A gharial from the Oligocene of Puerto Rico: transoceanic dispersal in the history of a non-marine reptile.
The Indian gharial (Gavialis gangeticus) is not found in saltwater, but the geographical distribution of fossil relatives suggests a derivation from ancestors that lived in, or were at least able to withstand, saline conditions. Here, we describe a new Oligocene gharial, Aktiogavialis puertoricensis, from deltaic-coastal deposits of northern Puerto Rico. It is related to a clade of Neogene gharials otherwise restricted to South America. Its geological and geographical settings, along with its phylogenetic relationships, are consistent with two scenarios: (i) that a single trans-Atlantic dispersal event during the Tertiary explains the South American Neogene gharial assemblage and (ii) that stem gharials were coastal animals and their current restriction to freshwater settings is a comparatively recent environmental shift for the group. This discovery highlights the importance of including fossil information in a phylogenetic context when assessing the ecological history of modern organisms.
Vélez-Juarbe
Jorge
J
Department of Geology, University of Puerto Rico, Mayagüez, PR 00681, USA.
Brochu
Christopher A
CA
Santos
Hernán
H
D000489:Alligators and Crocodiles / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics; D000818:Animals; D005580:Fossils; D010802:Phylogeny; D011647:Puerto Rico; D009626:Terminology as Topic