Historical biogeography of trilophodont gomphotheres (Mammalia, Proboscidea) reconstructed applying Dispersion-Vicariance Analysis

ALBERDI, MARÍA TERESA; PRADO, JOSÉ LUIS; ORTIZ-JAUREGUIZAR, EDGARDO; POSADAS, PAULA; DONATO, MARIANO H.

4th European Meeting on the Palaeontology and Stratigraphy of Latin America

Instituto Geológico y Minero de España

Lugar: Madrid; Año: 2007; p. 9 - 14

DIVA application resulted in an exact solution requiring three vicariant events, and 15 dispersal events, most of them (i.e., 14) occurred at terminal branches. The single dispersal event at an internal node was the aforedescribed for the common ancestor to Sinomastodon plus the clade Cuvieronius - Stegomastodon. Ancestral distribution for trilophodont gomphotheres included Africa - Europe - Asia -- North America. This distribution could be achieved during earliest Miocene, a time of low sea-levels and low temperatures. A vicariant event took place resulting in two isolated groups: 1) Amebelodontinde (Africa - Europa - Asia) and 2) Gomphotheriidae (North America). The Amebelodontidae clade was split by a second vicariant event: Archaeobelodon (Africa and Europe), and the ancestors of the remaining genera of the clade (Asia). On the other hand, Gomphotheriidae clade evolved mainly in North America. A dispersal event expanded the range of the common ancestor to Sinomastodon plus the clade Cuvieronius - Stegomastodon again to Asia. A new vicariant event split North America and Asia resulting in the isolation of Sinomastodon in the latter, and the ancestor of the clade Cuvieronius - Stegomastodon in North America. Finally, these two genera reached South America in two independant dispersal events. Biogeographic history of trilophodont gomphotheres have been signed by sea-level changes. During low sea-level episodes trilophodont gomphotheres expanded they distribution by means of intercontinental dispersion events, and during high sea-level episodes they underwent vicariant event.