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 : 53

Ceratophrys sp. (MLP 34.V.10.8; 88.V.20.1; MACN 17585; 17936; 18074) from the vicinity of the city of Mar del Plata along the Atlantic Cost of the province of Buenos Aires, Argentina ( Mercadal de Barrio & Barrio 2002)

Numerous Pleistocene fossils, especially mammals, have been collected from a series of localities along the Atlantic Cost of the province of Buenos Aires between the cities of Mar del Plata and Miramar ( Fig. 1 , locality 8; Cione & Tonni 2005; Marshall et al. 1984). Several fragmentary remains of anurans (MLP 34.V.10.8; 88.V.20.1; MACN 17585; 17936; 18074) also were collected from localities from this area (e.g., Punta Vorohué, Arrollo Lobería, and Chapadmalal) and identified as Ceratophrys sp. by Mercadal de Barrio & Barrio (2002).

Osteological features. MLP 34.V.10.8 ( Fig. 5A, B ) is a nearly complete right maxilla (which possesses most of the characters described below) and a posterior fragment of the left maxilla. This bone has a high, ornamented pars facilis that predominates the forward part of the maxilla anterior to the pterygoid process ( Fig. 1B ).The lingual surface of the maxilla lacks a discrete pars palatina in its anterior half. Posteriorly, the pars palatina is oriented dorsomedially; possibly, the anterior ramus of the pterygoid, which is evident in continuity with the subtriangular pterygoid process ( Fig. 5B ), articulated with the maxilla in this region. Others scars that would indicate bone articulations with the lingual surface of the maxilla are also evident. One is an elongated socket that reaches the level of the fourth dental position; it would have articulated with the maxillary process of the premaxilla.The second, posterior scar seems to represent the articulation of the maxilla with the planum antorbitale. The few complete teeth lack distinct crowns and pedicels.

MACN 17585 ( Fig. 5C, D ) is the anterior portion of a left maxilla bearing a high, ornamented pars facilis; a distinguishable pars palatina is absent, but a series of articular scars are present. A long and elongated anterior socket for the maxillary process of the premaxilla is evident ( Fig. 5C ). No teeth seem to be completely preserved.

MACN 17936 ( Fig. 5 E–G) is two skull fragments—the posterior part of a skull roof and the posterior part of a neurocranium. The skull roof is primarily represented by a pair of ornamented, synostotically articulated frontoparietals ( Fig. 1E, F ). A lateral process of the left frontoparietal forms a robust temporal arcade (or parieto-squamosal arch) of the postorbital fenestra. Although the posterior neurocranium is extremely fragmentary, it is clear that at least exoccipitals, prootics, parasphenoid, and probably the pterygoids are indistinguishably fused ( Fig. 1G ).

The two bones of MACN 18074 ( Fig. 5 H–K) are a fragmentary left maxilla and a right squamosal. The maxilla has an ornamented, high pars facilis that bears a well-developed crest posteriorly ( Fig. 5I ). The lingual side of the maxilla lacks a distinguishable pars palatina and a long, elongated socket that probably accommodated the maxillary process of the premaxilla anteriorly ( Fig. 5H ). A few, non-pedicellate teeth are preserved. The squamosal has a well-developed, but incompletely preserved, otic plate; thus its shape and size cannot be described ( Fig.5J, K ). However, the plate has a concave dorsal surface and bears a lateral wall. A crest is present at the edge of the dorsolateral part of the otic plate; the crest extends anteriorly over the zygomatic ramus. A fragmentary medial projection may represent part of the squamosal portion of the temporal arcade. The posterior border of this projection seems to be complete and to have formed a postorbital fenestra.

Remarks. All these remains possess the proposed and possible synapomorphies for Ceratophryidae and Ceratophrys that can be evaluated, as follow: MLP 34-V-10-8. —exostosis, non-pedicellate teeth, anterior maxillary pars palatina absent ( Ceratophryidae ), and long maxillary processes of premaxilla ( Ceratophrys ); MACN 17585.—exostosis, anterior maxillary pars palatina absent ( Ceratophryidae ), and long maxillary processes of the premaxilla ( Ceratophrys ); MACN 17936.—exostosis, parieto-squamosal arch ( Ceratophryidae ), and postorbital fenestra ( Ceratophrys );. MACN 18074.—exostosis, anterior maxillary pars palatina absent ( Ceratophryidae ), postorbital fenestra, long maxillary processes of premaxilla ( Ceratophrys ). Thus, the foregoing should be assigned to Ceratophrys . MLP 34-V-10-8, MACN 17585, and MACN 17936 lack diagnostic characters of a less-inclusive taxon. MACN 18074 has a combination of characters present in the [ C. aurita – C. joazeirensis ] clade, C. calcarata , and C. ameghinorum (i.e., lateral crest and squamosal otic plate with lateral wall); however, this specimen is too fragmentary to justify its attribution to any of these taxa.

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.