#silesaurid

[pleistocene-pride]

Pisanosaurus is an extinct genus of early dinosauriform reptile which lived throughout what is now South America during the Carnian stage of the Triassic period some 231 to 227 mya. The first and only known specimen of Pisanosaurus consisting of a single partial skeleton was unearth in 1962 by Galileo Juan Scaglia at the Hoyada del Cerro Las Lajas locality in the Ischigualasto Formation of La Rioja Province, Argentina. It was later described by Argentine paleontologist Rodolfo Casamiquela in 1967 who named the animal Pisanosaurus meaning "Pisano’s lizard" in honor of Argentine paleontologist Juan Arnaldo Pisano of La Plata Museum. With the species name mertii being a reference to the late Araucanian naturalist Carlos Merti. Reaching around 3.3 to 4.3ft (1 to 1.3m) in length and 4 to 5lbs (1.8 to 2.7kgs) in weight, Pisanosaurus was a small and lightly built facultative biped animal. Due in part to its fragmentary nature, Pisanosaurus has been variously interpreted as being either a very basal ornithischian dinosaur, perhaps the earliest known, or as being a silesaurid: a group of non-dinosaur dinosauriform archosaurs. The placement of Pisanosaurus is reliant on the placement of silesaurids as a whole, a situation which in itself is of much debate. While Silesauridae is often considered a monophyletic sister group of dinosaurs, some studies consider it a paraphyletic grade ancestral to ornithischian dinosaurs as a whole. There in Pisanosaurus could have been both a silesaur and a primitive ornithischian. Reguardless of its taxonomic position, pisanosaurus was a small herbivore with likely spent its life in the underbrush of coniferous forests feeding upon various vegetation such as ferns and horsetails.

Art used in can be found at the links below

[a-dinosaur-a-day]

Artwork by @drawingwithdinosaurs

[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!

[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.

[alphynix]

Last week I mentioned the one oddball dinosauriform that had crocodilian-like osteoderm armor, so let's take a look at that one too.

Lewisuchus admixtus lived in what is now northwest Argentina during the late Triassic, around 236-234 million years ago. About 1m long (3'3"), it was an early member of the silesaurids – a group of dinosauriforms that weren't quite dinosaurs themselves, but were very closely related to the earliest true dinosaurs.

(They've also been proposed as instead being early ornithisichians, but we're not getting into that today.)

Much like its later silesaurid relatives Lewisuchus had a long neck and slender limbs, and was probably mainly quadrupedal, possibly with the ability to briefly run bipedally to escape from threats. Its serrated teeth suggest it was carnivorous, likely feeding on both smaller vertebrates and the abundant insects found in the same fossil beds.

Uniquely for an early dinosauriform it also had a single row of bony osteoderms running along its spine. Although it lived at close to the same time as the similarly-armored Mambachiton their last common ancestor was at least 10 million years earlier, and no other early dinosaur precursors with osteoderms are currently known – so this was probably a case of Lewisuchus independently re-evolving the same sort of feature.

—

NixIllustration.com | Tumblr | Patreon

[mineralsrocksandfossiltalks]

Day 9: Almost Dinos

Today's competitors are very, very closely related to dinosaurs...so much in fact, that both were thought to be dinosaurs for a while.

Why isn't Silesaurus a dinosaur?

1.) Lacks an elongated deltopectoral crest (ridge on the humorus for muscle attachment).

2.) Lacks epipophyses on cervical verts (parts that branch off the vertebra)

Pisanosaurus, not a dino? This little guy is still under hot debate. It could be a transitional form between silesaurids and basal ornithischians OR is could be a basal ornithiscian. More data is needed.

REBLOG for SILESAURUS

LIKE for PISANOSAURUS

[dynamoterror1011]

Slightly more chaotic collection of Flocking-together Paleostream sketches this time. Starting on the left is Hupehsuchus, going after a shoal of tiny Conodonts. On the bottom is a Bobosaurus, snatching a Pseudoglyphaea lobster from the seafloor. On the right is a Eocoelophysis (not closely related to the dinosaur Coelophysis, but instead a fragmentary Silesaurid) strutting along, and on the top is the remarkably billfish-like placoderm Carolowilhemina.

[misterrogers22]

Welcome to the Juras-Sick Park-Cast podcast, the Jurassic Park podcast about Michael Crichton's 1990 novel Jurassic Park, and also not about that, too.

0:00 - Introduction

Find the episode webpage at: Episode 39 - Lex. www.jurassickparkcast.blogspot.com/2022/11/episode-39-lex.html

09:30 - Interview with terrific guest "Tom Jurassic" Fishenden.

29:00 - Details on his Youtube audiodrama, "Tales from a Jurassic World."

In this episode, my terrific guest Tom Fishenden joins the show to chat with me about: British dinosaurs, the Maidstone Iguanodon, Baryonyx, the Isle of Wight, Jurassic Park, Primeval, the Jurassic Park Podcast, fandom, audio dramas, the Dino Watch Podcast, World War Z, Battle of Big Rock, hypothetical dinosaur behaviours, the Lysine Contingency, the Lysine Contingency, engaging in fandom, Lex Murphy, Lewis Dodgson, the future of the Jurassic Park as an intellectual property, dinosaur designs, #StaySafeStayJurassic, more sense, and much more!

Plus dinosaur news about:

02:25 - Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira (silesaurids!)

06:27 - Binocular Vision in Theropod Dinosaurs

00:34 - Featuring the music of Snale https://snalerock.bandcamp.com/releases Intro: Latebloomer. Outro: Grow Old Or Don't.

The Text: This week’s text is Lex, spanning from pages 210 – 217.

55:55 - Synopsis of the chapter Lex in Jurassic Park Synopsis: Tim finds Lex hiding in a culvert under the road, and they climb out to find Dr. Grant. Meanwhile, Ed Regis climbs out from the bounders in which he’d been hiding, feeling great shame for having abandoned the kids during the tyrannosaur attack. As Regis emerges, he’s tackled and eaten by the juvenile tyrannosaurus, which pushes Grant and the kids to escape further into the park, rather than following the road back to “safety.”

01:03:09 - Analyzing the literary and stylistic techniques in the chapter Tim

01:12:11 - Discussions surround Show Don't Tell, Daddy issues, What's in a name, Timeline, and Believe me, I know!

Corrections:

Side effects: May cause you to login to Zoom twice, creating a ghost account, which can only be spoken to via a Ouigji board.

Find it on iTunes, on Spotify (click here!) or on Podbean (click here). Thank you! The Jura-Sick Park-cast is a part of the Spring Chickens banner of amateur intellectual properties including the Spring Chickens funny pages, Tomb of the Undead graphic novel, the Second Lapse graphic novelettes, The Infantry, and the worst of it all, the King St. Capers.

You can find links to all that baggage in the show notes, or by visiting the schickens.blogpost.com or finding us on Facebook, at Facebook.com/SpringChickenCapers or me, I’m on twitter at @RogersRyan22 or email me at ryansrogers-at-gmail.com.

Thank you, dearly, for tuning in to the Juras-Sick Park-Cast, the Jurassic Park podcast where we talk about the novel Jurassic Park, and also not that, too. Until next time! #JurassicPark #MichaelCrichton

[new-dinosaurs]

Which phylogeny does this blog defer to regarding the silesaurid question?

For now I'm operating under the traditional idea that silesaurids were not dinosaurs (which is why I didn't write an article on Gamatavus last year). If the silesaurids-are-ornithischians hypothesis starts becoming the mainstream consensus though, I have no issue with adding them to this blog's coverage.

[esmaniottoart]

Too Much Green for a Silesian Reptile_A Silesaurus Portrait. 

Digital, 2020.

[otussketching]

Oc-tober day 30: Fantasy concept: Hunter.

Here's another fantasy character I've been developing. She's a big game hunter who catches peculiar (and big) specimens for clients.

Her steed may look a bit weird, but it is a Silesaurid, so it's a given, basically.

[dinosaurs-dinosaurs-dinosaurs]

Silesaurus by FunkMonk, in the public domain. Retrieved from Wikipedia. 

[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

[allosuchus]

Sacisaurus reconstruction by Nobu Tamura.

[saritawolff]

#Archovember Day 20 - Prestosuchus chiniquensis

The Triassic was truly when Pseudosuchians ruled the earth. They came in a variety of different shapes and sizes and filled almost every niche. During this period, nearly every apex predator was a pseudosuchian. In the Middle Triassic of Brazil, this niche was filled by Prestosuchus chiniquensis. Originally estimated at around 5 meters long, a Prestosuchus specimen found in 2010 now places their upper size limits at nearly 7 meters (23 feet) long, making them one of the largest Triassic pseudosuchians, only surpassed by Saurosuchus. Like the crocodilians who would come later Prestosuchus walked on four legs, but in a more dinosaurian upright stance. Large Prestosuchians are assumed to be ambush predators, and this is supported by the finding of one Prestosuchus specimen in a fossil deposit assumed to be a local watering hole, a location ambush predators would have frequently haunted. This particular specimen had such a well-preserved hind leg that paleontologists were able to study its precise muscle groupings and confirm that Prestosuchus would have only been able to walk quadrupedally, unlike the related bipedal Poposaurus.

Prestosuchus chiniquensis could have preyed on most anything in Middle Triassic Brazil. Dicynodonts like Dinodontosaurus and Stahleckeria would have been their largest prey items. It could have hunted smaller pseudosuchians like Decuriasuchus, Pagosvenator, and Procerosuchus. Other archosauromorphs would have included silesaurids like Gamatavus, aphanosaurs like Spondylosoma, and rhyncosaurs like Brasinorhynchus. Cynodonts like the carnivorous Chiniquodon and the herbivorous Exaeretodon would have also been on the menu.

[chile-and-yi-official]

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

For a larger image of the comic, go here.