Odorrana narina ( 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 : 10

Odorrana narina ( Stejneger, 1901) — Okinawa Tip-nosed Frog

Figure 4.8–4.14

Occurrence (MNI). Minatogawa: 40; Sashiki (lower unit): 5.

Referred material. Minatogawa: 45 female humeri (21 right and 24 left: YMHF-MA 004 ), 32 male humeri (16 right and 16 left: YMHF-MA 005 ), and 53 ilia (22 right and 31 left: YMHF-MA 006 ); Sashiki (lower unit): 8 female humeri (4 right and 4 left: RUMF-GF-04014), 1 male humerus (right: RUMF-GF-04015), 1 pelvic girdle (RUMF-GF-04016), and 1 ilium (left: RUMF-GF-04017) .

Humerus. The humerus of this middle-sized frog ( Figure 4.8–4.13 ) can be distinguished from that of other anurans examined (except allied species, see below) by having a series of character states: a slender shaft with an almost uniform diameter throughout the length; a straight ventral edge of the crista ventralis that is often nearly parallel to the dorsal edge of the shaft (in mediolateral views); the distal edge of the crista ventralis that forms an oblique angle with the ventral outline of the shaft (in mediolateral views); a distinct crista paraventralis that extends proximally to the level of the ventrodistal corner of the crista ventralis; a weak spina tubercli medialis; a distinct and shallowly concaved fossula dividens; a scarcely protruded epicondylus radialis; the proximal part of the epicondylus ulnaris that protrudes medially (more than the distal part in dorsoventral views); and a gently round outline of the proximal part of the olecranon scar (in dorsal view). The crista medialis and the crista lateralis are fringe-like in the female ( Figure 4.8, 4.10 ), while in the male, the former extends medially beyond the level of the medial edge of the epicondylus ulnaris, and the latter forms a straightedged ridge of the shaft ( Figure 4.11, 4.13 ). Nokariya (1984) did not provide useful observations on the humerus of this species.

Ilium. Nokariya (1984) noted that the tuber superior of this species is separated from the acetabular margin. Other informative character states on the ilium ( Figure 4.14 ) are: the tuber superior that is well-defined and encircled by a ridged margin; a parallelogram- or drop-shaped tuber superior with a weakly angulated posterodorsal corner and straight, steep posterior edge; the tuber superior that is higher than the anteroposterior length; the crista dorsalis that is thick, low (the height is less than that of the acetabulum), and weakly tapered anteriorly with a straight dorsal edge; a medial inclination of the crista dorsalis (except the posterior end); the pars ascendens with a posteriorly curved anterior edge; and a fused supracetabular fossa.

Remarks. It is difficult to discriminate the humerus and the ilium of O. narina from those of allied species of the Ryukyus ( O. amamiensis , O. supranarina , and O. utsunomiyaorum ) based solely on the morphological characters. The species-level identification of the fossils discussed here is based on the species’ exclusive occurrence on the island.

Figures

FIGURE 4. Fossils referred to Odorrana ishikawae (1–7) and Odorrana narina (8–14), 1–3, right female humerus (one of 10 registered as RUMF-GF-04009) in ventral (1), medial (2), and dorsal (3) views; 4–6, right male humerus (one of three registered as RUMF-GF-04010) in ventral (4), medial (5), and dorsal (6) views; 7, right ilium lacking the anterior part with part of the ischium (one of five registered as RUMF-GF-04011) in lateral view; 8–10, right female humerus (one of eight registered as RUMF-GF-04014) in ventral (8), medial (9), and dorsal (10) views; 11–13, right male humerus lacking the proximal part of the shaft and the distal part of the epicondylus ulnaris (RUMF-GF-04015) in ventral (11), medial (12), and dorsal (13) views; and 14, pelvic girdle (fused right and left ilia [lacking anterior parts] with the ischium and the pubis: RUMF-GF-04016) in right lateral view. Abbreviations are the same as Figure 3. Arrows indicate the proximal ends of the crista paraventralis. Scale bars equal 5 mm.