A gharial from the Oligocene of Puerto Rico: transoceanic dispersal in the history of a non-marine reptile |
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Authors: | Vélez-Juarbe Jorge Brochu Christopher A Santos Hernán |
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Affiliation: | Department of Geology, University of Puerto Rico, Mayagüez, PR 00681, USA. |
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Abstract: | 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. |
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Keywords: | biogeography Crocodylia Gavialis gharial Aktiogavialis phylogeny |
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