Calluella capsa, Das, Indraneil, Min, Pui Yong, Hsu, Wayne W., Hertwig, Stefan T. & Haas, Alexander, 2014

Das, Indraneil, Min, Pui Yong, Hsu, Wayne W., Hertwig, Stefan T. & Haas, Alexander, 2014, Red Hot Chili Pepper. A New Calluella Stoliczka, 1872 (Lissamphibia: Anura: Microhylidae) from Sarawak, East Malaysia (Borneo), Zootaxa 3785 (4), pp. 550-560 : 552-556

Calluella capsa , new species

( Figures 1–2 )

Holotype. UNIMAS P0610, at the road from the Borneo Golf and Jungle Resort (01.173889o N, 110.20000o E), Gunung Penrissen, Padawan, Sarawak, East Malaysia (Borneo), altitude 939 m ASL (GPS datum WGS 84), coll. Y. M. Pui, 28 March 2012. Adult male.

Paratype. UNIMAS 9389, from Summit Trail (ca. 0 1.673889o N, 110.166667o E), Kubah National Park, Matang Range, Sarawak, Malaysia, altitude ca. 700 m ASL (no GPS data taken), coll. V. Shakhparonov, 3 September 2012. Adult male.

Diagnosis. A mid-sized (SVL 34.2 and 36.0 mm in the two specimens known, both adult males) species of Calluella , sharing the following characters: body rounded, depressed; head wide; snout short; eyes small; tympanum covered with skin; maxillary and vomerine teeth present; a shovel-like, inner metatarsal tubercle present; finger- and toe-tips not dilated; toes with reduced webbing; lack of spinous processes on elbow and heel; manus lacking enlarged tubercles ( Inger 1966; Manthey and Grossmann 1997; Parker 1934).

The new species can be diagnosed from other members of the genus as presently constituted in showing the following suite of characters: dorsum granular; a faint dermal fold across forehead; supratympanic fold indistinct; toe tips obtuse; webbing on toes basal; lateral fringes on Toes I, II, III and IV present; outer metatarsal tubercle present; pupil rounded; and dorsum olive with red spots and venter with a large area of red.

Etymology. The species name, capsa , alludes to the bright red and olive colour of the new species as capsicum is derived from ‘capsa’, Latin for box, in reference to the hollow, compartmental structure of pepper pods (see Szallasi and Blumberg 1999). We suggest the English name, ‘Bornean chili frog’ for the species.

Description of holotype (adult male). A mid-sized species of Calluella , SVL 34.2 mm; body rounded, depressed; head wider than long (HW/HL ratio 1.92); snout obtusely pointed when viewed dorsally and obliquely truncate laterally; projecting slightly beyond mandible; nostrils rounded, laterally positioned, slightly nearer tip of snout than to eye (E–N/E–S ratio 0.47); internarial distance greater than distance from anterior margin of eye to nostril (IN/E–N ratio 1.55); eye small (ED/HL ratio 0.32); its diameter subequal to eye to nostril distance (ED/E–N ratio 1.18); interorbital width greater than upper eyelid width (IO/UE ratio 3.05); canthus rostralis obtuse; loreal region vertical; maxillary teeth present; a weak ‘W’-shaped notch (= symphysial knob) on anterior edge of mandible; mouth extends to posterior corner of eye; choanae located against anterior of palate, partially visible when viewed from below; vomerine teeth set on two straight transverse ridges behind choanae, separated by a narrow mesial diastema; paired dermal ridges transversely across palate; tongue oval, smooth, slightly nicked apically, free for approximately half its length, not forming a pocket; pupil rounded, without clear orientation; tympanum not visible; oval, median subgular vocal sac.

Forelimbs short; fingers free of web or skin fringes; an indistinct metacarpal tubercle; relative length of fingers (measurements in parentheses, in mm): III (3.7)> II (3.2)> IV (3.1)> I (1.7); finger tips pointed; subarticular tubercles distinct, numbering one on Fingers I, II and IV and two on Finger III; one palmar tubercle at base of Finger I; nuptial pads absent on fingers; no enlarged glands on lower arm.

Hind limbs short (TBL/SVL ratio 0.40); a few tubercles on dorsal surfaces of thigh and tibia; toes free of web; dermal fringes present on Toes I, II, III and IV; relative length of toes (measurements in parentheses): IV (9.7)> III (6.5)> V (5.2)> II (2.5)> I (1.7); toes obtuse; subarticular tubercles distinct, numbering one on Toes I, II and V, two on Toe III and three on Toe IV; a large (2.9 mm), crescentic inner metatarsal tubercle, that is larger than Toe I (1.7 mm), and a small, compressed outer metatarsal tubercles.

Dorsum granular, with well-developed, round warts that are concentrated medially, from the postorbital region, across scapular region, to mid-dorsum, those posteriorly raised as tubercles; warts also present on tympanic region; rest of dorsum granular, eyelids and upper surfaces of limbs smooth; an indistinct fold across interorbital region; indistinct supratympanic fold extends from posterior corner of orbit to end of gape; a fine dermal fold extends from mid-snout to the posterior of forehead; abdomen and inner side of thighs finely granular.

Colour. The overall impression is of an olive-and-red frog. The olive dorsum bears numerous bright red areas that surround wart-like structures, while the venter is brightly patterned with large areas of red and black. Formal colour description follows: in life, dorsum finely vermiculated Fuscous (Color #21), most tubercles pale-tipped and surrounded by irregular concentric rings of Spectrum Red (Color #11) and Flesh Ocher (Color #132D) areas.

Snout-tip with a pale pink stripe, which runs along a dermal fold to back of forehead. Upper surface of fore and hind limbs Fuscous (Colour #21), with indistinct, darker bands. Under surface of fore and hind limbs Sepia (Color #219). Dorsum of digits with Fuscous (Color #21) and Spectrum Red (Color #11) bands, these colours showing less contrast than on dorsum of body. Throat Spectrum Red (Color #11) to around midbelly, lower belly unpatterned cream. Irregular Sepia (Color #219) blotches on midbelly. A cream coloured patch in inguinal region. A red streak runs directly across area above vent. Pupil black, area surrounding pupil Salmon Color (Color #106); rest of iris Sulphur Yellow (Color #57), with dark network peripherally; an irregular, wavy dark line along periphery of orbit of eye present.

Measurements (in mm) of holotype and paratype (in parentheses). SVL 34.2 (36.0); HL 8.2 (10.1); HW 15.7 (17.0); HD 8.0 (9.2); BW 21.5 (17.8); TBL 13.8 (17.9); ED 2.6 (3.6); UE 2.0 (2.2); IN 3.4 (2.4); IO 6.1 (4.1); E-S 4.7 (5.0); E-N 2.2 (2.0); and A-G 10.7 (11.7).

Ecological notes. The holotype was found at around 1530 h, immediately preceding a heavy thunderstorm, from the edge of a fragmented patch of secondary submontane forest, surrounded by grasslands, at an elevation of 939 m asl. The locality lies at the upper reaches of Gunung Penrissen, a mountain range forming the boundary between Sarawak ( Malaysia) and Kalimantan ( Indonesia). About 20 species of frogs have been found at this elevational band (900–1100 masl) on Gunung Penrissen (Das and Pui, unpubl.). The paratype was found dead on the summit trail to Gunung Serapi, an isolated massif of the Matang Range, north of Gunung Penrissen. Das et al. (2007) reported on 55 species of amphibians from Matang Range but another five species have since been found in the area (Das, Haas and Pui, unpubl.).

The two localities where the types were found are on discontinuous mountain ranges ( Fig. 3 ), separated by a distance of ca. 56 km (linear distance between the two localities estimated using http://www.movable-type.co.uk/ scripts/latlong.html) of plains and the low, limestone hills of the Bau region. The known distribution thus suggests that the species may be more widespread in western Borneo, when further inventories of the poorly-known mountain systems of western Borneo are conducted.

Morphological comparisons. The new species from western Sarawak is compared with all known congeners, listing only opposing suites of characters for congeners: Calluella brooksii ( Boulenger 1905) , distribution: Bidi, Bau, as well as Kuching, western Sarawak ( Malaysia) and one locality in north-central Kalimantan ( Indonesia); see Inger et al. 2004: SVL 51–55 mm in males, 60–73.5 mm in females ( Manthey & Grossmann 1997; Table 1 ), besides a larger adult size the following character states further distinguish C. brooksii from the new species; pupil vertically elliptical; outer metatarsal tubercle absent; interorbital fold absent; and dorsum tuberculate, with two dark stripes or rows of spots and flanks with small black dots; C. flava Kiew 1984 , distribution: Gunung Mulu National Park, northern Sarawak, Malaysia, SVL 35 mm in the only specimen known ( Manthey & Grossmann 1997), whose sex was unspecified, dorsum smooth; toes with expanded tips; outer metatarsal tubercle absent; dorsum orange-yellow, with a dark brown forehead; and flanks without dark blotches and without red bars; C. guttulata ( Blyth 1856) , distribution: eastern Myanmar, Thailand, Vietnam, Laos and south-western Cambodia, SVL 34–45 mm in males, 38–50 mm in females ( Manthey & Grossmann 1997), dorsum smooth; webbing on Toe IV broad up to basal subarticular tubercle, reaching penultimate tubercle as a narrow sheath; and outer metatarsal tubercle absent; C. minuta Das et al. 2004 , distribution: Peninsular Malaysia, interorbital fold absent; toe webbing broad to median subarticular tubercle; flanks and venter unpatterned; and dorsum tuberculate, with yellowishbrown, with darker variegation and a large, dark, central area; C. smithi ( Barbour & Noble 1916) , distribution: northern Sarawak and Sabah, SVL 37–39 mm in females; male size range remains unknown ( Manthey & Grossmann 1997); dorsum smooth; interorbital fold indistinct; outer metatarsal tubercle absent; no red areas in gular region; and dorsum with a large, dark-centred blotch with laterally projecting branches and flanks with pinkedged black blotches; C. volzi (van Kampen 1905), distribution: known from two isolated localities, Tanjung Laut, and Sauraya, on the Alas River, from north-western and south-eastern Sumatra, respectively, both in Indonesia (Islandar & Mumpuni 2004; see also material examined in Appendix 1), SVL 31.3–34 mm, toe tips dilated; toes two-thirds webbed; outer metatarsal tubercle absent; subarticular tubercles present; distinct dermal fold in interorbital region typically present; dorsum tuberculate, with reddish-brown, with black spots; and venter lacks red pigmentmentation on gular and abdominal regions; and C. yunnanensis Boulenger 1919 , distribution: Yunnan, Sichuan and Guizhou Provinces of south-western China, and the Fansipan Mountains of Viet Nam ( Orlov et al. 2002), SVL 30.0– 37.2 mm in males, 40.0– 48.8 mm in females (Yang 1991), toe tips swollen, toe webbing between Toes III and IV reaching beyond level of distal tubercle of Toe III ( Parker 1934); distinct interorbital fold present; dorsum tuberculate, pale pinkish-grey with traces of a dark lateral band from canthus rostralis to mid-flanks; and venter lacks red pigmentation on gular and abdominal regions. An additional species has been described in the genus- Calluella ocellata Liu (1950) , from “Szekuaipa, Chaochiaohsien, Sikang, 7,800 feet ” (currently, Sikuaiba, Zhaojue County, Sichuan Province, China). However, Liu and Hu (1961) placed the name in the synonymy of C. yunnanensis Boulenger 1919 , despite its obvious morphological differences, including fully webbed toes (vs. toes with at least one phalange free of webbing) and small finger IV (vs. Finger IV> Finger I). C. ocellata differs from the new Bornean species in showing a completely webbed toes; Finger IV smaller than finger I; and a dark vinaceous grey dorsum and inguinal region with paired ocella.

Table 1 lists measurements and meristic data for adults of the genus Calluella .

Phylogenetic Relationships. The final alignment from MAFFT consisted of 857 bp of which 430 positions were variable and 370 were informative. The final ML Optimization Likelihood of the resulting tree is -11492.0. The holotype and paratype of Calluella capsa form a monophyletic clade that is morphologically diagnosable, and further, show a low genetic distance of 0.6%. The phylogenetic position of C. capsa as a basal branch within a clade consisting of the remaining species of Calluella and Glyphoglossus is well-supported (Fig. 4). Calluella is paraphyletic with respect to Glyphoglossus . This result is in agreement with Matsui et al. (2011), who presented a consensus tree showing Glyphoglossus within Calluella . Pyron and Wiens (2012) recovered a sister-relationship between Glyphoglossus molossus and Callulla guttulata . However, they had a single representative from the latter genus in their sample. These relationships recovered suggest paraphyly of the group currently allocated to the genus Calluella , the lineage also including Glyphoglossus that is clearly embedded in it. Should further investigations, with more intense sampling, especially of the members from the Asian mainland, revalidate our results and those of Matsui et al. (2011), it would lead to a revised taxonomy of the group, with the reallocation of members from Calluella to its older generic name, Glyphoglossus .

Figures

FIGURE 1. Live holotype of Calluella capsa sp. nov. (UNIMAS P 0610). A. Dorsolateral view; B. Ventral view and C. Dorsolateral view of head.

FIGURE 2. Preserved holotype of Calluella capsa sp. nov. (UNIMAS P 0610). A. Dorsal view of body (scale marker = 10 mm); B. Body venter (scale marker = 10 mm); C. Left hand (scale marker = 5 mm) and D. Left foot (scale marker = 5 mm).

FIGURE 3. Map of Borneo and adjacent regions in south-east Asia, showing type localities of Calluella capsa sp. nov. at the Matang Range (1) and Gunung Penrissen (2) in Sarawak State, East Malaysia. Base map generated using GeoMapApp version 2 (Lamont-Doherty Earth Observatory, Columbia University).