GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 118-20
Presentation Time: 9:00 AM-6:30 PM

PALEOBIOGEOGRAPHY OF PELOMEDUSOID TURTLES AND NEW DATA FROM THE OLIGOCENE-MIOCENE SAN SEBASTIAN FORMATION IN PUERTO RICO, LAGUNITA FORMATION IN CUBA AND YANIGUA-LOS HAITISES FORMATION IN DOMINICAN REPUBLIC


CRUZ VEGA, Eduardo Josue, Department of Geology, University of Puerto Rico, Mayaguez Campus, PR-108, Mayag├╝ez, Mayaguez, PR 00682

Pelumedusoids are an ancient linage of freshwater turtles, with oldest specimens dating back to the early Cretaceous period in the geologic record, that nowadays are geographically restricted to Sub-Saharan Africa and Northern South America. Fossils of the Pelomedusidae family have been recently found in the Caribbean. Six undescribed specimens were collected, 3 from the San Sebastian Formation in Puerto Rico, two specimens were collected in the Lagunita Formation in Cuba, and one specimen was collected in the Yanigua-Los Haitises Formation in Dominican Republic.

This project will serve as a preliminary test and study of the complex paleobiogeographical history of the Pelomedusoides clade. Given so, this will be the first time that a biogeographic analysis of extinct and modern species of the Pelomedusoides clade will be done with Caribbean specimens. The specimens will be incorporated in a combined molecular and morphological character matrix (Romano et al 2014). A heuristic search of 10,000 replicates and tree-bisection-reconnection algorithm will be run using PAUP 4.0b10 (Swofford, 2002). Bootstrap values from 1,000 replicates will be calculated to estimate statistical support of each node. Then, a text file with the geographic data of each species of the phylogenetic analysis will be made and analyzed using R and the BioGeoBears package (Matzke, 2013).

Due to limitations in the amount of collected samples and their state of preservation, the specimens will not be described at a species level. Nonetheless, it is expected to obtain a polytomy of the Pelumedusoid fossils. If obtained, there will be enough data to classify the specimen at a family level, which will lead to building a biogeographical reconstruction. The resulting biogeographic analysis of the combined molecular and morphological character matrix, in addition to the geographic data matrix, will provide insights into the past history of the Pelomedusoides.