Rana chapaensis ( Bourret, 1937 )

Chuaynkern, Yodchaiy, Ohler, Annemarie, Inthara, Chantip & Duengkae, Prateep, 2010, A Revision Of Species In The Subgenus Nidirana Dubois, 1992, With Special Attention To The Identity Of Specimens Allocated To Rana Adenopleura Boulenger, 1909, And Rana Chapaensis (Bourret, 1937) (Amphibia: Anura: Ranidae) From Thailand And Laos, Raffles Bulletin of Zoology 58 (2), pp. 291-310 : 301-302

Rana chapaensis ( Bourret, 1937)

Hylarana chapaensis Bourret, 1937: 34 . [Syntypes: MNHN 1938.58–65 and 1948.144–147 (12 specimens) (formerly LSNUH). MNHN 1938.61 (formerly LSNUH Z 270), designated lectotype by Dubois (1992). Type-locality: “Chapa” (=Sa Pa), Lao Cai Province, Vietnam.]

Material examined. – Laos: Saravan Province, Samoy District, Xe Sap National Biodiversity Conservation Area (FMNH 262576–577, THNHM 02736). Vietnam: Ha Tinh Province, Huong Son (AMNH A 161182–183, AMNH A 161186–187); Lao Cai Province, Sa Pa (MNHN 1999.5865–885).

Taxonomic notes. – Rana chapaensis was described by Bourret (1937; as Hylarana chapaensis ) based on thirteen specimens collected from Chapa ( Vietnam). Chou (1999: 391, table 1) examined vocal sacs in this species as “indistinct”. Our examination showed distinct external vocal sacs visible as wrinkled skin on throat at the corner of lower jaw. The nuptial pads of this species form two largely separated pads on prepollex and median surface of first finger.

Diagnostic characters. – Rana chapaensis is characterized by the following combination of characters: (1) body stocky; (2) SVL of adult males 40.8 ± 1.9 (36.8–44.2 mm), adult females 45.8 ± 3.3 (41.0– 51.8 mm); (3) nostril directed laterally; (4) marginal grooves on fingers present or absent; (5) marginal grooves on toes present; (6) mid-dorsal stripe present or absent; (7) external vocal sac present; (8) nuptial pad present, separated into two pads (on prepollex and median surface of first finger); (9) suprabrachial gland present and large; (10) nest construction behavior present; (11) spinules on back absent or few above vent; (12) spinules on ventrum absent; (13) tibio-tarsal articulation to level of nostril; (14) finger tips dilated; (15) toe tips dilated; (16) relative length of fingers II<I=IV<III; (17) relative length of toes I<II<V<III<IV; (18) pigmented eggs; (19) larval keratodont formula 1:1+2/1+1:2; (20) Calling: 3 weak “gulo-gulo-gulo” notes, like playing a rubber band on a little box.

Distribution. – Laos (Saravane Province); Vietnam (Ha Tinh and Lao Cai provinces).