Avisaurus darwini here lived at the very end of the Cretaceous, about 66 million years ago, in what is now the Hell Creek fossil beds in Montana, USA.
It was a member of a diverse group of Mesozoic birds known as enantiornitheans, which retained claws on their wings and often still had toothed snouts instead of beaks – and being part of the avisaurid family it was also one of the larger known examples of these birds, similar in size to a modern hawk at around 60cm long (~2′).
Although this species is only known from isolated foot bones, the remains have distinct enough anatomical features to show that Avisaurus had powerful gripping talons similar to those of modern hawks and owls, suggesting it had a similar lifestyle hunting small vertebrate prey in the ancient swampy Hell Creek ecosystem.
References:
- Clark, Alexander D., et al. “New enantiornithine diversity in the Hell Creek Formation and the functional morphology of the avisaurid tarsometatarsus.” PloS one 19.10 (2024): e0310686. https://doi.org/10.1371/journal.pone.0310686
- “Predatory birds from the same fossil formation as SUE the T. rex.” Field Museum, https://www.fieldmuseum.org/about/press/predatory-birds-from-the-same-fossil-formation-as-sue-the-t-rex
- Wikipedia contributors. “Avisauridae” Wikipedia, 21 Oct. 2024, https://en.wikipedia.org/wiki/Avisauridae
- Wikipedia contributors. “Avisaurus” Wikipedia, 09 Nov. 2024, https://en.wikipedia.org/wiki/Avisaurus
Could I ask your thought process behind the beak? I was excited when I saw your reconstruction, as it seems like the first rigorous (as much as the fossils allow) attempt at Avisaurus in quite a few years. I know toothy, dromaeosaur-esque heads used to be the norm for these guys, but with more “beaked” Enants being known these days I was curious if the consensus changed? Or at least your reasoning was.
My original sketch for thisdid have visible teeth, similar to one of the reconstructions on Wikipedia – and, much like that wiki image, I was going for something similar to the unnamed Adamantina Formation enantiornithean specimens with a slightly “hooked” upper jaw tip.
But ultimately I decided to try to leave the snout a little more visually ambiguous since enantis had so much diversity and convergence and unexpected weirdness going on with their jaws. It can be read as a proper toothless beak if you like, or it could also be a more “traditional” toothy snout with lips covering the teeth with the mouth closed.
(Basically, I just didn’t want to commit too hard one way or the other!)
Understandable! Thanks for the info, I hadn’t heard about the Adamantina specimens, I’ll have to look into that!
I love the design of the Avisaurus, did you base the design off of the red tailed hawk, because I am getting a Hawk vibe from it, good job on the design
Also I’m sorry about the Hadrosaur thing, I did not mean that in a rude way.