Rhacophorus viridis viridis ( 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 : 12-14

Rhacophorus viridis viridis ( Hallowell, 1861) — Okinawa Green Tree Frog

Figure 6.5–6.11

Occurrence (MNI). Minatogawa: 1; Sashiki (lower unit): 6, (upper unit): 1.

Referred material. Minatogawa: 2 gender unknown humeri (1 right and 1 left: YMHF-MA 011 ); Sashiki (lower unit): 7 female humeri (2 right and 5 left: RUMF-GF-04025), 1 gender unknown humerus (left: RUMF-GF-04026), 1 ilium (right: RUMF-GF-04028), and 1 pelvic girdle (RUMF-GF-04029); Sashiki (upper unit): 1 male humerus (left: RUMF-GF-04027) .

Humerus. These middle-sized slender humeri ( Figure 6.5–6.10 ) can readily be referred to rhacophorine genera (e.g., Kurixalus , Polypedates , and Rhacophorus ) on the basis of having a developed crista medialis and crista lateralis; a slender shaft with a mediolaterally thin proximal part; an indistinct olecranon scar; a gently curved ventral and distal edges of the crista ventralis (in mediolateral views); the distal edge of the crista ventralis that meets at a slight angle to the ventral outline of the shaft (in mediolateral views); and a small and proximodistally elongated eminentia capitata ( Nokariya, 1983b).

The fossil humeri resemble those of Rhacophorus viridis , the only indigenous rhacophorine species in the Central Ryukyus, and differ from those of Polypedates leucomystax (a rhacophorine species naturalized in the Ryukyus: see above) in having a crista ventralis that extends distally to almost the midpoint of the shaft (vs. usually confined to one-third of the shaft: Nokariya, 1983b) and male’s crista medialis that extends medially beyond the level of the medial edge of the epicondylus ulnaris (vs. less-developed). The gender of the fossil humeri was inferred from the developmental degree of the crista lateralis and the crista medialis ( Nokariya, 1983b).

Ilium. The fossil ilia ( Figure 6.11 ) are referred to rhacophorine frogs on the basis of having a wide preacetabular zone ( Nokariya, 1983b), a small and tubercle-like tuber superior, a thick and low crista dorsalis (the height is much less than that of the acetabulum), and a nearly fused supracetabular fossa. They resemble those of Rh. viridis and differ from those of P. leucomystax in having a tuber superior that is separated from the acetabular margin (vs. contact: Nokariya, 1983b) and a straight dorsal margin of the crista dorsalis that is in parallel with the ventral margin of the ilial shaft (vs. a posteriorly sloping posterior part of the crest: Nakamura et al., 2009).

Remarks. Currently, two subspecies are recognized under Rhacophorus viridis ( Maeda and Matsui, 1999) . The fossils are referred to Rh. viridis viridis on the basis of the exclusive occurrence on the island.

Order CAUDATA Fischer von Waldheim, 1813

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.