Thursday, March 25, 2010

The Antiquity of Pachyrhinosaurus

For those of you relatively unfamiliar with ceratopsian dinosaurs, Pachyrhinosaurus may be an unfamiliar name. It's one of my favorite dinosaurs, partially because it's one of Alaska's Mesozoic saurians. It's also just plain wierd--instead of horns, Pachyrhinosaurus has a bony boss, like that of a musk ox or bison, except over its nose instead of its forehead. There are two known species: Pachyrhinosaurus lakustai is the better-known of the two and is represented by hundreds of bones and dozens of individuals. It was only recently named and described, in 2008. This is what it looks like, more or less:

Notice the spikes and bosses. This was a strange-looking ceratopsian, fo' reel, yo. But it's the second species named. The first species--and the genus--was named back in 1950 by Charles Sternberg. It is Pachyrhinosaurus canadensis, and our man Charles named a whole new family based on the holotype skull, since as he could not easily fit it into the Chasmosaurinae or Centrosaurinae,* so he erected the Pachyrhinosauridae for his new critter. P. canadensis actually doesn't look too horribly different from P. lakustai, but Sternberg was working with a partial skull and didn't really know what to make of this hornless wonder. So he crafted a 1/6th scale clay model for all to see, shown below:

It looks like a Protoceratops with a handy plate to put your drink on its nose. It's also smiling. Still, this is important: here we have the first life restoration--crude though it may be--of this most bizarre ceratopsid dinosaur. I very much like Sternberg's description of the beast:

"The specialized development, the large massive head and the great thickness of bone is suggestive of the freakish development that took place among some of the dinosaurs near the very close of the Cretaceous, about Lance time."

Well put, Charles, well put. You didn't know the half of it....

*Back then, the Ceratopsia was a sub-order, divided into two familiest: Chasmosauridae and Centrosauridae, so Sternberg erected a third family. Today, we recognize the Ceratopsidae as a family, with the Chasmosaurinae and Centrosaurinae as sub-families. Sternberg's Pachyrhinosaurus-centric group still exists, however, as the Pachyrhinosaurini, which includes both species of Pachyrhinosaurus and Achelousaurus.


tanystropheus said...

Pachyrhinosaurus has long since been a favorite of mine as well for precisely the reasons you've cited.

Traumador said...

cool start to a series on pachyrhinos... a series right, PLEASE :P

my only humble request, as an avoid follower of palaeo history (especially those that worked in alberta at some point). could you either refer to "charles" with his m middle initial (for mortram, one of my fav names :P) or as charlie (as was his popular nickname) to differentiate him from his dad charles h. sternberg.

i'm reading a bunch of michael everhart's books (which are fantastic... if you're into cretaceous marine reptiles) and in one he talks about "george sternberg's" work in kansas in the 1880's. this confused the heck out of me as the george sternberg i'm familiar with was charles h.'s son and charlie m.'s brother. this 1880's george would have been roughly the same age as charles h to work in 1880...

well reading further it turns out this was charles h.'s brother, who he named his son after... however without the explaination right away i was questioning dr. everhart's book for several pages. thinking he'd made a major research error...

anyways just a timing issue. as i hit this sternberg problem two nights ago. now that my (non angry :P) rant is done, i thank you again for the great intro to pachyrhinos discovery!

(love the old skool restoration! i've never seen or heard of it before... would you consider posting a copy of this post on ART Evolved... or a whole article on pachyrhinos reconstructions? we miss you alaskan guys on ART Evolved...:P)

Zachary said...

Sure, Craig. I keep meaning to get back into the Art Evolved swing of things, but my new job's been keeping me VERY busy. I'm only now getting a firm schedule down.