Francesca Pignataro's research

Francesca is working on her Honors Thesis in Biological Anthropology and Anatomy at Duke University. Her project is to document and to describe quantitatively how (or whether) dental microwear changed in multituberculate mammals after the end-Cretaceous extinction event 65.5 million years ago. She is working with Research Associate Anne Weil.

Dental microwear can indicate what types of food an animal ate in the weeks before it died. Francesca is studying multiple individuals from before, immediately after, and about 350,000 years after the extinction event. Multituberculates probably ate mostly plants, and major floral changes have been documented in this time period. We don't know how specialized multituberculates' diets might have been, however, so we don't know what to expect from the microwear.

Francesca is a University Scholar, and a recipient of a 2004-2005 Faculty Scholars Award, which is given for outstanding undergraduate research. Francesca has also contributed to recovery and description of the Alamo Wash Local Fauna from the Late Cretaceous San Juan Basin of New Mexico.

 

Francesca working at the ESEM

Most of the teeth Francesca is studying are small to begin with, and the microwear is studied at about 200x magnification. To do this she has to use the Environmental Scanning Electron Microscope. Here she is taking photomicrographs and logging which settings are giving the clearest pictures.

Microwear on a molar tooth of Mesodma

These are both photomicrographs that Francesca took of a right upper first molar of the multituberculate mammal Mesodma. This specimen is Paleocene. The red arrow points to the cusp that is shown in the larger-scale picture. Note the pits and scratches on the side of the cusp. These were made by particles of food the animal was chewing before it died. The pattern within the tooth enamel near the cusp tip shows the prismatic structure of the enamel itself.