Tyrannosaurs Don’t All Have Bananas for Teeth

One of the things that I’ve been itching to do is generate a database of variation in dental series across a variety of taxa, virtually most if not all variations of archosaurs and beyond. This is to assess the quality of jaw shape with tooth shape, tooth function, jaw function (not always overlapping), and diet. Fun stuff … for me. It would be incredibly repetitive, boring, and time-consuming research, and probably something that would take me years of world-hopping to achieve (although I can work from casts just as well as real specimens).

Why?

Troodontid Teeth – WP#6

A small selection of troodontid theropod teeth is presented below. Before you get to it, however, note that for among some of these taxa, their identities are a little shaky. This has a lot to do with one of the more persistent “wastebasket” taxa among theropods, Paronychodon lacustris [1]. Among other tooth-based taxa, Paronychodon lacustris and Paronychodon sp. (a general container for a large variety of things, several of which may be unique taxa on their own) includes the morphology of triangular theropod teeth with vertical ridges. Aberrant ridges, carinae, and the apparent absence of denticles in some otherwise theropodan teeth appear on occasion in collections, and most, if not all, of them are referred to the taxon Paronychodon in one of several ways, which I will get into in a different post dedicated to the taxonomy of taxonomy (you heard me).

The Domed and the Tooth(less)

This post will discuss soemthing that a paper has already done in full — however, some conclusions about this paper’s result means that I will re-cover what it did, and make a different argument. That paper is Krause et al. [1]

This is a tale of two taxa, Majungasaurus crenatissimus [2] and Majungatholus atopus [3]. The first was discovered at the Maeverano region on western Madagascar in the 1890′s, while the latter was discovered a bit afterward. Both are likely to be the same animal, as covered in [1], and this argument is not to rehash that or dispute it.

Carcharodontosaurus — a Bloody Tooth-Taxon

Carcharodontosaurus saharicus is a taxon many potential readers may be familiar with. Through the work of paleontologists like Ernst von Stromer and Paul Sereno, much of what we know about this taxon is possible. It would surprise you then to know that much of what we know is not based on the original material that was used to give us the name Carcharodontosaurus saharicus.

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.

Tooth-Based Taxonomy

Taking abreak here to discuss something more germane to this blog’s theme. We’ll get back to oviraptorosaurs and their nearly utter lack of teeth shortly.

Tooth-based taxonomy (or TBT) is something you will see frequently from here on in this blog. It is fundamental to my primary direction of research, in that species named based solely on teeth are limited in their comparability to species not based on teeth or species for which no teeth are known. To resolve this issue, the topic of the importance of isolated teeth (the basis of TBT) will fill this (dense) post. More below.