Placerias: Giant Triassic Herbivore

[@Jameslpinto]

Hi! I'm a paleontology student researching fauna from the Triassic (among other periods), and I led a lot of the research on sexual dimorphism and tooth vestigiality in Placerias shown here (everything from the poster Pinto et al., 2022). I just wanted to say thank you so much for featuring my work and helping spread the word on the changing perception of stem-mammals in the Triassic! We actually just submitted the paper describing the dimorphism in Placerias in much more detail, and that should be published in a few months. The information throughout the video was also very well put together! A few tiny corrections you may find interesting (a lot of this info will be further explained in the upcoming paper): - Technically all of the Placerias skeletons you can see on display in museums are casts; none have any actual fossil material. They were made from one fossil composite skeleton assembled from Placerias Quarry material which was then housed as separate elements in the University of California Museum of Paleontology. - Saying that Placerias "cooccurred with at least 2 other dicynodont species" is not provably incorrect, but there isn't direct evidence for this (yet). Eubrachiosaurus is only reliably known from one locality that is separated in place and time from any record of Placerias, and the Pekin Formation taxon, while possibly distinct from Placerias (which may also occur there), only occurs in North Carolina, quite far from the Arizonan Placerias Quarry population. It's true that all of these species were in North America at around the same time, but the Placerias Quarry (and the Chinle Formation as a whole) only have the one dicynodont. There are actually multiple other unnamed species of dicynodonts known from other parts of Triassic North America, but they are still being described... Let me know if you have any questions or things I can help to clarify about Placerias or my research, and thanks again! This is one of my first published studies, so it really made my day to see it being discussed!

[@julianshepherd2038]

Land walrus.

[@Fede_99]

That title was already taken by Tiarajudens

[@justinwilliam6534]

It goes to show how science has changed since Walking With Dinosaurs.

[@bkjeong4302]

The sheer amount of Triassic animals that get overlooked or even outright slandered because of people thinking only of dinosaurs when they think of the Triassic is tragic.

[@joaosenra2775]

Too sad that claim that there was a surviving Dicynodont from the Cretaceous of Australia wasn't true, but I wouldn't be surprised to see that more Triassic relics would have survived in Australia and Antarctica, as well as Koolasuchus.

[@midnitemoon1153]

I know! Wish they managed to hold on at least until the KPG extinction

[@gattycroc8073]

whether it's Cretaceous Temnospondyls or Miocene Notosuchians I love animals that managed to survive longer their perspective groups. makes me disappointed that Walking with Beast didn't feature any Sebecids as Walking with Dinosaurs featured both Placerias and Koolasuchus.

[@thelaughinghyenas8465]

Thanks for the fascinating content and also thanks to the Mandelorian for a great narration! Real interesting stuff. I would love to see more on Lisowicia, especially combined with Smok wawelski. The Polish duel of the Triassic!

[@posticusmaximus1739]

Don't forget Ozimek!!!

[@AntoekneeDE]

This was an excellent review of these late dicynodonts, thank yiu

[@traikentercept144]

My only thought I had when I saw this was "YES!" I just knew that it was only a matter of time before you covered this. Thank you.

[@robertroy8803]

Excellent video, I like the pointing out that Dinosaurs were not some super breed that just hopelessly out competed everything, but in fact the ones lucky enough to survive the specific horrible conditions of the mass extinction. Also great narration again, he's been a huge contribution to your channel.

[@posticusmaximus1739]

I think you should do an overview video on the Triassic-Jurassic extinction event. I feel like the Great Dying is assumed to be the event that cleared the way for Dino domination when it was not. Everyone knows about the Great Dying and the Kpg extinction but not the TJ. What even caused it?

[@chimerasuchus]

I covered the topic in my video about Triassic dinosaurs. It was even supposed to be about the end-Triassic mass extinction when I started writing it.

[@posticusmaximus1739]

I think a full standalone video would do more justice than a few minutes at the end of a long video. How does the TJME differ from the Great Dying? Both were volcanic events on Pangaea but why was GD worse than the TJME. The GD was believed to be a mantle plume but what was the TJME. Was it a chain of yellowstone super volcanoes going off? It was in the middle of Pangaea, which was more arid and sparely inhabited. So it's strange that select groups of Archosaurs/morphs were knocked off when many would've had similar adaptations as dinosaurs. Also, how were the marine reptiles affected? The GD & Kpg decimated both land and sea, what about the TJME? Just some thoughts I had.

[@johnball320]

@@posticusmaximus1739 TJME was caused by volcanism related to plate tectonics during the break-up of Pangea.

[@posticusmaximus1739]

Volcanism caused the Great Dying too, a "mantle plume". So what was the TJME? What was the "volcanism" and why was the extinction that followed so "selective". Non-dino archosaurs were eliminated, temnospondylsmade it through, sauropterygians too. Very mysterious extinction event.

[@johnball320]

@@posticusmaximus1739 As I said, the volcanism was linked with the break-up of Pangaea and a newly formed divergent plate margin. Therefore, the cause is not much different to the K-T extinction. There was a pulse of magmatism, creating the Central Atlantic Magmatic Province, leading to volcanic activity and the break-up of Pangaea. As for why it was 'selective', it was a matter of some creatures were less adapted to survive, but others were. There may be subtle differences in the degree of uninhabitable regions between extinction events, but it's not my expertise, but there will be several papers exploring this.

[@Tuishimi]

I wish we had more information about lisowicia... (sp?). Hopefully we will and you will be able to do a video on in the future. :)

[@erichtomanek4739]

I wonder if the keratin sheaths that may have covered the tusks were brightly coloured, like some bird's beaks? Also, how large could they have grown? Almost large enough to prevent efficient feeding? Excellent video, informative and visually appealing.

[@TheAnimalKingdom-tq3sz]

I wonder why Placerias and Postosuchus moved so slow in New Blood when they can run fast

[@bendonoghue7009]

A big part of the plot of the New Blood episode is showing how advanced the dinosaurs were and how that ensured their survival to dominate the world. It’s now been confirmed that other animal groups were much more dominant and it’s now more likely the dinosaurs took over more because all their competitors were wiped out by the Triassic extinction.

[@thomaszaccone3960]

This was awesome. The Triassic was an interesting period.

[@notquitenick8442]

congrats on the milestone! I love learning about fascinating but lesser known prehistoric creatures, keep up the great work!

[@CaptJohnsen]

I just love your channel. Watching one of your videos right before bed is the best way to wind down.

[@bencake28]

Dicynodontia ❤ Amazing lifeforms. And very successful! Thank you for this great Video about these Guys. 🦖 If I have had a "time machine" 🛸 I want to travel to the last period of Triassic. Cause of so many reasons! 🤓

[@lerneanlion]

Upon seeing the thumbnail, it's my childhood there. Some information from Walking With Dinosaurs maybe outdated but all of its episodes are still entertaining to watch. Also, have you ever thought of what the world will looked like if the dinosaurs never evolved and the synapsids remained at the top of the food chains? Will the apes that eventually evolved into us humans will evolved much sooner than in our timeline? And if that is the case, how far developed we will be before the certain incident that happened in spring at 65 million years ago will happened?

[@chimerasuchus]

Apes as we know them almost certainly wouldn't have evolved due to the butterfly effect.

[@nightshadeentertainment6568]

Awesome video. I'm still politely asking for that Rutiodon Video, if you could please. Love the content.

[@luis180386]

Loved the video, keep up the good work

[@Clearlight201]

There's some evidence for the theory that during mass extinction events some species which become extinct were also on the decline for a long time prior to the events. Thus it's not necessarily an either/or situation with dinosaurs replacing earlier species as the dominant life forms. Usually it's thought that 'either' they out-competed them 'or' they were in the right place at the right time during the extinction events. I think both factors together are the likely scenario. Furthermore, even the term 'out-compete' is perhaps not the most accurate. Every species evolves in and is adapted to a certain environment and certain food sources and there's only so much further evolving and adapting a species can do before, after millions of years, the environment and food sources are so different that it is no longer well suited and it begins to decline. Newer species are better adapted and suited to the new environments and newer food sources and do better, but only because they are more closely matched to these environments and food sources. Thus if anything a species is eventually 'out-competed' not so much by other species as by the environment itself. No species is built to last forever as that would imply infinite adaptability to ever-changing environments and ever-changing food sources. (This will very much apply to humans eventually too).

[@ecurewitz]

Congrats on reaching 50000

[@DarthBobCat]

Welcome back!

[@HassanMohamed-jy4kk]

I’ve got some great ideas and some great suggestions for you to make KZbin Videos Shows about some more Prehistoric Extinct Crocodilian Species, such as Lazarussuchus, Plesiosuchus, and Metriorynchus adding that to your collection on the next Chimerasuchus coming up next!!👍👍👍👍👍⭐️⭐️⭐️⭐️⭐️

[@posticusmaximus1739]

Agreed, I don't know if he's done a video on Thalassosuchians yet

[@akiraasmr3002]

Can you also do videos on creodonts like Hyaenodonts and Oxyaenids. Also Mesonychids since they were always intriguing to me.

[@chimerasuchus]

I don't have any plans to make videos about Cenozoic mammals.

[@zzraven362]

My first creature that I brought back to the present in minecraft prehistoric fauna mod.And my favorite proto mammal aswell!

[@Numidiary]

Great video and great narration

[@johnshields6852]

220 million years, as if I don't feel insignificant enough already, so geologically speaking we're here for like couple milliseconds.

[@Dr.Ian-Plect]

no

[@mlggodzilla1567]

Another great video 😎

[@geckoraptor9397]

WWD introduced me to this animal

[@JasonBezemer]

Since I don’t exactly know much about Placerias, this was certainly pretty interesting to watch, especially when it came to sexual dimorphism in the genus.

[@CJ-111]

Nice video

[@Djingoclottates]

Fossils being common and uncommon kinda makes me wonder how paleontologists in the far future will interpret our layer. "The domestic chicken was one of the most succsessfull organisms of the early computer age. They even build intricate shrines where they would lay dead chickens to rest by the thousands, the mural on the walls seems to depict some kind of hominid with facial fur and runes spelling KFC in a forgotten alphabet. The importance of chickens to the hominids is further highlighted by the afformentioned shrines being found in almost every large settlment site "

[@unoriginalname2842]

I drew the thumbnail :)

[@hatsudopia5085]

Stem mammals are so cool

[@mivapusa]

Walking with Dinosaurs gave me a childhood love for these beauties

[@Techpriest_Skitarii4935]

Their voice...I can hear it from my inner childhood

[@MrYvax]

Can you do a video about Euparkerya, please??

[@threebythestreet]

What is this image at 11:00 taken from?

[@newt9303]

If you can could you make a video on Pantylus or Peltobatrachus? They are my favorite prehistoric amphibians😁

[@alexandermorrison1010]

Good cool vid

[@ГерманМак-д4ы]

"Walking with dinosaurs"

[@threebythestreet]

Were their any dicynodonts that stayed rather small during the late triassic or did thay all get larger like Placerias?

[@quantumcat7673]

Could you make a video on the famous badassaurus?

[@jackwalters5506]

Not related to this video but I've seen some paleoart of quadrupedal non-dinosaurs that are slender, almost like gazelle. I want to learn more about that but can't seem to find anything by googling it. Do you have any idea what I might be talking about?

[@chimerasuchus]

I think you are referring to silesaurs (usually called "silesaurids"). They are either the closest relatives of the dinosaurs or are the first ornithischian dinosaurs.

[@jackwalters5506]

@@chimerasuchus yep that was it. Thanks a ton!

[@chimerasuchus]

@@jackwalters5506 You're welcome!

[@johnball320]

I feel the synapsids and even non-dinosaur archosaurs get an unfair dismissal in people's minds. They are seen as archaic, less well adapted life whose time had run out when dinosaurs could out-compete them. As you have alluded to. Shows like Walking with Dinosaurs were great, but the science was of their time. Not like this should take away from dinosaurs, since they were fascinating themselves and led to the evolution of birds. However, the synapsid link with mammals is fascinating for understanding how we came to be, surely, but that link is far less known among the layperson.

[@vermicelledecheval5219]

One interesting fact is that dicynodonts made it through the Permian Triassic extinction but no therapsids carnivores.

[@chimerasuchus]

The large predator Moschorhinus did survive into the Early Triassic, as did smaller carnivores

[@jensphiliphohmann1876]

...like Cynognathus, for example.

[@Afrologist]

I never liked the term "stem/proto mammal" because of the assumption that just because it's a Synapsid that it must be closely related to Mammals. I'm seeing a lot of papers that place Testudines into Diapsida despite having Anapsid skulls. If the number of fenestrae isn't set in stone &, like dentition, is typically conservative yet capable of convergent development, then I don't see how being a Synapsid automatically makes you closer to Mammals than anything else. You can readily see from their morphology alone that Dicynodonts & other Anomodonts are fairly divergent from the Cynodonts & Eumammalia. I personally feel that a big reason these animals are underappreciated by most of the public & academia is the assumption that they are mere failed experiments or primitive, basal holdovers compared to the more derived Mammalia which came after them.

[@Dr.Ian-Plect]

"I never liked the term "stem/proto mammal" because of the assumption that just because it's a Synapsid that it must be closely related to Mammals." - well, it denotes a degree of relatedness that a synapsid and non-synapsid don't have (more below) "I'm seeing a lot of papers that place Testudines into Diapsida despite having Anapsid skulls. If the number of fenestrae isn't set in stone &, like dentition, is typically conservative yet capable of convergent development, then I don't see how being a Synapsid automatically makes you closer to Mammals than anything else." - that phylogenetic placement is based upon common ancestry (cladistics), now I have my own gripes about this and many other examples where a group is placed in a clade because of ancestry regardless of whether it still has the trait. Testudines are indeed morphologically anapsid, but diapsid by grouping - however, your point about synapsid-mammal relatedness is flawed. To be deemed synapsid means your lineage has split from say Testudines, as you mentioned them already. Testudines are sauropsids, the sister clade to synapsids. When these 2 lineages split from a common ancestor the genetic similarity (relatedness) diverges in each lineage. And so later synapsids (mammals) retain greater relatedness with early synapsids than they do to any sauropsid

[@TedShatner10]

​@@Dr.Ian-PlectI still feel we modern mammals are ultimately very derived or divergent Amniote reptiles (alongside modern birds).

[@Dr.Ian-Plect]

@@TedShatner10 Explain; a) what you mean by 'feel' b) why you feel so

[@TedShatner10]

@@Dr.Ian-Plect Basal Synapsids (like pelycosaurs) most certainly had more in common with basal Diapsid sauropsids at the time than with post-Triassic crown mammals, sharing a common Amniote stem-reptile ancestor that was more recent in the Permian period than the last common Jurassic period mammal ancestor is to modern day placental and marsupial mammals.

[@Dr.Ian-Plect]

@@TedShatner10 Your understanding is obsolete; - pelycosaurs is an obsolete term, early synapsids can be summarised with the current terms stem/proto mammals - the amniote common ancestor of synapsids and sauropsids was NOT a stem-reptile. This is obsolete, we no longer think that. And, you can't nominate a stem lineage that later on diverges into distinct lineages _before_ one of those lineages becomes what the term 'stem reptile alludes to! As the first point above notes, early synapsids are known as stem mammals, not stem reptiles or the obsolete 'mammal-like reptiles'. That amniote common ancestor came from the reptilomorph lineage (in turn, that lineage name is a legacy of older thinking, don't seize upon it to bolster your thinking!), those being tetrapods closer to the amniote common ancestor than to modern amphibians

[@shockdrake]

What is the genetically closest modern animal of Placerias?

[@chimerasuchus]

All mammals share a more recent common ancestor with each other than with Placerias, so none of them are any closer to it than any other.

[@brianedwards7142]

Do we know for a fact they didn't have an outer ear or is that just assumption? Just wondering what they sounded like and how good their hearing was.

[@chimerasuchus]

The development of the mammalian ear happened much later. From what I remember, earlier synapsids had reptile-like ears.

[@brianedwards7142]

@@chimerasuchus Thankyou.

[@maozilla9149]

nice

[@МаксимМалеев-и7д]

Great

[@mammadingo9165]

Place rias Cory or quarry?

[@chimerasuchus]

Quarry.

[@TeamFortress2Official]

So it's archosauria ceratopsians but real

[@the_royal_frick634]

Papa's Placerias

[@rkozakand]

Lisowycia is pronounced Leesovychia. with the ch as in church.

[@Sirdilophosaurusthethird2.0]

He eat plants

[@myhonestreaction3120]

Dinosaurs aren't reptiles.

[@kade-qt1zu]

Nope, they're archosaurs, which are in-turn reptiles. Unless you also don't consider crocodiles as reptiles.

[@Predation_records]

All dinosaurs are reptiles

[@TeethToothman]

🪳⚡🪳

[@Stachosaurus001]

Placerias

[@RemusKingOfRome]

Yes, when I first saw these in Walking with Monsters, I thought, that's the weirdest, defenseless creature I've ever seen. No wonder it died out. :D

[@chimerasuchus]

Placerias was far from defenseless. If anything, it is the most dangerous herbivore that has been found in Late Triassic North American.

[@LudosErgoSum]

Dinos dominated mammals so hard because...welll...just look how ugly and chubby these mammals were! Dinos were true buff chads that ate up all these unfit simpsaurs. Only an asteroid can destroy chad kingdom. I miss when dinos were around to chomp down those ugly mofos.

[@chimerasuchus]

Dicynodonts weren't mammals, and like the non-avian dinosaurs they only became extinct due to a mass extinction.

[@marcinm.8037]

😀😀😀😀😀😀😀😀😀😀😀😀👍👍👍👍👍👍👍👍👌👌👌👌👌👌👌👌👌👌