Ceratophrys cf. ornata (Fernicola, 2001)

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 : 57-59

publication ID

https://doi.org/ 10.11646/zootaxa.4658.1.2

publication LSID

lsid:zoobank.org:pub:16EDCB6E-49D1-4214-AEB3-203C19CA56A0

persistent identifier

https://treatment.plazi.org/id/3C7387AF-FFBE-FF85-19E5-FEEE23E253CC

treatment provided by

Plazi

scientific name

Ceratophrys cf. ornata
status

 

Unidentified Ceratophrys cf. ornata View in CoL from Chuquisaca, Bolivia ( Vergnaud-Grazzini 1968)

Two partial skulls, an isolated premaxilla, and a series of postcranial elements from Ñuapua locality ( Fig. 1 View FIGURE 1 , locality 9) in the department of Chuquisaca, Bolivia, have been attributed to Ceratophrys cf. ornata by Vergnaud-Grazzini (1968). These remains were collected in the second member of the Ñuapua Formation, Ñuapua 2, which was attributed to the Holocene ( Marshall et al. 1984; Vergnaud-Grazzini 1968). Vergnaud-Grazzini (1968) briefly described and partially illustrated (photographs) the remains (plate XXXVII figs. 1 – 9). The author did not report where the specimens were deposited, but they were located in the Paleontological Collection of the Muséum National d’Histoire Naturelle and they lack collection numbers. In addition to the published photograph of the material, the museum provided photographs of the remains.

Osteological features. Neither skull is complete. One consists of most of the ossified neurocranium and skull roof, and part of the left maxilla ( Fig. 6C, D View FIGURE 6 ), whereas the other is the posterior part of the central cranium ( Fig. 6E View FIGURE 6 ). Both resemble these respective areas in all other Ceratophrys . The condition of the teeth cannot be described because none is completely preserved. Likewise, the poor preservation obviates description of the shape and extension of the squamosal otic plate ( Fig. 6C View FIGURE 6 ). The vomers are in medial contact and bear dentigerous processes in most complete specimen ( Fig. 6D View FIGURE 6 ); however, I could not determine whether true vomerine teeth were present. No crests are evident in the preserved skull roofs.

The isolated premaxilla of this assemblage ( Fig. 6F, G View FIGURE 6 ) possesses a high, but incomplete, alary process, which is as long as the pars dentalis of the bone. The anterior surface is rounded. In lingual view, the premaxilla lacks a pars palatina, but possesses a distinct, well-developed palatine process. A well-developed, short maxillary process, with a sharp, dorsally directed end also is evident ( Fig. 6F View FIGURE 6 ).

Vergnaud-Grazzini (1968) provides information and illustrations of the postcranial elements of the assemblage. The vertebrae attributed to Ceratophrys have neural arches considerably wider than long ( Vergnaud-Grazzini 1968: pl. XXXVIII, figs. 2–4; 9). The atlantal vertebrae have discrete, rather than contiguous cotyles. The transverse processes and diapophyses of the vertebrae are nearly as long as the corresponding neural arches.

Half of a pectoral girdle is represented by three fused elements—scapula, clavicle, and coracoid. The scapula is extremely wide, with the glenoid fossa being nearly three times the shaft width; the pars acromialis is not expanded and the lateral margin is not posteriorly deflected ( Vergnaud-Grazzini 1968: pl. XXXVIII, fig. 7).

Remarks. The most complete skull of the assemblage ( Fig. 6C, D View FIGURE 6 ) has all the proposed synapomorphies for Ceratophryidae (skull exostosis, parieto-squamosal arch, maxilla-squamosal contact, expanded squamosal otic ramus overlapping prootic, and absence of pars palatina on anterior maxilla) and Ceratophrys (robust, bar-shaped maxillary processes of nasals, postorbital fenestra). Although its attribution to Ceratophrys is well supported, it is not possible to associate it with a less-inclusive taxon.

Although the other skull of the assemblage ( Fig. 6C View FIGURE 6 ) is morphologically similar to those of Ceratophrys , it lacks any diagnostic osteological features of the genus. The skull seems to be exostosed. However, exostosis is a highly homoplastic character among anurans and certainly not exclusive to Ceratophryidae ; thus, its occurrence in this fossil does not support attribution to the family.

The premaxilla ( Fig. 6F, G View FIGURE 6 ) has all of the proposed diagnostic characters of this bone for Ceratophryidae (absence of pars palatina, long alary process) but it lacks those proposed for Ceratophrys . The premaxillae of Ceratophrys lack anteriorly convex alary processes, like those of Lepidobatrachus , Chacophrys , and this fossil. Likewise, members of Ceratophrys lack the discrete palatine process and short, acuminate maxillary process present in this fossil. Thus, the attribution of this element to Ceratophryidae is well supported, whereas its assignment to Ceratophrys is questionable. Assuming that this element represents the same taxon as the most complete skull in the assemblage would require that the assemblage of remains represents a taxon with a combination of characters different from that of all known Ceratophryidae . Given the disarticulated condition of the fossils and the presence of other anurans in the same levels, it is more reasonable to conclude that the fossils represent different taxa.

The vertebrae attributed to Ceratophrys by Vergnaud-Grazzini (1968) for which photographs are available lack the possible synapomorphies of Ceratophryidae proposed for these elements. The atlantal cotyles are separate and the transverse processes of the anterior vertebrae shorter than (or of equivalent length to) the corresponding neural arch widths. The neural arches are considerably wider than long ( Vergnaud-Grazzini 1968: pl. XXXVIII, figs. 2–4). Thus, the attribution of these elements to Ceratophryidae is not supported.

The pectoral girdle remains are consistent with the morphology of the pectoral girdle of Ceratophryidae . No possible synapomorphies are recognized in these elements, given their similarities with the elements of the pectoralgirdle of the possible closed related Odontophrynidae .

The occurrence of Ceratophrys at this fossiliferous locality is evidenced by the most complete skull described herein. However, only the premaxilla in the remaining elements, can be attributed to Ceratophryidae , and no evidence supports its placement in Ceratophrys . The pectoral girdle remains could represent ceratophryids in the assemblage, although they cannot be unequivocally attributed to this clade. There is no evidence to assign the vertebrae to Ceratophryidae .

Kingdom

Animalia

Phylum

Chordata

Class

Amphibia

Order

Anura

Family

Ceratophryidae

Genus

Ceratophrys

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