Rhacophorus norhayatii, Onn & Grismer, 2010

Onn, Chan Kin & Grismer, L. Lee, 2010, Re-assessment of the Reinwardt’s Gliding Frog, Rhacophorus reinwardtii (Schlegel 1840) (Anura: Rhacophoridae) in Southern Thailand and Peninsular Malaysia and its re-description as a new species, Zootaxa 2505 (1), pp. 40-50 : 42-45

Rhacophorus norhayatii sp. nov.

Norhayati’s Gliding Frog

Figure 2–C

Rhacophorus reinwardtii Berry 1975:107 ; Dring 1979:216; Grandison 1972:75; Manthey & Grossman 1997:136

Holotype. Adult male ( UKMHC 714 ), collected by Norhayati Ahmad, Nurol Huda and Daicus Belabut on 13 June 2005 from Bunker Trail (01°51.759 N, 103°53.186 E; 20 m asl.), Gunung Panti Bird Sanctuary in the Gunung Panti Forest Reserve, Johor, Peninsular Malaysia.

Paratypes. Three adult males ( LSUHC 9773 , ZRC 1.12445, 1.12446) and three adult females ( LSUHC 9774 , 9775 , ZRC 1.12447 ) collected on 27 January 2010 from Gunung Besar Hantu , Negeri Sembilan, Peninsular Malaysia (N3°13'51.41" E102° 1'4.22") at 250 m a.s.l.

Diagnosis. We allocate this species to the genus Rhacophorus based on the following combination of characters: the presence of an intercalary cartilage between the terminal and penultimate phalanges of each digit; tips of digits expanded into large discs bearing circum-marginal grooves; fingers webbed; vomerine teeth present; eyes large ( Brown & Alcala 1994; Inger 1966; Vitt & Caldwell 2009). Rhacophorus norhayatii can be distinguished from all other congeners by the following combination of characters: males reaching 64.7 mm SVL, females reaching 83 mm SVL; first finger with 1.5 phalanges free of web; solid green dorsum without any spots or markings; rusty brown coloration on flanks; interdigital webbing black with blue spots and streaks with a high degree of black pigmentation.

Description of holotype. Adult male 64.7 mm SVL; head as wide as long (HW/HL=102%), relatively flat; snout pointed, sloping anteroventrally, slightly protruding beyond lower jaw, distance from front of eye to snout longer than horizontal diameter of eye (SL/EL=180%); canthus rostralis sharp, loreal region slightly concave; nostrils not protuberant, closer to snout than to eye (NS/EN=78%), internarial distance 48% of distance between front of eyes; eyes large, protuberant, 28% of head length; tympanum distinct, subcircular, 75% of horizontal eye diameter; supratympanic fold prominent; tongue attached anteriorly; choanae oval; vomerine teeth in two series between the choanae; single median vocal sac; single vocal slit at base of each side of tongue.

Forearms short (FLL/SVL=25%), robust, shorter than hand (FLL/HAL=87%); humeral gland absent; relative finger length from shortest to longest: I<II<IV<III (TFL= 16.8 mm); finger discs large, horizontally elongate bearing circum-marginal and transverse ventral grooves; relative width of finger discs from narrowest to widest: I<IV<II<III; width of third finger disc slightly less than tympanum diameter (3FW/ TYD=94%); webbing present on all fingers; finger webbing: I 1.5–1 II 0–0 III 0–0 IV; subarticular tubercle between penultimate and adjoining proximal phalange well developed, rounded; other subarticular tubercles present but indistinct; nuptial pad absent; prepollex prominent, oval; inner and outer palmar tubercles present, flat, indistinct; supernumerary tubercles absent.

Hind limbs long, less robust than forelimbs, femur length 50% of SVL, tibia 46% of SVL, femur slightly longer than tibia (FL/TL=107%); tibiotarsal articulation does not extend beyond snout; relative length of toes from shortest to longest: I<II<III<V<IV; toe discs round, as wide as high, smaller than finger discs (4TW/ 3FW=73%) with circum-marginal and transverse ventral grooves; webbing complete on all toes: I 0–0 II 0–0 III 0–0 IV 0–0 V; subarticular tubercles distinct, rounded; inner metatarsal tubercle present but indistinct; outer metatarsal and supernumerary tubercles absent.

Skin on dorsum smooth, flanks roughly wrinkled, underside of chin, chest, belly and thighs prominently granular; dorsolateral fold absent; dermal fringe along outer, lateral edge of forearm and to a lesser extent from tip of toe V, continuing along tarsus and to the heel where it forms a slightly pointed flap; anal flap present, bilobed.

Coloration in life. Dorsal surfaces apple green, immaculate; interdigital webbing on fingers and toes black with blue and green spots and streaks; web pigmentation entirely covers dorsal surfaces of fingers I, II and III except for finger discs which are dull green; inner surface of brachia black, mottled with blue spots; flanks rusty brown, overlain with strong, black marbling that is partially outlined with fine, blue spots and lines; inner surfaces of thighs, tibia and tarsus black, mottled with blue spots; web pigmentation entirely covers dorsal surfaces of toes I, II, III and proximal 50% of toe IV, toe discs dull green; ventral surfaces chalky white; chin and vocal sac bear a prominent network of black patches mottled with small, blue spots; chest, belly and underside of thighs marbled with black and mottled with small, blue spots; underside of arms and tibia black ( Fig. 2–C ).

Coloration in preservative. Dorsal surfaces lavender; blue pigments faded to grey, black pigments unchanged; rusty brown coloration on flanks remains.

Distribution. Northwest and extreme Southern Thailand ( Chan-ard 2003; Dring 1979); Peninsular Malaysia: Ulu Muda Forest Reserve, Kedah ( Norhayati et al. 2005); Cameron Highlands, Pahang; Janda Baik, Pahang ( Berry 1975); Gunung Benom, Pahang ( Grandison 1972); Gunung Lawit, Terengganu ( Dring 1979); Endau-Rompin National Park, Johor ( Wood et al. 2008b); Gunung Panti Forest Reserve, Johor ( Chan et al. 2010b); Gunung Besar Hantu, Negeri Sembilan (This report); and provisionally Sumatra ( Werner 1900). See Fig. 1 .

Natural History. Rhacophorus norhayatii is usually associated with lowland and hill forests up to 550 m elevation ( Chan et al. 2010b; Dring 1979; Grandison 1972; Norhayati et al. 2005; Wood et al. 2008b). However, Berry (1975) reported this species from Tanah Rata, Cameron Highlands, Pahang, which is located at approximately 1500 m a.s.l. Frogs can be found on low vegetation or in trees up to 7 m above ground in the vicinity of muddy, stagnant puddles or other temporary pools. Frogs have also been found in water-filled depressions caused by tire tracks along logging roads. Other rhacophorids that have been found in sympatry with R. norhayatii are R. pardalis and R. nigropalmatus (see above references). Male R. norhayatii produces a rattling, woodpecker-like call and a sonogram of this call can be found in Dring (1979:Fig. 14).

Etymology. Due to the poor condition of the type of Rhacophorus reinwardtii var. lateralis from Sumatra ( Werner 1900), it can not be ascribed to either R. reinwardtii or R. norhayatii with much certainty. However, according to Werner’s (1900) description, it most resembles R. norhayatii and we provisionally consider both populations as conspecific pending acquisition of fresh material from Sumatra. In the event of conspecificity, the junior homonym lateralis still has to be rejected as it is currently being occupied by Rhacophorus lateralis Boulenger 1883 which takes precedence under Article 60 of the International Code of Zoological Nomenclature.

The specific epithet norhayatii honors Dr. Norhayati Ahmad from the National University of Malaysia (UKM) for her immense contributions to the study of herpetology in Peninsular Malaysia.

Comparisons. Rhacophorus norhayatii can be differentiated from R. reinwardtii by having a larger adult male SVL [64.7 mm SVL (n=5) vs. 55 mm (n=11)] and an immaculate, apple green dorsum as opposed to a dorsum covered with small, dark spots (including fore-and hind limbs; Fig. 2–A,B,C,D ). Additionally, Bornean frogs have faint, white spots on the dorsum interspersed with the dark spots which are not observed in Javanese frogs or R. norhayatii ( Fig. 2–D ). Interdigital webbing of R. reinwardtii is black with blue veins as opposed to being black with blue spots and streaks as in R. norhayatii . The amount of black pigmentation on the webbing of R. norhayatii is more intense and extensive and covers the upperside of the first to third fingers and the first to fourth toes whereas these areas are only partially covered in R. reinwardtii . In R. reinwardtii , the webbing between the first and second fingers and first and second toes is yellow or orange and lacks black pigmentation (sometimes present in minute amounts restricted to the base of the web) whereas these areas are prominently pigmented with black in R. norhayatii . The inner surfaces of the thighs and brachia are yellow or orange in R. reinwardtii ( Fig. 2–A,B ), as opposed to being black and mottled with blue spots in R. norhayatii ( Fig. 2–C ). The flanks of R. reinwardtii are orange or yellow with a black spot in the axillae and have blue and black marbling which fades posteriorly whereas the flanks of R. norhayatii are rusty brown, strongly overlain with black marbling that is partially outlined with fine, blue dots and lines ( Fig. 3– G ). The ventral surfaces of R. reinwardtii may be white, yellow or orange ( Fig. 2–E ). Some specimens show dark mottling on the belly and underside of thighs, but the chest and chin are unmottled. Ventral surfaces of chin, chest, belly and limbs of R. norhayatii are chalky white with strong black and blue marbling. The degree of marbling, especially on the chin, varies. In preservative, the dorsum of all frogs is lavender. Dorsal spots of R. reinwardtii are not visible. The flanks of R. reinwardtii are dull white or light brown with a few black patches and white spots that correspond to skin glands as opposed to R. norhayatii which remain brown, strongly overlain with black, and lack white, glandular spots. Ventral surfaces of R. reinwardtii are dull white, with or without dark mottling on the belly and thighs whereas ( Fig. 3–E ) in R. norhayatii , they remain chalky white with distinct, black marbling ( Fig. 3–F ). Rhacophorus norhayatii differs from R. nigropalmatus in having smaller adult males (64.7 mm vs. 89 mm SVL), females [83 mm vs. 100 mm SVL ( Inger & Stuebing 2005)], and half of the penultimate phalanx free of web on the first finger vs. fully webbed. It differs from R. kio in having smaller adult males (64.7 mm vs. 79.1 mm SVL) and lacking a spine-like flap of skin on the heel ( Ohler & Delorme 2006). Rhacophorus norhayatii can also be distinguished from R. nigropalmatus and R. kio in numerous color-pattern differences which are summarized in Table 1. Meristic data for the type series and examined specimens are presented in Table 2.

Figures

FIGURE 1. Current distribution of Rhacophorus norhayatii in Peninsular Malaysia.

FIGURE 2. A– Rhacophorus reinwardtii, Sukabumi, West Java. B– Rhacophorus reinwardtii, Gunung Gede, West Java. C– Holotype Rhacophorus norhayatii (UKMHC 714). D– Rhacophorus reinwardtii, Batang Ai, Sarawak, Borneo. E– Ventral view of specimen D.

FIGURE 3. A– Dorsal view of hand, Rhacophorus reinwardtii (ZRC 1.6833). B– Dorsal view of foot (ZRC 1.6833). C– Dorsal view of hand, holotype Rhacophorus norhayatii (UKMHC 714). D– Dorsal view of foot (UKMHC 714). E– Ventral view of female Rhacophorus reinwardtii (ZRC 1.3641). F– Ventral view of female Rhacophorus norhayatii (ZRC 1.10355). G– Flank of Rhacophorus norhayatii (ZRC 1.12447).