Limnonectes namiyei ( Stejneger, 1901 )

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 : 6

Limnonectes namiyei ( Stejneger, 1901) —Namiye’s Frog

Figure 3.1–3.4

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

Referred material. Minatogawa: 1 female humerus (left: YMHF-MA 001 ); Sashiki (lower unit): 1 ilium (left: RUMF-GF-04000) .

Humerus. A left humerus lacking the proximal part of the shaft, the distal half of the distal condylar part, and the crista ventralis ( YMHF-MA 001: Figure 3.1–3.3 ), is referred to this large-sized frog. The identification is based on the absence of the crista medialis and the crista lateralis, and the possession of a stout and scarcely waisted shaft, a massive distal condylar part, a well-concaved fossula dividens, a very weak spina tuberculi medialis (sensu Bolkay [1919, p. 330–331], which refers to a ridge on the shaft extending distally from the tuberculum mediale of the caput humeri), and a pointed proximal tip of the olecranon scar (in dorsal view). The gender (female) is inferred from the slender overall shape. Practical observations on the humerus of this species by Nokariya (1984) are confined to the presence of the fossula dividens and the crista paraventralis (the crest was mistakenly referred to as the “spina tuberculi medialis” in his publication; see Nokariya and Hasegawa [1979, figure 2]).

Ilium. A left ilium lacking the anterior part of the ilial shaft (RUMF-GF-04000: Figure 3.4 ) is referred to this species. Nokariya’s (1984) observations on the ilium of this species note a well-developed crista dorsalis and the tuber superior that is separated from the acetabular margin. The following combination of character states may be useful to discriminate the ilium from those of other Japanese anurans examined: a thin, high (the height [from the ventral edge of the ilial shaft, same hereafter] is higher than that of the acetabulum), and anteriorly tapered crista dorsalis with an angulated posterodorsal corner; a straight posterior edge of the crista dorsalis that forms at a sharp angle with the anterior edge of the pars ascendens; the tuber superior that is mediolaterally thin, subround in shape, and defined by a weakly ridged margin; a straight anterior edge of the pars ascendens; and a distinct supracetabular fossa.

Figures

FIGURE 3. Fossils referred to Limnonectes namiyei (1–4) and Babina holsti (5–11). 1–3, left female humerus lacking the proximal and distal parts and the crista ventralis (YMHF-MA 001) in ventral (1), medial (2) and dorsal (3) views; 4, left ilium lacking the anterior part (RUMF-GF-04000) in lateral view; 5–7, right female humerus (one of six registered as RUMF-GF-04003) in ventral (5), medial (6) and dorsal (7) views; 8–10, right male humerus lacking the proximal part (one of two registered as RUMF-GF-04004) in ventral (8), medial (9), and dorsal (10) views; and 11, right ilium lacking the anterior part (one of nine registered as RUMF-GF-04005) in lateral view. Abbreviations: acet, acetabulum; acet.m, acetabular margin; cr.dors, crista dorsalis; cr.lat, crista lateralis; cr.med, crista medialis; cr.par, crista paraventralis; cr.ven, crista ventralis; e.cap, eminentia capitata; ep.rad, epicondylus radialis; ep.ul, epicondylus ulnaris; fo.div, fossula dividens; il.sh, ilial shaft; ol.sc, olecranon scar; p.asc, pars ascendens; stm, spina tuberculi medialis; supr.fo, supracetabular fossa; tub.sup, tuber superior. Scale bars equal 5 mm.