Cophixalus rajampatensis, Guenther, Rainer, Richards, Stephen, Tjaturadi, Burhan & Krey, Keliopas, 2015

Guenther, Rainer, Richards, Stephen, Tjaturadi, Burhan & Krey, Keliopas, 2015, Two new species of the genus Cophixalus from the Raja Ampat Islands west of New Guinea (Amphibia, Anura, Microhylidae), Zoosystematics and Evolution 91 (2), pp. 199-213 : 199-205

Taxon classification Animalia Anura Microhylidae

Cophixalus rajampatensis sp. n.

Holotype.

MZB Amph.12094 (field number, FN: SJR 7638); adult male collected at unnamed camp near Urbinasopen Village, Waigeo Island, Raja Ampat Islands, West Papua Province, Indonesia (00°20.231'S, 131°15.528'E) (Fig. 1) on 12/06/2005 by S. Richards, B. Tjaturadi and K. Krey.

Paratypes.

MZB Amph.12097 (FN: SJR 7615), MZB Amph.12169 (FN: 7617), same data as holotype; MZB Amph.12098 (FN: SJR 7575), MZB Amph.12095 (FN: 7592) collected at Warinkabom Camp, Batanta Island, Raja Ampat Islands, West Papua Province, Indonesia (00°50.196'S, 133°43.318'E on 7 and 9/06/2005 respectively by S. Richards, B. Tjaturadi and K. Krey; MZB Amph.12092 (FN: SJR 7551), MZB Amph.12096 (FN: SJR 7559), MZB Amph.12163 (FN: 7516) collected at Waire Camp, Batanta Island, Raja Ampat Islands, West Papua Province, Indonesia (00°50.384'S, 130°31.534'E on 6-7/06/2005 by S. Richards, B. Tjaturadi and K. Krey. All seven paratypes are adult males.

Diagnosis.

With an SUL of 17.6-19.5 mm in eight adult males, the new species is one of the smaller species of Cophixalus . Body slender, dorsum smooth except for occasional scattered tubercles and partly interrupted dorsolateral skin folds; legs moderately long (TL/SUL 0.48-0.52), third toe clearly longer than fifth. Toe and finger discs distinct, those of fingers slightly larger than, or equal in size to, those of toes (T4D/F3D 0.8-1.0), except that of first finger which is scarcely wider than penultimate phalanx. Call a short train of peeps or whistles, each with a mean duration of 178 milliseconds (ms). Number of notes (= peeps) per call 2-5 (mean 3.42), repeated at a rate of 3.3-4.6 notes/s (mean 3.96) and dominant frequency 3.7 kHz.

Description of the holotype

(Fig. 2 a–d). For measurements see Table 1. Head much broader than long (HL/HW 0.78), canthus rostralis rounded; loreal region flat; snout protruding in profile and nearly rounded in dorsal view; nostrils directed laterally; horizontal eye diameter greater than eye-naris distance; tympanic annulus scarcely visible, tympanum less than half eye diameter (TyD/ED 0.38), supratympanic fold short; internarial distance greater than distance between eye and naris (END/IND 0.75); tongue large, broadened posteriorly with a small notch, posterior and lateral margins free; prepharyngeal fold not serrated; long vocal slits on both sides of the tongue. Legs moderately long, no webbing between fingers or toes; disk of third finger wider than disk of fourth toe (T4D/F3D 0.89), disks of fingers II, III and IV about the same width as those of toes II, III and IV, first finger much smaller than other fingers, its disk only scarcely wider than the penultimate phalanx; relative length of fingers 3>4=2>1; third toe clearly longer than the fifth, disk of first toe slightly smaller than disk of fifth toe, disks of remaining toes clearly wider than those of first and fifth toe; all finger and toe disks with terminal grooves; relative length of toes 4>3>5>2>1, subarticular, metatarsal and metacarpal tubercles not or only scarcely developed. Some tubercles on flanks, posterior back and dorsal shanks and irregular and partly interrupted dorsolateral skin folds from near eye to inguinal region. All remaining dorsal, lateral, and ventral surfaces smooth, except a gular fold between insertion of the fore limbs that indicates posterior margin of the vocal sac.

In preservative dorsal surfaces of head, body and extremities mid-brown, most tubercles with dark base and light tip, dorsolateral folds are accompanied by dark brown stripes. A fine light middorsal line from snout to anal opening. Body sides blotchy; a conspicuous whitish fleck extends from posterior of eye through tympanum to arm insertion. Ventral surfaces of extremities off-white with dense irregularly shaped brown spots; belly off-white with a few brown spots anteriorly, throat and chest intensely brown; region around anal opening blackish. In life dorsal surfaces bronze-brown with a few dark brown flecks laterally; tubercles pink. Conspicuous is an off-white stripe from tip of snout along canthus rostralis and margin of upper eyelid and reaching to posterior eye margin (this off-white stripe has nearly disappeared in fixative), and a dark brown “face-mask” covering loreal and gular region up to insertion of upper arm. Iris silvery with orange parts anteriorly and posteriorly and many irregular dark brown spots.

Variation in the type series.

Mensural variation for the type series is shown in Table 1. Basic colour and colour pattern elements of all preserved paratypes are fairly uniform and closely resemble the holotype. Characteristic for most paratypes is a lighter brown dorsum which is bordered by irregular blackish dorsolateral lines and dark brown upper flanks. Three paratypes exhibit a dark mid-dorsal line; none have a light mid-dorsal line like the holotype. Abdomen from unspotted to various degrees of spotted; throat and chest uniform dark brown or heavily spotted; loreal, subocular and gular region middle to dark brown in fixative and blackish in life. All specimens with a large off-white postocular fleck which is bordered antero-dorsally by a smaller dark spot and ventrally by the posterior “face-mask”. Six specimens have a small blackish spot above insertion of fore leg. The conspicuous pale canthal stripe that was present in all living specimens is very inconspicuous in the fixed ones.

Vocalisation.

Most calling activity occurred at night after rain. Calls of three males (MZB 12095, 12096 and 12163) recorded at temperatures of approximately 26 °C were analysed. Calls each contained 2-5 (mean 3.4, SD 0.7) finely pulsed notes which sound like peeps or whistles (Fig. 3), and 4-6 calls were uttered in succession (a call series) with variable intervals between individual calls (4-20 s) and between call series (20 s to some minutes). The shortest time between two successive calls within a series was 3.5 s. The call length was 0.40-1.54 s, mean 0.88 s, SD 0.22, n=52. Mean of means of note length was 178 ms, SD 10.4, range of means 158-202 ms, n=52; total range of note length 142-238 ms. Mean of means of internote length 115 ms, SD 34.9, range of means 68-172 ms, n=52; total range of internote intervals 63-179 ms. Mean note repetition rate was 3.96 notes/s, SD 0.37, range 3.3-4.6 notes/s, n=52. Frequencies are concentrated mainly between 3.4 and 4.0 kHz, with a dominant frequency of 3.7 kHz (Fig. 4). Most notes start explosively with nearly maximum amplitude, and volume may remain constant during the entire note but may also undulate, with the greatest volume mostly in the middle of the note. The end of the note has a less steep amplitude slope than the beginning. The first note of a call is nearly always the longest.

Distribution and ecological remarks.

Cophixalus ampatensis sp. n. is currently known from two localities on Batanta Island and one locality on Waigeo Island, both in the Raja Ampat Island group off western New Guinea (Fig. 1). It was found to be common in moderately to heavily logged lowland rainforest where males called from the surfaces of leaves in low foliage ~30 cm - 1 m above the ground after heavy rain at night. Intensive searches on nearby Salawati Island failed to detect this species there despite similar climatic conditions and high activity of other frogs on that island. A number of other faunal lineages show evidence of a disjunction between Salawati and Batanta (e.g. Oliver et al. 2008), reflecting the different geological histories of these islands within the Raja Ampat Island Group. Batanta shares much of its biogeographic history with Waigeo, and the deep Sagewin strait that separates them from Salawati appears to be a major barrier for at least some taxa. Together these observations suggest that Cophixalus rajampatensis sp. n. probably does not occur on Salawati, and may be endemic to Batanta and Waigeo Islands.

Etymology.

The latinized specific epithet rajampatensis refers to the fact that the species occurs on the Raja Ampat Islands off the western tip of New Guinea.

Comparison with other species.

Cophixalus species described from New Guinea and adjacent islands that can be immediately distinguished from Cophixalus rajampatensis (with males 17.6-19.5 mm) by their smaller adult size are (sizes presented below are for adult males unless otherwise indicated): amabilis Kraus (13.6-14.3 mm), ateles (Boulenger) (12-14 mm), desticans Kraus & Allison (13.1-16.2 mm), humicola Günther (14.5-16.2), iovaorum Kraus & Allison (13.2-16.0 mm), kethuk Kraus & Allison (12.4-13.5 mm), linnaeus Kraus & Allison (13.4-14.7 mm), misimae Richards & Oliver (15.5-16.1 mm), phaeobalis Kraus & Allison (15.3 mm), timidus Kraus & Allison (13.5-17.5 mm), tomaiodactylus Kraus & Allison (13.2-16.1 mm), tridactylus Günther (14.3-16.2), and viridis Günther, Richards & Dahl (15.8-16.2 mm). With an SVL of 15.7 mm the only known specimen of Cophixalus pictus Kraus is smaller than Cophixalus rajampatensis but its description was based on a rather poorly preserved (and presumed immature) male from the Bomberai Peninsula of West Papua Province ( Kraus 2012) and, if immature, this distinction could disappear once adult material has been documented. However the new species also differs from Cophixalus pictus in a number of features that are unlikely to reflect the immature status of the holotype and only known specimen, including having (vs. lacking) a distinct supratympanic fold, in having longer legs (TL/SUL 0.48-0.52 vs. TL/SVL 0.47) and in having a very different ratio of internarial distance to eye-to-naris distance (END/IND 0.67-0.85 vs. 1.08 in Cophixalus pictus ) ( Kraus 2012). A further 15 species can be readily distinguished by their much larger size: balbus Günther (26-28 mm), biroi ( Méhely) (to 27 mm; Zweifel 1979), caverniphilus Kraus & Allison (25.5.2-36.7 mm), cheesmanae Parker (to 31 mm; Zweifel 1979), clapporum Kraus (23.2-27.5 mm), cryptotympanum Zweifel (to 30 mm (both sexes) at the type locality; to 40 mm elsewhere: Zweifel 1956, 1962, Menzies 2006), cupricarenus Kraus & Allison (23.4-28.7 mm), kaindiensis Zweifel (to 28 mm; Zweifel 1979), montanus (to 26 mm (sex not stated; Parker 1934), nubicola Zweifel (22.4-24.3 mm), parkeri Loveridge (to 30 mm), riparius Zweifel (to 45 mm) and verrucosus (Boulenger) (to 25 mm).

From the species with overlapping body sizes: Cophixalus albolineatus Kraus (16.8-20.5 mm), Cophixalus interruptus Kraus & Allison (16.6-18.7 mm), Cophixalus melanops Kraus & Allison (16.4-18.9 mm), Cophixalus tagulensis Zweifel (to 18 mm), Cophixalus tenuidactylus Günther & Richards (18.4-20.3 mm) and Cophixalus verecundus Zweifel & Parker (15-17 mm) the new species can be immediately distinguished by having finger discs of the same size or larger than toe discs (vs. smaller than the toe discs). Cophixalus variabilis Kraus & Allison (13.6-18.6 mm) has a tuberculate (vs. smooth) dorsum with extensive colour variation including longitudinal stripes in about 50% of specimens (lacking in rajampatensis ). Cophixalus bewaniensis Kraus & Allison (15-17 mm) and Cophixalus shellyi Zweifel (~17 mm) have strongly reduced first fingers and Cophixalus sphagnicola Zweifel & Allison (15.8-18.5 mm), in contrast to Cophixalus rajampatensis sp. n., completely lacks discs on fingers and toes. Cophixalus pipilans Zweifel (16.1-18.5 mm) has longer legs (TL/SVL>0.53 vs. TL/SUL 0.48-0.52) and calls with 20-33 (vs. 2-5) peeping notes. Cophixalus daymani Zweifel (to 21.7 mm [females]) is distinguished by very short hind legs (TL/SUL less than 0.38 vs. 0.48-0.52) and occuring higher than 2200 m a.s.l. Cophixalus nexipus Kraus (18.9-22.7 mm) differs by having basal webbing on toes and advertisement calls consisting of a single, long note lasting more than one second (vs. 2-5 short, finely pulsed peeps). Cophixalus wempi Richards & Oliver (15.5-16.1 mm) has (vs. lacks) a distinct spiniform tubercle above the eyelid and has advertisement calls with 28-33 (vs. 2-5) peeping notes.

On the basis of external morphology Cophixalus tetzlaffi and Cophixalus monosyllabus exhibit most similarities to Cophixalus rajampatensis sp. n. and are compared in more detail. With an SUL of 20.0-22.7 mm, mean 21.3 mm, SD 0.92, n=8, Cophixalus tetzlaffi is larger than Cophixalus rajampatensis sp. n. with an SUL of 17.6-19.5 mm, mean 18.3, SD 0.60, n=8 (Fig. 5). Relative tibia length of Cophixalus tetzlaffi is significantly greater than that of Cophixalus rajampatensis sp. n. (TL/SUL 0.51-0.53 vs. 0.48-0.52; p=0.008, Fig. 6), although the values overlap. There are also significant differences between these species (no overlap in the values) in their advertisement calls; note length of Cophixalus tetzlaffi (347-518 ms) is longer than that of Cophixalus rajampatensis sp. n. (142-238 ms); internote interval in the former is longer (186-299 ms) than in the latter (63-179 ms); and note repetition rate in the former is slower 1.5-1.8 notes/s than in the latter 3.3-4.6 notes/s.

Ten male specimens of Cophixalus monosyllabus have a larger snout-urostyle length than eight males of Cophixalus rajampatensis sp. n. and there is no overlap: 20.6-24.3 mm, mean 22.9 mm (SD 1.04) vs. 17.6-19.5 mm, mean 18.3 mm (SD 0.56) and also differ significantly in the following body ratios ( monosyllabus vs. rajampatensis ): F3D/SUL (0.055-0.067 vs. 0.044-0.054: Fig. 7), F3L/SUL (0.26-0.28 vs. 0.21-0.25), F1D/SUL (0.017-0.031 vs. 0.010-0.017), HW/SUL (0.37-0.42 vs. 0.34-0.37: Fig. 8) and END/IND 0.84-0.96 vs. 0.67-0.85, p=0.001). Moreover, Cophixalus monosyllabus and Cophixalus rajampatensis sp. n. differ in their advertisement calls. Calls of the former consist of single notes while calls of the latter always contain 2-5 notes, mean 3.4 notes, SD 0.7.