#marasuchus

[saritawolff]

#Archovember Day 6 - Lewisuchus admixtus

Lewisuchus admixtus was a silesaurid, a type of Triassic archosaur closely related to dinosaurs. Silesaurids all had the same general body plan: a long neck, long legs, and a mostly quadrupedal stance. However, they seem to have all filled a variety of niches. The white-tailed deer-sized Silesaurus was an insectivore. The collie-sized Kwanasaurus was an herbivore. But the smaller, earlier silesaur Lewisuchus was a carnivore, with teeth unique among silesaurids. In fact, its teeth and other anatomical features are so unique that some consider it to be a basal dinosauriform, coming before the silesaurids and dinosaurs split into two groups. It was also found with a single row of osteoderms down its back, something that other silesaurids don’t seem to have. Either way, it was a tiny, unique predator that paved the way for its strange, long-legged cousins.

Living in Late Triassic Argentina, Lewisuchus could have shared habitat with (and probably been hunted by) yesterday’s species, Herrerasaurus. But in the slightly older Chañares Formation, it was more likely to come across Proterochampsids such as Chanaresuchus, Tropidosuchus, and Gualosuchus, and probably competed with them for food. It would have also lived alongside other early dinosauriforms such as Marasuchus, early pterosauromorphs such as Lagerpeton, and the tiny pseudosuchian Gracilisuchus. Cynodonts were plentiful here, and Lewisuchus could have hunted small ones such as Probainognathus.

[apsaravis]

Tarjadia and Marasuchus.

Photoshop

[shinonart]

#ArchosaurArtApril Day 2 - #marasuchus . I'm trying to get more creative with the poses. It's surprisingly hard to not do a side view when all the references are like that. Anywau, I saw some interpretations of marasuchus with feathers and I can't say no to a good fluffy boy. . . . . #archosaur#sketch #sketchbook #smltart #paleoart #animalart#animals #animalartist #drawing #pencildrawing#pencilart #traditionaldrawing #traditionalartist#traditionalart #dailydrawing #dailyart #instart#instartist #artistsoninstagram https://www.instagram.com/p/Bvwy0O0JEZ-/?utm_source=ig_tumblr_share&igshid=up216kiy2pkw

[huxley-paleozoo]

The Reptile House

A sleepy Marasuchus takes a nap in a log.

The Reptile House is one of the more overlooked areas at Huxley Paleozoo, but it’s probably worth a visit. The building is filled with non-dinosaurian sauropsids, giving a glimpse at the wide variety of reptiles present in Earth’s past and present.

The house is divided into three halls. The E.S. Goodrich Hall is the main hall, and contains a wide variety of reptiles. The center of the hall has a large exhibit for Meiolania, which extends underneath the floor (they like sheltering under it). The room’s walls are lined with numerous exhibits and terraria with animals like Longisquama, Marasuchus and Coelurosauravus.

The Susan Evans Hall focuses on squamates. The sides of the hall contain exhibits for numerous lizards and snakes, from the tiny Tetrapodophis to the komodo dragon-sized Palaeosaniwa. The room terminates with the large partially-flooded exhibit of our Titanoboa, Debra.

The Steve Irwin Memorial Hall specializes in pseudosuchians. A sample of the variety of weird pseudosuchians throughout the ages is present here, with an emphasis on terrestrial stem-crocs from the Cretaceous, including the infamous “boarcroc” Kaprosuchus and the small, lithe Araripesuchus.

Animals here:

Evans Hall

Dinilysia

Gueragama

Obamadon

Palaeosaniwa

Saniwa

Tetrapodophis

Titanoboa

Goodrich Hall

Coelurosauravus

Longisquama

Lagerpeton

Marasuchus

Meiolania

Scleromochlus

Sharovipteryx

Rutiodon

Irwin Hall

Anatosuchus

Araripesuchus rattoides

Araripesuchus wegeneri

Effigia

Kaprosuchus

Simosuchus

[i-draws-dinosaurs]

Were dinosaurs in the early-middle triassic just a bunch of nondescript eoraptor-esque critters or were some already starting to get bigger and weirder despite the current domination of pseudosuchians and therapsids?

As far as we know, yeah they would've all been small scurrying guys. Thing is though, we have no definitive evidence of any true dinosaurs in the middle or early Triassic, except for the very un-definitive Nyasasaurus.

What we do have though are dinosauromorphs, the group of small dinosaur-y things that aren't quite yet dinosaurs! Even so, most of these also come from the late Triassic (like the fantastically leggy Marasuchus), and ones from the middle Triassic like Asilisaurus kongwe from Tanzania were absolutely part of the Tiny Little Guy genre. Like this is just a weird dog:

Image ID: Digital illustration of the small four-legged dinosauromorph Asilisaurus, in a half-crouched posture facing to the right. Its head is upright and alert, its mouth slightly open. Its body is covered in protofeathers, and mottled light brown fading to light and dark stripes on the tail. The snout is dark grey and the face has a red wattle of skin below the yellow eye. End ID.

We don't see any larger than this until the late Triassic, when dinosaur fossils seem to suddenly burst into the fossil record about 233 million years ago with Staurikosaurus and then they're everywhere!

Image ID: Size diagram of Asilisaurus and the earliest definitive dinosaur Staurikosaurus next to a light grey human silhouette. The Asilisaurus' head comes to the mid thigh of the human, and the Staurikosaurus' head comes to the human's hip. End ID.

[stavrosskundromichalis]

A sample of Triassic terrestrial fauna, from Early to Late Triassic. From left to right: Lystrosaurus murrayi, Proterosuchus fergusi, Galesaurus planticeps, Erythrosuchus africanus, Shringasaurus indicus, Batrachotomus kupferzellensis, Dinodontosaurus turpior, Teleocrater rhadinus, Marasuchus lilloensis, Silesaurus opolensis, Hyperodapedon gordoni, Ornithosuchus woodwardi, Postosuchus kirkpatricki, Pseudochampsa ischigualastensis, Hesperosuchus agilis, Poposaurus gracilis, Blikanasaurus cromptoni, Desmatosuchus spurensis, Caelestiventus hanseni, Smilosuchus gregorii and Megazostrodon rudnerae.

[drawingwithdinosaurs]

What is Tawa (dinosaur)

Tawa hallae is a pretty nifty little theropod from the Late Triassic! For starters, we’ve got a couple fairly complete skeletons of it to work with, along with several bones from other individuals in the same quarry, so it’s anatomy is well known:

(Source, Scott Hartman)

But Tawa is significant though not just because it’s complete, but because it appears to be intermediate in shape and anatomy between earlier diverging predatory dinosaurs like herrerasaurs and Eoraptor and the ‘proper’ theropods like coelophysoids at the base of Neotheropoda (the ‘core’ theropods, if you will).

See, Neotheropoda is a pretty consistent group, all the major clades within it (e.g. coelophysoids, megalosauroids, allosauroids, coelurosaurs) are agreed to belong together and their relationships are considered pretty solid.

Triassic dinosaurs like herrerasaurs, Eoraptor and so on are less stable and have been more prone to jumping between positions at the base of Dinosauria because of how “primitive” they are, for a lack of better word. Eoraptor for instance has hopped around as an early sauropodomorph, theropod and outside those two all together:

(Source, Scott Hartman. Again.)

Tawa has some of the characteristics shared by neotheropods (at least initially), implying that Tawa is a close relative of them, branching off before the common ancestor of neotheropods acquired all of their traits. Other traits however are more like those of the earlier predatory dinosaurs, so it has a weird combination of ‘primitive’, ancestral traits and some of the ‘advanced’, derived traits found in neotheropods. 

In that sense, it’s an intermediate between those early predatory dinosaurs and the neotheropods, both in terms of its anatomy and its evolutionary relationships. As much as the term is discouraged, I’m going to describe it as almost a textbook example of a transitional fossil, a species that diverged during the process of the evolution of a new group from an ancestral stock with a series of intermediate traits between the two.

(Source, originally from Sues et al. 2011)

The cladogram above shows herrerasaurs, Eoraptor and Daemonosaurus (misspelled with an ‘i’) and Tawa as successive branches on the line leading to neotheropods. 

As is the way of things though, a lot of the early predatory dinosaurs have continued to bounce around. If you’re familiar with The Befrickening that was Ornithoscelida, you’ll know how that analysis found herrerasaurs to be related to the sauropodomorphs, rather than a true theropod, for example. But in each case, Tawa has consistently remained as the closest relative to neotheropods, so its relationship to them seems like a solid deal.

Tawa demonstrates then that neotheropods probably rose from this stock of early predatory dinosaurs somewhere, albeit if we’re not quite sure which ones yet. It at least means that it’s very unlikely the early predatory dinosaurs represent a totally distinct group of dinosaurs from the core theropods, which in the mess early dinosaur relationships currently are, is major step forward!

(Hayden Quarry dinosauromorphs, by Donna Braginetz for Issue 5836 of Science magazine.)

Tawa is also very interesting ecologically too! The fossils were discovered in Hayden Quarry in New Mexico, part of the Late Triassic Chinle Formation known for the likes of Coelophysis, Postosuchus, and Placerias of Walking With Dinosaurs fame. At this time of the Triassic, it was presumed early relatives of the dinosaurs, dinosauromorphs like Lagerpeton, Marasuchus and silesaurids, and early dinosaurs like herrerasaurs were already extinct, wiped out by their more advanced relatives. But Hayden Quarry has several of these older, ‘primitive’ groups living alongside more derived dinosaurs, including Tawa.

Tawa co-existed with Chindesaurus, a predator typically grouped with herrerasaurs, and coelophysoids. So the ancestral stock, intermediate ‘transitional species’ and the ‘advanced’ descendent forms were all still kicking about at the same time as each other. It tells us that the evolution of predatory dinosaurs, as well as dinosaurs as a whole, wasn’t as simple as the ‘advanced’ dinosaurs out competing their older, less successful antecedents, but that they lived alongside each for millions of years.

There’s plenty to say, but I think I’ve prattled on about Tawa for long-enough of a post, but I think that about covers the gist of it! Yeah, Tawa hallae, very lovely little theropod. 

[kirby-and-knuckles]

Im just going through and posting all my “Good” Paintings here to catch you all up

One to skip a few, as in skip all the paintings from my awkward transitionary period. The other paintings ive posted so far I dont think clash that hard with my current style, but if you want to see the rest, theyre here on my Deviantart account. https://kirbyniferousregret.deviantart.com/gallery/

Name: The ‘Life Sized Dinosaur’ series (Theyre not all Dinosaurs)

Animals shown: Marasuchus lilloensis, Shuvuuia deserti, Nqwebasaurus thwazi, Epidexipteryx hui, Yi qi, and Scansoriopteryx helimanni

Original Description(s): I’m not copying and pasting all that, go to my DA and read them.

Things I’d change now: Marasuchus looks rushed, Shuvuuia has too much copy pasta feathers, Nqwebasaurus has weird remiges, and Yi had a much different membrane attachment.

[nathan-e-rogers]

Marasuchus lilloensis

Argentina, Ladinian Age of the Middle Triassic (Chañares Formation)

A small dinosauromorph archosaur (only about 40 cm long), Marasuchus lived in the shadows of larger animals and frequent volcanic activity. Relatives of Marasuchus, the dinosaurs themselves, would go on to dominate terrestrial ecosystems for millions of years.

Read more about Marasuchus, dinosauromorphs, and the Chañares Formation at Earth Archives.

[saritawolff]

#Archovember Day 26 - Chanaresuchus bonapartei

The proterochampsians were early archosauriforms from the Triassic period. Of them, Chanaresuchus bonapartei was fairly large, living in Late Triassic Brazil. It had a long, narrow snout. Unlike many other early archosauriforms, it had very little body armour, and just a single row of small osteoderms down the back. It is hypothesized that Chanaresuchus lived a similar lifestyle to pseudosuchians and phytosaurs due to its upward facing nostrils and eyes. However, there is a distinct lack of aquatic animal fossils in the Chañares Formation, suggesting that the area was dry and arid.

Chanaresuchus would have lived alongside dicynodonts like Dinodontosaurus, cynodonts like Probainognathus and Massetognathus, silesaurs like Lewisuchus, the lagerpetid Lagerpeton, the basal dinosauriform Marasuchus, the pseudosuchians Gracilisuchus and Luperosuchus, and fellow proterochampsian Gualosuchus.

[apsaravis]

Tarjadia and Marasuchus, work in progress.

[gentlemendinosaurs]

Marasuchus

This is not actually a dinosaur but rather comes under the broader category of dinosauriform. Tricky! 

[blue-jade-blog]

Marasuchus.