FADAEL, Rudgie *; T�MKIN, Ilya ; DESALLE, Rob; BOLNET, Carolle; Medgar Evers College ; American Museum of Natural History; American Museum of Natural History; Medgar Evers College : Analysis of Shape Variation in Several Populations of Bivalves Genus Pinctada

The main purpose of the project was to test if phenotypically similar populations of bivalves from the genus Pinctada from different localities throughout the world are one species or several distinct species. Variation in their shapes and colors is immense in each population therefore these populations have been classified as different (for example P. fucata in Japan and P. imbricata in the Caribbean Islands). To address this question, we used a geometric morphometric approach. First, a digital database was created to take pictures of the shells from different localities, e.g. Western Atlantic, Indo-Pacific region, the Mediterranean Sea. One hundred twenty-seven pictures of the right valves were taken and ten landmarks were marked from each shell in the interior surface. The anterodorsal extremity of the shell is marked by the first landmark, the anterior pedo-byssal retractor muscle scar is marked by the second landmark, the third landmark is the accessory pedo-byssal retractor muscle scar, the fourth landmark marked the posterodorsal extremity, and so on. To analyze the variation of their shapes, two programs have been used, TpsDig and TpsRelw. The TpsDig program was used to define and capture landmarks and to also increase image contrast. The TpsRelw program used the thin plate spline function to compute relative wraps and to visualize variation in shell shape. Preliminary results do not show significant variation in the shapes of the shells from different geographical areas. In conclusion, the shells from different localities potentially represent a single species. This hypothesis will be further tested with genetic data.