#ornithoscelida

[a-dinosaur-a-day]

it's been a while, how's the validity of Ornithoscelida faring?

Pretty much dead in the water, the study that showed it was pretty bad it turns out

#ornithoscelida #I regret making a big deal of it tbh

[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

#science illustration #paleontology #paleoart #palaeoblr #lewisuchus #silesauridae #dinosauriformes #avemetatarsalia #archosaur #reptile #art #the early ornithischian idea is intriguing BUT it's also being pushed by the ornithoscelida gang #so that's a thing #(...i should probably also talk about the state of ornithoscelida at some point; it's been what almost seven years?) #(short version: we still dunno and early dinosaur relationships resolve in multiple equally-likely ways; More Data Is Needed)

[tlaquetzqui]

So turns out it’s probably better to include Ornithischia and Theropoda in “Ornithoscelida”, and then put sauropods and herrerosaurs over in the Saurischia.

Basically, it’s like if theropods were placental mammals, ornithischians were marsupials, and saurischians were monotremes. Ornithoscelida is like “therian mammals”.

#science marches on

[iknowdino]

Episode 415: A huge ornithomimosaur in Mississippi

I Know Dino Podcast Episode 415: A huge ornithomimosaur in Mississippi. Plus Ornithoscelida is dead; Stegoceras head-butting; Dinosaur bite forces; Sculpting an Amargasaurus head; and much more

Episode 415: A huge ornithomimosaur in Mississippi. Plus Ornithoscelida is dead; Stegoceras head-butting; Dinosaur bite forces; Sculpting an Amargasaurus head; and much more News: A new very large ornithomimosaur was discovered in Mississippi source Ornithoscelida is dead, but the dinosaur family tree might be getting another update source Scientists found that the early dinosaur Coelophysis…

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[etchif]

Thoughts on Saurischia-Ornithischia vs. Ornithoscelida-Sauropodomorpha? From what I've heard the evidence seems pretty equivocal right now but slightly favours the traditional Saurischia vs. Ornithischia split. I do quite like Ornithoscelida though because a) "lizard hipness" is a primitive trait shared by the common ancestor of all reptiles and is a symplesiomorphy in dinosaurs rather than a synapomorphy so doesn't necessarily define a clade, and b) evidence of feathers have been found in theropods and ornithischians but not sauropodomorphs as far as I know so it'd be nice to keep all the feathers in one clade. But I'm not a dinosaur specialist so if people who have looked into it way harder than I have still go with Saurischia-Ornithischia then at least there's the nostalgia of keeping those two groups intact?

I unfortunately don't know enough abt the topic to have an opinion on it but if anyone does you're more than welcome to enlighten me please!! :)

#asks

[paleonativeart]

Day 8: Scutellosaurus lawleri

A Navajo woman saw a small armored dinosaur right a side of her. Why give a nice taste of #nativember along with #Dinovember for the same month.

#my art #dinosaur #dinosaurs #paleoart #dinosauria #nativember #dinovember #draw dinovember #navajo nation #navajo #indigenous #indigenous people #southwest #ornithoscelida #ornithischia #genasauria #thyreophora #scutellosaurus

[ask-palaeoblr]

As how legit is the Ornithoscelida theory regarded these days? What are the pros and cons?

#ask #palaeoblr #ornithoscelida #ask-palaeoblr #Anonymous

[drawingwithdinosaurs]

What do you think of the reclassification of theropods and ornithopods into ornithoscelida? I think that it kinda makes sense but its still pretty weird.

This has been sitting in my inbox for ages because I’m lazy and forgetful, oops.

My initial reaction the day Ornithoscelida dropped boiled down to a giddy “NO WAY, WHAT?!?!” (albeit with more expletives). It was a pretty bold and exciting claim to make if it could be backed up, and while sceptical I was quite willing to embrace it. To me, it made enough sense on principle and neatly tied together a few things, like how theropod-like things like heterodontosaurids were. But when the hype died down and the study was dissected more, it turned out the phylogenetic data used that found Ornithoscelida was flawed, and rebuttal studies specifically testing early dinosaur relationships were published that still favoured Saurischia and Ornithischia over Ornithoscelida (just), and there’s an upcoming response using a fixed version of their data that doesn’t sound like it bodes well for Ornithoscelida. I found Ornithoscelida compelling when it was first published but I have to admit that today I’m more swayed that Saurischia and Ornithischia are correct after all.

Something I do appreciate Ornithoscelida for doing, though, is tearing down the rigid Saurischia/Ornithischia dichotomy that’s been emphasised in dinosaur education ever since they were brought back together in the 70s. The split between them had been treated as an important division amongst dinosaurs, but when you get down to it all the early dinosaurs are so similar to each other that there would be nothing particularly significant about it. The individual originations of theropods, sauropodomorphs and ornithischians would all have more merit than the split into Saurischia and Ornithischia by itself. The fact that studies have found that Ornithoscelida and even Phytodinosauria are only slightly less favourable than Saurischia is also pretty important in highlighting just how uncertain early dinosaur relationships are. Ornithoscelida may not be rewriting the books, but it has an important contribution to the sections on dinosaur evolution.

(I’m also really quite fond of the name too, especially since it’s resurrected from a long forgotten bit of dinosaur taxonomy, gotta love that. In hindsight though, I kind of wish it could have been brought back for the clade of silesaurids + dinosaurs. Like, Ornithoscelida was originally named for dinosaurs + the supposedly “dinosaur-like” Compsognatha, it fits so well thematically!)

#Dinosaurs #Ornithoscelida #magentas-dystopia

[astrodraws]

Inktober may be long past, but I still have my list! CARNOTAURUS SASTREI, the meat-eating bull. So mean.

#dinosaur #dinosauria #ink #ornithoscelida #therapod #Carnotaurus #paleoart #traditional art #carnivore

[killdeercheer]

It is a little known fact that the lives Mesozoic dinosaurs often depended on whether shaved apes 145 million years in the future care about you.

#Chilesaurus #Yi qi #Coelophysis #dinosaurs #dinosaur #Palaeoblr #paleontology #palaeontology #prehistoric life #theropods #ornithischians #news #Ornithoscelida #Tetanurae #Ornithischia #Theropoda #archosaurs #reptiles #Coelurosauria #Scansoriopterygidae

[jurassic-james]

isn't the Ornithoscelida hypothesis kind of divisive among paleontologists? Like last I heard the debate wasn't really settled

Like I mentioned in the post, it's still being debated and studied. Like most things in palaeontology, it's unlikely to stay still and fixed - honestly, the Seeley hypothesis shouldn't have remained unquestioned for as long as it did (though, it has had the occasional debate throughout history). Particularly at the moment, with a lot of new research happening in South America in relation to early dinosaur origins, this is unquestionably going to be in a state of flux for a while. Without doing a lot more in depth research that I don't have time (or money) for, I can't say, exactly, what the current consensus is, nor what all the most recent papers say.

However, from what research I did do tonight, it seems like most studies attempting to refuse Baron et al. have had issues in them, found only weak support for Ornithischia/Saurischia, or have created far more complicated classifications which seem unlikely.

For me, the Ornithischia/Saurischia classification was morphology based, while Ornithoscelida/Saurischia is phylogenetically based, and in modern palaentology we should be attempting to use phylogeny and cladistics wherever possible. And even if the Ornithoscelida hypothesis is contentious, the original hypothesis is also now contentious. So I think, if nothing else, it's always worth mentioning both, though I would err on the side of Ornithoscelida.

#ask #palaeontology

[mcblackneck]

Some Mongolian fauna consisting of “Tarbosaurus bataar” and “Tsaagan mangas”. My Opus magnum when it comes to photoshop and I must admit that I’m really satisfied with the result!

#dinosaur #bird #mongolia #fauna #wildlife #theropods #ornithoscelida #feather #scale #animal #photoshop #art #paleoart #paleontology #tyrannosaur #dromeosaur #raptor #tarbosaurus #tsaagan #velociraptor #realistic #saurian #formation #china #prey #extinct #mesozoic #cretaceous

[smthnwentwrong]

Tagged by @ornithoscelida  Sorry I didn’t see this at first!

Relationship status: Single and rather content with it atm

Favorite color: blue in all it’s lovely shades

Lipstick or Chapstick: Chapstick

Last Song Listened to: Passing Through a Screen Door by The Wonder Years 

Last Movie I watched: Thor: Ragnarok

Top Three Bands: All Time Low, Fall Out Boy, The Wonder Years

Top Three Shows: Agent Carter, Parks and Recreation, Teen Wolf 

(Wolf hell show is complicated because I still haven’t seen the final bit but it was deeply formative and a wonderful release during the worst summer of my life and is still very important to me)

Three Characters:  Peggy Carter, Stiles Stilinski, Bilbo Baggins. Honorable mention: Ben Wyatt, Gandalf

Book I’m Currently Reading: Oscar Wilde and a Death of No Importance by Gyles Brandeth and A Streetcar Named Desire by Tennessee Williams

#ornithoscelida #tagged

[probablydinosaurrpgideas]

A campaign in which the hierarchy of the gods are based on their phylogenetic position, and each paper reordering the phylogenetic trees causes a shakeup in the god hierarchy. Holy wars are major phylogenetic changes, awakenings are new species named. Consider: Ornithoscelida.

#phylogeny #world building #mod allos #ornithoscelida

[paleonativeart]

Day 24: Halszkaraptor escuilliei

Commonly known as Duck Raptor due living in the fresh watering holes in the late Cretaceous Mongolia.

#my art #dinosaur #dinosaurs #paleoart #dinosauria #ornithoscelida #theropoda #maniraptora #pennaraptora #paraves #halszkaraptorinae #unealagiidae #dinovember #draw dinovember #artists on tumblr