Buergeria japonica ( Hallowell, 1861 )

Nakamura, Y & Ota, H, 2015, Late Pleistocene-Holocene amphibians from Okinawajima Island in the Ryukyu Archipelago, Japan: Reconfirmed faunal endemicity and the Holocene range collapse of forest-dwelling species, Palaeontologia Electronica 28 (6), pp. 1-26 : 12

Buergeria japonica ( Hallowell, 1861) —Ryukyu Kajika Frog

Figure 6.1–6.4

Occurrence (MNI). Minatogawa: 1; Sashiki (upper unit): 1.

Referred material. Minatogawa: 1 female humerus (right: YMHF-MA 010 ); Sashiki (upper unit): 1 ilium (left: RUMF-GF-04024) .

Humerus. The female humerus of this tiny frog ( Figure 6.1–6.3 ) is unique among Japanese anurans in having a combination of character states: an indistinct olecranon scar ( Nokariya, 1983b), an angulated medial margin of the proximal part of the epicondylus ulnaris (in dorsoventral views) ( Nokariya, 1983b), a short epicondylus ulnaris that does not reach the level of the distal tip of the eminentia capitata ( Nokariya, 1983b), a mediolaterally widened shaft at the part proximal to the eminentia capitata, a ventrally-oriented and fringe-like crista medialis and crista lateralis, and the proximal part of the epicondylus ulnaris that protrudes medially (more than the distal part in dorsoventral views). The male humeri differ from those of females in having better developed crista medialis and crista lateralis (contra Nokariya, 1983b).

Ilium. The following character states differentiate the ilium ( Figure 6.4 ) from that of the other anurans examined: a narrow preacetabular zone ( Nokariya, 1983b); the tuber superior that is in contact with the acetabular margin ( Nokariya, 1983b); an elliptical tuber superior that is much higher than the length; a moderately high crista dorsalis (the height is almost the same as that of the acetabulum) with a uniform height across most of the length (most of the crest was lost in the referred specimen: Figure 6.4 ); a laterally overhanging posterior part of the crista dorsalis; an angulated posterodorsal corner of the crista dorsalis; a posteriorly curved anterior edge of the pars ascendens; and an indistinct supracetabular fossa (see also Nakamura et al., 2009).

Figures

FIGURE 6. Fossils referred to Buergeria japonica (1–4) and Rhacophorus viridis viridis (5–11). 1–3, right female humerus lacking the proximal part (YMHF-MA 010) in ventral (1), medial (2), and dorsal (3) views; 4, left ilium lacking most part of the crista dorsalis (RUMF-GF-04024) in lateral view; 5–7, left female humerus (one of seven registered as RUMF-GF-04025) in ventral (5), medial (6), and dorsal (7) views; 8–10, left male humerus (RUMF-GF-04027) in ventral (8), medial (9), and dorsal (10) views; and 11, pelvic girdle (fused right and left ilia [lacking anterior parts] with the ischium: RUMF-GF-04029) in left lateral view. Abbreviations: pre.acet, preacetabular zone; the others are the same as Figure 3. Arrows indicate the proximal ends of the crista paraventralis. Scale bars equal 1 mm.