Tooth Denticles – WP#5

This is a short post; I’d write more about denticles, but I’d want to prepare more material to do so (it’s a detailed subject).

Most carnivorous archosaurs have denticles on their teeth. These are small, nearly microscopic nodules that persist on the carina of teeth (or sometimes off of it). They are serial (i.e., found in a line), and generally occur on the mesial and distal sides of a crown. They occur in non-carnivorous archosaurs, but are less recognized as such. Their shape can be diagnostic, but their presence has allowed systematists to confuse what are dinosaurs and what aren’t, up to including denticulate, blade-shaped crowns that are actually rauisuchian crurotarsans (croc-line archosaurs that include the awesome Postosuchus kirkpatricki and the stranger Effigia okeefeae). What is most odd is that, in the specific cases of some teeth, the identification to group for denticulate teeth can be confused on the morphology of the denticles themselves. Here’s an example:

Variation is not limited here, but it’s instructive. One of these is NOT a theropod dinosaur. Can you guess which is which?

Another Dinosaur Bites the Dust

Bill Parker over at Chinleana has covered this here, but I figured I’d highlight somethin he says, and something the paper notes.

The new archosauromorph Azendohsaurus madagaskariensis [1]  supplements our previosu taxon Azendohsaurus laaroussi [2,3], and provides damning evidence against the concept of Azendohsaurus being either an ornithischian [2] or a sauropodomorphan [3] dinosaur. While an abstract and presentation in 2002 [4] initially disputed its dinosaurian affinities, this hasn’t been published, although it intended to do so on the basis of Moroccan remains of the original species. This taxon derives from the Triassic of Madagascar, and expands the range of the taxon Azhendousaurus.