Sumaterana dabulescens, Arifin, Umilaela, Smart, Utpal, Hertwig, Stefan T., Smith, Eric N., Iskandar, Djoko T. & Alexander Haas,, 2018

Arifin, Umilaela, Smart, Utpal, Hertwig, Stefan T., Smith, Eric N., Iskandar, Djoko T. & Alexander Haas,, 2018, Molecular phylogenetic analysis of a taxonomically unstable ranid from Sumatra, Indonesia, reveals a new genus with gastromyzophorous tadpoles and two new species, Zoosystematics and Evolution 94 (1), pp. 163-193 : 175-180

Sumaterana dabulescens sp. n. Figs 2 Clade C, 5b, 6b

Holotype.

MZB.AMPH.29396 (male, Fig. 5b), Desa Jamat, Taman Buru Linge Isaq, Kabupaten Aceh Ten gah, Provinsi Aceh, Sumatra, Indonesia (04.36482°N, 097.24783°E), 440 m a.s.l., 6 March 2014, 20:02, coll. U. Arifin and G. Cahyadi.

Paratypes (24).

ZMH.A14159 (female, Fig. 6b) and MZB.AMPH.29398 (female) and five males MZB.AMPH.29400 (male), MZB.AMPH.29402 (male), ZMH.A14161-62 (males), ZMH.A12667 (male), same data as holotype, (20:00-21:31, except ZMH.A12667 at 13:00). UTA.A64917 (male), stream at Enang-Enang Resort, road of Takengon-Bierut, Provinsi Aceh, (04.88649°N, 096.72689°E, 604 m a.s.l.), 7 August 2015, 20:00-21:00, coll. E. N. Smith and F. Akhsani. UTA.A64919 (male), Kabupaten Bener Meriah, Provinsi Aceh, (04.82623°N, 096.74841°E), 924 m a.s.l., 6 August 2015, coll. I. Sidik and F. Akhasani. UTA.A64921 (male), 04.93841°N, 095.98375°E, 314 m a.s.l., UTA.A64922 (male) and UTA.A64923 (male), 04.93852°N, 095.98294°E, 323 m a.s.l., UTA.A64924 (male), 04.93869°N, 095.98250°E, 333 m a.s.l., Kruong Meuriam, Kecamatan Tangse, Kabupaten Pidie, Provinsi Aceh, 6 June 2016, I. Sidik and W. Trilaksono. MZB.AMPH.29381 (male), MZB.AMPH.29383 (male), MZB.AMPH.29385 (male), MZB.AMPH.29387 (male), MZB.AMPH.29389 (male), ZMH.A14154-58 (males), ZMH.A12668 (male), Kecamatan Mane, Kabupaten Pidie, Provinsi Aceh, (04.93869°N, 095.98250°E), 761 m a.s.l., 20 March 2014, coll. U. Arifin and G. Cahyadi.

Referred specimens (22).

13 adults, one juvenile, and 8 tadpoles (Appendix 1).

Diagnosis.

(1) medium sized frog, SVL males (n = 27) 34.69-40.86 mm and females (n = 3) 48.03-66.60 mm; (2) dorsum finely granulated with scattered round, distinct tubercles; generally gray with dark gray spots on tubercles; (3) tympanum distinct and translucent (not transparent), supratympanic fold present, posttympanic fold absent; (4) dorsolateral fold absent; (5) venter smooth, granulated posteriorly, white; (6) tibia length 58.08-68.81% SVL; (7) Finger I 58.57-94.16 Finger II; (8) width of disc of Finger III 105.13-144.53% width of disc of Toe IV; (9) rear of thigh mottled; dark blotches on light background; (10) iris silver-gray with dark netting, slightly yellow to orange golden in the upper part; (11) all toes fully webbed to base of discs (I(1+/-―1+/-)II(1+/-―1+/-)III(1+/-―1+/-)IV(1+/-―1+/-)V); (12) outer metatarsal tubercle absent, inner metatarsal tubercle present; (13) males with paired vocal sacs, divided nuptial pad, humeral gland absent.

Comparison.

Sumaterana dabulescens sp. n. differs from S. crassiovis comb. n. and S. montana sp. n. (character in parentheses: S. crassiovis comb. n.; S. montana sp. n.) by gray dorsum with dark markings on tubercles, lighter area forming irregular network pattern (green background with dark markings on tubercles, lighter area forming irregular network pattern; brown background with lighter sports, Fig. 5); iris color in life silver gray with dark reticulation, slightly yellow to golden in the upper part (golden yellow with reddish color in the anterior and posterior sector and dark netting pattern; golden brown in the upper quadrant of the iris, remaining iris with dense bright red stippling on black background; Fig. 3); rear of thigh mottled, dark blotches on light background (generally barred, dark bars on light background; mottled, light spots on dark background; Fig. 3); dorsal skin texture coarsely granulated with scattered round tubercle, vary in size and density (finely granulated with scattered tubercles, vary in size, shape, and density; shagreened, without tubercles); dorsolateral fold absent (absent; present, thin); length of Finger I <Finger II (Finger I <Finger II; Finger I ≈ Finger II); nuptial pad on male divided (undivided; undivided; Fig. 3); webbing full on all toes (I(1+/-―1+/-)II(1+/-―1+/-)III(1+/-―2+/-)IV(2+/-―1+/-)V; I(1―11/2)II(0―2)III(0―3)IV(3―0)V).

Description of holotype.

Male, vocal sacs distinct and paired; nuptial pad distinct, divided, covering dorso-medial face of proximal Finger I to level of subarticular tubercle; humeral gland absent; body relatively slender; head width 90.11% head length; in dorsal view, snout obtusely pointed, in lateral view acutely projecting; canthus rostralis sharp, constricted behind nostrils; loreal area deeply concave; vomerine teeth present, in oblique groups, between choanae; tongue lanceolate; rictal ridge present; eye-nostril distance 177.84% snout-nostril distance; interorbital distance 89.27% width of upper eyelid; tympanum distinct, translucent, diameter> 50% ED (TYv/ED = 64.85; TYh/ED = 69.36%); supratympanic fold distinct, posttympanic fold absent; pineal spot visible; dorsolateral fold absent; dorsum and flanks finely granulated with scattered rounded tubercles on the dorsal region up to the upper part of the flanks; venter skin smooth, finely granulated in the posterior region; hindlimb long, articulation of the heels reach far beyond the tip of snout when limb aligned with body; thigh length 94.90% tibia; tibia 64.02% SVL; fingers slender, without webbing; Finger I 94.16% Finger II, Finger III longest; skin flaps present on the outer phalanges of all fingers; subarticular tubercles on fingers and toes distinct; disc width of Finger III 105.13% disc width of Toe IV; discs of toes and fingers diamond-shaped, both with cirmummarginal grooves; toe lengths: I <II <III <V <IV, Toe V slightly longer than Toe III; toes fully webbed; inner metatarsal tubercle distinct, oval, 118.59% T4DW; outer metatarsal tubercle absent; tarsal fold absent.

Holotype coloration.

In life, dorsum and flanks generally gray; scattered tubercles on the dorsum and the upper part of flanks usually embedded in dark color; lighter area of the dorsum form an irregular network; golden color with dark spot between eye and nostril; upper lip grayish-white with dark spots (right: 4; left: 4); lower lip whitish with dark spots (right: 3; left: 2); iris silver-gray with dark netting, golden orange in the upper part; tympanum gray with light spot in the center; venter, chest, and throat fully whitish; forearm with four distinct dark cross-bars; hind limbs with thick dark cross-bars dorsally (thigh: 5; tibia: 5); rear of thigh with dark mottling on light gray background; legs light brownish ventrally; webbing brown. Dorsal coloration turned from gray with dark spots into uniformly dark brown in preserved specimens; flanks remained gray, lighter ventrad; iris color changed to uniform gray; no color change in the dark markings or pattern.

Holotype measurements (mm).

SVL 36.13, HL 14.87, HW 13.40, SL 5.67, SN 1.94, EN 3.45, IND 3.88, IOD 3.66, ED 5.32, UEW 4.10, TYv 3.45, TYh 3.69, ETD 1.19, LAL 7.76, HAL 12.80, FE 21.95, TL 23.13, FL 19.19, IMTL 1.85, F1L 4.03, F2L 4.28, F3DW 1.64, T4DW 1.56.

Variation.

(1) dorsum generally with round tubercles, lighter spots vary from few to dense; (2) number of dark-round tubercles on dorsum and flanks: few to many tubercles; (3) size of dark wound tubercles on dorsum and flanks: small to big tubercle; (4) life coloration of dorsum background: lighter grey or slightly grayish-green to dark gray; (5) iris upper sector: light yellow to orange; (6) dark netting of iris: loose to dense; (7) throat, chest, and venter with or without marking, ranging from none to marking reaching venter; (6) marking on upper and lower lip: variable in size; (9) number of cross bars on limbs: 2-4 (arm between wrist and elbow), 4-7 (thigh); (10) thickness of cross bars on limbs: variable; (11) composition of dark color on lighter background of mottling pattern on rear of thigh: dense to less dense dark pattern on lighter background. Metrics in Tables 4-5.

Sexual dimorphism.

Males smaller than females. Tympanum diameter 38.54-72.94% ED in males and 28.18-45.70% ED in females. Adult males with divided nuptial pads and vocal sacs, covering dorso-medial face of proximal Finger I to level of subarticular tubercle, humeral gland absent.

Etymology.

The species epithet dabulescens is an artificial construct of “dabul”, “gray” in Gayo language, combined with the Latin ending “-escense”, here in the sense of "tending to be", in allusion to the gray appearance of this species. The Gayo are a local tribe in the Aceh region of Sumatra and after which the Gayo highlands have been named.

Common name.

We propose Gayo Cascade Frogs as the English common name and Katak Jeram Gayo as name in Bahasa Indonesia.

Distribution and natural history.

Provinsi Aceh, particularly localities in the northern and middle part of Aceh: Kecamatan Mane, Kabupaten Pidie; Krung Meuriam, Kecamatan Tangse, Kabupaten Pidie; Kabupaten Bener Meriah; Road Takengon-Bierut, Enang-Enang Resort, Kabupaten Aceh Tengah, and Taman Buru Linge–Isaq, Kecamatan Takengon, Kabupaten Aceh Tengah (Fig. 9). Known elevation for this species was 314-1000 m a.s.l.. The holotype was caught 100 cm above water level on a rock wall at the stream slope. The paratypes were perching on vegetation above the stream (15-200 cm above water) or on rocks in the stream or at the stream bank. The other specimens were collected from rocks or vegetation either in stream or approx. 30-100 cm away from the water (e.g., Fig. 10c). Tadpoles were collected between 23:00-24:00 from rocks (diameter ~1 m) in a fast flowing stream (4 m wide), local protected forest, Kecamatan Mane, Kabupaten Pidie.

Tadpoles.

We examined eight tadpoles of Sumaterana dabulescens sp. n.. Stage 25: UA20140336 (n = 5), ZMH.A12655 (n = 1), Stage 28: MZB.AMPH.29411 (n = 1), Stage 37: MZB.AMPH.29413 (n = 1). Tadpole assignment to species was justified by 100% genetic match (12S rRNA+16S rRNA+ tRNAval) of the selected tadpole to an adult from the same locality (Fig. 2). For the following description we refer to MZB.AMPH.29413 (Stage 37) because this specimen has the most advanced developmental stage in the series: in dorsal view, body slightly rectangular, snout broadly rounded, body rounded at both posterior corners; in lateral view, dorsoventrally depressed, streamlined; maximum body width 65.51% body length; eyes dorsolateral, oriented laterally; ED = 1.61 mm; IND/IOD = 48.01%; SN/ES = 45.23%; nostrils directed anterolaterally; nostril opens without raised rim; infraorbital gland cluster (left: 6 glands; right: 3) and postorbital gland cluster (two in each side) present; oral disc ventral, a groove separating upper lip from snout, oral disc width 68.00% body width; edge of oral sucker protruding snout contour in dorsal view; oral disc marginal papillae short, arranged in a single row; on upper lip marginal papillae present only on lateral parts, on lower lip in uninterrupted row; two short submarginal papillae in lateral area of upper lip; LTRF: 8(5-8)/8(1); upper jaw sheaths broad, heavily keratinized, smooth, undivided, thick but medial part conspicuously thinner than lateral parts; lower jaw sheaths undivided, smooth, V-shaped, thick; both jaw sheaths finely serrated along their edges; very large abdominal sucker in posterior continuation of oral disc, SUL/BL = 70.47%, SUW/BW = 82.94%; spiracle sinistral, tube long, posterior half free from body wall; spiracle directed posterodorsally; anal tube median, free from tail fin, directed posteriorly; strong muscular tail: TMH/BH = 76.19%, TMH/MTH = 66.74%; upper fin convex; maximum upper fin height is approx. 34.99% MTH at approx. 49.00% TAL; tail tip pointed.

In life, dorsal coloration of body and tail densely mottled with brown and golden blotches on a grayish background with dense fine dark stippling; lower flanks with a conspicuous wedge-shaped white area; tail muscle dark with dense-dark stippling overlain by yellowish-golden to orange mottling; lateral tail vein visible in first third of tail, including dorsal branching along myosepta; upper and lower fin mostly transparent, stippled with melanophores, especially towards the fin margin; yellowish-golden stippling also present in the upper and lower fin; iris background color black, with dense golden to orange iridophore stippling; abdomen whitish laterally and densely stippled with golden iridophores medially; golden iridophores stippling also present in the anterior region of the snout and oral disc; abdominal sucker mostly transparent except for the central spot with golden iridocytes and scattered pigment along the rim. In preservative: color of dorsal region became gray with dense darker dots and dark brown mottling; darker region were obvious on the upper flanks and between eyes and naris; iris all black; lens grayish-white; ventrally uniformly transparent with dark pigments in the anterior region of snout, oral disc, and lateral.

Body proportions between Stage 25, Stage 28, and Stage 37 were variable, e.g., BW/BH in Stage 25 (165.01%)> in Stage 28 (160.72%)> in Stage 37 (144.97%); SUW/BW in Stage 25 (89.58%)> in Stage 28 (86.66%)> in Stage 37 (82.94%); TAL/BL in Stage 25 (153.74%) <Stage 37 (174.06%) <in Stage 28(183.00%); TMH/BH in Stage 25 (61.38%) <in Stage 37 (76.19%) <in Stage 28 (84.71%); TMH/MTH in Stage 25 (60.53%) <in Stage 37 (66.74%) <in Stage 28 (71.00%). Variation: Body shape in the Stage 25 and Stage 28 were oval; the posterior region gradually arched towards the end of the body (e.g. Stage 28; Fig. 11 d–f). Color patterns were also variable among the specimens. For example, in life, MZB.AMPH.29411 (Stage 28, Fig. 11 d–f) had less mottling on upper side of body and tail than MZB.AMPH.29413 (Stage 37), more extensive golden color in the iris, smaller orange blotches in the tail region, very few golden spots in both upper or lower fin region, golden iridopores and pigments were less in the ventral region. In preservative, MZB.AMPH.29411 is lighter than MZB.AMPH.29413.