Theloderma palliatum, Rowley, Jodi J. L., Le, Duong Thi Thuy, Hoang, Huy Duc, Dau, Vinh Quang & Cao, Trung Tien, 2011

Rowley, Jodi J. L., Le, Duong Thi Thuy, Hoang, Huy Duc, Dau, Vinh Quang & Cao, Trung Tien, 2011, Two new species of Theloderma (Anura: Rhacophoridae) from Vietnam, Zootaxa 3098, pp. 1-20 : 13-16

Theloderma palliatum sp. nov.

Holotype: AMS R 173131, adult male, on tree leaf approximately 1 m above the ground,> 10 m from stream, in montane evergreen forest in Bidoup-Nui Ba National Park, Lac Duong District, Lam Dong Province, Vietnam (12.1865º N, 108.7151º E, 1625 m). Collected at 22:30 h on 26 July 2010 by Le T. T. D.

Paratypes: AMS R 173130, adult male, on a leaf of tree approximately 1 m above the ground,> 10 m from stream, in montane evergreen forest in Bidoup-Nui Ba National Park, Lac Duong District, Lam Dong Province, Vietnam (12.1865º N, 108.7151º E, 1625 m). Collected at 22:35 h on 26 July 2010 by Le T. T. D. UNS 00140/AMS R 173508, juvenile, on the ground, approximately 2 m from a small, rocky stream, in montane evergreen forest in Bidoup-Nui Ba National Park, Lac Duong District, Lam Dong Province, Vietnam (12.1735º N, 108.6991º E, ~ 1500 m). Collected at night on 18 August 2009 by Le T. T. D.

Etymology. specific epithet from palliatus L., meaning cloaked or disguised, in reference to the ability of the new species to change dorsal colouration and patterning from relatively dull to highly contrasting.

Suggested common name. Cloaked moss frog (English), Ếch cây sần trá hình (Vietnamese).

Diagnosis. The new species is assigned to the genus Theloderma by the presence of tuberculate skin on the dorsum, a distinct tympanum, terminal phalanx with a Y-shaped distal end, intercalary cartilage between the terminal and penultimate phalanges of digits, tips of digits expanded into large disks bearing circummarginal grooves, and the absence of co-ossification of the head skin to the skull ( Liem 1970). Theloderma palliatum sp. nov. is distinguished from all other Theloderma by a combination of (1) small body size (26.1–26.4 in two adult males), (2) absence of vomerine teeth, (3) presence of minute dorsal asperities, (4) no webbing on the hands, (5) pale to medium brown dorsum with characteristic dark brown blotches and dark brown lateral surfaces extending from snout to groin, and (6) a bicoloured iris, being pale gold in upper third and dark red in lower two-thirds.

Description of holotype. Body relatively slender; head length 90% of head width; snout bluntly truncate in dorsal view, truncate in profile; canthus rostralis relatively indistinct, rounded; loreal region sloping, slightly concave; interorbital region slightly convex; nostrils oval, not protuberant, without flap of skin laterally, much closer to tip of snout than eye; pupil diamond-shaped, horizontal; tympanum distinct, tympanic rim elevated relative to skin of temporal region, 63% of eye diameter; pineal ocellus absent; skin not co-ossified to forehead; vomerine teeth absent; choanae oval, at margins of roof of mouth; tongue attached anteriorly, wide, deeply notched posteriorly; vocal sac and vocal sac openings absent; supratympanic fold barely visible, extending to just beyond level of axilla. Forelimbs slender, relative length of fingers I <II <IV <III; tips of all fingers with well-developed disks with distinct circummarginal grooves, disks relatively wide compared to finger width (third finger disk width 228% third finger width), disks slightly wider than long (third finger disk width 107% of length), third finger disk width 74% of tympanum diameter; webbing on fingers absent; dermal fringing absent; subarticular tubercles prominent, rounded, formula 1, 1, 2, 2; two palmar tubercles; accessory palmar tubercles present, small, distinct; prepollex with low tubercle; nuptial pad present on Finger I. Relative length of toes I <II <III = V <IV; tips of toes with well-developed disks with distinct circummarginal grooves; disks smaller than those of fingers; webbing formula I2 -–2+ II1 ½–3- III2 -–3 IV2 ½–1½V; subarticular tubercles rounded, distinct, formula 1, 1, 2, 3, 2; inner metatarsal tubercle distinct, oval; outer metatarsal tubercle small, circular. Dorsal skin weakly rugose with sparsely scattered minute, pearly asperities; ventral surface of thighs and belly coarsely granular, chest and throat smooth. Dermal fringes and pointed projection at tibiotarsal articulation absent.

Colour of holotype in life. Dorsal surface pale coppery brown with distinct dark warm brown markings (Figure 8). Triangular inter-orbital blotches that abut the anterior edge of the inner margins of the orbital bulge, three mid-dorsal blotches decreasing in size posteriorally; the largest 3.0 mm diameter, circular, approximately midway along back; middle blotch circular, 2.0 mm diameter; smallest blotch laterally compressed, approximately 1.5 mm x 0.4 mm. Single dark warm brown band running across ventral surface of tibiotarsus and thigh, and on to body to nearly join middle mid-dorsal blotch, approximately 2.5 mm wide; when leg is adpressed, forms a continuous line. Dark warm brown patches over heels and knees. Lateral surfaces dark warm brown, from tip of snout, through nare, under canthus rostralis, through eye, over tympamum and along sides of body. Dorsal surface of arms (except for elbows), hands and feet dark warm brown, the latter with faint white speckling. Ventral surfaces dark warm brown with pale bluish white marbling on chest, inguinal region, anterior surface of thighs and tibiotarsus. Faint white speckling on the throat and ventral surfaces of arms, extending laterally onto upper lip and flanks. Iris pale gold in upper third, and dark reddish brown in lower two-thirds; division of eye colour matches skin coloration adjacent to eye.

Colour of holotype in preservative. As in life, but base colour of dorsal surface fades to creamy white, and dark brown is slightly less warm in tone; overall specimens have a more contrasting pattern ( Figure 9 ). The white marbling and speckling on ventral surface is also more distinct.

Variation. Measurements of the type series are shown in Table 2 . As was noted for T. licin ( McLeod & Norhayati 2007) , and T. nebulosum sp. nov. (above), the new species has the ability to change colour over time. Upon capture (at night), the dark brown patterns were paler and background dorsal colour darker. The holotype (AMS R 173131) was a medium brown colour on the dorsal surface of head, extending along the back towards central mid-dorsal spot ( Figure 8 D). The distinct darker markings were still evident, but less distinct, and the dorsal surface of hands and feet were brownish grey. Diurnally, and in preservative, all specimens have nearly identical dorsal patterns and colours. Both the holotype (AMS R 173131) and adult male paratype (AMS R 173130) have distinct nuptial pads on Finger I.

Distribution and ecology. The new species is known only from montane evergreen forest above 1500 m at the type locality of Bidoup-Nui Ba National Park ( Figure 10 ). During approximately 20 field surveys at the park between 2008–2010, only three specimens of T. palliatum sp. nov. were ever observed. Due to the small size and arboreal nature of these frogs, the apparent rarity of the species may be due simply to poor detectability.

Comparisons. The small body size, absence of vomerine teeth, presence of only minute dorsal asperities, no webbing on the hands, pale to medium brown dorsum with characteristic dark brown blotches and dark brown lateral surfaces extending from snout to groin, and a distinctly bicoloured iris distinguishes T. palliatum sp. nov. from all species of Theloderma (Table 1). Theloderma palliatum sp. nov. is most morphologically similar to the small T. lateriticum , T. licin , T. rhododiscus and T. truongsonense comb. nov. Theloderma palliatum sp. nov. differs morphologically from T. lateriticum by having a pale to medium brown dorsum with dark brown dorsal markings (versus a dorsum with a deep brick-red wash overtop dark black-green, without the dark brown dorsal markings), dorsal tubercles the same colour as the dorsum (versus distinctly white tubercles on flanks and dorsal surface of limbs) and a distinctly bicoloured iris (versus uniformly deep brick red iris). From T. licin , T. palliatum sp. nov. differs by lacking webbing or fringing on hands (versus lateral dermal fringes and basal webbing on hands), having dark brown interorbital markings, bands across the tibiotarsus and patch on knee (versus no dark brown interorbital markings or bands across the tibiotarsus or knee), a distinctly bicoloured iris (versus uniformly red iris) and tuberculate as opposed to a smooth dorsum. From T. rhododiscus , T. palliatum sp. nov. differs by having the ventral surfaces of disks being brown to greyish brown (versus orange-red), and a distinctly bicoloured iris (versus uniformly reddish brown). From T. truongsonense comb. nov., T. palliatum sp. nov. differs by having three, dark brown middorsal spots (versus a single dark brown mid-dorsal spot), and a black/dark brown belly and ventral surface of thighs, with white/pale brown marbling (versus a grey belly and ventral surface of thighs with white spots). In addition, Theloderma palliatum sp. nov. has an uncorrected sequence divergences at the 16S rRNA gene of>8.5% for all Theloderma for which homologous 16S rRNA sequences are available.

Available names. Three available names are currently considered as junior synonyms of valid species names in the genus Theloderma . These names need to be considered as possible earlier names for T. nebulosum sp. nov. and T. palliatum sp. nov. Ixalus tuberculatus (type locality Kakhyen Hills", Myanmar; Anderson 1879 "1878") is considered an invalid senior objective synonym of T. andersoni ( Ahl 1927) (see Bossuyt & Dubois 2001). In the original description, I. tuberculatus was described as having a uniformly olive dorsum and yellowish chest and belly with very fine brown reticulations (compared to brownish dorsum and chest and belly dark brownish black with pale blue/white marbling in T. nebulosum sp. nov. and T. palliatum sp. nov.). Philautus albopunctatus (type locality Yaoshan, Kwangsi, China; Liu & Hu 1962) is considered a junior synonym of T. asperum ( Yu et al. 2007) . The holotype of P. albopunctatus (adult male) is clearly referrable to T. asperum in dorsal coloration, with large patches of white and dark brownish grey on dorsum in life (versus a brownish dorsum lacking white patches in both T. nebulosum sp. nov. and T. palliatum sp. nov.), and is 32.5 mm SVL (compared to <30 mm SVL in T. nebulosum sp. nov. and T. palliatum sp. nov.). Rhacophorus fruhstorferi (type locality “ Tonkin ”, Vietnam; Ahl 1927) is considered a junior synonym of T. corticale ( Wolf 1936) , and is considerably larger than T. nebulosum sp. nov. and T. palliatum sp. nov. (69 mm SVL compared to <30 mm SVL in T. nebulosum sp. nov. and T. palliatum sp. nov.), and has a whitish throat (versus dark brown throat in T. nebulosum sp. nov. and T. palliatum sp. nov.).

Figures

FIGURE 8. Adult male holotype of Theloderma palliatum sp. nov. (AMS R 173131) in life (A) dorsolateral view, diurnal colouration, (B) dorsal view, diurnal colouration (C) ventral view, and (D) in situ with nocturnal colouration.

FIGURE 9. Adult male holotype of Theloderma palliatum sp. nov. (AMS R 173131) in preservative (A) Dorsal view, (B) ventral view, (C) lateral view of head, (D) ventral surface of right hand, and (E) ventral surface of right foot. Scale bars = 2 mm.

FIGURE 10. Habitat at type locality of Theloderma palliatum sp. nov. in Bidoup-Nui Ba National Park, Lam Dong Province, Vietnam.