Pelophylax sp.
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publication ID |
https://doi.org/ 10.26879/1156 |
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persistent identifier |
https://treatment.plazi.org/id/03C287BE-8320-7802-D2E9-F926F163F050 |
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treatment provided by |
Felipe |
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scientific name |
Pelophylax sp. |
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Figure 5 View FIGURE 5 G-J
Material. UBB V 953/1-2 two fragmentary frontoparietals; UBB V 954/1-2 one premaxilla, one angulosplenial; UBB V 955/1-2 two humeri; UBB V 956 one fragmentary ilium.
Description. Two fragmentary frontoparietal specimens, preserving the posterior halves of the bones, are flattened dorsoventrally with their dorsal surface shallowly concave, and delimited laterally by a low crest; the dorsal surface preserves also several irregular superficial grooves; on the ventral side of the bone, two shallow concave bony surfaces represent the endocranial imprints.
The premaxilla preserves a relatively short and dorsally tapering dorsal process and a prominent, triangular shaped palatine process. The pars dentalis is damaged at its lateral part.
The body of the angulosplenial is sinuous, strongly compressed mediolaterally and provided with a shallow Meckelian groove. The coronoid process is wide, lamellar with its dorsal surface shallowly wrinkled.
The humeri preserve their distal parts only. The humeral shaft bears a relatively well-developed medial crest, and the medial epicondyle is larger than the lateral epicondyle.
The only fragmentary ilium preserves the acetabular region and the proximal part of the ilial shaft. The dorsal protuberance is flush with the dorsal margin of the dorsal crest and there is no thickening of this margin; there is a well-preserved deep supraacetabular fossa.
Remarks. The fragmentary frontoparietals, preserving on their dorsal surfaces a shallow network of grooves, are typical for large specimens of Pelophylax ridibundus ; such a sculpture is lacking in the members of Rana (VM pers. obs.). The widened and lamellar coronoid process of the angulosplenial with its dorsal surface wrinkled is also typical for the genus Pelophylax ( Bailon, 1999: fig. 9h). The dorsal protuberance of the ilium is prominent and compressed mediolaterally, however, the iliac shaft is broken off distally, and it is not possible to evaluate the height of the complete dorsal crest. The remaining bones are also reminiscent in size and morphology to those of the genus Pelophylax .
SQUAMATA Merrem, 1820
LACERTIDAE Bonaparte, 1831 Lacertidae sp. indet. 1.
Figure 6 View FIGURE 6 A-D
Material. UBB V 957/1-4 one fragmentary maxilla, three fragmentary dentaries; UBB V 958 one dentary.
Description. The material is fragmentary, each specimen preserving a various number of teeth of pleurodont type. The outer surface of the only maxillary fragment lacks a labial sculpture. The dentary specimens represent different portions from the dentary. The specimen UBB V 957/2, representing an anterior portion of a dentary, preserves a relatively wide lamina horizontalis delimited ventrally by a narrow and open Meckel’s groove ( Figure 6A View FIGURE 6 ); the subdental shelf is narrow and moderately deep. The tooth shaft is compressed mesiodistally, whereas the crowns are monocuspid and projected about one third of their height above the dental parapet. The tooth shafts in the specimens representing more posterior portions of the dentary (UBB V 957/3 and 4) are cylindrical, possessing bicuspid tooth crowns with the main cusp positioned distally ( Figure 6 View FIGURE 6 B-C). The specimen UBB V 958 represents a nearly complete left dentary of a smaller individual ( Figure 6D View FIGURE 6 ). The horizontal lamina is relatively thin, whereas the subdental shelf is shallow. The tooth shafts are cylindrical and moderately high. The preserved tooth crowns are bicuspid without any sign of striations.
Remarks. The maxilla and dentary specimens, possessing closely spaced and cylindrical tooth shafts and provided with bicuspid tooth crowns are reminiscent of the recent genus Lacerta (e.g., L. agilis , L. viridis or L. trilineata ) (Kosma, 2004). The relatively wide and rounded margin of the lamina horizontalis and the posteriorly open and deep Meckel’s groove is also comparable to the genus Lacerta . Compared to the recently reported fossil specimens from the late Miocene (MN 9) of Gritsev, Ukraine, the size and morphology of the larger specimens’ approach to those of Lacerta sp. , type I., whereas the smaller specimen (UBB V 958) to that of Lacerta sp. , type II, described by Roček (2019). Nevertheless, due to the fragmentary state of the available material a more resolved assignment of the above specimens is not possible.
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Royal British Columbia Museum - Herbarium |
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