LAUSR

Abstract A new species of “guitarfish" from the Lower Cretaceous Tlayua Formation of Puebla, Mexico is here described as †Tlalocbatos applegatei gen. et sp. nov. The new species is based on a nearly complete articulated specimen and represents the first chondrichthyan from this formation. The inclusion of a new character and two additional taxa into a phylogenetic analysis based on previous studies generates a novel phylogenetic hypothesis of batoid phylogeny. Paraphyly of the “guitarfishes” is corroborated, although a new clade was recovered comprising the modern Platyrhinidae plus †Britobatos primarmatus as the sister group of the node formed by †Stahlraja, †Tlalocbatos, plus the Trygonorrhinidae. †Tlalocbatus differs from other batoids by the following combination of characters: nasal capsules with horn-like anterior processes; homodont dentition; presence of a well-developed median uvula; lateral uvulae not differentiated; pectoral propterygium, extending as far as the anterior part of the nasal capsules; two radials articulating directly with the scapulocoracoid, between the mesopterygium and the metapterygium; two dorso-lateral nuchal cartilages, unfused with the synarcual; and an elevated number of post-synarcual centra (115–118). The distribution of †Stahlraja (†Tlalocbatos (trygonorrhinids)), suggests that this clade originated in the western part of the Tethys-Caribbean region with a later dispersion westward towards the Pacific.