The vaquita is believed to represent a relict population of an ancestral species.
The vaquita is believed to represent a relict population of an ancestral species, most clearly related to Burmeister’s porpoise, that crossed the equator from the Southern Hemisphere during a period of Pleistocene cooling. Genetic analyses have corroborated this interpretation. Affinities of the axial skeleton and external morphometry suggest that Phocoena sinus evolved from a Pleistocene stock of Burmeister’s porpoise (Phocoena spinipinnis.)
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• Sources | (Brownell, 1982; NOAA, 2008; Norris & McFarland, 1958; Rojas-Bracho, Reeves, & Jaramillo-Legorreta, 2006; Rosel & Rojas-Brach0, 1999)