Wednesday, November 28, 2012

Archosaurs of Alabama

Welcome back, everybody! Where last we left off, I'd done a brief, illustrated survey of some notable Alabama Cretaceous marine fauna. Here, we turn out attention to some of the archosaurs that would have lived in the parts of the state not covered in seawater. 

I speak, of course, of dinosaurs. Mostly. 


Nodosaurid  © Asher Elbein
Alabama has quite decent nodosaur remains, most of them the product of carcasses washed out to sea by floods and river currents. There, the bodies bloated and were extensively scavenged before they sank to the bottom. This is my first ever attempt at an armored dinosaur (or at least, the first I'm willing to show in public) and I initially thought of restoring it with bright warning coloration, similar to that of a hornet or a yellow jacket. Suffice to say, it didn't really work, so I defaulted to a more hippo-like pattern instead.

 I'm somewhat taken with the idea of nodosaurs dozing in mudpits, small feathered dinosaurs perching on their spikes. It might be worth illustrating at some point.

Lophorhothon © Asher Elbein
Lophorhothon is Alabama's main hadrosaurid, and like the nodosaur remains it occurs primarily in marine deposits. It has the twin dignities of being both Alabama's first recorded dinosaur genus and being one of its most taxonomically uncertain; there's some debate as to where, precisely, it fits with regards to other hadrosaurs (or if it's even a hadrosaur at all.) Following the prevailing opinion, I went ahead and restored it as something similar to Prosaurolophus. I wanted something restrained and somewhat dignified, so I turned to a color scheme reminiscent of African grazing mammals.

Dromaeosaurid  © Asher Elbein
The most speculative reconstruction of the bunch. Dromaeosaur fossils in Alabama are extremely rare, centering around a few scattered bits and a preserved feather or two. It's not that surprising; small size and light bones make dromaeosaurs fairly chancy when it comes to preservation, and in marine deposits the likelihood of a carcass lasting is virtually nil. Given that, this is best understood as guess at what an Alabama dromaeosaur might look like.

 I took this illustration as a chance to play around with some different ways to render feathers (I'm particularly proud of the neck region.) The patterns are based--extremely loosely--on the Caracara, a modern raptor that spends a fair amount of time on the ground.

Appalachiosaurus © Asher Elbein
No Cretaceous dinosaur assemblage is complete without a big theropod, so here we have Appalachiosaurus, the 30 foot tyrannosaurid. Appalachiosaurus also has the distinction of being the most completely known theropod from the eastern coast of North America, a part of the country that lacks the excellent fossil fields out west. The mounted specimen at the McWayne Science Center shows large, three clawed arms. I'm unsure of the accuracy--nothing has apparently been published yet--so I chose to restore Appalachiosaurus as a fairly typical albertosaurid. I gave it a sparse covering of protofeathers on the head and neck, and based the coloration on that of the Emerald Swift, an extremely pretty little lizard common in Central America. There was no particular scientific reason for doing so; I just liked the challenge of adapting the color scheme to an animal of radically different size and shape.

Of all of the reconstructions, this is the one I suspect is going to be rendered invalid by later publications, but one of the nice things about paleontological art is that it affords you the opportunity to make guesses that may or may not be correct.

Pteranodon © Asher Elbein
Finally, Pteranodon. Probably the most famous animal in this post, and naturally so. Everybody loves Pteranodon. I chose to reconstruct this particular beast with the wing arrangement favored by John Conway, as I've always found it very aesthetically pleasing. I also gave the animal a small mane under the crest, which would fluff up for display purposes. I decided to avoid the typical sea bird coloration for this illustration. While there a good reasons to believe that Pteranodon might have been so adorned, I wanted to try something different; to wit, a giant fruit bat. I also chose to make the crest less brightly colored, again for the sake of being contrary.

And that's it, folks! This artistic summary of Alabama's Cretaceous life now draws to a close. If you liked the art, feel free to head over to ashere.deviantart.com, for all your folkloric and dinosaurian needs.

Tune in next time for more comic book dinosaurs and a dissection of why, exactly, The Valley of Gwangi is so great.




8 comments:

  1. These are lovely, and I appreciate that you took the time to give us a little background behind your artistic and scientific decisions. Looking forward to those future posts, too.

    ReplyDelete
  2. Dignified hadrosaurs for the win! These are beautiful again, and that dromaeosaurid is just gorgeous. I of course enjoying reading about the thoughts behind your decisions too.

    ReplyDelete
  3. Thirded. Wonderful stuff, and a great way to highlight an underappreciated region in paleontology.

    ReplyDelete
  4. I like the crest on the Pteranodon. Larry Felder did something similar with his pteranodon with "In the Presence of Dinosaurs".

    ReplyDelete
  5. Very cool idea!

    (And, if I may add, these would all make excellent silhouettes....)

    ReplyDelete
  6. Good stuff and I, too, appreciate reading a little about your thoughts behind each piece.

    With regard to Appalachiosaurus, I think the earlier thinking has been that it was more basal, like Dryptosaurus, and it has therefore been assumed to have had longer arms and three-fingered hands. The fact that both of their skulls are not as massive as the more derived Tyrannosaurids further east might indicate that there was not the same evolutionary pressure to reduce weight at the front end, and to shift the focus to the jaws for prey capture and processing.

    Guess we'll have to wait for some more bits to be discovered before we can be definitive about whether it was more like Dryptosaurus or Albertosaurus or something else.

    ReplyDelete
  7. Too bad you never got around to fixing the dromaeosaur's wing. Still nice work all around though, otherwise.

    ReplyDelete
  8. Im unaware of any modern references placing Lophorhothon in Hadrosauridae, though I don't follow ornithischians closely. What are they?

    As for Appalachiosaurus, we lack any forelimb remains, and don't even know if Dryptosaurus had two fingers or three. Well, if you follow the consensus, Raptorex shows Appalachiosaurus had two, but I'm doubtful about it being so basal...

    ReplyDelete

Trolls get baleted.