Rhacophorus indonesiensis, Hamidy, Amir & Kurniati, Hellen, 2015

Hamidy, Amir & Kurniati, Hellen, 2015, A new species of tree frog genus Rhacophorus from Sumatra, Indonesia (Amphibia, Anura), Zootaxa 3947 (1), pp. 49-66 : 52-57

Rhacophorus indonesiensis sp. nov.

Rhacophorus sp. 1: Kurniati 2011: page 444

Holotype. MZB Amph 21831, an adult male, from Birun Village, Merangin District, Jambi Province, Sumatra, Indonesia (2°11’51.65” S, 101°52’10.30” E, alt. 500 m asl, Fig. 1 ) collected on 10 July 2011 at 20:00 h by Mediyansyah.

Paratypes. 17 specimens, MZB Amph 21847 (adult male), locality, collection time, and collector are same as the holotype; MZB Amph 23613 (adult female), MZB Amph 23614–23627 (adult males) collected from Teluk Nauli, Sibolga, North Sumatra Province, Sumatra, Indonesia (1°04’4.09” N, 99°02’2.15” E, alt. 950 m asl, Fig. 1 ) on 6 March 2003 at 20:15 h by HK; MZB Amph 23628 (adult male) collected from Sungai Durian, Sipurak, Kerinci Seblat National Park, Jambi Province, Sumatra, Indonesia (2°19’0.8” S, 101°44’6.40” E, alt. 1100 m asl, Fig. 1 ) on 26 January 2005 at 20:30 h by HK.

Etymology. The specific name refers to the Republic of Indonesia, the country where the new species was found.

Diagnosis. The new species is placed in the genus Rhacophorus on the basis of it possessing following characteristics: the presence of intercalary cartilage between terminal and penultimate phalanges of digits, terminal phalanges of finger and toes Y-shaped, tip of the digits expanded into large disks bearing circum marginal grooves, webbed fingers, horizontal pupil, and the skin not co-ossified to skull ( Malkmus et al. 2002; Brown & Alcala 1994; Duellman & Trueb 1986; Liem 1970; Inger & Stuebing 2005). Rhacophorus indonesiensis sp. nov. is distinguished from its congeners by combination of the following characters: (1) small-size (adult males 28.8–31.2 mm SVL and adult female 37.8 mm SVL), (2) vomerine teeth absent, (3) both males and females having distinct black spots on the ventral surface of the hand and foot webbing, (4) reddish brown dorsum with irregular dark brown blotches, and distinct black dots scattered on the dorsal surfaces of the body and limbs, (5) venter, particularly in the chest and belly with a distinct white kite-shaped marking in life (5) raised white spots on the dorsum or on the head, (6) dorsal surface of the fingers and toes yellowish orange.

Description of holotype. Small-sized of rhacophorid frog with SVL 30.0 mm; head longer (HL 10.0 mm, 33.3% of SVL) than wide (HW 9.3 mm. 31.0% of SVL); snout (SL 4.6 mm, 15.3% of SVL) slightly longer than eye (EL 4.4 mm, 14.7% of SVL), rounded dorsally, truncate in profile, and projecting over lower jaw; canthus distinct, curved in profile; lore slightly oblique; nostril slightly protuberant, without flap of skin, closer to the tip of snout (2.7 mm, 9.0% of SVL) than to the eye (3.1 mm, 10.3% of SVL); internarial distance ( IND 2.7 mm, 9.0% of SVL) much smaller than interorbital distance (IOD 3.5 mm, 11.7% of SVL); interorbital distance wider than eyelid (UEW 3.1 mm, 10.3% of SVL); pineal spot absent; eye large (ED 3.5 mm, 11.7% of SVL), protuberant, pupil horizontal; tympanum visible externally, circular, diameter (TD 1.7 mm, 5.7% of SVL) approximately half eye diameter and separated from eye (T-EL 0.5 mm, 1.7% of SVL) by approximately one-third of tympanum diameter; tympanic fold distinct, elevated from the posterior of eye to the arm insertion; choanae circular; vomerine teeth absent; median subgular vocal sac present, vocal slits on both sides near the base of the tongue; tongue attached anteriorly and deeply notched posteriorly.

Forelimb slender, length (FLL 19.3 mm, 64.3% of SVL); lower arm and hand length (14.5 mm, 48.3% of SVL); relative finger length I<II<IV<III; length of first finger (1FL 3.5 mm, 11.7% of SVL) shorter than length of eye (4.4 mm, 14.7 % of SVL); tips of all fingers expanded into large disks with circum marginal and transverse palmar grooves; disk of third finger (3FDW 2.1 mm, 7.0% of SVL) wider than tympanum (1.7 mm, 5.7% of SVL); fingers moderately webbed ( Fig. 6 A); webing formula I 1 ½ – 1 II 0 – 1 III ½ – 0 IV; subarticular tubercles rounded, formula 1, 1, 2, 2; nuptial pad absent; supernumerary tubercles indistinct; prepollex absent; oval inner palmar tubercle (IPTL 2.2 mm, 7.3% of SVL) and outer palmar tubercle indistinct.

Hindlimb slender, length (HLL 49.8 mm, 166.0% of SVL), about 2.6 times length of forelimb; thigh (16.0 mm, 53.3% of SVL) shorter than tibia (TL 16.3 mm, 54.3% of SVL), heels overlapping when limbs are held at right angles to body; tibiotarsal articulation of adpressed limb reaching beyond the snout; foot (12.3 mm, 41.0% of SVL) shorter than tibia; relative length of toes I<II<III<V<IV; tips of toes expanded into round disks with distinct circum marginal grooves, smaller than those of outer fingers (4TDW 1.6 mm, 5.3% of SVL vs 4FDW 2.0 mm, 6.7% of SVL); toes fully webbed, toe webbing formula I 0–0 II 0–½ III ½–0 IV 0–0 V ( Fig. 6 B); subarticular tubercles distinct, rounded, formula 1, 1, 2, 3, 2; supernumerary tubercles absent; low, oval inner metatarsal tubercle, length (IMTL 1.6 mm, 5.3% of SVL) more than half length of first toe (1TOEL 3.8 mm, 12.7% of SVL); no outer metatarsal tubercle.

Dorsum nearly smooth, scattered with non-spinose tubercles; flank wrinkled; underside of chin and chest smooth, abdomen and thigh coarsely granular; the granulation much denser in the cloacal region; outer margin of hand, fore arm, foot, and heel with low dermal ridges; the dermal ridges reach the tibiotarsal articulation but not forming pointed projection; very low supra cloacal dermal ridges present; a pair of raised white spots on the dorsum.

Color. Color in life reddish brown above with indistinct and irregular dark brown blotches; distinct black dots scattered on the dorsum, head, and limbs; a pair of white spots on the dorsum; pale brown to whitish on the dorsolateral; dorsal side of lower arm much paler, yellowish orange without pattern; forearm, thigh, tibia, and foot with dark brown bars dorsally; dorsal part of the finger and the toes yellowish orange; tip of the fingers and toes, and web reddish orange dorsally; ventral part of forearm, hand, foot, webbing, and tarsus yellowish, with distinct black spots; below pale orange, white on the chin and chest; a white kite-shaped pattern on chest and belly; pupil horizontal with iris color brown reddish (night) and cream (day); sclera (orbital arc) whitish. In alcohol dorsal color fades to pale brown.

Variation. Morphometric data are summarized in Table 1 . The single female is larger (37.8 mm in SVL) than all males (28.8–31.2, 30.2± 0.7 mm in SVL). Based upon the single female found, males appear to have relatively shorter inter orbital distance than females (IOD: 10.9–12.8%, median=11.9% of SVL in males vs. 13.0% of SVL in female), larger tympanum (TD: 5.1–6.3%, median 5.7% of SVL in males vs 4.2% of SVL in female), shorter forearm (FLL: 56.9–66.3%, median=63.4% of SVL in males vs 69.3% of SVL in female), and shorter first finger (1FL: 9.9–11.8%, median=11.1% of SVL in males vs13.5% of SVL in female). The low supra cloacal dermal ridge appears more distinct in male than in the female. Specimens are fairly constant in coloration, except that some specimens have single, distinct white spot on the dorsum and others have a pair of distinct white spots. The coloration of the white spots disappears when the body color fades. All individuals have black dots spread on the dorsal of the head, back, and the limbs. The black dots vary in number from 23 to 64. In some individuals the black dots concentrated on the dorsal of the head or randomly scattered on the dorsum. The distinct black spots on the ventral surfaces of the hand and foot webbing vary in size but are always present. These black spots are much distinct on the ventral side of the outer fingers and toes.

Comparisons. The dorsal color of R. indonesiensis sp. nov. is reddish brown, which clearly distinguishes it from all rhacophorid species from Sundaland, Sulawesi, and Philippines that have dorsum with a green background: R. achantharrhena , R. bipunctatus , R. borneensis , R. dulitensis , R. edentulus Müeller , R. georgii Roux , R. monticola , R. nigropalmatus , R. norhayatiae , R. penanorum , R. prominanus Smith , R. reinwardtii . Rhacophorus monticola and R. modestus , have both green and reddish brown on the dorsum, however these species have a much larger body size than R. indonesiensis sp. nov. (adult male in SVL> 40 mm vs <35 mm). Having whitish flanks without any pattern and similar in color to the lateral sides of the body, distinguishing R. indonesiensis sp. nov. from species that have distinct yellow flanks ( R. catamitus ), black marbled flanks ( R. bengkuluensis ) or reticulated flanks ( R. pardalis ). The snout of R. indonesiensis sp. nov. is truncate laterally in both sexes, distinguishing it from congeners with a pointed snout: R. angulirostris , R. barisani , R. baluensis , R. bifasciatus , R. fasciatus , R. poecilonotus , R. pseudacutirostris , R. rufipes . Rhacophorus indonesiensis sp. nov.

lacks a pointed projection on the heel, distinguishing it from R. bimaculatus (Peters) , R. gadingensis , R. catamitus , R. margaritifer , and R. gauni . Rhacophorus indonesiensis sp. nov. has reddish orange webbing dorsally, distinguishing it from the black webbed species R. harrissoni , and R. robinsonii Boulenger. The absence of vomerine teeth differentiates R. indonesiensis sp. nov. from all known congeners from Sundaland, Sulawesi, and the Philippines, except R. belalongensis , R. cyanopunctatus , R. gauni , and R. edentulus . Rhacophorus indonesiensis sp. nov. has distinct black spots on the ventral side of the webbing, hand, forearm, foot, and tarsus, which differentiates it from all known species in the genus Rhacophorus . Finally, Rhacophorus indonesiensis sp. nov. differs from all synonyms of Rhacophorus species occurring on Sumatra and adjacent islands ( R. barbouri , R. javanus , R. phyllopygus , R. pulchellus and R. pardalis rhyssocephalus ), by having vomerine teeth absent (present in all synonyms) and having distinct black spots on the ventral of the webbing, hand, forearm, foot and tarsus (absent in all synonyms). The new species further differs from R. barbouri , R. javanus , R. pulchellus and R. pardalis rhyssocephalus by having a male SVL 28.8–31.2 mm (versus male SVL> 35 mm), and from R. phyllopygus in having a snout rounded in dorsal view and truncate in profile view (versus a pointed snout in both dorsal and profile views in R. phyllopygus ) in both adult males and females. In addition, uncorrected sequence divergences between R. indonesiensis sp. nov. and all homologous 16S rRNA sequences available on GenBank (from individuals assigned to 22 of 32 Rhacophorus species from Sundaland, Sulawesi, and Philippines) were>8.5%.

Range. Sumatra, Indonesia: Jambi (Merangin), Kerinci Seblat National Park (Sungai Durian), North Sumatra (Teluk Nauli).

Natural history. A pair of R. indonesiensis sp. nov. in axillary amplexus was found in July 2013 ( Fig. 3 ) in Merangin. The female paratype (MZB Amph 23613) collected in March 2003 had cream ovaries with diameters of 0.90–1.10 mm. We do not have data on the advertisement call or the tadpoles. Other species found around the collection site of Merangin were Nyctixalus pictus (Peters) , Metaphrynella sundana (Peters) , Hylarana luctosa (Peters) , Microhyla superciliaris Parker , Megophrys nasuta (Schlegel) , Rhacophorus nigropalmatus , R. prominanus , R. norhayatiae . The pond where the holotype was collected is approximately 500 m from a nearby river where other species including R. modestus , Ansonia leptopus (Günther) , Hylarana parvaccola (Inger, Stuart, & Iskandar), Limnonectes kuhlii (Tschudi) , Limnonectes blythii (Boulenger) , Phrynoidis aspera (Gravenhorst) , Hylarana picturata (Boulenger) , Odorrana hosii (Boulenger) were found. Among the species collected from the collection site of Merangin, R. nigropalmatus , Microhyla superciliaris Parker , Hylarana luctosa , were breeding in the same pond as R. indonesiensis sp. nov. (Mediansyah pers. obs.). The holotype and one? paratype (MZB Amph 21831) were collected from an elephant wallow in primary forest, with a diameter of about 5 m and a depth of 80– 100 cm. Other paratypes (MZB Amph23613–23627) were collected from a pond with a size 3 x 1 m, and depth of 40 cm ( Fig. 7 ). The paratype MZB Amph 23628 was collected from a pond of 1 m diameter and depth of 30 cm. Because all the specimens of the new species were collected from ponds, we assume that R. indonesiensis sp. nov. primarily reproduces in this kind of water body.

Figures

FIGURE 1. Map of Sumatra showing the known localities of Rhacophorus indonesiensis sp. nov. (solid diamonds). Map modified from Sadalmelik (2007).

FIGURE 3. Dorsolateral view of Rhacophorus indonesiensis sp. nov. in life (A) adult male paratype MZB Amph 23624 from Teluk Nauli, diurnal coloration, (B) adult male paratype MZB Amph 23617 from Teluk Nauli, diurnal coloration, (C) adult male paratype MZB Amph 23620 from Teluk Nauli, nocturnal coloration, (D) adult male paratype MZB Amph 23628 from Sungai Durian, nocturnal coloration. Not to scale.

FIGURE 6. Palmar view of hand (A) and platar view foot (B) of holotype (MZB Amph 21831) Rhacophorus indonesiensis sp. nov. after preservation. Scale bar = 5 mm.

FIGURE 7. The wallow in Teluk Nauli where 15 paratypes (MZB Amph 23613 – 23627) were collected.

Tables

TABLE 1. Measurement in adults of Rhacophorus indonesiensis sp. nov. SVL (means ± SD, in mm) and medians of ratio (R) of other characters to SVL, followed by ranges in parentheses. See the text for abbreviations.

Characters	male (n=17)	female (n=1)
SVL	30.2 0.7 (28.8–31.2)	37.8
HL	35.0 (33.3–36.1)	33.1
HW	32.8 (31.0–34.7)	31.0
IND	9.1 (8.7–9.2)	8.9
IOD	11.9 (10.9–12.8)	13.0
UEW	10.1 (9.0–11.2)	8.9
SL	15.7 (14.7–16.4)	16.1
EL	14.8 (14.1–15.5)	14.0
ED	12.0 (10.9–13.2)	10.8
TD	5.7 (5.1–6.3)	4.2
T-EL	1.9 (1.7–2.6)	1.8
FLL	63.4 (56.9–66.3)	69.3
LAL	48.5 (47.5–52.1)	48.1
1FL	11.1 (9.9–11.8)	13.5
IPTL	7.3 (6.7–8.0)	8.2
THIGH	52.6 (49.7–54.9)	52.9
TL	54.2 (53.0–56.2)	54.2
FL	43.9 (41.0–46.2)	43.4
HLL	166.0 (162.0–170.0)	162.0
IMTL	5.6 (5.3–6.3)	5.8
1TOEL	13.5 (12.2–14.2)	13.2
3FDW	7.6 (6.8–8.3)	8.2
4FDW	6.7 (6.2–8.0)	7.4
4TDW	5.9 (5.1–7.1)	6.1