pseudosuchian

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Two artists’ renderings of “Proavis”, a hypothetical bird ancestor. The lizard-limbed would-be creature is certainly a product of its time, as birds were once thought to be descendants of the clade Pseudosuchia (the name Crurotarsi is more commonly used today and generally includes the same taxa). Traditionally, Pseudosuchia was considered a suborder of the now-obsolete order Thecodontia.

Gerhard Heilmann laid out the hypothesis of a pseudosuchian ancestry of birds in his highly influential 1926 book The Origin of Birds, which was considered the last word on the subject of bird evolution for several decades after its publication. Heilmann acknowledged a close relationship between non-avian theropod dinosaurs and birds but rejected the notion that the former directly gave rise to the latter. One example of his reasoning was that birds have a furcula (wishbone), a feature which non-avian theropods did not appear to him to possess (though we now know otherwise), yet ancient reptilian fossils that predated dinosaurs did show clear evidence of a furcula-like structure. Though the evidence to which we now have access overwhelmingly supports the hypothesis that birds are indeed the descendants of dinosaurs rather than the crocodile-like “thecodonts”, much of the book’s research remains of interest.

(“Proavis” art sources: x x)

Why is this month’s circle different than some of the others I’ve posted?

New research, of course! 

A paper came out between last month and this reevaluating Archosauromorphs - and this was the result! Enjoy!

Better Resolution Here

Watch out for this fearsome Fossil Friday!

Although Prestosuchus chiniquensis was a large animal with big claws and a huge head with sharp-toothed jaws, it was not a dinosaur. This creature belongs to a larger group called Pseudosuchians, which also includes modern day crocodilians. 

Today, these creatures are only represented by a couple dozen species, but back in the Triassic, they were extremely diverse, and in direct competition with early dinosaurs. Late in the Triassic, multiple extinction events led to the demise of many major Pseudosuchian lineages, opening up niches for dinosaurs to take advantage of. Thus, the rest of the Mesozoic became the age of dinosaurs. Learn more about this extinction in the most recent episode of Shelf Life

This specimen is a reconstructed composite of several Prestosuchus specimens collected in Brazil and dating from the Late Triassic, about 210 million years ago.

Find this skeleton cast in the Museum’s Hall of Vertebrate Origins.

AMNH/D.Finnin

The Carolina Butcher

Last year, a new species of crocodilian relative was discovered from Late Triassic North Carolina.  Dubbed Carnufex carolinensis - “the Carolina butcher” - this animal grew up to nine feet long, and was capable of walking on its hind legs.

Carnufex is interesting for being a basal crocodylomorph - a member of the clade that includes modern crocodilians.  This proves that crocodylomorphs were vying for apex-predator positions during the Late Triassic, along with early theropods, as well as several other groups of pseudosuchians known as rauisuchids and poposauroids.  

This extreme diversity of predators proved unsustainable, and many of these animals - including Carnufex - died out by the time the Triassic period was over.  Theropod dinosaurs became the top predators for hundreds of millions of years afterward, while Carnufex’s surviving relatives were relegated to less dominant positions.

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More Free Icons Because PTEROSAURS, MAN
✧・゚:* \(◕‿◕✿)/ *:・゚✧

(Also Pseudosuchians and Testudines, but most importantly PTEROSAURS).
I’d also like to announce the long awaited reveal nobody asked for:

I’ve finally set up Patreon

Way overdue, I know. By now most of you must have pledged your money elsewhere, but this is mostly for the few loud followers who demanded the thing. I figured a couple extra bucks a month should help me with groceries. In short, these are the two major things that you can expect to show up on my Patreon.

Daily Drawings
Basically all the things you see from me here on a daily basis. Except in high-resolution. That you can use for any personal purpose. Sure, one month from now my daily saurians will be over, but I’ll keep drawing animals on a daily basis, albeit under different themes, because it does help me a lot with anatomy. And the files are all yours to use, because why not.

P.S., in fact, I’m planning another series that I might run together with the daily saurians, which means I may do more than 2 drawings a day when I’m not working on something else.

The Srs Stuffs™
In parallel to the daily drawings, I will also create one (or two) bigger, more elaborate works per month. These may range from artistic interpretation of scientific articles to fancy shmancy infographics done in collaboration with sciencepersons on tumblr (hint: @cyan-biologist is my first victim). In addition to regular WIPs, I will also upload the low-resolution PSD file with annotations to explain each step of my creative process, including the fails and sharp turns I take to achieve the final result. Higher tier patrons may also opt to receive these srs stuffs as a t-shirt.

But it’s mid February already
I KNOW, I’m lame. As an apology, I’d like to kick this off by offering a mega pack for you early burbs. All patrons pledging this month will receive all Saurian Morphology drawings I’ve done up to the end of February (approx 65 drawings). Higher tier patrons will receive the PSD files of all three #pokemon20 tribute drawings.

I hope that’s good enough to convince you lot, eh.

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T-shirts · Other Products · Patreon · Website

Desmatosuchus, one of that mighty lineage of armor-backed pseudosuchians, the aetosaurs (or as Darren Naish once aptly termed them, the armadillodiles). It joins its distant relatives ShuvosaurusEffigia, and Simosuchus in defying the carnivory we may come to expect from croc-line archosaurs. The shovel-like snout and peg-shaped teeth of aetosaurs would seem to pin them as herbivores.

All the same, it has been postulated before that these were instead adaptations for insectivory, and an abstract has been around since 1995 toting around the supposed discovery of a carnivorous aetosaur. Personally I wouldn’t be surprised if they were something more akin to boar-like, omnivorous scavengers of Triassic forests.

Desmatosuchus was among the larger members of the family, spanning about 5 meters (16 feet) in length. It’s known from the Late Triassic of Texas.

Latha Naomh Anndra sona dhuibh!

Happy St. Andrew’s Day!

Since Ryuu did stuff for Día de los Muertos, and Jack did stuff for Bonfire Day, and I don’t give a shit about America (even more so now), and it’s the “month of celebrating dinosaurs + human culture”, so -

Here’s some stuff about dinosaurs from Scotland! 

Non-Dinosaur Dinosauromorphs

Saltopus is a small, hopping ALMOST dinosaur from the Late Triassic of Scotland! Specifically the Lossiemouth Sandstone! 

By Ashley Patch, @apatchsketches​ 

Though not a true dinosaur it was not far away from being one, and would have behaved very similarly to early ones - a fast, bipedal animal, living alongside many other weird Archosaurs and Triassic age reptiles. In fact, this is also the formation that houses Scleromochlus, an interesting Avemetatarsalia that may represent early stages of Pterosaur evolution! Rhynchosaurs, Aetosaurs, and more derived Pseudosuchians (crocodile-line Archosaurs) are also present in this formation. If I could draw, I would definitely draw this interesting community! 

Non-Avian Dinosaurs from Scotland

Sadly, though Scotland has a long and proud history of paleontological discoveries from the Jurassic, most of these are of marine environments, which did not include nonavian dinosaurs. That doesn’t mean there isn’t ongoing research there though, or that nonavian dinosaurs never lived there! 

An indeterminant sauropod, named Dougie the Dinosaur, was found on the Isle of Skye. It comes from the Middle Jurassic and, as such, was probably a Cetiosaurid! 

In fact, the remains of Sauropods from Scotland are quite extensive. A very large and expansive trackway is known from the same island - the tracks measuring out over an area that’s 15 by 25 meters in size!

These Cetiosaur-like dinosaurs skirted lagoons and other sources of water, probably using them as sources of food!

This is really exciting as middle-Jurassic dinosaurs are some of the most poorly known, and that is exactly the time frame in which these Scottish dinosaurs are from! 

Other dinosaur bones and trackways are also known from the Isle of Skye. Other finds include a Coelophysis-like tailbone, which is extremely interesting as most Coelophysoid grade theropods were dying out during this period. An extremely early Thyreophoran bone is also known from there, one of the earliest known members of the group - the bone being part of the Ulna. Bones of a theropod - probably a Megalosaur - are also known. 

Tracks from Megalosaur-like theropods are extensive from the Isle of Skye, as well! 

If I could draw, I would definitely reconstruct this ecosystem for you all - a small, but probably complex early community of dinosaurs, living in a very wet and insular environment, with some of the earliest members of many groups - and the latest of others! And as the country is explored more, there is bound to be more and more exciting discoveries, such as the extensive Sauropod trackway. 

For the Pterosaur fans - since this blog loves all Avemetatarsalians, not just dinosaurs - very few pterosaurs are known from Scotland, just indeterminant remains. And there is only one fossil formation in Scotland from the Cretaceous, which sadly only includes a Gastropod fossil. 

Avian Fossils? 

For avialan dinosaurs (which I will hereon refer to only as birds), the Mesozoic record is completely blank in Scotland. That doesn’t mean, of course, that there weren’t birds in Scotland - and the lack of Cretaceous formations doesn’t mean that there were no Cretaceous dinosaurs of any kind. It just means we don’t know what kinds may have lived there! 

And, sadly, the Cenozoic-era fossil formations in Scotland are also nonexistent. So though we know Cenozoic-era birds did live in Scotland - after all, there are fossils there today - we don’t know, sadly, what they were. 

However, we do know that the Great Auk lived in Scotland; sadly, though, it is now extinct. 

Modern birds?

Tha dìneasaran air mhaireann ann an eòin!! 
(Dinosaurs survive in birds!)

Luckily, today Scotland boasts a wide variety of bird species, so many that I couldn’t possibly list all of them! In fact, there seem to be about 557 different species of Scottish birds, with 17 endangered or threatened. These include many species of water fowl, land fowl, pigeons and doves, divers, petrels, skuas, puffins, falcons, owls, eagles, and of course many songbirds. In fact, due to Scotland’s extreme maritime nature, many birds from Scotland take advantage of that! 

Some of my favorite birds from Scotland include: 

The Common Raven

The European Turtle Dove

Golden Eagle

Little Owl

Snowy Egret

And the Mallard!

There are of course, MANY other species of birds in Scotland, so be sure to check out the links below! 

Happy St. Andrew’s Day! Alba gu bràth!

Image by @north-wyrm!

Sources:

All bird images come from Wikipedia

http://news.nationalgeographic.com/2015/12/151201-dinosaur-sauropod-scotland-footprints-science/

https://depositsmag.com/2016/08/02/dinosaurs-in-scotland/

http://www.gla.ac.uk/~gxha14/Dino.html

https://paleobiodb.org/navigator/

http://avibase.bsc-eoc.org/checklist.jsp?region=UKsc&list=howardmoore

https://en.wikipedia.org/wiki/Great_auk

http://www.rampantscotland.com/birds/

http://avibase.bsc-eoc.org/checklist.jsp?region=UKsc&list=howardmoore