Daurlong wangi, a new and amazingly preserved dromaeosaurid from the Jehol Biota

[Concavenator]

Daurlong wangi, gen. nov., sp. nov., is a dromaeosaurid hailing from the Early Cretaceous and it is part of the Jehol Biota. The holotype is so well-preserved that it even has intestinal contents. Look at that beautiful fossil!



Here's the phylogenetic analysis presented in the paper:



It has been recovered as Zhenyuanlong's sister taxon.

[andrewsaurus rex]

wow, exciting find.  It has a weird little head.

[Halichoeres]

Mmm, Mesozoic chitterlings

[Mamasaurus]

That is beautiful! Is that preserved integument along the back of the neck?

[Faelrin]

@Halichoeres That's one way to think of it lol.

Been quite a while since there's been a dromaeosaurid this well preserved? I mean I think Zhenyuanlong was the last. Great to see in any case.

Edit: Got them long legs like Zhenyuanlong too. I can see why they said it was related, if not other reasons, such as location, etc.

[ceratopsian]

Here's the link to the paper in Nature - not paywalled.  An exciting find!

https://www.nature.com/articles/s41598-022-24602-x

And here's the artwork by Delrio, produced under supervision of one of the authors:

[ceratopsian]

There is a frog preserved on the slab, but not from exactly the same level, so not simultaneous deaths.

[andrewsaurus rex]

Beautiful artwork.  Fleshed out, the head doesn't look so weird after all.  Quite an elegant looking little guy.

Why did so many dromaeosaurs have large sickle claws if they were only eating small, bite sized prey?

[ceratopsian]

Cau has an article here on the post mortem displacement of bones making it look like the animal had in life a crest:

https://theropoda.blogspot.com/2022/11/daurlong-strangecrest-or-how-i-learned.html?fbclid=IwAR03CN1U_56kNgT4p2-OFx3oNv2ubC1_z2HaVwr3US79Z2-wvgZ4OLhgeLM

[Sim]

I'm always happy to see a new dromaeosaurid!  I notice it has a short tail like Tianyuraptor, since these two have that I guess Zhenyuanlong most likely had a short tail too.

The results of the phylogenetic analysis are interesting.  Tianyuraptor and Zhenyuanlong are recovered as separate with Daurlong being Zhenyuanlong's closest relative.  Linheraptor and Tsaagan are also separate.  While Velociraptor osmolskae is recovered as the closest relative of Velociraptor mongoliensis, something that hasn't always happened.

Why did so many dromaeosaurs have large sickle claws if they were only eating small, bite sized prey?

The sickle claw could be used to impale small prey causing its swift death.  I get the impression dromaeosaurids would eat small prey if they caught it, however there is actually quite a bit of evidence that they hunted relatively large prey at least sometimes.
For Velociraptor this is suggested by the Fighting Dinosaurs specimen which has its sickle claw in the Protoceratops's throat area - the Velociraptor might have known that could kill the Protoceratops.
For Deinonychus, it's now known it had a powerful bite that could penetrate Tenontosaurus bone, and how often Deinonychus remains are found associated with Tenontosaurus specimens suggest the former hunted the latter.
For Dromaeosaurus and Atrociraptor, their powerful jaws suggest they hunted prey that was bigger than bite-sized.
And Utahraptor and Achillobator took this to an extreme, being very powerfully built but not very fast, suggesting they hunted relatively large prey that they took down with power.  Interestingly these two were apex predators, Utahraptor being the largest predator in its ecosystem and Achillobator being as large as the contemporary gracile tyrannosauroid Alectrosaurus.
For all these dromaeosaurids a large sickle claw could have helped them grip and kill prey.
Microraptor though does seem to have preferred bite-size prey, having been documented to have eaten a small mammal, bird and lizard.  It's also known to have eaten fish although I'm not sure how big.

[stargatedalek]

Long toes and claws are also useful for catching smaller prey, spreading them out like a net while leaping to get a better grip on mid sized prey animals or be more likely to catch bite sized prey.

[andrewsaurus rex]

Long toes and claws are also useful for catching smaller prey, spreading them out like a net while leaping to get a better grip on mid sized prey animals or be more likely to catch bite sized prey.

That's interesting.  But it doesn't explain the evolution of a highly specialized retractable toe claw.  Just normal toes with normal claws would accomplish the same thing.  The extra large size and ability to be held up at nearly 90 degrees to the other claws suggests a far more specialized purpose.

[stargatedalek]

Long toes and claws are also useful for catching smaller prey, spreading them out like a net while leaping to get a better grip on mid sized prey animals or be more likely to catch bite sized prey.

That's interesting.  But it doesn't explain the evolution of a highly specialized retractable toe claw.  Just normal toes with normal claws would accomplish the same thing.  The extra large size and ability to be held up at nearly 90 degrees to the other claws suggests a far more specialized purpose.

The sickle claw likely evolved for latching onto mid-sized prey. Picture how hawks and falcons dig their claws into a pigeon or similar sized bird while pinning it to the ground. And it was retained in members that started taking alternative smaller prey.

[andrewsaurus rex]

ah that's interesting and it was retractable I guess, just because it would be in the way during walking and running, due to it's large size.   Not as sexy as the slashing toe claws of days gone by,  but interesting nonetheless.