r/Paleontology

Is there any evidence of dromaeosaurs having decorative plumage or is it just speculative?
What is the evidence for a possible keratinized covering on the "snout" (not sure what the right word is)?

Personally I like the idea of them having feathers for display or mating purposes like modern day raptorial birds and there's a picture of a hawk eagle as an example

paleoart by https://x.com/JoannaKobierska?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor

can prehistoric crocodile like the deinnosuchus have it's mouth taped and not be able to open it? like the modern crocodile? it suddenly came into my mind and I'm not sure if this has been asked since I can't find any. I'm a noob at paleantolgy so I don't know alot about them.

I knew there were some footprints close to this beach in Portugal, there was not signaling or anything, I just climbed some rocks and there they were. Can someone confirm if they are real? And if so, any clue what type of dino they would belong to?

since the Morrison spanned for 156.3–148.1 million years within several counties and localities there was definitely some fauna that never lived with each other or never evolved to meet which is why i'm asking do we have any slight comprehensive ideas of what lived with what within the many eras of the Morrison formation?

Found at Manasota Key, Florida, USA on Sunday. About 1 cm long.

so the title of largest carch was originally giganotosaurus. However it was based off a single jawbone and 3 d scanning proved it wasnt much bigger than the holotype. The holotype itself is 12 m or so in length and so it brings down the rest of the animal to that length.

this creates a tie between it and mapusaurus and carcharodontosaurus. These 2 are both usually estimated between 12-12.5 m in length. the issue is these 2 are estimated based off fragmentary remains. so which one is truly bigger is uncertain.

giganotosaurus's size has the greatest confidence since the holotype is 70 percent complete. but the other 2 have fragmentary but giant remains that cant be ignored.

my theory is that Thylacosmilus hunted prey that was much, much larger than itself(like a weasel). Thylacosmilus immediately stands out from all sabretooths, having by far the most extreme sabres - they have a triangular cross section, and were very thin and blade-like(even compared to other sabretooths.) Thylacosmilus may have had among the most fragile teeth of any sabretooth. they were also proportionally among the the longest and most deep rooted. these sabres were so extreme, that their eyes were almost side facing - if Thylacosmilus was an ordinary sabretooth, all of these adaptations would be unnecessary - longer, thinner teeth means higher risk of breakage when subjected to random directional forces, and even a slightly higher risk is too much to be evolutionarily stable unless if there is a less risky alternative. there is no real benefit to having longer, thinner canines if Thylacosmilus was regularly eating similar sized prey - shorter, stronger teeth can still pierce just as deep and still lacerate the cartoid and windpipe with a lesser risk of breakage. semi-side facing eyes are a big disadvantage when hunting agile 100-200kg ungulates. tracking prey is important for predators, but with a blind spot and semi side facing eyes, this would become difficult. to add to this, thylacosmilids also had bony flanges, which are metabolically costly and unnessecary if it used a smilodon style hunting method(smilodon did not have bony flanges). it all seems like its maladapted to the smilodon niche now picture a Thylacosmilus hunting a one ton megafaunal animal, and all of its extreme adaptations make sense - it doesn't need excellent vision to track a huge lumbering Toxodon. giant animals often have thicker hides, so having thinner canines allows smoother puncturing. longer canines might be more fragile, but they also pierce deeper and inflict more damage, which is exactly what you need to subdue giant prey with thicker layers of muscle and skin. large animals often have poorer senses, so a Thylacosmilus wouldnt have to be as stealthy as it would for a fast, alert Theosodon. another feature that Thylacosmilus has is the lack of bone tolerance. this means that more food has to be found, as it cannot derive nutrients from the marrow as a more generalised carnivore could - if hunting smaller prey every bit of energy should be consumed, because each hunt puts the predator at risk and expends lots of energy. for a pedator that eats prey much larger than itself, it can be pickier(and doesnt have to compromise its sabres) because much more soft flesh is available in a 1.1 tonne toxodon than in an 100kg adinotherium. so, how could it hunt prey that is bigger than itself? my main theory is that it would latch on(like a weasel) - its body is very well suited to this - it has semi opposable thumbs on both its hind legs and front legs(allowing greater grip). its body is very low slung which makes them significantly harder to shake off(due to the low centre of gravity) and improves ballance. the stiff back acts like an anchor. plantigrade feet increase stability giant megafauna have slow reactions, poor reflexes and have many blind spots - attacking from behind or from other angles could give an easily accessible window of opportunity. after latching on, the Thylacosmilus will repeatedly drive its canines into the flesh of the prey - the beauty is that the location doesn't particularly matter- a deep bite can cause serious shock and blood loss anywhere, because the canines are 7 inches long(respectable length if you ask me). if this is true, then it does not have to wrestle prey to the ground and target a particular area of the neck(as smilodon did) which is super risky, especially for the canines, which are literally even more fragile inThylacosmilus. large animals tire much more quickly than smaller ones, so it wouldn't have to latch on for that long before blood loss and shock would weaken it. when prey is weakened, more directed bites can happen. lastly i would like to explore a case study of extreme macropredation in nature. a weasel and a rabbit. rabbits are about 10 times heavier than a typical least weasel- a typical least weasel can max out at around 13km/h for short distances - rabbits can bound around 50km/h for longer distances so can easily out pace a weasel(thylacosmilus was probably faster than its prey). rabbits have very acute senses, with almost 360 vision and excellent hearing, they can detect threats much better than a typical megafaunal herbivore. rabbits are very agile and can bound in a zigzag motion to evade predator, but no megafaunal animal can do this to the same extent. note that weasels probably have much higher metabolisms than thylacosmilus, because weasels are much smaller and have a higher eutherian metabolism - this means that thylacosmilus would not have to employ this risky tactic as often as a weasel would. this doesnt prove the theory, but does show that the "persistence latching" strategy might actually scale, well, and behaviours like this arent out of the question. also, to clarify, i am not stating that thlacosmilus couldnt hunt similar sized prey, I'm suggesting that it may have been able to regularly subdue and consume prey that was several times larger than itself. still this is just a theory and needs more evidence and actual biomechanical studies to prove, and I will remain open minded to your thoughts - please ask any questions/objections you like

https://www.rnz.co.nz/news/top/595701/colossal-biosciences-says-breakthrough-means-it-s-a-step-closer-to-resurrecting-giant-moa

While looking at the sizes of various tyrannosaurs I went to the Nano wiki page since the phylogenies had a pretty good list of tyrannosaurs and I ended up noticing some interesting things I hadn't noticed before. I also remember seeing basically no one actually talk about these phylogenies when they almost outshined Nano itself for me(I'm aware they need further testing, but they're still super interesting to me). I'll be focusing on the Tyrannosaurid phylogenies specifically since that's what interests me the most about them.

Both Phylogenies

Starting with something I did notice back then, the expansion of Albertosaurinae. More specifically Jinbeisaurus being part of the clade, which expands the clade into Asia. Bistahieversor joining the clade is also neat since it was either placed outside of Tyrannosauridae or as a Tyrannosaurine.

Phylogeny A

Phylogeny A's most interesting thing to me is it nuking Teratophoneini with Teratophoneus being an Albertosaurine and Lythronax being in the tribe Tyrannosaurini. Lythronax's placement supports Tyrannosaurini originating in North America as it'd be the earliest member of the group, predating both Zhuchengtyrannus and the Hunter Walsh Tyrannosaur.

Phylogeny B

The big thing with phylogeny B is Asiatyrannus's placement as an Alioramin. This maybe Tarbosaurus is typically placed closer to other tribes of Tyrannosaurine, and with its recent synonymizing with Tarbosaurus this placement only stands out more to me.