#silesaurids

[saritapaleo]

Patreon request for @/rome.and.stuff (Instagram) - Asilisaurus kongwe

Asilisaurus kongwe means “Ancient Ancestor.” As one of the first silesaurs, Asilisaurus is one of the oldest-known Avemetatarsalians (the clade which includes dinosaurs, silesaurs, and pterosaurs.) Found in the Manda Formation of Tanzania, it lived during the earliest portion of the Late Triassic. It appears to have been very common (or at least very prone to fossilization) as it is known from a relatively large amount of fossils.

Based on the length of its limbs, Asilisaurus was likely quadrupedal, but probably could have also reared up on its hind legs. It had no teeth in the tip of its snout, indicating the presence of a small beak, and also had fewer teeth than other silesaurs. Because of this, it is hypothesized that Asilisaurus was an omnivore or even a herbivore. The peglike shape of its teeth may have also lended to piscivory. As silesaurs seemed to have diets which were just as varied as dinosaurs (the Argentinian Lewisuchus was a specialized carnivore, the North American Kwanasaurus was an obligate herbivore, and the Polish Silesaurus was an insectivore and herbivore), Asilisaurus’ diet can’t be based on phylogenetic bracketing.

There seem to be two different adult morphologies of Asilisaurus: a “slender” form and a “robust” form. While traditionally regarded as a sign of sexual dimorphism, newer studies show that this could have simply been individual variation and a difference of growth in plentiful vs depleted environments (ie epigenetics), similar to differences seen in Plateosaurus and the modern Alligator.

In the Early Carnian of Tanzania, Asilisaurus kongwe would have lived alongside a variety of pseudosuchians such as Nundasuchus and Mambawakale, as well as the possible early dinosaur, Nyasasaurus. The environment was rich in synapsids as well, including dicynodonts like Angonisaurus, Kannemeyeria, and Tetragonias, and cynodonts like Cynognathus and Diademodon. Asilisaurus would have been preyed on by the aphanosaur Teleocrater and possibly some of the larger, carnivorous cynodonts, which is why I have given it spots for camouflage!

[a-dinosaur-a-day]

Artwork by @drawingwithdinosaurs

what's THIS dinosaur(iform)

Diodorus

Eucoelophysis

Kwanasaurus

Lutungutali

Sacisaurus

Silesaurus

Technosaurus

Voting ended onMar 16, 2024

[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.

[chile-and-yi-official]

“Whose phone is ringing? Mine, it’s mine!”

For a larger image of the comic, go here.

[a-dinosaur-a-day]

i’m sorry if someone else has asked this and i missed it, but what’s the story of silesaurus possibly being a dinosaur?

SO

Silesauridae is a group of interesting little bird-line archosaurs that have a lot in common with dinosaurs, so for most of our understanding of their history, they came out as sister group to dinosaurs - ie, the things most closely related to dinosaurs without just being dinosaurs

HOWEVER

recent studies have indicated they may actually be Ornithischians, some of the earliest ones

So a lot of phylogenies have them come out as Ornithischians, but some still have them come out as sister-to-dinosaurs

And when you think about it, that's not a lot of different steps, right? That's just moving Silesaurs up two steps in the tree. So it makes sense that its murky. Its very likely that Avemetatarsalia itself diversified very quickly, so the changes that happened at each step were more subtle than longer diversification times.

At any rate, hopefully the puzzle will be solved. I personally think them being Ornithischians makes a certain degree of sense, but its too soon to tell either way

[saritawolff]

Archovember Day 9: Silesaurus opolensis

Silesaurids were not dinosaurs, but of all the animals confused for dinosaurs they are the closest related. Found in late Triassic Poland, these dinosauriforms occupied a wide variety of ecological niches, but followed a pretty consistent body plan: a long neck and four long, usually quadrupedal, legs.

Silesaurus opolensis is one of the best represented of these species, with around 20 specimens found. It was a slender, agile animal, about 7.5 feet long and as tall as a great dane. It had small, conical teeth, but the very tip of it’s jaws show evidence of a small keratinous beak. Coprolite content tells us that S. opolensis was an insectivore, and may have used this beak to peck at beetles and other arthropods.

Silesaurus opolensis lived in scrub and swamplands and was probably social, due to how common its fossils are. (Imagine a herd of these strange deer chickens roaming through the forest pecking the underbrush for bugs.) There was a wide range of arthropods for S. opolensis to snack on in this environment, but it also would have been preyed upon by the pseudosuchian Polonosuchus. Here, it is briefly standing on its hind legs to scan for danger.

[ask-palaeoblr]

Hypothetically, if silesaurids had evolved to become large herbivores, what do you think they'd have looked like?