Comments on: The Mysterious Marshosaurus

By: Kenneth Carpenter

Kenneth Carpenter — Thu, 01 Dec 2011 19:01:12 +0000

The skull of Marshosaurus at the Carnegie was reconstructed by David Gilpin under my direction before I left Denver (Gilpin is a volunteer at the Denver Museum of Nature & Science). I borrowed all the material from the Carnegie and Utah Museum of Natural History to mold and cast. Each institution got a full set of the casts, plus casts of the Denver material. I had proposed to both institutions that a mounted skeleton could be done using casts of the subadult Ceratosaurus owned by Western Paleo Labs in Lehi, Utah. Such a skeleton is now on display at the new Natural History Museum of Utah (note the name change) standing over a prone Stegosaurus skeleton.

When we made the skull, I was surprised how long and slender it was compared to other Morrison theropods. There is actually a slight notch at the premaxillary-maxillary boundary, which appears to have been filled in in the skull pictured above (too bad). It can still be seen in the Carnegie version (although the long, low profile of the skull is hard to appreciate in the Wikipedia photo).

Roger Benson is the lead author on a description of all the Marshosaurus material. Oh, and Madsen described the specimen in 1976, hence the species name “bicentesimus” – to celebrate the US bicentennial.

By: Robert Sloan

Robert Sloan — Thu, 17 Nov 2011 14:47:30 +0000

I can see that Megalosaurus fills a gap in predation. In living ecosystems there are a larger number of smaller predators that go after smaller animals and also come in to scavenge carcasses from larger ones. Could Megalosaurus be the jackal of the Jurassic?

Sure, it’s 18 feet long and enormous compared with today’s big predators, but with Allosaurus, Torvosaurus and the rest all occupying that ecosystem, something mid-sized could have scavenged from them, hunted juveniles of prey species and anything else in its size range.

I’m sure paleontologists have thought of this. It’s an obvious idea. I hope you’ll follow up on it and that some stomach contents will be found to help show how this animal hunted and what it hunted or scavenged.

By: Katie

Katie — Wed, 16 Nov 2011 21:06:40 +0000

Wow, what great timing! I was at the Carnegie just two weeks ago and noticed the Marshosaurus skull on display, too! The plaque said it was “enigmatic.” With descriptors like that and “mysterious,” I’m starting to think this dinosaur was a super-spy killer for hire! Marshosaurus: Ninja of the Jurassic!