Ansonia echinata, Inger & Stuebing, 2009

Inger, Robert F. & Stuebing, Robert B., 2009, New Species And New Records Of Bornean Frogs (Amphibia: Anura), Raffles Bulletin of Zoology 57 (2), pp. 527-535 : 528-529

Ansonia echinata , new species ( Bufonidae ) ( Figs. 1, 2 )

Holotype. – FMNH 272784 , collected at Bukit Kana , Bintulu Division , Sarawak (2°39.363'N 112°54.219'E), on 28 Mar.2007, by Leong Tzi Ming , Freddy Julus, Patrick Francis, and Jacinta Richard. This specimen was collected at night perched on dead leaves at the edge of a small stream (3 m wide) in primary rain forest.

Paratypes. – All collected at the same locality and along the same stream as the holotype . FMNH 272785 a male collected on the same night as the holotype but perched on the leaf of a shrub 1.0 m above ground ; FMNH 272787 a male collected 3 Apr.2007, perched less than 1.0 m above ground on the leaf of a small herb 2.5 m from the water’s edge ; FMNH 272788 a male collected on 4 Apr.2007, perched on the leaf of a small herb 3.5 m from the water’s edge .

Diagnosis. – A small species of Ansonia , adult males 20.0– 21.3 mm; males with black spines under mandible; first finger much shorter than second, tips of outer fingers not expanded; toes three and five with at least one phalange free of webbing; back with small and large rounded tubercles, those in dorsolateral region tipped with small black spines; chest and abdomen with rounded tubercles, ventrolateral ones larger and tipped with small black spines, tubercles on top of snout set with black spines.

Etymology. – Specific name from echinatus, Latin for thorny, referring to the spinose tubercles on top of the snout and on the sides.

Description. – Habitus moderately stocky; body wider than head in males; snout truncate in dorsal view, oblique in side view, projecting well beyond tip of mandible, snout longer than eye diameter; nostril lateral, near tip of snout; canthus sharply angular, constricted behind level of nostrils; lores vertical, not concave; eye diameter greater than eye-nostril distance; interorbital wider than upper eyelid; tympanum superficial, diameter slightly greater than half eye diameter; no crests on head.

Tips of all fingers rounded, not expanded; first finger much shorter than second, not reaching rounded tip of second; subarticular tubercles obscure; palm with low, rounded tubercles. Tips of all toes rounded; fifth toe projecting farther than third; first two toes fully webbed to tips laterally; third toe with 1–1 1/2 phalanges free of web laterally; fifth toe with two phalanges free of web medially; fourth toe with three phalanges free; subarticular tubercles obscure; sole of foot with small, low, rounded tubercles; two metatarsal tubercles, both oval and slightly raised; no tarsal fold.

Dorsal surfaces covered with small and large rounded tubercles, tubercles not arranged in distinct rows, those down center of back and along dorsolateral regions largest; tubercles along dorsolateral regions tipped with one or two small black spines; top of head with smaller rounded spinose tubercles, spines of these tubercles larger than those on back; eyelid with similar though smaller tubercles; sides and abdomen covered with low rounded tubercles, those in ventrolateral region larger (some ca. half diameter of tympanum) and tipped with small black spines; entire surfaces of limbs covered with spinose tubercles.

Colour in preservative dark brown above, raised tubercles yellowish brown; ventrally light yellowish brown without pattern; limbs with dark crossbars; no light streak below and behind eye.

Males have subgular vocal sacs with one large slit-like opening on either the right or left side in the floor of the mouth. The nuptial pad is a dense cluster of very fine dark spinules on the dorsal surface of the first finger. The ventral surface of the mandible has black spines, in two or three irregular rows beneath the symphysis and in a single row below the remainder of the jaw.

Measurements (mm) and body proportions (holotype in parentheses). – Snout-vent length 20.0–21.3 (20.0); T/SVL 0.470 –0.502 (0.470), HW/SVL 0.309 –0.315 (0.315), TYM/ SVL 0.054 –0.075 (0.054), eye/snout 0.711 –0.811 (0.811).

A juvenile ( FMNH 272786 ), SVL 13.5 mm, has the spinose tubercles characteristic of this species. It was captured in water of a small stream (width 3 m) at the type locality .

Comparisons. – Eleven species of Ansonia are known currently from Borneo. Only four of these— albomaculata , hanitschi, minuta, and platysoma —have adult males <25 mm SVL ( Inger, 1960). However, the last three of these four differ from A. echinata (males <22 mm) in having widened, spatulate tips to the outer fingers and in lacking enlarged, spinose tubercles ventrolaterally and spinose tubercles on top of the snout. Ansonia albomaculata also differs from A. echinata in lacking enlarged, spinose tubercles ventrolaterally, spinose tubercles on top of the snout, and mandibular spines under the jaw. The light streak from below the eye that characterizes A. albomaculata ( Inger, 1960) is absent in A. echinata .

The relatively short first finger and small size distinguish Ansonia echinata from A. leptopus , A. longidigita , and A. spinulifer , all of which have males larger than 30 mm and the first finger reaching the swollen tip of the second ( Inger, 1960). Ansonia latidisca , A. guibei , A. fuliginea , and A. torrentis are larger (males> 30 mm) than the new species and none has spinose tubercles dorsolaterally or on top of the snout ( Dring, 1983; Inger, 1966). In contrast to A. echinata , A. latidisca has the tips of the outer fingers expanded while A. guibei males have the web reaching the swollen tips of the third and fifth toes. The nuptial pad of A. fuliginea consists of a cluster of 15–25 large black spines ( Inger, 1966), very different from the cluster of very fine spinules in A. echinata .

As to the continental species, A. ornate Günther , A. siamensis ( Kiew, 1984) , and A. latiffi ( Wood et al., 2008) are signifi cantly larger (males> 25 mm snout-vent) than A. echinata and differ further in lacking spines on top of the snout. Males of A. malayana , A. ornata , A. rubigina (Pillai & Pattabiraman, 1981) , A. inthanon ( Matsui et al., 1998) , and A. kraensis ( Matsui et al., 2005) differ from A. echinata in having the third and fifth toes webbed to the swollen tips. Ansonia penangensis differs from A. echinata in having a longer first finger, which reaches the swollen tip of the second ( Inger, 1960). None of these continental species has elevated, melanic spines on top of the snout. The recently described A. jeetsukumarani ( Wood et al., 2008) is approximately the same size as A. echinata but lacks spinose tubercles on the snout and ventrolaterally, such as characterize A. echinata , and has the venter dotted with light spots. The Sumatran species, A. glandulosa (Iskandar & Mumpuni, 2004) , is much larger (male 39.6 mm) than A. echinata and has no spines on top of the snout.

At the type locality, Bukit Kana, Sarawak, of Ansonia echinata we collected three kinds of Ansonia tadpoles, larval A. longidigita (as defined in Inger, 1992) plus two unassigned. Although strikingly different from one another, the last two are recognizably larval Ansonia —oral disc expanded and ventral, labial tooth rows 2/3, marginal papillae continuous across lower lip, upper beak divided into two separate pieces, muscular tail with relatively low fins. They differ in colouration, in size, in the degree of separation of the halves of the upper beak, in relative lengths of the upper and lower rows of labial teeth, in papillae of the lower lip, and in pattern of the coiling of the gut. One of the unnamed forms is identical to the Ansonia ‘cruciform’ tadpole described previously ( Inger, 1992). Absence of tissues from Ansonia echinata prevented associating either of these two larval forms to that species by means of DNA sequencing.

Figures

Fig. 2. Ansonia echinata new species. Ventral view of holotype. Scale in mm.