Tuesday, October 27, 2009

Pachycephalosaurus-Stygimoloch-Dracorex debate now in print (sort of)

At the 2007 Society of Vertebrate Paleontology meeting Jack Horner presented a talk on Pachycephalosaurus, Stygimoloch and Dracorex, basically saying that Stygimoloch and Dracorex are growth stages of Pachycephalosaurus. This talk has been being debated pretty much every day since it was given by someone (see an example of past blog post discussion here). Now people can finally read the findings of Horner and Goodwin in PLoS ONE (here). As I have not even had a chance to read it yet I will leave the analyzing and debating to the numerous other blog post that I am sure will start to trickle in today and throughout the rest of the week. Enjoy!

Dracorex (top left) and Stygimoloch (top right), as growth stages of Pachycephalosaurus (bottom). Art by Holly Woodward from the November 23rd, 2007 issue of Science.

Citation: Horner JR, Goodwin MB (2009) Extreme Cranial Ontogeny in the Upper Cretaceous Dinosaur Pachycephalosaurus. PLoS ONE 4(10): e7626. doi:10.1371/journal.pone.0007626 (link)

Horner JR, Goodwin MB, Woodward H (2007) Synonymy consequences of dinosaur cranial ontogeny. J Vert Paleont 27: 92A


Anonymous said...

Yes, I did see "Dinosaurs Decoded," which mentioned this find, but I want to know what YOUR opinion is, if you've done any research on Pachys.

ReBecca Hunt-Foster said...

I do not have an informed opinion yet, b/c I have not read the paper and have only heard the talk. I have a preliminary opinion after hearing the talk, but I would like to read the paper first.

Doug said...

I had also heard about this on "Dinosaurs Decoded" as well as Laelaps. And I'll side with Brian on this one: "More fossils, please." I think we need more fossils before we can be sure. Also, the reabsorbing of the spikes is very peculiar.

I was musing with someone in a comments section somewhere aboutthis issue. He made a suggestion that could have some merit (again, more fossils required). He suggested that maybe Stygimoloch is an immature male. I think this may have merit because i have seen some Pachycephalosaurus skulls with nodules and some with spikes. Who knows where this debate will go.

Three Ninjas said...

Hey guys, here's the thing: I am not a paleontologist. I don't even have a bachelor's degree in anything. All I am is a self-educated nerd, and all I have is an extreme emotional reaction on this issue: DO NOT WANT

I'm sorry for diluting the discussion with my whininess, but I feel so much better for having said that.

Monado, FCD said...

Ah! It makes sense! We'll have to see how the arguments and evidence stack up.

There's also ONE duoceratops, as in only one ever found. It's at the Smithsonian natural history museum. I'd guess it's a triceratops that suffered a developmental malfunction.