseudogavialis, but not quite as much as the still poorly known Rhamphosuchus crassidens. It had more of an overbite rather than the interlocking teeth seen in modern gharials and crocs, may have grown to 8 meters in length and we still don't really know how these guys related to other gavialoids really.

This whole paper did inspire me to give the Wikipedia page for Rhamphosuchus a complete overhaul tho and despite the scarcity of proper descriptions I'm actually still quite happy with it.

Piscogavialis laberintoensis Our third and final gavialoid for 2025 is yet another species of an established genus, this time all the way over in Peru. Piscogavialis laberintoensis is known from the Miocene Laberinto area of the Pisco Formation (keep an eye open for the upcoming formation piece by Joschua Knüppe). As in the type species, the snout of Piscogavialis laberintoensis is very long and narrow, but the transition between the snout and orbital region is a lot more abrupt and not as fluid. And of course as its relative, this species was a marine animal. Body length has been estimated to range from 5.4 to 6.2 meters.

Crocodylus sudani The geologically youngest new fossil crocodile of last year takes us to Sudan, hence its name, specifically to the 60.000 year old rocks found near the Atbara River, one of the tributaries of the Nile. Theres several fascinating things to mention for this species. Morphologically for example it combines both the presence of a pronounced boss before the eyes with upturned squamosal horns. Evolutionarily, despite being as young as it is, Crocodylus sudani is not closely related to todays Nile or Sacred crocodiles but may actually be part of the Paleoafrican Crocodylus species, which includes the enormous Crocodylus thorbjarnarsoni. Perhaps one of the more out there claims by the authors is the idea that maybe, just maybe, this species is still out there.... Now granted, modern crocs are more diverse than we give them credit for and many a crypic species is still likely hidden out there, only distinguished by subtle features, differences in the genome and hidden by harsh and inaccessible environments. However as Salih and co. themselves admitt, its gonna require some substantial research into modern Sudanese crocodile populations to proof that this is more than just wishfull thinking.

Artwork again by Michael Tripoli

January passed so fast probably cause its the shortest month but we still got a handfull of papers out of it. So lets get right into it.

The function of the armor of Stagonolepis

Getting us started in the Triassic is a paper on the osteoderms of the aetosaur Stagonolepis: "The histology and function of the dermal armour of the aetosaur Stagonolepis olenkae Sulej, 2010 (Archosauria, Pseudosuchia) from Krasiejów (SW Poland)". Now as you probably figured from the handfull of times I've talked about aetosaurs on here, their osteoderm armor is very characteristic, very important in telling them apart and VERY extensive.

The results of this study are interesting. For starters, although osteoderms frequently serve a function in thermoregulation in modern crocs and even temnospondyls, this does not appear to have been the case for Stagonolepis. Now superficially, aetosaur osteoderms do show the same pitted surface as modern croc armor, which is caused by the elements absorbing bone and depositing it elsewhere throughout growth, something that reduces mass while maintaining stability and also increases surface area. However, Stagonolepis osteoderms are not vascularized like those of modern crocs, lacking the densely packed blood vessels that help absorb heat. The external surface of the osteoderms also doesn't show signs of thick sharpeys fibres, which are generally used to anchor the osteoderm in the soft tissue. What this means is that the osteoderms were not deeply embedded in skin (as has been suggested for some notosuchians) but rather were covered in keratin like those of modern crocs. But if not for thermoregulation, then what are the osteoderms for. Well on the one hand, obviously they work as armor. Their structure makes them robust yet leight weight and they are firmly embedded through sharpeys fibres present on the lower cortex of the osteoderms (tho its highlighted that they aren't as densely packed as in ankylosaurs). The keels that mark the osteoderms further prove to be quite usefull when it comes to reducing stress from a vertical attack. If you really want an additional reason for the armor, the authors offer the suggestion of being an adaptation to prevent water loss. Finally, histology shows that the osteoderms do not feature lines of arrested growth (basically signs for poor growth throughout the animals life), which suggests that the environment inhabited by Stagonolepis was quite moderate and did not have strong seasons that might influence the animals growth throughout its life.

Bottom: A diagram of Stagonolepis is sideview, showing the various types of osteoderms covering its body. Reconstruction by S. Górnicki

Growth strategy in Trialestes and its implications

Up next something not too different from a study we had in January. Last time we had a study on the growth of a peirosaurid notosuchian, this time "A fast start: Evidence of rapid growth in Trialestes romeri, an early Crocodylomorpha from the Upper Triassic continental beds of Argentina based on osteohistological analyses" brings us something similar except for the "sphenosuchian" Trialestes (more on that group later).

So what did we learn? Well for starters, neither of the examined specimens (which included the holotype) were mature, both in terms of sexual maturity and skeletal growth. What is weird is that morphology (specifically bone fusion in the vertebra) indicates the opposite to what has been concluded based on bone microstructure, which may suggest that in Trialestes either reached sexual maturity at a delayed rate of that histology and sexual maturity do not correlate all that much. Anyhow, based on crosssections of the bones, they are estimated at a minimum of two years and one year of age at the time of their deaths. Histology also shows that Trialestes appears to have grown quite rapidly. Curiously a previous study estimated a third specimen to have been one year old, eventhough this new study recovered the same age for a specimen only half that size. This seems to suggest that age and growth do not really correlate for some unknown reason, with possible explanations including differences between sexes or simply differing environmental conditions. Looking at the results at a grander scale, similar growth rates have previously been calculated for other nimble crocodylomorphs such as Terrestrisuchus and Saltoposchus, with the latter growing even faster than Trialestes. Of course when you get into more derived members of Crocodylomorpha strategies start to change, for example the slightly more derived Hesperosuchus was growing at a slower speed than Trialestes and if you recall January we know that Notosuchians can differ even within a genus (see Araripesuchus). Modern crocs appear to generally grow slower overall in their ontogeny, tho in some like the broad-snouted caiman environmental conditions seem to play quite the rolle. Nevertheless, the paper concludes that faster growth rates appear to be more widespread in early crocodylomorphs and may have been the ancestral condition.

Below: Reconstruction of the head of Trialestes by Joschua Knüppe (there is really not much art of this guy out there)

Now for two papers that are very relevant to my efforts on Wikipedia, namely two studies on the European alligatoroid Diplocynodon.

Growth strategy of Diplocynodon hantoniensis

First of all, sorta the same thing we just had for Trialestes but applied to Diplocynodon hantoniensis, a species from the Eocene of southern Britain (and actually one of the first Diplocynodon species discovered). The greater goal of "Evolution of growth strategy in alligators and caimans informed by osteohistology of the late Eocene early-diverging alligatoroid crocodylian Diplocynodon hantoniensis", as you might guess from the title, is actually to use Diplocynodon in order to figure out how growth strategies evolved in the two modern groups of alligatoroids, gators and caimans, who share similar strategies despite having been separated from another since before the extinction of the dinosaurs.

With 9 studied upper leg bones, the sample used in the study ranged from immature specimens to adults, which in the case of D. hantoniensis might reach lenghts of 1.2–3.4 meters. The growth strategy of Diplocynodon is recovered as both being determinate (meaning that they stop growing at a certain point) and seasonally controlled (which feels self-explanatory), both also seen in modern alligatoroids. Now assuming that the growth marks accurately reflect yearly intervals (which may not necessarily be the case), then the studied individuals ranged between 5 and 26 years old at the least. Skeletal maturity seems to have been reached in a similar range as modern alligatoroids (gators reaching maximum size between 30 and 40 and caimans between 12 and 18). As with Trialestes earlier, there are some individuals that show signs of being fully grown, yet are less than half the size of other individuals, possibly indicating sexual dimorphism (female gators stop growing earlier and at a lower size than males) or environmental conditions that affected growth (though there is doubt cast over this latter interpretation). The study concludes that, based on Diplocynodon hantoniensis, alligatoroids are simply relatively conservative in their growth strategy and what we see in gators and caimans is likely their ancestral strategy, rather than having been developed independently.

Below: A photo of the skull of Diplocynodon hantoniensis (taken by John Cummings), not actually relevant to the study but I mean it shows what this thing looked like.

The sense of smell and EQ of Diplocynodon tormis

Moving away from the Eocene of the UK and to the Eocene of Spain, we got a different species of Diplocynodon as the main subject of "New data on the inner skull cavities of  Diplocynodon tormis  (Crocodylia, Diplocynodontinae) from the Duero Basin (Iberian Peninsula, Spain)". Specifically, the study deals with the description of and what we can learn from a CT-scan that gives us insights into the forebrain, olfactory bulbs, nasal cavity, air sinuses, etc..

Overall the shape of the brain matches the idea that Diplocynodon is an early alligatoroid, including some distinctive features of this clade and some traits that are basal to crocodilians. Like modern alligators, Diplocynodon tormis seems to have had a good sense of smell, though not as keen as that of crocodyloids. The holotype specimen falls within the upper values in terms of olfactory acuity among alligatoroids, but still clearly outside of the range exhibited by crocodyloids, while another studied specimen performed a lot poorer (though its also not as well preserved). As for cognitive abilities, the study also calcuated the Reptilian EQ of D. tormis. The authors note that the EQ of Diplocynodon tormis appears below the average of other medium-sized crocodilians and instead comes closer to the EQ of large forms. Tho it is also noted that damage to the specimen might have affected the results.

Left: A 3D model of the holotype skull of Diplocynodon tormis Right: A 3D model of that same skull but highlighting the various internal structures such as the brain, nasal cavity, nerves, etc..

A history, redescription and the biology of the teleosaur Macrospondylus

Ah Macrospondylus bollensis, once known under the name Steneosaurus (like every other teleosauroid lets be honest), perhaps one of the most well known members of this group given its extensive fossil record from the Posidonia Shale in Germany. Despite this, and also like many other teleosauroids, its history is confusing, long and just a whole can of worms. One dealt with in "A re-description of the teleosauroid Macrospondylus bollensis (Jaeger, 1828) from the Posidonienschiefer Formation of Germany".

To give you the abridged version, the holotype of Macrospondylus bollensis was found all the way back in 1755 (meaning it was discovered so long ago even Napoleon wasn't born yet) and quickly recognized as some sort of crocodile relative. It was named Crocodilus Bollensis in 1828, described in the 1830s and given the genus name Macrospondylus in 1831 (and then again by a different author in 1837, seemingly independent of the previous study).

Being this old, of course the fate of Macrospondylus would be shaped by historical events, specifically the German revolutions of 1848–1849, when a fire set by revolutionaries in Dresden grew out of control and spread to the collection, damaging but thankfully not destroying the fossil. Chaos ensued unrelated to that as various researchers proceeded to lump Macrospondylus into either Teleosaurus, Mystriosaurus or even Geosaurus before circling back to Crocodilus, eventually settling on Steneosaurus in the 1960s. Scientists did eventually grow wise to Steneosaurus being an overlumped wastebasket of a taxon, but this was not fixed until 2020 when this gordian knot was hacked to pieces once more, resulting in the revival of Macrospondylus.

Keeping all this confusion in mind, recent work including this paper still finds that Macrospondylus is actually the most abundant Toarcian teleosaur and especially common in Germany (no doubt thanks to the Posidonia Shale, this doesn't necessarily reflect how things were at the time). In terms of ecology, Macrospondylus may have been a long-snouted generalist, being able to consume a much wider selection of and overall bigger prey than some of its rarer relatives. Size might also have been a factor, since large Macrospondylus reach up to 5 meters in length and would therefore have access to more robust and larger prey. Its wide distribution might also suggest that it was less picky than other teleosauroids about where it lived and though previously suggested to have been more marine, this new study seems to favor the idea that it was still fairly amphibious throughout its life. This is interesting given that the Posidonia Shale, where so many specimen are known from, is a pelagic off-shore open ocean environment, with the potentially more terrestrial Platysuchus and the shallow water Plagiophthalmosuchus being much rarer. Of course, there is always the possibility that this idea of Macrospondylus being super common is skewed simply by the preservation and the excavation at Holzmaden, which as said before might not reflect the state of the entire species population.

Left: A fossil of Macrospondylus next to Dr. Michela Johnson, photo by Meike Rech Right: Thalattosuchians from Tübingen by Pascal Abel, the two skeletons on the left wall and the bottom slab on the right all represent Macrospondylus Bottom: Macrospondylus photographed by Sven Sachs

The metabolism of Notosuchians

Back to something less constrained to any specific taxon, we got "Revisiting the aerobic capacity of Notosuchia (Crocodyliformes, Mesoeucrocodylia)",a paper on notosuchian metabolism, which is one of those things that might surprise people unfamiliar with them.

Of course Notosuchia is the great post-Triassic terrestrial radiation of the crocodile-lineage, bringing forth a great diversity of land-dwelling froms from small omniv, ores, bulky herbivores and even lanky carnivores. Despite this, it might come as a surprise that they were in fact not "warm blooded". This is again reinforced by this months paper by Sena and colleagues, who recover that their mass-independent maximal metabolic rates lie somewhere between modern crocs and monitor lizards (which again fits with previous studies on the matter). This means that fitting with their anatomy and lifestyle, they were more active than modern crocs and able to sustain more vigorous activity. Being ecto-thermic, they were still dependent on outside temperatures to heat them up before they were able to really take things to their fullest. Consequently it has also been hypothesized quite a bit that to cool down, they might have entered burrows later in the day.

Left: Two Baurusuchus are shown hunting a small Caipirasuchus, with all individuals shown as being fast, agile and terrestrial. Artwork by Deverson da Silva Right: Armadillosuchus emerging from its burrow under a tree stump with a herd of sauropods in the back. Artwork by Julia d'Oliviera

Now, for what I'm guessing all five of you that made it this far have been waiting for. The newly named crocs....which I didn't have time to make dedicated posts for. Look shit sucks alright, weekends have been really brief this month and I feel very tired.

Pattisaura: A new sphenosuchian from Texas

Getting us started on Pattisaura, a new genus of "sphenosuchian" (I told you I'd come back to them) from the Late Triassic Cooper Canyon Formation of Texas. Described in "A new crocodylomorph (Pseudosuchia, Crocodylomorpha) from the Upper Triassic of Texas and its phylogenetic relationships", this little guy generally represents what one might see as a quintessential sphenosuchian. A somewhat body pointed skull with large eyes, terrestrial habits, long and slender legs, a far cry from what we tend to associate with crocodylomorpha today.

The name Pattisaura was coined in honor of Mrs. Patricia Kirkpatrick, who's family has let paleontologist look for fossils on their farm (gee I wonder why that name sounds familiar) and the species name gracilis derives from....I mean do I even need to say it?

Unsurprisingly, the phylogenetic analysis of this study shows that Sphenosuchia is paraphyletic and doesn't actually form a single clade, instead simply representing a series of consecutively branching early crocodylomorphs. What can be said is that Pattisaura seems to clade with Redondavenator.

While perhaps unassuming in size or ferocity, little Pattisaura is nonetheless an interesting addition to the pseudosuchian fauna of the Cooper Canyon Formation, which has previously yielded the remains of the phytosaur Machaeroprosopus, various aetosaurs including Desmatosuchus, Aetosaurus, Typothorax and Paratypothorax, poposauroids like Shuvosaurus and the iconic Postosuchus alongside many other Triassic classics such as drepanosaurs, silesaurids, lagerpetids, coelophysoids and more.

Left: The skull of Pattisaura photographed by Aaron dp Right: The skull in top, bottom and sideview, reconstructed to account for taphonomic distortion and damage to the material

Thilastikosuchus: Brazil's oldest notosuchian

And the final one for this month is Thilastikosuchus scutorectangularis (mammal crocodile with rectangular scutes) described in "Anatomical description and systematics of a new notosuchian (Mesoeucrocodylia; Crocodyliformes) from the Quiricó Formation, Lower Cretaceous, Sanfranciscana Basin, Brazil". This little guy, and I mean little as it is based on a juvenile specimen, was recovered from the Early Cretaceous Quiricó Formation of Brazil and represents a new member of the obscure family Candidodontidae.

To give a brief description, Thilastikosuchus was a small, slender-limbed animal, although admittedly we only have a juvenile to go off from. Its teeth are prominently heterodont, meaning that rather than having jaws filled with relatively similar conical teeth its dentition was a lot more diverse, specifically consisting of subconical incisiforms and molariforms with multiple cusps. The armor of the body, as the name suggests, is rectangular with a smooth outer and back edge, eventually transitioning into the square osteoderms of the tail that possess a prominent keel down their middle. As with most notosuchians, there were only two rows that run down along the spine, rather than the more complex armor seen in modern crocodiles.

Perhaps most interesting are the phylogenetic and evolutionary implications of this animal. Thilastikosuchus is the oldest known notosuchian from Brazil and perhaps even the oldest notosuchian of all of South America, which might have big implications for the groups evolution. It is placed as a member of the Candidodontidae, a family coined to include Candidodon and Malawisuchus but not always regarded as a distinct group throughout publications. This new paper specifically places them at the very base of Notosuchia, branching off even before Uruguaysuchidae and Peirosauria. Given the very mammal-like teeth of candidodontids, this raises the question whether or not such dentition was simply convergently evolved by them and sphagesaurids (assuming their position amongst notosuchians holds true) or if its the ancestral condition that was later lost by groups such as uruguaysuchids and baurusuchids. It also adds an interesting aspect to the diversification of the group. As things stand, the oldest known notosuchian is Razanandrongobe from the Jurassic of Madagascar, but this taxon and its significance are poorly understood. With this new paper, we definitely see a clear diversification of notosuchians in the earliest Cretaceous through candidodontids, another radiation later in the Albian with uruguaysuchids and peirosaurs and a final burst in diversity towards the end of the Cretaceous with the numerous forms known from the Bauru group.

Left: Skeletal reconstruction of Thilastikosuchus with special focus on the osteoderms by Felipe Alves Elias Right: Live reconstruction by the same artist with an adult individual looming in the background