Ceratophrys (Lynch, 1971)

Nicoli, Laura, 2019, The fossil record of Ceratophrys Wied-Neuwied (Anura: Ceratophryidae): a revision and update of fossil South American horned frogs, Zootaxa 4658 (1), pp. 37-68 : 59

Ceratophrys sp. (MLP 86.III.25.150–151) from the archeological locality Arroyo Tapalqué, Buenos Aires, Argentina ( Mercadal de Barrio & Barrio 2002)

Two fragmentary specimens (MLP 86.III.25.150–151, Fig. 6 H–K) from the archeological locality Arroyo Tapalqué ( Fig. 1 , locality 2), in the Partido of Olavarría in the province of Buenos Aires were referred to Ceratophrys sp. by Mercadal de Barrio & Barrio (2002). This sequence dates to the middle Holocene ( Fingini et al. 1998).

Osteological features. MLP 86. III.25.150 is a well-preserved right maxilla ( Fig. 6I, J ) and squamosal ( Fig. 6H ); although isolated, both elements articulate perfectly, indicating that they were from the same individual. The maxilla has a high, ornamented pars facialis ( Fig. 6I ), and lacks a distinct pars palatina in its anterior half ( Fig. 6J ). It bears a socket anterior to the level of the fourth tooth; presumably, the maxillary process of the premaxilla articulated with the maxilla via this socket. The fang-like teeth are monocuspid, with no evidence of a distinct crown and pedicel. The squamosal is nearly complete and heavily ornamented ( Fig. 6H ). The robust zygomatic ramus bears a lateral bony lamina that underlies the pars facialis of the maxilla when the elements articulate. The otic ramus is expanded in a subquadrangular plate that has an incomplete medial projection; the latter seems to correspond to the squamosal portion of a parieto-squamosal arch that would have delimited a postemporal fenestra.

MLP 86. III.25.151 consists of a pair of ornamented frontoparietals from one individual ( Fig. 6K ). Although disarticulated, the bone doubtless were medial contact in the living animal. Posteriorly, each frontoparietal has an oblique medial margin; this suggests that the bones were (at least partially) fused and broke as a result of disarticulation. Each bone has a lateral projection that seems to correspond to the frontoparietal part of the parieto-squamosal arch, which delimited a postorbital fenestra.

Remarks. Both fossils possess all possible synapomorphies of Ceratophryidae and Ceratophrys that can be evaluated on the preserved elements ( MLP 86. III.25.150.—exostosis, non-pedicellate, monocuspid teeth, absence of pars palatina on anterior maxilla, maxilla-squamosal contact, parieto-squamosal arch [ Ceratophryidae ], premaxilla with long maxillary process, postorbital fenestra [ Ceratophrys ]; MLP 86. III.25.151.—exostosis, parieto-squamosal arch [ Ceratophryidae ], postorbital fenestra [ Ceratophrys ]). The generic assignment of these fossils to Ceratophrys is well supported, but the remains cannot be attributed to a species.

Figures

FIGURE 1. Distributional map of extant and fossil Ceratophrys. The phylogeny of the extant species of Ceratophyrs were proposed by Faivovich et al.(2014). The numbers in circles represent the fossiliferous localities mentioned in the article: 1, Arroyo Chasicó; 2, Arroyo Tapalqué; 3, Conchillas; 4, Farola Monte Hermoso; 5, Fortín Necochea; 6, Lagoa Santa; 7, Laguna de Los Tres Reyes; 8, Mar del Plata and Miramar cities; 9, Ñuapua; 10, Olivos; 11, Puerta de Corral Quemado; 12, Quehué; 13, San Antonio and Paso Alsina; 14, Tarija. Black circles: localities where the presence of Ceratophrys was confirmed; white circles: the presence of Ceratophrys remains unconfirmed. The distributions of the extant species of Ceratophrys are represented by areas that approximately include all the reported records for each species; the distribution of most species, however, is not well known. Distributions are based on Lynch (1982) with corrections and additions from Barrio-Amorós 2004; Barrio 1980; Langone 1995; Maciel et al. 2013; Maneyro & Langone 2001; Ortiz et al. 2013; Peters 1967; Rivero 1961; Stuart et al. 2008.

FIGURE 6. Quaternary fossils attributed to Ceratophrys. A, fossil columella (MLP 86.VIII.1.5) from Laguna Los Tres Reyes Locality, province of Buenos Aires, Argentina, attributed Ceratophrys cf. ornata by Perí (1993). B, columella of C. cranwelli (FML 5475). C–G, two incomplete skulls (C–E) and a premaxilla (F, G) from Ñuapua, Bolivia, attributed to Ceratophrys cf. ornata by Vergnaud-Grazzini (1968). H–K, fossils from the Arroyo Tapalqué locality, Buenos Aires, Argentina, listed as Ceratophrys sp. by Mercadal de Barrio & Barrio (2002); H–J, MLP 86.III.25.150: squamosal (H) and right maxilla (I, J); K, MLP 86.III.25.151: frontoparietals. A,C, H, K, dorsal views; B, ventral views; D, J, lingual views; E, I, labial views. Abbreviations: as, angulosplenial; d, dentary; fp, frontoparietal; pp, premaxillary palatine process; ppa, discrete pars palatina absent; lc, lateral crest; mk, mentomeckelian; mop, material of preparation; mp, maxillary process of nasal; mpp, maxillary process ofpremaxilla; mps, socket that would receive the maxillary process of premaxilla; ncs, socket that would have received the ossification of the nasal cartilages; oc, occipital condyle; otc, otic capsule; pas, socket that would have received the ossifications of the planumantorbitale; pf, pars facialis; pof, space delimiting by the showed bone that corresponds to the postorbital fenestra; pp, pars palatina; ppa, discrete pars palatina absent; psa, portion of the bone that forms the parieto-squamosal arch; psf, parasphenoid; pt, pterygoid; ptp, pterygoid process; qj, quadratojugal; th, teeth; slw, squamosal lateral world; sop, squamosal otic plate; sf, space delimiting by the showed bone that corresponds to the subtemporal fenestra; v, vomer; vr, squamosal ventral ramus; zr, squamosal zygomatic ramus. Scale bar is 5 mm.