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Armin Reindl @arminreindl.bsky.social · 13h

Aetosaurs are an interesting group that I want to dig deeper into at some point (if I find the time), but rest assured the osteoderms are incredibly distinct in these guys
This does mean that frustratingly theres a bunch of species just named from a handful of armor plates tho

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Armin Reindl @arminreindl.bsky.social · 13h

It's shown quite nicely in this illustration of Gorgetosuchus by Matt Celeskey

An illustration of Gorgetosuchus by Matt Celeskey. The animal is shown in 3/4 view from behind. It is heavily armored with a triangular snout and a broadened nose tip. A close up shows the overall appearance of a ring of osteoderms, with notes describing its anatomical details.

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Armin Reindl @arminreindl.bsky.social · 13h

While the osteoderms are isolated, we can see the anterior bar in the bones of Rioarribasuchus, therefore we can tell whats the front and whats the back of each osteoderm and therefore see that the spikes curve forward

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Armin Reindl @arminreindl.bsky.social · 13h

Great question, the reason we know is due to how the armor of aetosaurs interlocks. Generally speaking, aetosaur osteoderms overlap the ones behind them, and the region that is overlapped is known as the anterior bar (its really obvious in some species).

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Armin Reindl @arminreindl.bsky.social · 14h

Really its an entire saga I do recommend reading up on, thankfully a lot of the procedure has been thoroughly documented by Mike Taylor and Darren Naish around the time of the events in 2007/2008

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Armin Reindl @arminreindl.bsky.social · 14h

Of course the case of Rioarribasuchus/Heliocanthus was not the only thing to cause Aetogate, another notable case is what was the New Mexico team seemingly plagiarizing or at least taking credit for the findings of Jeff Martz (illustrator of the first image) and other such cases

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Armin Reindl @arminreindl.bsky.social · 14h

changing their mind, publishing an incredibly brief (not even 2 full pages) report coining the name Rioarribasuchus before Parker was able to publish his own study, which would have named the animal Heliocanthus

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Armin Reindl @arminreindl.bsky.social · 14h

a sentiment that William G. Parker did not share, instead suggesting that the animal was its own distinct taxon that was yet to be given a name (something Parker was working on).
The New Mexico team continued to refer it to Desmatosuchus, that is until suddenly...

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Armin Reindl @arminreindl.bsky.social · 14h

So Aetogate is a controversy that took place in the late 2000s when several researchers of the New Mexico Museum of Natural History were accused of plagiarism. In the case of Rioarribasuchus for instance the animal was long considered a species of Desmatosuchus...

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Armin Reindl @arminreindl.bsky.social · 14h

Day 9 of #Croctober, featuring Rioarribasuchus
Outwardly a fascinating and imo quite underappreciated animal given the strange, forward-pointing spines on the tail scutes
But while it looks unique, Rioarribasuchus is better known for being central to the Aetogate controversy

An illustration of "Rioarribasuchus" by Jeff Martz. It is shown as a robust animal with extensive armor plating and a small triangular head. The front limbs are shorter than the hindlimbs and the tail features a ridge of forward pointing spines throughout most of of its length.

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Armin Reindl @arminreindl.bsky.social · 1d

But for a more thorough description go see doi.org/10.1080/0272...

Articulated skeletons of the aetosaur Typothorax coccinarum Cope (Archosauria: Stagonolepididae) from the Upper Triassic Bull Canyon Formation (Revueltian: early-mid Norian), eastern New Mexico, USA

We report two nearly complete, articulated skeletons of the crurotarsan archosaur Typothorax coccinarum from the Upper Triassic Bull Canyon Formation of east-central New Mexico. These are the mos...

doi.org

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Armin Reindl @arminreindl.bsky.social · 1d

Part of me thinks this might be the most well known thing I've covered so far, but at the same time I hardly know what people are actually aware of and how much is just nische knowledge
anyways the figure is from Lucas and Heckert 2011

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Armin Reindl @arminreindl.bsky.social · 1d

For day 8 of #Croctober I'm going way back.
This is Typothorax, an aetosaur from the Triassic of New Mexico best known for how well armored it was.
In fact it was so well armored even the cloaca is surrounded by an arrey of osteoderms

The skeleton of Typothorax in multiple views. The very top shows a fossil, flipped on its back and missing the head but nicely showing the osteoderms. Below that a lateral view of the skeletal reconstruction shows the animal had short frontlimbs and longer legs, a tiny head and a plump body covered in armor. The ventral view shows how even the cloaca was surrounded in bony scutes and a front view highlights not just how tiny the head is but also how square the body is proportioned.

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Armin Reindl @arminreindl.bsky.social · 2d

Boverisuchus meanwhile is a planocraniid, a family of Eusuchia (or maybe even Crocodilia) that ranged across essentially all of former Laurasia, with members having been found in the USA, Europe and China.
If you're unfamiliar with the name, its basically Pristichampsus

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Armin Reindl @arminreindl.bsky.social · 2d

Artwork by Scott Reid and Corbin Rainbolt
Despite shared terrestrial habits, the two are not related, with Bergisuchus being a member of the clade Notosuchia that managed to persist into the Cenozoic, tho the origins of European members remains somewhat nebulous

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Armin Reindl @arminreindl.bsky.social · 2d

Day 7 of #Croctober
The Messel Pit in Germany is well known for its fossil crocs, which includes not one but two distinct lineages of terrestrial forms.
On the one hand the sebecoid Bergisuchus dietrichbergi, on the other the eusuchian Boverisuchus magnifrons

A digitall painting of Boverisuchus by Corbin Rainbolt. The animal is shown barreling through the underbrush of an ancient rainforest, chasing down a tiny early horse. Compared to Bergisuchus the head is a lot more similar to modern crocs, although boxier and not as flattened.

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Armin Reindl @arminreindl.bsky.social · 2d

Thank you so much. I just enjoy sharing my passion in crocs where possible

Armin Reindl @arminreindl.bsky.social · 2d

I hate to say it but the pun did cross my mind at one point lmao

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Armin Reindl @arminreindl.bsky.social · 3d

Also big shout out to Adam Yates not just for his tireless croc research but also for thinking my recons were good enough to be included in that graphical explanation you see in the first post

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Armin Reindl @arminreindl.bsky.social · 3d

When you actually look at the material it's almost a no-brainer that they are from a single individual, but stuff like this is what makes the research history fun.
doi.org/10.26879/1355

Ultrastenos revised

A reinterpretation and taxonomic revision of Ultrastenos willisi Stein, Hand and Archer, 2016, a short-snouted mekosuchine crocodylian from the Oligocene of nor

doi.org

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Armin Reindl @arminreindl.bsky.social · 3d

Due to priority rules the animal got to keep the genus name Ultrastenos, but the species name was switched to the older "huberi" rather than willisi.
As a consequence the name aged horribly, as Ultrastenos was named under the assumption that it had long and narrow jaws

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Armin Reindl @arminreindl.bsky.social · 3d

#Croctober Day 6
Heres a fun one from a research history POV.
In 1997 researchers described a snout tip under the name Baru huberi and in 2016 skull elements were given the name Ultrastenos willisi
Only last year did we recognize that both fossils belonged to a single individual

An image created by Adam Yates comparing a photo of the "complete" cranial material of Ultrastenos huberi with prior interpretations of the material. At the bottom left sits a reconstruction of Ultrastenos willisi based on the 2016 interpretation of it as a narrow-snouted animal with a circle around the skull table and an arrow pointing to the skull table of the "completed" Ultrastenos skull in the middle. The top right corner shows a reconstruction of "Baru" huberi based on pre-2024 ideas of the animal. The snout tip is encircled and an arrow points towars the snout elements of the Ultrastenos huberi fossil. This shows how both individual fossils were once interpreted vs how it actually looked like put together. The finished fossil suggests a small animal with a fairly traditional looking crocodilian snout.

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Armin Reindl @arminreindl.bsky.social · 4d

doi.org/10.1080/0272...

A new freshwater teleosaurid from the Jurassic of northeastern Thailand

The core of the fossil record of Teleosauridae, a family of thalattosuchian crocodylomorphs, is well known from western Tethyan marine deposits of the Jurassic. Outside this province, their fossil ...

doi.org

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Armin Reindl @arminreindl.bsky.social · 4d

As depicted in the artwork above by Joschua Knüppe, we know of a mass death site that preserves a collection of multiple individuals (10 of varying ages in total). This may have been the result of the animals becoming trapped in a shrinking body of water during a drought.

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Armin Reindl @arminreindl.bsky.social · 4d

Give it up for #Croctober Day 5
While most frequently associated with coastal marine waters, teleosauroids thalattosuchians are also known to have lived in freshwater habitats.
A good example is Indosinosuchus from the Late Jurassic Phu Kradung Formation of Thailand

A group of three Indosinosuchus, appearing similar to modern gharials with typically "crocodilian" bodies and elongated snouts, huddled together in what used to be a body of water, now merely cracked mud. Over the horizon dry, orange vegetation is visible and a lone sauropod traverses the former wetlands

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