#ornithoscelida

[dinofloof]

Huh, come to think of it, I wonder if Ornithoscelida ever gained any steam…

…

Nope, doesn’t look like it! ¯\_(ツ)_/¯

[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

[tyrannus55]

Dinosaur rEvolution and Extreme Dinosaurs Part 2 were right all along!

Quilled and scaly Psittacosaurus specimen... at last out!

According to Nature Communications, It seems that we finally have it… the rumoured feathered Psittacosaurus specimen I have been advancing is finally out… not like a half-porcupine this time, butbody covered in feathery, quill-like integument, combined with… scales. Yes, the two skin elements coexisted, as it would only be natural. Keratin rules! The main thesis of the exhibition Dinosaur…

[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.

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[bobnichollsart]

My 25 years of palaeoart chronology...

My Nature cover from 2017 and the draft drawings (the featured paper was re Ornithoscelida, by Baron et al). I called this painting "In the Spotlight" and it depicts Kulindadromeus.

[hesperocyon-lesbian]

if i wanted to seriously learn about (non-avian) dinosaurs what would be a good place to start? books, articles, meticulously maintained amateur websites? is it a good idea to pick a specific clade and / or era to begin with?

Honestly that’s a tough question that I’m not sure I have a good answer for. I’d honestly say well cured amateur blogs like you mention are a good bet. My ground rule with books on paleontology is that they’re a bad investment because they’ll be outdated in 5 years, but they’re good at giving accurate overviews. I’ll need to find the title when I get home but I’ve got some sort of Dinosaur guide by Gregory S Paul that I find to be a solid overview. I also love the YouTube channels PBS Eons and Your Dinosaurs Are Wrong. The former does great science communication in more of a pop science niche but they’re good at introducing you to more obscure phenomena in paleontology that you might not hear about otherwise, and the latter is more rigorous and technical content about dinosaur anatomy. His videos on the Ornithoscelida debate circa 2017 were what got me into the subject of phylogenetics

[s-lycopersicum]

Okay, so there's this one channel called Your Dinosaurs Are Wrong, and it's the best dino content I've had since my childhood (some gaps in memory notwithstanding).

I like that their stuff really goes deep into the science of the field, I mean, they have two whole videos on the re-classification (?) of Ornithoscelida, which even includes a small intro to cladistics.

As a starting point, I recommend this video on Alossaurus:

They really dive into the presumed behavior of these animals, and how we arrived at these conclusions just from bones and the context in which they were found (also there's a great story bit in the end).

And they are really clear on the point that these were animals that once lived in the world, and not monsters or under-adapted failures, just waiting for mammals to take over. Good videos on those are the Velociraptor and Iguanodon episodes.

But my personal favorite is possibly the follow up on their Styracosaurus episode:

There's so much good info about how specimens are investigated, the sort of detective work that the professionals of the field do to achieve such detailed and interesting knowledge from the meager fragments that survived the eons.

Anyway, they have lot's of stuff like that, so if it sounds like your jam, check out their channel, and there's also a couple of older videos they had on a different channel. Some of those are quite small, if you'd like something bite-sized!

Who wants to watch some videos about dinosaurs?

[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.

[ask-palaeoblr]

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

[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!)

[astrodraws]

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

[bobnichollsart]

My 25 years of palaeoart chronology...

Here's my Nature cover from 2017; the featured article was the Ornithoscelida paper by Baron et al. I called this painting "In the Spotlight" and it depicts Kulindadromeus.

[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!

[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.

[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.

[paleonativeart]

Day 24: Halszkaraptor escuilliei

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