Hyla undetermined

Hyla sp. Figure 20 Material. Hambach 6C: one sacral vertebra (IPB-HaH 2195). Hambach 11: one ilium (IPB-HaR 2088). Description. The sacral vertebra (Figure 20 A-D) is moderately small and has an anterior cotyle and two posterior condyles. The posterior condyles are well separated. The neural canal is elliptical and the dorsal surface of the neural arch does not present a distinct carina neuralis. The prezygapophyses are suboval and slightly tilted dorsally (about 30°). The transverse processes are broken off, but, judging from the preserved portion of the left one, they seem to have been anteroposteriorly extended. IPB-HaR 2088 (Figure 20E) is a small ilium with a globular and laterally-bending dorsal tubercle. The dorsal crest is absent and the preacetabular zone is strongly expanded anteroventrally. The posterior portion of the ilial body is broken. Remarks. Following the diagnostic criteria reported by Bailon (1999), these two fossils can be attributed to a tree frog. The combination of features that is diagnostic for the sacral vertebra is: anterior cotyle; two well-differentiated posterior condyles; extended transverse processes; and no carina neuralis. The diagnostic combination for the ilium is, on the other hand: no dorsal crest; expanded preacetabular zone; and globular and laterally-bending dorsal tubercle. A specific identification of European Hyla species based on isolated bones is considered impossible by most authors (e.g., Bailon, 1999; Sanchiz, 1981; Sanchiz and Młynarski, 1979a; Sanchiz and Sanz, 1980). Nevertheless, it is possible that at least the ilium coming from the most recent level in Hambach pertains to the Hyla arborea (Linnaeus, 1758) species complex, including the extant European species of the genus (Faivovich et al., 2005; Stöck et al., 2008).