Showing posts with label Abelisaur. Show all posts
Showing posts with label Abelisaur. Show all posts

Sunday, January 13, 2013

Animal of the Day: Coelophysis

Today's Animal of the Day is Coelophysis!  The picture of the cast you see off to the left (taken by me at the Denver Gem and Mineral Show a few months back) is from the AMNH (American Museum of Natural History) in New York.  I actually know a little bit more about this particular specimen of Coelophysis than I believe was labeled there, as I remembered seeing this specimen in my Dinosaur Atlas book from DK Publishers.  One of around 500 or so individual Coelophysis specimens discovered at a place called Ghost Ranch in New Mexico, this particular specimen was once thought to reveal something interesting about the species: Coelophysis was once thought to probably be a cannibal, as the remains of a baby Coelophysis were found in the area of the stomach!

Dinosaur cannibalism is not unheard of, and almost certainly occurred in the Late Cretaceous Abelisaur Majungasaurus from Madagascar.  However, this was disproven in 2002 by Rob Gay, when he showed that the baby Coelophysis were either crushed by the smaller ones, or that they weren't even baby Coelophysis!  Instead, many of them were found to be other, small reptiles, such as the archosaur Hesperosuchus, a member of the same group as the crocodilians, dinosaurs, and pterosaurs, amongst others.  So for now, it looks like Coelophysis was probably not a cannibal, but future discoveries may force us to change our minds once again!
Another picture of Coelophysis that I took, at the DMNS

Coelophysis is one of the oldest known dinosaurs, inhabiting North America around 220 million years ago (MYA), during the Late Triassic Period.  The site at Ghost Ranch is interesting, because there are just so many different specimens all clumped together.  Some paleontologists have suggested that a flash flood drowned a huge herd of these animals, or perhaps that they died while trying to cross a river.  We might never know what, exactly, killed these dinosaurs, or why so many of them died in such close proximity.  

Monday, December 10, 2012

Top 10 Favorite Dinosaurs by Zack Neher (Part 3)

Part three of my Top Ten Favorite Dinosaurs list.  Enjoy!

3. Masiakasaurus
A fairly small dinosaur at only around six feet, Masakisaurus knopfleri, as discussed IN A PREVIOUS POST, was named for the famous musician Mark Knopfler.  The animal, found in Madagascar, was named in 2001 by Matthew Carrano, Catherine A. Forster, and Scott Sampson, the author of Dinosaur Odyssey and the dude from Dinosaur Train.  Living on what was still an island, the little dinosaur lived about 70 MYA during the  Late Cretaceous Period, and was a contemoporary of the abelisaur Majungasaurus, the bird-like Rahonavis, and the sauropod Rapetosaurus.  Although Masiakasaurus sounds pretty unremarkable thus far, a quick glance at the picture below (which many of you have no doubt already done) says otherwise: Masiakasaurus definitely had some funky teeth!  These teeth are clearly not suited tearing into food like the teeth of Allosaurus or Velociraptor would be, and many paleontologists (including myself, even though I am not really a paleontologist.  I guess it would be better to say "many paleontologists, paleontologists-in-training, and myself."  There, much better.) believe that these weird, pointy teeth are an evolutionary adaptation to a piscivorous (fish-based) diet.  A look at various marine reptiles such as the plesiosaurs (like Elasmosaurus) and Liopleurodon show a similar pattern of interlocking teeth that point outside of the mouth.  Excellent when it comes to catching fish, and not so excellent when it comes to most, if not all, other diets, be they meat- or plant-based.  

TO BE CONTINUED IN PART 4

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