Wednesday, September 22, 2010

Endemism in the Time of Chasmosaurs

After tossing about ideas for the title of this blog for a while, I settled on a twist on the title of Gabriel Garcia Marquez's Love in the Time of Cholera. I then had to decide between dinosaurs with a nice hard "C" at the beginning of their generic name. There were some good ones. I ultimately chose "chasmosaurs" because I've always liked the name, and I liked that it wasn't a single dinosaur, but rather a whole tribe of ceratopsids, always one of my favorite groups. In contrast to their centrosaurine relatives, the chasmosaurine ceratopsids are distingushed by larger brow horns and frills.

Today, a team of scientists led by Dr. Scott Sampson has published a paper in PLoS One, revealing two new members of the chasmosaurine line: Kosmoceratops richardsoni and Utahceratops gettyi. They were denizens of the southern part of Laramidia, a small continent formed by the sea that clove North America in twain during the Late Cretaceous. Kosmoceratops sported especially odd headgear: long, sideways-pointing brow horns and swept-forward spikes lining the top of its frill.

Utahceratops and Kosmoceratops with a map of Laramidia. Copyright Lukas Panzarin, provided by the University of Utah.

As you would expect from research led by Dr. Sampson, the paper concerns itself with larger issues of dinosaur ecology. The authors present a convincing scenario of two coexisting lines of chasmosaurs, one in the north and one in the south, separated by an as-yet unknown barrier.

Laramidia was a strange place. There was a narrow strip of land crammed between the sea mentioned earlier and a great mountain range containing the future Sierra Nevadas (the Rockies were only just beginning to form). Most of the North American late cretaceous dinosaurs we know are from this ribbon of low-lying land on Laramidia, a veritable dinosaurian paradise. This is the big, exciting question the paper asks. Why was there such a stunning diversity of dinosaurs in such a small area? I'm looking forward to more discoveries, and more reconstructions by Lukas Panzarin. Dude's got skills.

The Open Source Paleontologist (the blog of paper co-author Andrew Farke)
DinoChick Blogs
Dinosaur Tracking
Discovery News
University of Utah press release


  1. "Kosmoceratops Richardsoni". I think Kramer would be thrilled to know he has a dinosaur named after him. I assume it is because the frill resembles Kramer's hair.

    This completely flips the picture of the late Cretaceous as being one of narrow speciation. So there was a sample bias! Our fossil sample for the era comes mostly from two small, isolated geographical regions. There actually is very diverse speciation within that small sample.

    So maybe the late Cretacious species weren't just the final remaining embers of Dinosauria, overspecialized and on their way to extinction. This makes it seem as if Dinosaur species were thriving and adapting right up until the end.

  2. And just think of what we're missing from Appalachia... there's a sample bias for you!

  3. Kosmoceratops drawing, and a link to this blog, at the webcomic Dawn of Time:

    A great comic - well drawn and with entertaining story lines. And it features a brave triceratops named Blue, what is not to love!?

  4. Yeah, I love Dawn of Time! Very cool kosmo drawing too. Those combed forward frills are so great. He needs to add a feed to it so I can add it to my "morning comics" folder on Google Reader.


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