Did dinosaurs survive the impact?

This is stunning news, if true. Using a new uranium-lead dating method, researchers have determined the age of a fossil dinosaur bone from New Mexico with far greater accuracy than could be done before. Here’s the twist: the fossil bone dates from 64.8 million years ago — 700,000 years after the extinction event at the end of the Cretaceous Period that supposedly wiped out all the dinosaurs. Abstract, news coverage, press release.

The idea that some dinosaurs survived at least part of the way into the Paleocene is something that one of the paper’s co-authors, James Fassett, has been promoting for some time, generating all kinds of controversy. This is not, in other words, the first or last word on the subject. Take this news in that context.

Now if you wanted to be excessively clever, you could argue that of course dinosaurs survived into the Paleocene, because birds are a clade of dinosaurs, and birds survive today. But you know what is meant here: non-avian dinosaurs.

A horned dinosaur with 15 horns

Kosmoceratops richardsoni

Two new horned dinosaurs were described in a new research article published today: Kosmoceratops richardsoni and Utahceratops gettyi. The article discusses them in the context of the dinosaur provincialism hypothesis — were dinosaurs in Cretaceous western North America part of a single biome, or were they fragmented into distinct habitats? — but never mind that shit: look at all the bloody horns on that Kosmoceratops! Ten on the frill and five on the face — and I bet you thought Styracosaurus was something. Via io9.

(Image of Kosmoceratops skull from the article: Sampson SD, Loewen MA, Farke AA, Roberts EM, Forster CA, et al. (2010) New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism. PLoS ONE 5(9): e12292. doi:10.1371/journal.pone.0012292. Creative Commons licence.)

Tiny tyrannosaurs

Tyrannosaurus was one of the largest carnivorous dinosaurs, but for most of their history, tyrannosaurs and their ancestors were rather small, according to a phylogenetic review in a recent issue of Science. The best-known tyrannosaurs are late Cretaceous members of the tyrannosaurid family, such as Albertosaurus, Daspletosaurus, Gorgosaurus and Tyrannosaurus itself, which were varying degrees of ginormous. But based on new fossil discoveries, the tyrannosauroid superfamily originated in the middle Jurassic and stayed small — human-sized — for 80 million years. (Also, they didn’t all have those little two-fingered arms.) It was only when the existing large carnivores — carnosaurs like Allosaurus, for example — got out of the way that tyrannosaurs were able grow larger and take over the large-predator niche.

(Remember, tyrannosaurs are coelurosaurs, not carnosaurs: they’re more closely related to ostrich dinosaurs, birds and, well, velociraptors than they are to other big meat-eaters like Allosaurus and Megalosaurus.)

More entries below »