Thylacoleo ate my baby!

The Western Australian Museum has posted some amazing pictures on the Nature News Website of the marsupial lion Thylacoleo carniflex from the Nullarbor Plain in southwestern Australia.

All fossil mammal teeth look the same.

Paleontologists have that strange ability to see things that others don't or can't see. Nowhere is this case best illustrating in mammal teeth. Each bump and grove indicates a unique species or genus in the fossil record. Skilled paleontologists can identify a species of any mammal that lived, just by looking at several of its teeth. This amazing diversity in mammal teeth hides the fact that overall mammalian teeth are rather conservative in their general form and particularly in their function. They all mainly serve to break down and chew food. So undoubtedly teeth also reveal a mammal's diet. Paleontologists are left with a quandary. How much does diet and how much does taxonomy contribute to a tooth's form? Or presented in a different way, if you analysis a number of fossil mammal teeth for similarities, do these similarities reflect similar diets OR similar relationships. I've often questioned the utility of using teeth in systematic studies of taxonomic relationships because you may end up with groupings that reflect similar diets instead. In a recent article in Nature Alistair R. Evans and colleagues present a study of computer generated models of modern mammal teeth using a high-resolution laser scanner. The constructed models were analyzed for similarities. The researchers conclude that the surface complexity of tooth crowns directly reflects the foods they consume, and that there are high-levels of similarity in the tooth shape between widely divergent diets, such as carnivores and herbivores.


Evans, A., Wilson, G.P., Fortelius, M. and Jernvall, J., 2007. High-level similarity of dentitions in carnivorans and rodents. Nature 445, 78-81 (4 January 2007) | doi:10.1038/nature05433.

Gliding Jurassic Mammal

Volaticotherium antiquus is no ordinary beast. It is over 150 million years old and was the first mammal to glide over the landscape using its elongated skin folds or "patagium." Discovered from Inner Mongolia and described by Dr. Meng Jin at the American Museum of Natural History, Volaticotherium antiquus is also a very primitive mammal, grouping with such basal mammals as Morganucodon, Sinoconodon and most closely with the Triconodont mammals such as the recently described, but much younger Jeholodens. Volaticotherium antiquus was a small mammal, weighting 70 grams, and with a length of about 12 to 14 cm. It is amazing that this little mammal glided over giant dinosaurs such as the Stegosaurus-like Chialingosaurus.


Meng, J. et al. (2006). A Mesozoic gliding mammal from northeastern China. Nature 444, 889-893 (14 December 2006) | doi:10.1038.

Hairy Glyptodon?

Mammals do some strange things... Armadillos for instance exhibit protective bony plates. These bony plates are called osteoderms. Armadillos belong to the order Xenarthra and the group Cingulata, which includes some very peculiar fossil forms; the Glyptodonts and Pampatheres. All members of this group exhibit some form of osteoderm, and until recently little was known of the morphological and histological diversity of these osteoderms. December's issue in the Journal of Morphology features an article by Robert Hill on the comparative anatomy of these strange structures, and how they might have operated in life, utilizing armadillos as modern analogues. One of the fascinating things about these osteoderms is the little openings covering the surface. These openings allowed hair follicles and sweat to pass through the armor.


Hill, Robert V. (2006). Comparative anatomy and histology of xenarthran osteoderms. Journal of Morphology. 267:12 pg. 1441-1460.