Identity of Rhacophorus rhodopus Liu & Hu, 1960 and Rhacophorus namdaphaensis Sarkar & Sanyal, 1985

Rhacophorus rhodopus was described by Liu & Hu in 1960 on a holophoront (CIB 571171) and 20 male and 2 female specimens from Meng-yang in Yunnan (China) (copy of original description in appendix). It is a rather small frog (males 31.7–39.3 mm, females 49.2–53.4 mm) with pointed snout, with a red brown or yellow dorsum, indistinct dark markings, usually with dark brown X-shaped marking, posterior back with dark transverse stripes; flanks brightly yellow; legs with dark crossbars, and red web. In the original description it was compared to the species of Anderson and was distinguished by the dorsal colour (green, violet after death, in R. maculatus) and shape of snout (rounded in R. maculatus).

Specimens mentioned by Taylor (1962) from Chiang Mai (Thailand) as Rhacophorus bipunctatus are similar to the specimens of R. rhodopus by the presence of a dark line between eyes, faint x-shaped mark on shoulder.

Inger et al. (1999) reported specimens of Rhacophorus bipunctatus from Boun Luoi (Vietnam), compared them to the description of Rhacophorus rhodopus and concluded that they belonged in the same biological species. Inger et al. (1999) did not consider Anderson (1871) as the original author of the taxon with the valid name Rhacophorus bipunctatus. They did not compare their specimens with the onomatophores of Anderson’s taxon. Though they mentioned specimens from Assam, Myanmar, Thailand and Vietnam, they discussed only differences between Thai and Vietnamese specimens, thus no specimens of the same biological species as Rhacophorus maculatus Anderson, 1871.

In conclusion, specimens of Vietnam studied by Inger et al. (1999) are to be assigned to the same biological species as R. rhodopus from Yunnan. In contrast these authors did not provide evidence of the identity of this species with Rhacophorus maculatus Anderson, 1871 and their synonymy therefore has no support.

It is true that both R. bipunctatus and R. rhodopus have pointed snout, but the dorsal coloration of all symphoronts of R. maculatus from Assam is bluish, thus green in life, whereas R. rhodopus had brown dorsal colour. The two species show several other morphological differences which confirm their specific difference.

In 1985, Sarkar & Sanyal described a new species, Rhacophorus namdaphaensis from Arunachal Pradesh, India (holophoront, ZSI A.7180, ♂; Fig. 2 A, B, C), which they compared to Rhacophorus dulitensis (Boulenger, 1892) from Sumatra. It is a small sized Rhacophorus (SVL ♂ 31.6–36.5 mm) with reddish-brown dorsal colour intermixed with variable black spots. Upper surface of limbs show faint cross bars and undersurface of hindlimbs is reddish brown. A large, more or less round black spot is present on side behind the armpit. Study of the hypodigm confirms this description (see detailed redescription of the holophront in appendix). It corresponds in size and coloration pattern to the specimens described as Rhacophorus rhodopus by Liu & Hu (1960). These specimens match also the specimens mentioned by Taylor (1962), Inger et al. (1999) and Wilkinson et al. (2005) as Rhacophorus bipunctatus (or R. bimaculatus). The dorsal pattern corresponds to the orange to tan coloration with a darker brown pattern (blotching or an X mark) on the dorsum described by Wilkinson et al. (2005) as R. bipunctatus. The specimens included in the original description of R. namdaphaensis have the distinct crossbands on the limbs and reduced webbing between fingers. These specimens have a single round spot behind armpit as mentioned by Wilkinson et al. (2005) for R. bipunctatus.

Specimens of R. rhodopus have been collected in Phongsaly province and Luang Prabang province (Laos) (MNHN 2004.0409–0410, MNHN 2006.2518–2519) and in Doi Chiang Dao (Thailand). These specimens are morphologically very similar and show the colour pattern described above. Thus they are distinct from the specimens described by Anderson (1871). Morphometrical comparison of specimens including the hypodigm of Rhacophorus maculatus and R. namdaphaensis showed statistically significant differences for snout-vent length, head width, head length and tibia length and for ratio of head width/snout-vent length (Table 1; Fig. 3). R. bipunctatus is larger and has a relatively larger head than R. rhodopus.

Thus the specimens referred to of R. bipunctatus by Wilkinson et al. (2005) are to be considered conspecific with those described as R. namdaphaensis by Sarkar & Sanyal (1985) and those described as R. rhodopus by Liu & Hu (1960) and this also applies to the specimens mentioned as R. bipunctatus (or R. bimaculatus) by Taylor (1962) from Chiang Mai (Thailand), Inger et al. (1999) from Buon Loi (Vietnam). Its valid nomen is Rhacophorus rhodopus. This species has a distribution area which extends from NE India to Myanmar, northern Thailand, Laos, Vietnam and southern China. Thus, it is sympatric in part of its range (NE India, Myanmar) with Rhacophorus bipunctatus Ahl, 1927 as defined by the onomatophores of Rhacophorus maculatus Anderson, 1871.