Leptobrachium kanowitense, Hamidy, Amir, Matsui, Masafumi, Nishikawa, Kanto & Belabut, Daicus M., 2012

Hamidy, Amir, Matsui, Masafumi, Nishikawa, Kanto & Belabut, Daicus M., 2012, Detection of cryptic taxa in Leptobrachium nigrops (Amphibia, Anura, Megophryidae), with description of two new species, Zootaxa 3398, pp. 22-39 : 35-36

Leptobrachium kanowitense sp. nov.

Holotype. KUHE 42575, an adult female collected from upper part of Kanowit River (02°07’59.7’’N, 112°08’48.1’’E, 60 m a.s.l.), Sibu Division, Sarawak, Borneo, Malaysia, collected by M. Matsui, K. Nishikawa, Daicus M. Belabut, Norhayati Ahmad, and Chan Kin Onn on 21 November 2008.

Paratypes. SRC 0 0 0 2 (former KUHE 42587), KUHE 42588–42590, four adult females, KUHE 42574, an adult male, collectors and locality same as for holotype.

Etymology. The specific name refers to the place where the type series was collected.

Diagnosis. A small-sized Leptobrachium of the L. nigrops group, with SVL 38.6–44.8 mm in females and 32.9 mm in males; finger tips weakly pointed; tympanum visible, uniformly dark brown; dorsum uniformly dark brown, lacking conspicuous markings; laterally light brown with few dots near groin; ventrum whitish dotted with black particularly on belly and on throat; chest and ventral side of limbs whitish with only few black dots; thin black bars on dorsal side of limbs including digits; clear markings only at groin and posterior thigh; ventral thigh whitish with some dots; femoral glands large in white blotch.

Description of holotype (measurements in mm). Small sized (SVL 44.8); habitus moderately stocky, body tapering to groin, head wider than body, broad and depressed, longer (HL 19.8: 44.2% SVL) than wide (HW 17.4: 38.8% SVL); snout obtusely pointed, rounded triangle from above, truncate in profile, slightly projecting beyond lower jaw; eye large and obviously projecting from sides of head, longer (EL 7.4: 16.5% SVL) than snout (SL 7.2: 16.1% SVL); canthus rostralis sharp, loreal region oblique, moderately concave; nostril lateral, below canthus, distinctly closer to snout (S-NL 3.8: 8.5% SVL) than to eye (N-EL 4.3: 9.6% SVL); internarial distance ( IND 3.1: 6.9% SVL) much narrower than interorbital distance, (IOD 5.2: 11.6% SVL), latter slightly narrower than upper eyelid (UEW 5.8: 12.9% SVL); no pineal spot; tympanum visible, diameter (TD 3.2: 7.1% SVL) less than half that of eye and separated from eye by more than half of its diameter (T-EL 1.7: 3.8% SVL); vomerine teeth absent; tongue heart-shaped, without papillae, notched posteriorly.

Forelimb slender and long (FLL 31.7: 70.8% SVL), about three-fifths of hindlimb; fingers moderately slender, unwebbed; first finger (1FL 4.8: 10.7% SVL) slightly longer than fourth and second, third much longer (3FL 6.6: 14.7% SVL); finger tips weakly pointed; inner palmar tubercle large (IPTL 1.8: 4.0% SVL), not extending onto first metacarpal and larger than outer palmar tubercle (OPTL 1.5: 3.4% SVL); subarticular tubercles indistinct, replaced by low callous tissue.

Hindlimb slender and relatively short (HLL 56.4: 125.9% SVL); heels not meeting when legs held at right angles to body; tibia distinctly longer (TL 17.6: 39.3% SVL) than foot (FL 14.3: 31.9% SVL); tibiotarsal articulation of adpressed limb reaching to beyond anterior edge of tympanum; third toe longer than fifth; toe tips similar to those of fingers and hooked; toe webs very poorly developed; webbing formula I 1 3/4–2 1/ 4 II 1 1/4– 3 III 2–3 3/ 4 IV 3 3/ 4– 2 V; inner metatarsal tubercle small (IMTL 1.6: 3.6% SVL), low and oval; outer metatarsal tubercle absent; subarticular tubercles obscure, but elongated, replaced by low callous tissue.

Skin above nearly smooth, with granules scattered posteriorly, particularly around sacrum; ventrum slightly granular, especially on belly; very low supratympanic ridge from posterior corner of eye to axilla; indistinct low dermal ridges on upper surface of limbs; flat pectoral gland at medial border of axilla behind arm insertion; femoral gland on posterior surface of thigh in white spot.

Colour. In life, brown dorsally with large dark brown blotches on interorbital and parietal regions; laterally brown fading to whitish on ventral side, where black dots scattered, especially dense on belly; loreal region widely black, with some space before eye; tympanum uniformly brown, bordered above by very thin black line of supratympanic ridge; forelimb dorsally light brown with faint bars; chest and ventral side of forelimb whitish; throat darker mixed with guanophores; hindlimb ventrally whitish, spotted with black, particularly near groin and anterior thigh, with blue ground color; dorsolateral sides of fingers and toes light brown; iris black surrounded by light blue sclera visible in maximally opened eye. In preservative, dorsal ground colour darkened, but aspects of colour pattern remained.

Variation. Morphometric variations are shown in Table 3. The male paratype (KUHE 42574) is morphologically similar to holotype, but has smaller body, more rugose dorsal skin, and more distinct dark crossbars on dorsal side of thigh. It has an internal vocal sac and a pair of vocal sac openings. The female paratypes (KUHE 42587–42590) have smaller body, more densely dotted black on ventrum particularly on belly, and on lateral side between armpit and groin, and have more hooked tips of fingers and toes than the holotype. In three females, including holotype, and one male, tibio-tarsal articulation reaches to points beyond anterior border of tympanum, but in the remaining two females it reaches only to middle of tympanum.

Calls. At Kanowit, we heard the calls of L. kanowitense , but failed to record them. Calls were very similar to those of L. nigrops and L. ingeri to the human ear.

Comparisons. Leptobrachium kanowitense tends to have relatively longer head (43.0–45.8% SVL) and larger eye (15.4–16.5% SVL) than L. nigrops (41.2–45.3% SVL and 12.0–17.3% SVL, respectively). Morphometric and qualitative differences between L. kanowitense and L. ingeri are as noted above. Leptobrachium kanowitense is differentiated from L. ingeri by much less developed toe webs. In addition, the new species is differentiated from L. ingeri by having narrowly pointed finger tips. Leptobrachium kanowitense is similar to L. nigrops in the development of toe webbing, but on the outer side of the second toe, web is less developed in L. kanowitense (1 1/ 4–1 3/4 phalanges free of web) than in L. nigrops (1/2–1 2/3, mostly 1 phalange free of web). Leptobrachium kanowitense differs from L. nigrops and L. ingeri , by having whitish ventrum dotted with black (vs. usually reticulated in L. nigrops , and blotched in L. ingeri ). Dorsally, L. kanowitense lacks conspicuous blotched pattern, unlike L. nigrops and L. ingeri that have distinct blotches. In addition, L. kanowitense has uniformly dark brown tympanum whereas whole or upper half of tympanum is black in L. nigrops and L. ingeri .

Range. The inland area of western Borneo, so far only known from Kanowit, Sibu Division, Sarawak ( Figure 1 ).

Natural history. Type series was collected from a marshy area in a jackfruit plantation near a long house (traditional Iban house). Larval, and other ecological data are unknown, but the male paratype was found intermittently emitting calls, indicating late November is within the breeding season. Frog species observed associated with the type series were: Limnonectes paramacrodon (Inger) , Limnonectes ingeri (Kiew) , Fejervarya limnocharis (Gravenhorst) , Occidozyga laevis (Günther) , Ingerophrynus quadriporcatus (Boulenger) , Hylarana baramica (Boettger) , Hylarana raniceps (Peters) , Hylarana erythraea (Schlegel) , Hylarana glandulosa (Bouleger) , Hylarana signata (Günther) , Polypedates colletti (Boulenger) , Polypedates macrotis (Boulenger) , Polypedates leucomystax (Gravenhorst) , Polypedates otilophus (Boulenger) , Rhacophorus appendiculatus (Günther) , Rhacophorus pardalis Günther , Nyctixalus pictus (Peters) , Chaperina fusca Mocquard , and Microhyla malang Matsui.

Figures

FIGURE 1. Map of Malaysia and western part of Indonesia, showing sample localities of the L. nigrops group that are used in the molecular analyses (triangle) and morphological analyses (reversed triangle). Blue: L. nigrops. Yellow: L. ingeri sp. nov. Red: L. kanowitense sp. nov.). Details of localities are shown in Table 1.