Sunday, March 21, 2010

Tooth development in Trichechidae Part I

Alright, so this is not a complete post, but it's a start.
This Monday I will be visiting the Mammalogy Collection at the AMNH for one last data collection trip for the study of tooth development in the sirenian family Trichechidae. The Trichechidae is the family that includes modern manatees, as well as a number of fossil forms.
Aside from a comparatively abundant Pleistocene fossil record of manatees primarily found in Florida (subspecies Trichechus manatus bakerorum Domning 2005), most fossils of manatees are fairly scarce and poorly preserved, including the two Miocene taxa, Potamosiren and Ribodon, both from the Amazon River Basin of South America. Both of these taxa are known from little more than isolated teeth and some fragmentary maxillary or mandibular chunks.
But, thanks to two features of the skulls of fossil forms that pull their relationship closest to the modern manatees, there is a couple of oddball fossil forms from Belgium and Germany that ally closely with the Trichechinae (Potamosiren, Ribodon and Trichechus), the Miosirenae (Miosiren and Anomotherium)
Over the next several posts I will try to demonstrate some of the key features of all of these taxa, and how understanding some of the unique specializations in modern Trichechus (especially how those features in modern Trichechus vary inter- and intraspecifically), we can better grasp how these features evolved, possibly as a response to a rapid increase in abrasives in their mouths thanks to the uplift of the Andes.