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| Rana matsuoi Eto & Matsui, 2023 DOI: 10.5358/hsj.42.191 |
Abstract
Recent molecular analyses cast doubt on the subspecific relationships of Japanese brown frogs Rana tagoi tagoi, R. t. okiensis, and R. t. yakushimensis. Many samples of R. tagoi from three main islands, i.e., Honshu, Shikoku, and Kyushu tend to form a genetic unit with rich variation. On the other hand, R. t. okiensis, R. t. yakushimensis, and some insular samples are clearly isolated from R. t. tagoi and each other. Thus, we propose to treat each subspecies of R. tagoi as full species and describe part of the Goto Islands populations as Rana matsuoi sp. nov. The new species and R. tagoi show a complicated distributional pattern within the Goto Islands but the former is distinguishable from the latter by their smaller male body size, relatively longer limbs, more developed toe webs, nuptial pad formation in breeding male, and advertisement call with repetition of short notes.
KEYWORDS: Goto Islands, Oki Islands, Rana matsuoi new species, taxonomy, Yakushima Island
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| Dorsal, lateral, and ventral view of holotype of Rana matsuoi sp. nov. (top, scale=10 mm), a male paratype KMNH 2023419VR-KE2056 in life (bottom left, not scaled), and tadpoles (bottom right, scale=10 mm). |
Rana matsuoi sp. nov.
Suggested English name: Goto Tago's brown frog
Suggested Japanese name: Goto-tago-gaeru
Synonymy: Rana t. tagoi: Matsuo et al., 2011, p. 11 (part); Sueyoshi et al., 2013, p. 17 (part)
Rana t. tagoi (lineage A-9c): Eto et al., 2012, p. 666; Eto & Matsui 2014, p. 234
Diagnosis: A medium- to small-sized form of the genus (adult males 36.1–40.3 mm, females 38.9–46.7 mm in SVL after fixation); reddish-, dark-, or pale-brown dorsally; a dark mask covering tympanum; a dark shoulder chevron of inverted V shape present but indistinct and interrupted; dorsal and lateral skin nearly smooth with minute granules; supratympanic and dorsolateral fold present; brown mottling present in throat, chest, and ventrolateral area of trunk; usually dark dots present in flunks and ventral side of leg; heels overlapping when limbs are held at right angles to body; tibiotarsal articulation of adpressed limb beyond nostril; tip of digit blunt, slightly dilated but not grooved; toe web developed moderately; males with internal vocal sacs; larvae small, poorly-pigmented. The new species is similar to the other members of the Rana tagoi species complex but can be distinguished from them by the combination of the following characters: small adult body size; relatively long limbs; moderately developed toe webs; and advertisement call with high dominant frequency and repetition of short notes.
Etymology: The specific epithet is dedicated to Mr. Takanori Matsuo, who is a pioneer of herpetofaunal study in the insular regions of Nagasaki Prefecture including the Goto Islands.
Koshiro Eto and Masafumi Matsui. 2023. A New Brown Frog from the Goto Islands, Japan with Taxonomic Revision on the Subspecific Relationships of Rana tagoi (Amphibia: Anura: Ranidae). Current Herpetology. 42(2): 191-209. DOI: 10.5358/hsj.42.191
