Ceratophrys sp. (MLP 96.V.18.12) from the archeological locality Fortín Nechochea, Buenos Aires, Argentina (Mercadal de Barrio & Barrio 2002)

An incomplete skull (MLP 96.V.18.12) from the archeological locality Fortín Nechochea (Fig. 1, locality 5), in the Partido of General La Madrid in the province of Buenos Aires, Argentina, was referred Ceratophrys sp. by Mercadal de Barrio & Barrio (2002). This sequence was deposited during the middle Holocene (Prado & Alberdi 1999, and references therein).

Osteological features. MLP 96.V.18.12 (Fig. 6L, M) is an incomplete skull that lacks both premaxillae and most of the maxillae. The preserved regions generally resemble the skulls of Ceratophrys . Cranial crests are absent. Only the anterior region of the left maxilla is preserved; the bone lacks a distinct pars palatina, and bears a long socket that presumably articulated the maxillary process of the premaxilla. Teeth are incompletely preserved. The squamosal otic plates are too poorly preserved to describe their original shape or extension; however, a well-developed postorbital fenestrae is evident (Fig. 6L). The poor preservation of the anterior part of the skull obviates description of the vomers and neopalatines.

Remarks. MLP 96.V.18.12 possesses all the possible synapomorphies of Ceratophryidae (exostosis, maxillasquamosal contact, parieto-squamosal arch, expanded squamosal otic ramus overlapping prootic, absence of pars palatina on anterior maxilla) and Ceratophrys (robust, bar-shaped maxillary processes of nasals, postorbital fenestra, premaxilla with long maxillary processes). Thus, the referral of this material to Ceratophrys is well supported, but the skull is too incomplete to evaluate characters for its specific identity.