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 : 55

Ceratophrys sp. (MNHN 1560) from Colonia, Uruguay ( Rinderknecht 1998)

An isolated maxilla from the Conchillas Locality ( Fig. 1 , locality 3), department of Colonia, Uruguay, was described and attributed to Ceratophrys sp. by Rinderknecht (1998). The fossiliferous sediments are thought to have been deposited during the Upper Pleistocene ( Rinderknecht 1998). The fossil maxilla is housed in the Paleontological Collection of the Museo Nacional de Historia Natural de Montevideo (MNHN 1560). In addition to the illustration of the material available in the original publication, the museum graciously provided several photographs of this specimen.

Osteological features. MNHN 1560 ( Fig. 5O, P ) is a nearly complete maxilla with a high pars facialis and a conspicuous tuberculate ornamentation. A discrete pars palatina is absent on the anterior half of the bone; posteriorly, the pars palatina is deflected dorsally to form a groove within which the anterior ramus of pterygoid fit; the pterygoid process is subtriangular ( Fig. 5P ). A series of scars marking articulations of the maxilla with the surrounding bones are evident. Anteriorly, an elongated socket for the maxillary process of the premaxilla is visible; it extends to the position of the fourth tooth ( Fig. 5P ). This socket is contiguous with a scar that represents the articulation with the ossification of the nasal cartilages. Posteriorly, a second scar may mark the articulation of the maxilla with the ossification of the planum antorbitale. The few complete teeth do not have distinct crowns and pedicels.

Remarks. MNHN 1560 has all the proposed or possible synapomorphies of Ceratophryidae (exostosis, nonpedicellate teeth, anterior maxillary pars palatina absent) and Ceratophrys (long maxillary processes of premaxilla) that can be evaluated; thus, the placement in Ceratophrys is well supported, but a specific attribution Ceratophrys is not possible.

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 5. Neogene fossils attributed to Ceratophrys. A–K, fossils from the vicinities of the cities of Mar del Plata on the Atlantic Cost of the province of Buenos Aires, Argentina, attributed to Ceratophrys sp. by Mercadal de Barrio & Barrio (2002); A, B, MLP 34.V.10.8: nearly complete right maxilla; C, D, MACN 17585 anterior portion of left maxilla; E–G, MACN 17936: fragments of posterior skull roof (E, F) and neurocranium (G); H–K, MACN 18074: fragments of a left maxilla (H, I) and right squamosal (J, K). M–L, MACN 14323: fragmentary skull from Farola Monte Hermoso, Argentina, attributed to C.prisca var. subcornuta by Mercadal de Barrio & Barrio (2002). O, P, MNHN 1560: maxilla from the Conchillas Locality (Fig 2, locality 2), Colonia, Uruguay, attributed to Ceratophrys sp. by Rinderknecht (1998). Q–Y, MLP 88.V.20.1: skull (X, Y) and left mandible (Q) from the north of Mar del Plata, Argentina, attributed to Ceratophrys sp. by Mercadal de Barrio & Barrio (2002).A, D, I, O, labial views; B, C, H, P, Q, lingual views; E, J, M, X, dorsal views; F, G, N, ventral views; K, L, lateral views. Abbreviations: as, angulosplenial; d, dentary; fp, frontoparietal; 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 planum antorbitale; 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 showed 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.