Abavorana nazgul Quah, Anuar, Grismer, Wood Jr, Azizah & Muin 2017, sp. nov.
Creators: name: Muin, Mohd Abdul
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Ranidae
Abavorana
Abavorana nazgul

description: Abavorana nazgul sp. nov.
Gunung Jerai Black Stream-Frog
Fig. 2, 4 & 6
Rana luctuOsa Sukumaran, J. 2005: 38.
Holotype. An adult male (USMHC 2231) collected on 9 April 2016 from Gunung Jerai, Kedah, Peninsular Malaysia (5 °47.719’N; 100 °26.222’E, 948 m in elevation) by Evan S.H. Quah and David Chan.
Paratypes. Paratypes USMHC 2232 & USMHC 2233 bear the same locality data as the holotype. Paratype LSUHC 10512 was collected on 8 October 2011 while paratypes LSUHC 10513 and LSUHC 10514 were collected on 28 October 2011 by Evan S.H. Quah, M.A. Muin and Yusof Omar.
Diagnosis. Morphological analyses of the newly collected material from Gunung Jerai confirms the placement of this population in the genus Abavorana based on the combination of having a medium-sized, robust body; no vocal sacs in males; length of 1 st finger greater than 2nd finger; disc width to finger width ratios of finger 3 and toe 4 is 1–1.5; dorsolateral fold indistinct or absent; the colour of the dorsolateral line being white or yellow; the humeral gland in males is prominent, raised and centrally positioned on the ventral surface of the upper arm; a weak or absent rictal ridge; outer metatarsal tubercle weak or absent; skin of dorsum smooth or finely shagreened; throat, abdomen and flanks smooth; posterior section of ventrum and back of the thigh rugose; no pale colouration on the margins of the tympanum; flanks dark brown or black below the dorsal fold grading into a pale ventrum; dorsal surface of hind limbs speckled or mottled; posterior surface of thigh mottled (Inger 1966; Oliver et al. 2015). Abavorana nazgul sp. nov. can be differentiated from its congeners by the following combination of characters: adult males 42.1–50.0 mm SVL; nuptial pads absent in males; humeral glands in males small (2.3–2.5 mm); dorsolateral stripe continuous, orange to yellow in colour; mid-dorsal region of dorsum black, with or without faint orange or yellow speckles; flanks black, colouration unstratified; distinct cream spots on flanks, dorsal surfaces of limbs, and upper lip; venter grey-brown with prominent light spots on throat and belly, smaller spots on underside of thigh.
Description of holotype. Adult male, SVL 50.0 mm; head longer than wide (HL/HW=1.19); snout wider than long (SW/SL=1.38), longer than eye diameter (SL/ED=2.00), slightly projecting beyond lower jaw, dorsally concave, gradually tapering with a slight median point in dorsal view, slightly rounded and posteroventrally, sloping downward in lateral view; canthus rostralis distinct, lores vertical, slightly concave; nares open laterally, just below canthus, positioned closer to rostrum than eye, distance between nares smaller than snout length (IND / SL=0.78), approximately one-half of snout width (IND /SW=0.56); eyes large, slightly protruding beyond lips in dorsal view, diameter less than snout length (ED/SL=0.50) and interorbital distance (ED/IOD=0.43); pupils circular; interorbital region flat, distance smaller than snout width (IOD/SW=0.85) but greater than snout length (IOD/SL=1.17); tympanum distinct, round, as tall as wide, horizontal diameter equal to eye diameter (TD/ ED=1.00); choanae subcircular, separated by distance larger than their diameter; vomerine teeth small, indistinct; and tongue elongate, broadening posteriorly with a central terminal notch, posterior ⅓ free.
Forelimbs relatively long, slender (BL/SVL=0.14; FAL/SVL=0.15; ML/SVL=0.23), brachial and forearm length subequal (BL/FAL=0.93); enlarged humeral glands present on ventral surfaces of brachia; order of fingers from shortest to longest: II<IV<I<III (fingers I and IV subequal); fingers lack webbing; finger tips dilated into small, rounded discs bearing circummarginal grooves; numbers of subarticular tubercles are digit I(1), II(1), III(2), IV(2); subarticular tubercles prominently raised, oval, opaque on toes I and II and base of toes III and IV, second subarticular tubercles of toes III and IV indistinct; supernumerary tubercles absent; inner metacarpal tubercle large, oval, translucent; palmar tubercle oval, translucent, slightly smaller and not in contact with inner metacarpal tubercle; outer metacarpal tubercle oval, translucent, in contact, similar in size to palmar tubercle; nuptial pads absent. Hind limbs long, slender (FL/SVL =0.47; CL/SVL= 0.49; TL/SVL= 0.24), tibia slightly longer than femur (CL/FL =1.04); order of toes from shortest to longest: I<II<V<III<IV (toes III and V subequal); toe tips slightly dilated into small, rounded discs bearing circummarginal grooves; webbing formula: I1–1 ½ II 1–2 III 1 ½–3½ IV 3 ½–2½ V; subarticular tubercles prominently raised, translucent; number of subarticular tubercles on each toe varies by toe number: I(1), II(1), III(2), IV(3), V(2); inner metatarsal tubercle elongate, raised, translucent; outer metatarsal tubercle absent.
Dorsum, upper eyelid, interorbital region, snout, flanks and surface of limbs finely shagreened, lacking tubercles; dorsolateral and tympanic folds absent. Rictal glands absent, only a weak rictal ridge present; throat, stomach and ventral surfaces of limbs finely shagreened. Measurements of types are presented in Table 3.
Colouration in life (Fig. 2). The dorsum is black with faint orange specks along the vertebral line. A complete orange dorsolateral stripe extends from the rostrum (stripe yellowish-orange on the snout), along the canthus, lateral margin of palpebrae, and dorsolateral part of dorsum, and terminates at the sacrum where it forms a nearly complete loop. The lateral margins of the snout, anterior portion of the flanks, and dorsal surface of the limbs are black and gradually transition to dark-grey on the lower flanks. Along the upper lips are a single row of cream spots that form a streak beneath the tympanum and extend to the corner of the jaw. The tympanum is dark-brown. The flanks and dorsal side of the limbs bear round, creamy yellow spots, some of which connect to form short, elongate bars especially on the hind limbs. The venter is grey-brown and covered in whitish spots. The spots on the throat and belly are larger than those on the ventral surface of the thigh.
Colouration in preservation (Fig. 4). The dorsum, dorsal side of limbs and upper flanks are dark-grey while the dorsolateral stripe and spots–bars are cream. The lower flanks, fingers and toes are a lighter shade of grey. The venter is light grey-brown with the spots on throat, belly, and underside of the thighs whitish.
Variation. All paratypes closely resemble holotype in overall external morphology, colouration, and patterning. In a single paratype (USMH 2232) the narrow stripe outlining the snout and dorsolateral margin of the body is yellow instead of orange. In addition, the stripe along the snout of this specimen is discontinuous (Fig. 2D). Juveniles have a bolder colour pattern than the adults where the colour of the dorsum is darker and lacks any light mottling or faint specks. Juveniles also have fewer spots on the flanks of and no spots at the corners of the upper labial margins and the narrow stripe outlining the snout and dorsolateral margin of the body is bright orange or vermillion (Fig. 2F). In the female paratype (LSUHC 10514), the texture of the skin around the vent, posterior and ventral regions of the thighs is more rugose compared the male specimens. In addition, paratypes (LSUHC 10513 and 10514) have a small, weak, indistinct, round, outer metatarsal tubercle. This is not surprising as Inger (1966) reported observing the presence of a metatarsal tubercle in only approximately one-half of the A. luctuosa specimens he examined. Measurements showing variation in size within the type series are shown in Table 3.
Comparison. Morphological data for species comparison was obtained from Inger (1966) and the material examined (Appendix). Abavorana nazgul sp. nov. is differentiated from Peninsular Malaysian populations of A. luctuosa by the following characters: colouration of the dorsum (a black dorsum, with or without faint, fine orange or yellow speckling versus an orange or reddish-brown dorsum; dorsolateral stripes that are yellow or orange versus white or cream); spots on the upper lips (present, large yellow spots, especially prominent below the tympanum versus absent or only faint white spot at the corner of the jaws); pattern along the flanks (prominent yellow or cream spots versus an absence of spots or very fine, white spots); pattern on the upper surface of the limbs (large, prominent, cream or yellow spots or short bars versus fine white or greyish-blue spots or bars); pattern of venter (large, prominent cream or yellow spots versus an immaculate venter or with occasional fine, inconspicuous spots or reticulations on the belly or underside of the thigh) (Figs. 2–6). Occasionally, very dark individuals of A. luctuosa may be encountered or specimens with orange spots present on the dorsal surface of forearm, however these specimens can still be differentiated from A. nazgul sp. nov. by their immaculate flanks and venter or only very fine white spots present on the flanks (Figs. 3C & D), as well as their phylogenetic position. The difference in colour pattern between A. nazgul sp. nov. and Bornean populations of A. luctuosa is similar to those of Peninsular Malaysia with the exception being that the underside of the limbs in Bornean specimens have bold, cream-coloured bars (Inger 1966; see Fig. 159 in Malkmus et al. 2002). Examination of juveniles of both species shows that the juveniles resemble the adults (Figs. 2F, 3E, 3F), suggesting no ontogenetic changes in colouration for both A. nazgul sp. nov. and A. luctuosa. In addition to colour pattern, A. nazgul sp. nov. can be differentiated from Peninsular Malaysian populations of A. luctuosa by their larger size in adult males (42.1–50.0 mm SVL versus 42.7–44.5 mm SVL) and their smaller humeral glands (2.4 mm in 42.1 mm male versus 3.8mm in 42.0 mm male; Inger 1966). In comparison, Bornean male A. luctuosa are larger than A. nazgul sp. nov. (53.0– 58.8 mm SVL versus 42.1–50.0 mm SVL) (Inger 1966). The size range reported for female A. luctuosa are between 53.0–60.0 mm SVL (Inger & Stuebing 2005) which is larger than the single female A. nazgul sp. nov. (LSUHC 10514) examined (52.8mm SVL).
Abavorana luctuosa was previously grouped with frogs of the genus Pulchrana (Dubois 1992) prior to recent taxonomic revision (Oliver et al. 2015). However, A. nazgul sp. nov. can be differentiated from members of the Pulchrana picturata complex by the following characteristics; dorsolateral line (indistinct versus a fine or warty and poorly developed); position of humeral gland (ventral surface versus anteroventral surface of brachium); rictal ridge (weak versus a medium to well-developed); outer metatarsal tubercle (absent or weak versus present and large); and texture of flanks (smooth versus weakly warty) (Oliver et al. 2015). Abavorana nazgul sp. nov. can be further differentiated from P. centropeninsularis, a species with a similar colour pattern, by the following combination of characters; dorsum in adults that is black with faint orange or yellow speckles versus dorsum that is black and unmarked; orange or yellow versus bright vermillion dorsolateral stripe; larger size of adult males (42.1– 50.0 mm vs. 37.4–37.6 mm SVL); a small humeral gland on the ventral surface of the brachium versus large humeral gland on lateroventral surface of brachium; and absence versus presence of indistinct, translucent, supernumerary tubercles at the base of first phalanx on each finger. Pulchrana centropeninsularis is also a lowland species recorded from 90–105 m in elevation from central Peninsular Malaysia in the state of Pahang whereas A. nazgul sp. nov. is a montane species found only above 800 m in elevation at Gunung Jerai, Kedah (Chan et al. 2014a).
Distribution and natural history. Abavorana nazgul sp. nov. is only known from the upper elevations of Gunung Jerai, Kedah (Fig. 6). Sukumaran (2005) reports finding this species from 800–1200 m in elevation at three different locations, Mushroom Creek, Caecilian Stream, and Batu Kapal. The specimens we found were at the stream close to Telaga Tok Sheikh. This species is riparian and found in the vicinity of streams (Fig. 7). At night, frogs can be found hiding in the leaf litter, vegetation, tangled roots or overhanging banks along streams. Similar to observations by Sukumaran (2005), males can be heard calling from the banks of the stream, sometimes hidden among the roots of plants or in crevices. The males had a distinctive “mew”-like call and Sukumaran (2005) reports finding gravid females between November to March. He also reported observing tadpoles during this period that were found in deeper, sediment-bottomed, open pool sections of the creek during this same time period. We found recently emerged juveniles in April that indicates this species breeds in the later months and the beginning of the year which is the dry season in the Northwestern region of Peninsular Malaysia (Sukumaran 2005). Along the same stream where A. nazgul sp. nov. was found, Phrynoidis asper, Limnonectes blythii, L. khasianus and Odorrana hosii were observed. In the nearby vegetation, Polypedates leucomystax, Philautus petersi, and Roarchestes parvulus were also observed. These species were also noted by Sukumaran (2005).
Etymology. The specific epithet “ nazgul ” is a noun in apposition in reference to the “Nazgûl”, characters created by J.R.R. Tolkien in The Lord of the Rings (1954). Also known as Ring-wraiths, they were nine men who succumbed to Sauron’s power and were transformed into white ghostly figures wearing black cloaks—the colouration that the new population being described herein shares.
description: Published as part of Muin, Mohd Abdul, 2017, A new species of frog of the genus Abavorana Oliver, Prendini, Kraus & Raxworthy 2015 (Anura: Ranidae) from Gunung Jerai, Kedah, northwestern Peninsular Malaysia, pp. 272-288 in Zootaxa 4320 (2) on pages 276-279, DOI: 10.11646/zootaxa.4320.2.4, http://zenodo.org/record/891812