Amolops nidorbellus, Biju & Mahony & Kamei, 2010

Biju, S. D., Mahony, Stephen & Kamei, Rachunliu G., 2010, Description of two new species of torrent frog, Amolops Cope (Anura: Ranidae) from a degrading forest in the northeast Indian state of Nagaland, Zootaxa 2408 (1), pp. 31-46 : 33-38

publication ID	https://doi.org/ 10.11646/zootaxa.2408.1.2
persistent identifier	https://treatment.plazi.org/id/4D4087B5-FFAC-CA06-D9A6-AF09FD11FE03
treatment provided by	Felipe
scientific name	Amolops nidorbellus
status	sp. nov.

Treatment

Amolops nidorbellus View in CoL sp. nov.

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , 6 View FIGURE 6 ; Table 1)

Holotype. ZSI A 10965 View Materials , adult male, collected by SDB and RGK on 27 June 2007 from Lorü , 25°38’23’’N 94°03’31”E, 1575 m asl., Jotsoma village, Kohima district, Nagaland, northeast India ( Fig. 1 View FIGURE 1 ). GoogleMaps

Paratypes. ZSI A 10968, adult female, collected along with holotype ; ZSI A 10969–10970 , two adult females, and BNHS 5276 View Materials , adult male, collected by RGK on 4 June 2009 from the holotype locality .

Referred specimen. SDB 2009.335 , adult male, collected along with paratype BNHS 5276 View Materials .

Diagnosis. Amolops nidorbellus sp. nov. is here placed in the genus Amolops based on its overall morphological similarity to A. viridimaculatus . Recently the systematic status of the latter species was confirmed phylogenetically ( Cai et al. 2007). Amolops nidorbellus sp. nov. can be distinguished from known congeners by the following combination of characters: (1) large adult size (SVL male 76.4–82.3 mm; SVL female 85.4–98 mm); (2) head wider than long, HW:HL 102–107%; (3) tympanum distinct, TYD:EL 27– 34%; (4) digit I of hand without circummarginal groove on disk; (5) relative length of fingers I<II<IV<III; (6) feet fully webbed; (7) externally visible vocal sacs absent; (8) dorsal and ventral spinules and asperities absent in both sexes; (9) dorsally brown with small irregularly arranged cobalt green spots; (10) ventrally pale brown with small white spots on throat, chest and anterior and lateral abdomen.

Comparisons. Amolops nidorbellus sp. nov. differs from A. archotaphus , A. assamensis , A. chunganensis , A. compotrix , A. cucae , A. iriodes , A. larutensis , A. marmoratus , A. minutus , A. panhai , A. spinaspectoralis and A. vitreus by combination of its large adult male size, SVL> 65 mm with absence of externally visible vocal sacs (vs. males SVL <65 mm with externally visible vocal sacs); differs from A. daiyunensis , A. formosus , A. hongkongensis , A. ricketti , A. torrentis , and A. wuyiensis by the combination of its large adult male size, SVL> 65 mm and absence of circummarginal groove on the first finger (vs. males SVL <65 mm and presence of circummarginal groove on first finger); differs from A. aniqiaoensis , A. bellulus , A. chakratensis , A. cremnobatus , A. daorum , A. gerbilis , A. granulosus , A. jaunsari , A. jinjiangensis , A. kangtingensis , A. liangshanensis , A. longimanus , A. mengyangensis and A. monticola by its absence of dorsolateral folds or linear dorsolateral series of tubercles/pustules (vs. presence); differs from A. hainanensis , A. lifanensis , A. mantzorum and A. tuberodepressus by absence of tubercles on the dorsum or flanks (vs. presence); differs from A. loloensis by combination of its large adult male size, SVL> 65 mm and absence of spinules (vs. adult male size, SVL <65 mm and patches of spinules on the flanks, sides of head and posterior thigh); differs from A. himalayanus by absence of microspinules and externally visible vocal sacs (vs. microspinules arranged in patches at the rear of the mandible and often a large patch surrounding the vent region, externally visible vocal sacs present); from A. medogensis by its considerably smaller adult male size, SVL 76.5–82.3 mm (vs. 95 mm in A. medogensis ).

In general appearance and morphology, Amolops nidorbellus sp. nov. is most similar to A. caelumnoctis / A. splendissimus , A. kaulbacki and A. viridimaculatus . From A. caelumnoctis / A. splendissimus , this species differs by possessing oblique loreal region (vs. vertical for A. caelumnoctis and A. splendissimus ), nostril closer to the eye than snout (vs. nostril located midway between tip of snout and eye for A. caelumnoctis and unknown for A. splendissimus ), tympanic region and posterior angle of the jaw with dense tubercles (vs. smooth on A. caelumnoctis and A. splendissimus ), and dorsal colouration is brown with clusters of small green irregularly shaped spots, many of which join to form small blotches (vs. purple/black with small circular yellow spots for A. caelumnoctis and brown/black with small irregular shaped yellow spots for A. splendissimus ), throat, chest, anterior and lateral abdomen brown with distinct small white spots (vs. throat, chest and abdomen grey without distinct spots for A. caelumnoctis and A. splendissimus ); it differs from A. kaulbacki by snout subelliptical dorsally (vs. rounded), smaller tympanum, TYD:EL 27.0–33.8% (vs. 40.0% on holotype), and fore and hind limbs not banded, small white spots on ventral aspect of body (vs. limbs distinctly banded, ventrum plain); from A. viridimaculatus by HW>HL (vs. HW<HL), fore and hind limbs not banded (vs. distinctly banded), dorsum brown with clusters of small green irregularly shaped spots, many of which join to form small blotches (vs. maroon red with large green blotches).

Description of holotype. (all measurements in mm): adult male (SVL 76.4), body robust ( Figs. 2A–B View FIGURE 2 , 3A View FIGURE 3 ); head dorsally subelliptical ( Figs. 2D–E View FIGURE 2 ), wider than long (HW 26.9, HL 25.8, HW:HL 104%), flat above; snout rounded and slightly protruding in profile ( Fig. 2C View FIGURE 2 ), its length (SL 10.8) longer than the horizontal diameter of the eye (EL 7.4); canthus rostralis rounded, loreal region strongly concave, obtuse ( Fig. 2C View FIGURE 2 ); interorbital space flat, interorbital distance (IUE 6.8) greater than width of the eye lids (UEW 6.5), and narrower than the internarial distance (IN 9.1); nostrils laterally positioned, vertically ovular with slightly raised rim anteriorly, slightly closer to the eye (EN 5.1) than to the snout (SN 5.4); pupil horizontal; tympanum fully exposed (TYD 2.0), circular, tympanum–eye distance (TYE 4.6); pineal ocellus barely visible; vomerine ridge distinct, obtuse, bearing 6 long teeth each, slightly closer to each other than choanae, positioned level to choanae which are oval and transverse.

Arms moderately long, thick, forearm enlarged, length (FAL 17.8) shorter than the hand (HAL 26.0); relative length of fingers I<II<IV<III (FIL 9.4, FIIL 12.5, FIIIL 19.8, FIVL 14.1); finger tips on II–IV dilated with wide oval disks ( Fig. 2F View FIGURE 2 ), largest on digit III (FDIII 5.7, FWIII 1.8), finger I with distinct disk but only slightly dilated in relation to adjoining finger width, relative width of finger disks I<II<IV<III, circummarginal grooves present on digits II–IV only; terminal phalange shape unknown; fingers without distinct lateral fringes, webbing on fingers absent; subarticular tubercles prominently domed, circular; prepollex and outer metacarpal tubercle oval, distinct and flat, inner metacarpal tubercle absent; supernumerary tubercle on the base of finger IV barely distinguishable, others indistinct ( Fig. 2F View FIGURE 2 ).

Hind limbs long, shank (SHL 45.8) longer than thigh (TL 40.7) and foot (FOL 40.6); toes long and thin, relative lengths I<II<III<V<IV; tips of all toes expanded with transversely oval disks, smaller than those of the fingers (TDIII 4.4), relative width of disks 1<5<4<2<3, all with circummarginal grooves; toes completely webbed ( Fig. 2G View FIGURE 2 ); post axial groove on toe V extends from tip of toe to the basal subarticular tubercle; subarticular tubercles all present, prominently domed and circular, inner metatarsal tubercle prominent, oval and relatively long (IMT 4.4); tarsal glandular ridge, outer metatarsal and supernumerary tubercles all absent ( Fig. 2G View FIGURE 2 ).

Skin on dorsal surface of head, flanks, dorsal and ventral aspect of the body, throat and limbs smooth; area surrounding vent and adjoining posterior and ventral surface of the thighs granular, dorsal tubercles or pustular warts absent with exception of the temporal region posterior to the eye below the supratympanic fold, which is covered with enlarged glandular granules and warts; dorsolateral fold absent; supratympanic fold present but weakly developed; co-ossified skin absent; rictal and humeral glands absent ( Fig. 2C View FIGURE 2 ); dorsal and ventral asperities and/or horny spinules absent.

Colouration of holotype. In preservation ( Fig. 2A View FIGURE 2 ): dorsal surface of head, body, limbs and upper flanks brown; green spots are faded to greyish blue; all ventral surface are faded to pale brown and small round light spots with dark rim only visible on throat and chest; webbing cream with fine grey speckling. In life ( Fig. 3A View FIGURE 3 ): entire dorsal portion of the head, back, limbs and digits uniform brown with irregularly arranged clusters of small green spots; webbing yellow marbled with greyish brown; throat, chest and ventral surface of forelimb and thighs pale brown; abdomen, lower flanks, ventral surface of shank and tarsus yellowish brown, small white spots on the throat, chest, anterior and lateral abdomen; ventral surface of the hands and all digital disks, subarticular and inner metatarsal tubercles of the feet bluish grey; iris brownish black with dense yellowish green mottling.

Condition of type series. All type specimens are in good condition and fully intact with the exception of ZSI A 10965 View Materials (holotype), BNHS 5276 View Materials and ZSI A 10969 (paratypes) which have a portion of the ventral thigh muscle removed for molecular analysis .

Secondary sexual characters. Male: nuptial pad present, large, smooth ( Fig. 2E View FIGURE 2 ), mostly on basal phalange, extending slightly onto the distal phalange, dorsally light, posteriorly and ventrally dark blue/grey ( Fig. 3D View FIGURE 3 ); forearms considerably enlarged when compared to females; external vocal pouch absent. Female: posses a patch of small light tipped granules posterior to the supratympanic fold.

Variation. Mensural differences are provided in Table 1, otherwise the paratypes and referred specimen agree in all general morphology and colouration ( Fig. 3B View FIGURE 3 ) with the exception of the following details: weak supernumerary tubercles are variously distinct or indistinct on the base of all digits on hands; vomerine teeth range from 5–7 and vomerine ridges are subequally distant from each other and the choanae on ZSI A 10968 and SDB 2009.335 ; supratympanic fold is well developed on all paratypes and SDB 2009.335 ; relative toe length varies from III< V to V <III; pineal ocellus is not visible on ZSI A 10969 and SDB 2009.335 , and only weakly visible on remaining paratypes. The extent of dark pigment on webbing varies; on all recently collected specimens ( ZSI A 10969, 10970 , BNHS 5276 View Materials and SDB 2009.335 )––ventral brown with pale green spots on throat, chest and anterior and lateral abdomen, few smaller spots are scattered on the ventral thigh and tarsus ( Figs. 3C–F View FIGURE 3 ) .

Natural history. This species is currently known only from the type locality, Lorü, Jotsoma village, about 5 km west of Kohima town ( Fig. 1 View FIGURE 1 ). All specimens were collected after heavy showers between 19.00–23.00 h, from rocks in a small cascading stream. This species is found sympatrically with Amolops kohimaensis sp. nov. The stream is bordered on both sides by steep vegetated banks within a patch of degraded secondary broadleaf semi-evergreen forest containing sparse undergrowth. Holotype and two paratypes were found sitting on vertical rock surfaces below a section of a multileveled cascade. Another paratype was found clinging to a moss covered rock 2 m above ground level on the stream bank. The otherwise conspicuous markings of this species provide surprisingly good camouflage with the moss-covered rocks on which it was found, indicating that this species may occupy only a very specialized habitat niche. All individuals were collected within an approximately one metre stretch of the stream. No further individuals were observed neither up nor downstream of this location along the ca. 100 meters of stream bank surveyed. No behaviour associated with reproduction was observed, nor were tadpoles apparent in the stream during the survey period. When handled these frogs immediately produce excessive secretions from the skin which is extremely pungent and causes considerable irritation when in contact with broken skin on the collector’s hands.

Etymology. Derived from two Latin words–– nidor meaning ‘odor’ and bellus meaning ‘beauty’, referring to the beautiful appearance with strong odor of this species.

Suggested common name. Spotted Stinky Torrent Frog.

mm. H. holotype, P. paratype, RS. referred specimen.