A partial molecular phylogeny of Rhadinaea and related genera (Squamata, Dipsadidae) with comments on the generic assignment of Rhadinaea eduardoi

The genus Rhadinaea is a diverse clade of New World dipsadid snakes, with 22 species arranged in six recognized species groups. The most recently described species, Rhadinaea eduardoi, was described based on a unique specimen collected in the Santa Catarina Juquila municipality in the Sierra Madre del Sur of southern Oaxaca, Mexico. Here, based on a reexamination of the holotype and the results of a phylogenetic analysis of the holotype of Rhadinaea eduardoi and representatives of several genera closely related to Rhadinaea, we reassessed the generic assignment of Rhadinaea eduardoi. In our phylogenetic hypothesis, R. eduardoi was nested within a strongly supported clade of Coniophanes fissidens samples, thus making Rhadinaea paraphyletic with respect to Coniophanes. Additionally, our reexamination of the holotype of Rhadinaea eduardoi revealed that the alleged presence of a subpreocular scale is only true on the right side of the head, and that this scale appears to be a malformed preocular scale; also, a reduction in dorsal scale rows is present; and posterior enlarged maxillary teeth are grooved. Herein we consider that Rhadinaea eduardoi should be placed in the synonymy of Coniophanes fissidens. Consequently, we recognized only five species groups within the genus Rhadinaea.