Redescription and phylogenetic position of the fossil killifish †Carrionellus diumortuus White from the Lower Miocene of Ecuador (Teleostei: Cyprinodontiformes)
†Carrionellus diumortuus from the Lower Miocene of Loja, southern Ecuador, is the type species of †Carrionellus, the only American cyprinodontiform genus uniquely containing fossil species. It was first considered as a member of the cyprinodontid tribe Cyprinodontini, a group comprising extant taxa geographically restricted to North and Middle America, but recently it has been tentatively placed in the Neotropical family Anablepidae. †Carrionellus diumortuus is herein redescribed on the basis of examination of the type series. Re-evaluation of phylogenetic characters indicates that it is a member of the cyprinodontid tribe Orestiini, which comprises a clade endemic to the Andean region, which may be diagnosed be a unique angled anteroventral profile of the head in the area on the articulation between the lower jaw and the quadrate. †Carrionellus is distinguished from Orestias, the only other genus of the Orestiini, known only from recent species, by the former genus having tricuspidate jaw teeth, well developed pelvic fin, and 28-29 vertebrae.