Raorchestes kempiae ( Boulenger, 1919 ) Naveen, Chandramouli & Babu, 2024

Naveen, R. S., Chandramouli, S. R., Babu, S., Ryndongsngi, A. M., Karunakaran, P. V. & Kumara, Honnavalli N., 2024, Rediscovery and redescription of Ixalus garo Boulenger, 1919, and Ixalus kempiae Boulenger, 1919, with a reassessment of the taxonomic status of Raorchestes cangyuanensis Wu, Suwannapoom, Xu, Murphy & Che, 2019 and the description of a new species from the Garo Hills of Meghalaya, Herpetozoa 37, pp. 359-372 : 359-372

Raorchestes kempiae ( Boulenger, 1919) comb. nov.

Ixalus kempiae Boulenger, 1919

Rhacophorus (Philautus) kempiae – Ahl, 1931

Philautus kempiae – Bourret (1942)

Raorchestes cangyuanensis – Wu, Suwannapoom, Xu, Murphy & Che, 2019, syn. nov.

Material studied.

Holotype: ZSI 18859 (Fig. 4 above); sub adult, collected by Agnes Kemp, from “ Above Tura ” .

Topotypes: Five adult males, SACON VA 806 (Fig. 4 below), 301, 302, 297, 299 from Mikadogre Community Reserve (25.433660 ° N, 90.398981 ° E, 174 m), South Garo Hills, Meghalaya, India, collected by RSN on January 23 rd 2021 .

Diagnosis.

Raorchestes kempiae comb nov. is placed in the genus Raorchestes due to the combination of following characters: small body size, vomerine teeth absent, single translucent external subgular vocal sac present, and tips of all fingers and toes expanded into discs with circum-marginal grooves (see Biju et al. 2010). The species can be distinguished from congeners in the Indo-China region by the following combination of characters: A small-sized (mean SVL 24.1 mm in adult males) arboreal species with a rounded snout; tympanum indistinct and supratympanic fold prominent; vomerine teeth absent; single semi-transparent gular vocal sac; tongue without papilla; ventral aspect of the hind limb and groin yellow with black or brown spots; finger and toe discs well developed; toe webbing I 1-2 II 2 - 1 III 1 - 1 IV 1 - 2 V.

Description

(based on an adult male SACON VA 806). Small-sized frog (SVL 23.8 mm), with robust body. Dorsal skin mostly smooth with a few scattered spinules, ventral skin slightly granulose. Head broader than long (HL: HW 0.83); large (HL: SVL 0.33); with a short-rounded snout (ED: ES 0.72). Canthus rostralis evident and rounded; loreal region concave. Trunk short (AG: SVL 0.41) and stout (AG: BW 1.02); eyes large (ED: HL 0.38); nostrils, ovoid, with no visible rim, situated closer to the snout tip than to the eyes (EN: ES 0.61), directed laterally. Inter-orbital space broader than inter-narial space (IO: IN 0.69). Tympanum indistinct. Upper arms short (UAL: SVL 0.28), shorter than lower arms (UAL: LAL 0.57); palm slightly shorter than the upper arms (UAL: PAL 0.54); relative finger lengths III> IV> II> I; Subarticular tubercles distinct in both palmar and plantar surfaces, rounded; Supernumerary tubercles present in the palm; no webbing between fingers; fingers with well-developed rounded discs. Thighs short, nearly half as long as the body (FEL: SVL 0.32), slightly shorter than the tibia (FEL: TBL 0.83). Foot shorter than the thigh (FEL: FOL 2.83), toes short with well-developed rounded discs, partial webbing, webbing formula I 1-2 II 2 - 1 III 1 - 1 IV 1 - 2 V. Dorsum uniformly brown with a faint hourglass pattern. Loreals pale brown, iris dark golden brown. Venter granular, pale gray, spotted with gray and brown in lower trunk and thighs. Lateral aspect of the hind limb and groin orangish yellow with black and brown blotches (Fig. 5 ).

Variation.

Morphometric measurements of the holotypes and other preserved topotypes examined are presented in Table 3 . Variations noted during examination of preserved specimens and live individuals observed in the field. Dorsal coloration ranging from light brown to brownish black with or without an “) (“ pattern (present in VA 301 and VA 302). Brown or black stripes over the thighs and tibia. Some individuals have a bright yellow to white band across the interorbital region (Fig. 5 ).

Natural history and distribution.

Males were usually observed to start calling at dusk from bamboo bushes. The species was recorded from Mikadogre Community Reserve (25.434 ° N, 90.399 ° E, 174 m) and Bollonggre village (25.489 ° N, 89.995 ° E, 150 m) from South Garo Hills and Nengmandalgre Fish Sanctuary (25.494 ° N, 90.548 ° E, 410 m) from East Garo Hills. Based on these locations and the locality provided by Wu et al. (2019), we estimated the extent of occurrence of this species to be 242,491 km ². We observed it to be relatively abundant across an elevational gradient of 100 m asl to 1200 m asl. Therefore, we recommend that this species be downgraded from Critically Endangered to the least concern category.

Remarks.

Wu et al. (2019) described Raorchestes cangyuanensis from Yunnan Province, China. However, they did not compare this species with the senior taxon Ixalus kempiae , likely because I. kempiae had remained poorly known since its description and there had been no literature available on this species based on new sightings since it was first described. It is also unusual for frogs of the genus Raorchestes to have such wide distribution ranges (see Vijayakumar et al. 2014). We conclude that Raorchestes cangyuanensis is a junior synonym of Raorchestes kempiae based on molecular and morphological evidence (see Tables 1 , 3 ). In addition to this, Gouda et al. (2023) regarded Raorchestes cangyuanensis as a subjective junior synonym of R. manipurensis (Mathew & Sen, 2009) . Our analysis also revealed that specimens referable to both these names actually show characters that are diagnostic of Raorchestes kempiae ( Boulenger 1919) , a species described much earlier but overlooked until now due to improper and deficient comparisons. However, since we did not have molecular data or access to type specimens of R. manipurensis , we do not address this in the current work and recommend that resolving this taxonomic uncertainty should be a priority for further study.

Comparisons.

Raorchestes kempiae is genetically divergent (5.25–9.47 % on the 16 S rRNA gene) from congeners, with the least divergent species being Western Ghats endemic R. ghatei , with a divergence of 5.77 %. From congeners in this region, it can be easily distinguished by: absence of an externally visible tympanum (vs. present in R. garo , R. hekouensis , R. malipoensis , R. parvulus , R. dulongensis , R. hillisi , R. huanglianshan ); ventral aspect of the hind limb uniform creamy white (vs. dark gray in R. rezakhani ); ventral surface mostly smooth with slight granulation (vs. granulated and well developed whitish tubercles in R. hekouensis ); toe webbing I 1-2 II 2 - 1 III 1 - 1 IV 1 - 2 V in R. kempiae (vs. I 1-1 II 1 - 1 III 3 - 3 IV 3 - 2.5 V in R. garo , I 2–2 II 2–2 III 2–3 IV 3–2 V in R. malipoensis, II 1–2 III 1–2.5 IV 2.5–1 V in R. menglaensis, II 1–2 III 1–2.5 IV 2.5–1 V in R. hillisi, II 1–2 III 1–2 – IV 2–1 V in R. huanglianshan and I 2–2 II 1.75–2 III 1.5–3 IV 2.75–2 V in R. rezakhani ); snout rounded in R. kempiae (vs. pointed in R. annandalii and short and truncate in R. garo ).

Figures

Figure 4. The holotype of Ixalus kempiae (ZSI 18859) - not to scale (above); SACON VA 806 in preservation (below). A. Dorsal view; and B. Ventral view. Scale bars: 10 mm.

Figure 5. Raorchestes kempiae (dorso-lateral view of SACON VA 806 on top and dorso-lateral view of an uncollected male, bottom) from Garo Hills in life.