Ansonia vidua, Hertwig, Stefan T., Min, Pui Yong, Haas, Alexander & Das, Indraneil, 2014

Hertwig, Stefan T., Min, Pui Yong, Haas, Alexander & Das, Indraneil, 2014, Dressed in black. A New Ansonia Stoliczka, 1870 (Lissamphibia: Anura: Bufonidae) from Gunung Murud, Sarawak, East Malaysia (Borneo), Zootaxa 3814 (3), pp. 419-431 : 422-428

Ansonia vidua , sp. nov.

Holotype: NMBE 1061645 , field number HJ12–125 ( Figs. 2–5 ), GenBank accession number KJ488546 , from the summit trail between Church Camp and the summit of Gunung Murud, near the intersection with Sungei Murud, Gunung Murud , Pulong Tau National Park, Sarawak, East Malaysia (Borneo), altitude 2,152 m asl (N 03°54.721', E 115°29.954, GPS WGS 84), coll. Y. M. Pui, A. Jankowski and S. T. Hertwig, 28 February 2012. Adult female.

Paratype: NMBE 1066153 , field number SH13–291 ( Fig. 3 C, D), GenBank accession number KJ 488547 , 25 m away from the locality of holotype at the summit trail , coll. Y. M. Pui, T. Einecke, T. Keilholz and S. T. Hertwig, 10 March 2013. Adult female .

Diagnosis. The new species is assigned to the genus Ansonia based on its relatively slender body, long legs, indistinct subarticular tubercles, membraneous digitial webbing, the absence of parotoid glands, tympanum visible ( Inger 1960, 1966) and a robustly supported phylogenetic hypothesis ( Fig. 1 ).

Ansonia vidua sp. nov. can be differentiated from all other congeners by the following combination of characters: SVL 33.5 and 34.3 mm in the two females known; body not flattened; canthus rostralis slightly swollen; two low longitudinal interorbital ridges present; dorsum of body, flanks and upper surfaces of the limbs covered with numerous small, regular, low, rounded warts, resulting in a velvet-like appearance, only warts on scapular and temporal regions slightly enlarged; warts on dorsum, head and limbs terminating in a single fine, keratinous spine; first finger short, not reaching tip of second finger when adpressed; no sharp tarsal ridge; no skin flaps on posterior thigh near vent; third and fifth toe with 2½ phalanges free of web medially; colouration of the dorsal surface of head and body uniformly black-brown; limbs dark brown with lighter areas on joints of the limbs and phalanges; ventral surface uniformly dark grey to yellowish brown; dorsal and ventral parts of body and limbs completely patternless.

Description of holotype. Habitus slender; body as wide as head ( Figs. 2–3 A, B), body not dorsoventrally flattened; head slightly longer than wide ( Table 2 ); HWAJ/TBL 0.62; rostrum truncate in dorsal view, tip of snout rounded, longer than canthus, oblique in lateral view, projecting beyond tip of mandible, longitudinal, medial groove on the dorsal face of snout, rostral length greater than eye diameter; nostril lateral, closer to snout tip than eye ( Fig. 4); distinct vertical ridge between tip of snout and centre of maxilla ( Figs. 3 A, B, 4); canthus swollen with rounded edge, slightly arcuate in lateral view; lores vertical and concave; eye diameter greater than eye-nostril distance; interorbital distance subequal to upper eyelid ( Table 2 ); tympanum distinct, eye diameter 1.9 times greater than tympanic diameter ( Fig. 4, Table 2 ); two low, slightly curvestridges on head forming a parenthetical shape “()”extends from the anterior aspect of the interorbital region to a point approximately in line with the centre of the tympani ( Fig. 3 A), one supratympanic ridge in parotoid region ( Fig. 2 and 3 A).

Tips of fingers IV and V weakly expanded, spatulate, without distinct discs; first finger (II) much shorter than second (III), only reaching middle of second phalange of second finger; subarticular tubercles low; palm smooth with large, distinct rounded palmar tubercle. Tips of all toes rounded; fifth toe projecting farther than third; toes not fully webbed, first toe with one phalange free of web, second with 1½ phalanges free of web medially, third and fifth with 2½ phalanges free of web medially, fourth toe with 4 phalanges free of web medially; subarticular tubercles indistinct; two metatarsal tubercles, both oval and slightly raised ( Fig. 5); no tarsal fold ( Fig. 3 ). Left foot slightly deformed, toes shortened ( Fig. 3 A, B).

Skin of sides, back and dorsal surfaces of limbs uniformly covered with small, low, rounded tubercles; shagreened skin has a characteristic velvet-like appearance; tubercles not arranged in distinct rows, tubercles on top of head and eyelids smaller ( Figs. 2–4 ), slightly enlarged tubercles on scapular and temporal region and posterior of tympanum ( Figs. 2–4 ); one row of enlarged, spineless tubercles with darker pigmentation beneath mandibular symphysis ( Fig. 3 B), followed posteriorly by few smaller, spineless, irregularly arranged tubercles ( Fig. 3 B); tubercles on dorsal surfaces of head, body, and limbs tipped with one small, regularly shaped dark brown spine, tubercles on sides, venter and throat without spines ( Fig. 3 A); no skin flaps on posterior thigh near vent ( Fig. 3 A, B).

Colour in preservative uniformly dark brown above, slightly lighter areas on sides and on joints of limbs and phalanges; venter uniformly brownish grey, throat and chest uniformly yellowish brown ( Fig. 3 A, B). Colour in life uniformly black-brown above, limbs dark brown with lighter areas on joints of the limbs and phalanges ( Fig. 2 ). Iris black with small irregular intense red spots ( Fig. 2 ).

Variation. In the paratype ( Table 2 , Fig. 3 C, D), skin on sides is slightly smoother, abdomen and throat finely granular, tubercles smaller and indistinct, only a single row of enlarged tubercles with darker pigmentation present posterior of the mandibular symphysis. Skin fold on rear thigh near vent is a preservation artifact ( Fig. 3 C, D). Lighter areas on sides larger in preservative, colour of throat changes from light yellowish grey to yellowish brown anteriorly ( Fig. 3 C, D).

Comparisons Ansonia vidua sp. nov. can be distinguished morphologically from the 12 described congeneric Bornean species on the basis of an apomorphic combination of diagnostic characters (see ‘Diagnosis’). Bornean congeners differ from A. vidua as follows: A. albomaculata Inger, 1960 : interorbital ridges absent; tympanic annulum partially hidden by thickened skin; sharp tarsal ridge present; toes almost fully webbed; light band running from the posterior corner of the eye to the axilla, often with a subocular light spot ( Inger 1966; Inger & Stuebing 2005); A. echinata : interorbital ridges absent; dorsum with rounded tubercles both small and large; large ventrolateral tubercles (up to half diameter of tympanum) tipped with small black spines; spinose tubercles on top of snout; third and fifth toe with 1–2 phalanges free of web; limbs with dark crossbars ( Inger & Stuebing 2009); A. fuliginea : larger body size (females 38–44 mm); interorbital ridges absent; snout vertical in profile and not projecting; tympanum ca. 50% of eye diameter; submandibular spines arranged in a double row ( Inger 1960, 1966; Inger & Stuebing 2005); A. guibei Inger, 1966 : interorbital ridges absent; interorbital distance much greater than width of upper eyelid; tympanum diameter 25–33% of eye diameter; first finger reaches tip of second finger when adpressed; web reaches tips of first, second, third, and fifth toes; dorsal and dorsolateral warts topped with clusters of dark spinules; oblique flap of skin present on each side of vent; upper surfaces dark brown with irregular lighter spots on top of head and back, underside light grey with indistinct dark spots ( Inger 1966; Inger & Stuebing 2005); A. hanitschi : body flattened; narrower head (HWAJ/TBL 0.50–0.56); interorbital ridges absent; third and fifth toe with 1.5–2 phalanges free of web; skin on back with heterogeneous small rounded warts and a few oval warts, a few warts form short, slender ridges on the back; dark greenish-grey to reddish-brown colouration with dorsal markings, limbs with black crossbars, venter with pattern of dark blotches( Dring 1983; Inger 1966; Inger & Stuebing 2005); A. latidisca : larger body size (females 52.1–59.8 mm); canthus rostralis sharp, straight; interorbital ridges absent, but two rows of conical interorbital tubercles; tympanum diameter half of eye; tips of fingers dilated into truncate discs (that of third finger equal in width to tympanum); green colouration above with a distinct pattern of irregular brown spots, abdomen brown with scattered yellowish spots ( Inger 1966; Matsui et al. 2012); A. leptopus : larger body size (females to 60 mm); interorbital ridge absent; tip of first finger reaches swollen tip of second; chest and belly grey with darker mottling ( Inger 1966; Inger & Dring 1988; Inger & Stuebing 2005); A. longidigita : much larger size (females to 65 mm); canthus rostralis sharply angular; tip of first finger reaches swollen tip of second; third and fifth toe with one to two phalanges free of web; abdomen with faint dark spots on a pale background or dark with obscure pale spots, limbs with obscure light crossbars ( Inger 1966; Inger & Dring 1988; Inger & Stuebing 2005); A. minuta : smaller size (females 23–28 mm); interorbital ridges absent; interorbital distance 1.3 width of upper eyelid; distinct tarsal ridge; toes are three-fourth webbed in females; dorsum brown with irregular small orange or yellowish dots, side of head with dark and light bars with a whitish area below eye, abdomen pale with black spots ( Inger 1960, 1966; Inger & Stuebing 2005); A. platysoma : smaller size (females 20–25 mm); head and body flattened; interorbital ridges absent; skin with heterogeneous warts; 1–1.5 phalanges free of web on third toe; abdomen with light and dark mottling; limbs with light crossbars ( Inger 1960, 1966; Malkmus et al. 2002); A. spinulifer : larger body size (females to 40–45 mm); interorbital ridges absent; tip of first finger reaches swollen tip of second; dorsal and dorsolateral warts elevated, large and tipped with one to three substantial black spines; top of head and body black with a yellowish or whitish oval patch between shoulders and a light streak along flanks, venter black with small cream-coloured spots or black marbling ( Inger & Dring 1988; Inger & Stuebing 2005); A. torrentis Dring, 1983 : interorbital ridges absent; dorsum covered with numerous heterogeneous rounded tubercles; tips of tubercles without spines, except on temporal and scapular region; blackish in colour with yellowish to pale brown markings on flanks, limbs with light crossbars, abdomen with large greybrown blotches separated by pale areas ( Dring 1983).

Ansonia vidua sp. nov. is unambiguously separated from A. endauensis , A. inthanon , A. jeetsukumarani , A. kraensis , A. latiffi , A. latirostra , A. malayana , A. mcgregori , A. muelleri , A. penangensis , A . siamensis and A. tiomanica by phylogenetic signal of sequence data ( Fig. 1 ). The recently described species A. lumut Chan, Wood, Anuar, Muin, Quah, Sumarli , and Grismer is the sister taxon to a clade consisting of A. jeetskumaran , A. malayana and A. penangensis ( Chan et al. 2014) and, therefore, also not directly related to A. vidua sp. nov..

Etymology. The species name vidua means´widow´and refers to the uniform brownish-black colouration in life of this species, which is traditionally the colour of choice by widows. We suggest the English vernacular name ‘Murud Black Slender Toad’ for the species.

Ecological notes. The type series of Ansonia vidua sp. nov., consisting of two female individuals, was collected on two expeditions to the Pulong Tau National Park in 2012 and 2013. Males and larval stages of the new species are, as yet, unknown. Both specimens were found at night, resting on the leaves of lower vegetation at the edge of the summit trail to Gunung Murud, ca. two hours walk from Church Camp, a few meters from the edge of a small stream. The type locality is situated between this unnamed small side stream and the Sugei Murud that runs eastward from near the summit of Gunung Murud down to the plateau of the Kelabit Highlands. The type locality is situated just below the summit ridge of the Gunung Murud massif. In this undisturbed montane mossy forest ( Beaman 1999; Beaman & Anderson 1997; Mjöberg 1925), the following species of frogs have been recorded in sympatry: Limnonectes cf. kuhlii , Philautus mjobergi , P. cf. petersi, Pelophryne murudensis and Leptobrachium montanum . The amphibian fauna of Gunung Murud has been described by Das (2005, 2008). The discovery of a new and possibly endemic species from the Gunung Murud massif underlines the importance of the Pulong Tau National Park in the protection of the highly diverse montane amphibian fauna of Sarawak and that of Borneo.

Figures

FIGURE 1. Phylogenetic relationships of Ansonia vidua sp. nov. according to a RaxML-based Maximum Likelihood analysis of partial sequences of the mitochondrial 16 S rRNA gene. Node labels above branches show the bootstrapping support of ML analysis (only values> 50), below branches the posterior probability values of BI (only values> 70).

FIGURE 2. Holotype of Ansonia vidua sp. nov. (NMBE 1061645) in life.

FIGURE 3. Preserved type material of Ansonia vidua sp. nov.: A. dorsal view of holotype (NMBE 1061645); B. ventral view of holotype; C. dorsal view of paratype (NMBE 1066153); D. ventral view of paratype.

Tables

TABLE 2. Measurements of holotype and paratype of Ansonia vidua sp. nov., for details and abbreviations see text.

SVL BW	holotype NMBE 1061645 33.51 12.07	paratype NMBE 1066153 34.28 10.93	HTYD VTYD	holotype NMBE 1061645 1.99 2.13	paratype NMBE 1066153 2.01 2.26
AGD HL HWAE	17.7 11.4 4.69	16.4 11.36 4.9	TBL THL HND	15.96 16.26 9.18	15.99 15.54 9.14
HWAJ HD SL	9.88 4.63 4.16	10.1 4.46 4.23	FOT TI TII	12.88 1.68 2.49	12.69 1.7 2.58
NS EN IN	1.79 2.44 2.85	1.48 2.49 2.51	TIII TIV TV	3.79 7.3 4.76	4.0 7.53 4.81
ED UE IO	3.73 4.27 4.1	3.85 4.29 4.2	FI FII FIII	2.96 3.63 6.63	3.08 3.89 7.25
TED	0.49	0.41	FIV	4.31	4.29