The vaquita was not scientifically described until 1958, with full descriptions of external morphology not available until 1987.

Sources: (Mungia-Vega, Esquer-Garrigos, Rojas-Bracho, Vazquez-Juarez, Castro-Prieto, & Flores-Ramirez, 2007), (Norris & McFarland, 1958)
Image: Noelle M. Brooks