Rhacophorus norhayatiae Chan & Grismer, 2010

Fajri, Muhammad Ichsan, Tjong, Djong Hon & Hamidy, Amir, 2023, Identification and taxonomic status of a Sumatran population of Norhayati’s gliding frog (Anura: Rhacophoridae), Raffles Bulletin of Zoology 71, pp. 303-316 : 306-308

Rhacophorus norhayatiae Chan & Grismer, 2010

( Figs. 3 , 4A , 6B, C )

Rhacophorus reinwardtii var. lateralis Werner, 1900: 495 (fig. 6); Van Kampen, 1923: 266.

Rhacophorus reinwardtii Kurniati, 2009: 31 (table 1), 34 (table 3), 36 (table 4), 76 (fig. 94); Chan & Grismer, 2010: 41.

Material examined. 1 male ( MZB Amph 32625), Kambang , West Sumatra, Indonesia, 1.5650°S, 100.7795°E, 200 m

asl, coll. M. Ichsan, Fazly Saldayu, M. Akbar, Yeni Gusma Yanti, 2 February 2020.

Description. Morphometric measurements are presented in Table 3. (1) Head relatively flat, the head length (35% of SVL) and width (36% of SVL) about equal; (2) Snout pointed, anteroventrally sloping, slightly protruding beyond lower jaw; (3) Canthus rostralis sharp; (4) Loreal region slightly concave; (5) Nostrils not protuberant, closer to snout than to eye; (6) Eyes large, protuberant, shorter (10% of SVL) than eye-to-snout length (17% of SVL); (7) Tympanum distinct, subcircular diameter (7% of SVL) being about two-thirds of eye diameter (10% of SVL); (8) Tympanum to eye distance (2% of SVL) about one-third of tympanum diameter; (9) Supratympanic fold prominent.

(10) Forearms (19% of SVL) shorter than hands (28% of SVL); (11) Hands fully webbed except for first finger with 1½ phalanges free of web ( Fig. 3 ); (12) Webbing formula I 1½ – 1 II 0 – 0 III 0 – 0 IV; (13) Relative finger lengths I<II<IV<III from shortest to longest; (14) Dermal fringe present along the edge of forearm; (15) Finger disc large with circummarginal and transverse ventral grooves; (16) Third finger disc (6% of SVL) is slightly less wide than the tympanum; (17) Subarticular tubercle between the penultimate and adjoining proximal phalange well developed, and rounded; (18) Other subarticular tubercles present but indistinct; (19) Nuptial pad absent; (20) Prepollex prominent, oval; (21) Inner and outer palmar tubercles present, flat, and indistinct; (22) Supernumerary tubercles absent; (23) Hind limbs long; (24) Femur (45% of SVL) slightly shorter than the tibia (48% of SVL); (25) Feet (41% of SVL) shorter than the tibia; (26) Relative toe lengths I<II<III<V<IV from shortest to longest; (27) Feet fully webbed; (28) Dermal fringe present, extending around the tarsus from the edge of toe V to the heel, which has a slightly pointed flap; (29) Subarticular tubercles distinct, rounded; (30) Inner metatarsal tubercle present but indistinct; (31) Outer metatarsal and supernumerary tubercles of feet absent; (32) Dorsal skin smooth, and has wrinkles at the flanks; (33) Ventral surfaces of chin, chest, belly, thighs granular; (34) Dorsolateral fold absent; (35) Anal flap bilobed.

(36) Dorsal colour green, without spots or markings. (37) Flanks with strong black pigmentation, partially outlined with rusty brown streaks and a few blue spots; (38) Ventral surface chalky white; (39) Chin, chest, belly, and thighs are marbled with black mottling and small blue spots; (40) Webbing solid black with small blue spots and streaks ( Fig. 3 ).

Colour in preservation. The dorsal surface is lavender. Green pigments turned lavender, and blue pigments turned grey. Meanwhile, the rusty brown colouration on the flanks and black pigmentation did not change.

Natural history. In Kambang, a single individual was found at night perched on the edge of a small puddle. Neither tadpoles nor eggs were found.

Comparison. MZB Amph 32625 is very similar in morphology with the Peninsular Malaysian population in possessing a similar hand webbing formula, solid green dorsum without any spots or markings, extensive black and rusty brown colouration on flanks, and black interdigital webbing with blue spots and streaks. However, the SVL of this specimen is slightly greater than the males of the Peninsular Malaysian population ( Table 4). Compared to R. reinwardtii var. lateralis, MZB Amph 32625 also possesses solid black pigmentation on the flanks and webbing with predominantly black colouration ( Fig. 6B, C ), green dorsum without small black spots, and a ventral surface with black spots. Rhacophorus reinwardtii differs from R. norhayatiae in having a hand webbing formula of I 2 – 1 II 0 – 0 III 0 – 0 IV (vs I 1½ – 1 II 0 – 0 III 0 – 0 IV in R. norhayatiae ), and in having a green dorsum with small black spots (vs immaculate green in R. norhayatiae ) and shorter black pigmentation of the flanks with blue marbling (vs extended to the thighs with rusty brown and partially outlined with blue in R. norhayatiae ). Rhacophorus borneensis also differs from R. norhayatiae in having the hand webbing formula I 1½ – 1½ II 0 – 0 III 0 – 0 IV (vs I 1½ – 1 II 0 – 0 III 0 – 0 IV in R. norhayatiae ), black colouration only about halfway along flanks, with yellow and blue spots (vs extended to the thighs with rusty brown and partially outlined with blue in R. norhayatiae ), ventral surface yellowish-orange (vs chalky white with black marbling, and mottled with blue on side and chin of R. norhayatiae ), and males having a yellowishorange posterior surface. Compared to R. norhayatiae , R. kio differs in having a spine-like heel flap (vs absence in R. norhayatiae ), hand webbing formula I 1½ – 1 II 0 – 0 III 0 – 0 IV (vs I 1½ – 1 II 0 – 0 III 0 – 0 IV in R. norhayatiae ), a dark green dorsum with white spots and greenish-white markings (vs immaculate green in R. norhayatiae ), black pigmentation occurring only on the flanks, with a small black spot in the armpit (vs solid black pigmentation from armpit to the thighs with rusty brown and partially outlined with blue in R. norhayatiae ), and webbing with a network of yellow-orange lines (vs black with blue streaks and spots in R. norhayatiae ). Furthermore, R. helenae is distinguished from this specimen in having hand webbing formula I 1½ – 1½ II 0 – 0 III 0 – 0 IV (vs I 1½ – 1 II 0 – 0 III 0 – 0 IV in R. norhayatiae ), venter white without spots or marks (vs chalky white with black marbling, and mottled with blue on side and chin of R. norhayatiae ), a bluish-green posterior surface of the thighs with pale yellow marbling (vs green in R. norhayatiae ), and a low, single-lobed supercloacal dermal ridge (vs absence in R. norhayatiae ), and having a larger SVL size ( Table 4). Finally, R. nigropalmatus is distinguished by having complete hand webbing (vs I 1½ – 1 II 0 – 0 III 0 – 0 IV in R. norhayatiae ), dorsum green with small white spots on dorsal surface (vs immaculate green in R. norhayatiae ), ventral yellowish-white without black spots (vs chalky white with black marbling, and mottled with blue on side and chin of R. norhayatiae ), and flanks yellow with black veins (vs extensively solid black with rusty brown and partially outlined with blue in R. norhayatiae ).

Figures

Fig. 3. Sumatran specimen of R. norhayatiae, MZB Amph 32625. A, ventral view; B, dorsal view; C, dorsolateral view; D, webbing of left hand. Scale = 10 mm.

Fig. 4. Comparison of black pigmentation on flanks between A, preserved Sumatran R. norhayatiae MZB Amph 32625 and B, R. reinwardtii MZB Amph 32626.

Fig. 6. Comparison of dorsal view of webbings of A, R. reinwardtii, B, R. norhayatiae, and C, R. reinwardtii var. lateralis. The webbing colouration of R. reinwardtii var. lateralis is predominantly black which is most similar to R. norhayatiae rather than to R. reinwardtii. The figure of R. reinwardtii var. lateralis was modified from Werner (1900).