Cophixalus salawatiensis, 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 : 205-210

Taxon classification Animalia Anura Microhylidae

Cophixalus salawatiensis sp. n.

Holotype.

MZB Amph.12165 (FN: SJR 7797); adult male collected at Weybya camp, Salawati Island, Raja Ampat Islands, West Papua Province, Indonesia (00°57.383'S, 130°47.060'E on 27/06/2005 by S. Richards, B. Tjaturadi and K. Krey.

Paratypes.

MZB Amph.12157 (FN: SJR 7731), MZB Amph.12159 (FN: 7756), MZB Amph.12161 (FN: SJR 7755), MZB Amph.12162 (FN: SJR 7730), MZB Amph.12166 (FN: SJR 7757), MZB Amph.12167 (FN: 7772), MZB Amph.12168 (FN: 7760), MZB Amph.12170 (FN: SJR 7795), and MZB Amph.12171 (FN: SJR 7796), same data as for holotype, collected between 24-27/06/2005. All specimens are adult males and MZB Amph.12166 is considered a hermaphrodite (see below).

Diagnosis.

Cophixalus salawatiensis sp. n. can be distinguished from all congeners by a combination of the following characters: Body small (SUL of 10 males 19.6-22.5 mm), slender, dorsum smooth except for scattered tubercles, head laterally with a distinct dark 'face mask’ (grey in life); legs moderately long (TL/SUL 0.49-0.53), third toe clearly longer than fifth, no webbing between digits. Toe and finger discs distinct, those of fingers slightly larger than, or equal in size to, those of toes (T4D/F3D 0.82-1.0). Call a train of 6-8 notes that sound like peeps or whistles; calls last for approximately 0.5 s, notes are less than 50 ms and produced at a rate of 13.5-15.6/s.

Description of the holotype

(Figs 9 a–d): For measurements see Table 2. Head wider than long (HL/HW 0.79), canthus rostralis straight and rounded; loreal region flat; snout protruding in profile and acuminate in dorsal view; nostrils directed laterally and near end of snout; horizontal eye diameter greater than eye-naris distance; tympanum scarcely visible, about one third of eye diameter (TyD/ED 0.28), supratympanic fold weakly expressed and S-shaped; internarial distance only slightly greater than distance between eye and naris (END/IND 0.94); tongue medium-sized, a little broadened posteriorly and lacking notch, with posterior and lateral margins free; prepharyngeal ridge not serrated; long vocal slits on both sides of the tongue. Legs moderately long (TL/SUL 0.51), no webbing between fingers or toes; disks of fingers II, III and IV about same width as disks of toes II, III and IV, disks of finger I as well as of toe I and V much smaller than that of other fingers and toes, relative length of fingers 3>4>2>1; third toe clearly longer than the fifth, all finger and toe disks with terminal grooves; relative length of toes 4>3>5>2>1, no clearly expressed subarticular tubercles on fingers and toes and no distinct palmar or plantar tubercles. Some low, pale-tipped tubercles on flanks, dorsally on shanks, and in two weakly-defined rows on posterior surfaces of back. All remaining dorsal, lateral, and ventral surfaces smooth, except a gular fold between insertion of the fore limbs that indicates the posterior margin of the vocal sac.

In preservative dorsal surfaces of head, body and limbs light grey-brown, flanks lighter than dorsum; most tubercles with dark base and light tip; irregular dark brown flecks on limbs and flanks. A longish dark-brown postocular spot followed by a small dark-brown spot above arm insertion. A broad off-white fleck extends from posterior of eye through tympanum up to arm insertion. This fleck is bordered antero-dorsally by the dark postocular spot and ventrally by the posterior part of the dark brown “face-mask”. The face-mask continues below the eyes, runs along the loreal region and reaches to the snout tip. Ventral surfaces of limbs and abdomen off-white with irregularly shaped brown spots that are often reticulated, throat and chest dark brown with a few off-white speckles; region around anal opening blackish.

In life dorsum grey-orange, central dorsum more intensely coloured than flanks, conspicuous is a big orange spot on foreleg and a whitish canthal stripe that continues on upper eyelid. Dorsal surface of head with a mixture of grey and orange spots, face-mask greyish. The small dark and the big off-white postocular flecks less intensely marked than in fixative. Dorsal and lateral tubercles more strongly expressed than in preservative, a dorsolateral row of inconspicuous tubercles present.

Variation in the type series

(in preservative): Mensural variation for the type series is shown in Table 2. Basic colour and colour pattern elements of all paratypes are fairly uniform and resemble the holotype. Ground colour of dorsal surfaces light grey to light brown. Dorsolateral glandular ridges weakly developed and often interrupted - they extend in some specimens from eye to lumbar region, in others they are shorter and confined to middle and posterior back. Dorsolateral prior glandular ridges in most specimens indicated by rows of dark brown spots that vary from rare to numerous and can form shorter or longer stripes. Characteristic for most paratypes is a dark brown postocular spot as well as a spot of the same colour above insertion of fore arm. Tympanal region in all specimens off-white and clearly demarcated from the dark postocular spot and the dark ”face-mask”. Dark brown lateral colour of head merges into that of dark gular region. Lateral surfaces of body usually more strongly pigmented towards dorsal regions. One specimen (MZB Amph.12166) shows heavily spotted dorsal and lateral surfaces. Throat and chest in all specimens covered by a dense net of dark brown flecks, abdomen off-white with few small brownish flecks and ventral surfaces of limbs a little more mottled than abdomen. No specimen with either dark or light mid-dorsal line.

MZB Amph.12166 is considered a hermaphrodite because it has a well-developed vocal sac and two vocal slits in the floor of the mouth, but also has an ovary containing eggs in an advanced developmental stage (Fig. 10). This frog also uttered advertisement calls that were recorded and that did not differ from calls of conspecific males.

Vocalisation.

Calling occurred at night, predominantly after heavy rain. The advertisement call of Cophixalus salawatiensis sp. n. consists of a short series of 6-8 peeps or whistles (Fig. 11) with fairly long and irregular intervals between the calls. Shortest inter-call interval 7 s and longest 58 s. Thirty-nine calls of three males, (MZB Amph.12166-168), all recorded at 24 °C, were analysed. Mean duration of these calls was 0.53 s, SD 0.16, range 0.42-0.55 s. Mean number of notes/call 7.2, SD 0.77, range 6-8. Mean of means of note length 43.6 ms, SD 1.39, range 41-46 ms, total range of note length 32-50 ms. Mean of means of internote interval length 31.2 ms, SD 2.0, range of means 26-33 ms, total range 21-41 ms. Mean repetition rate 14.3 notes/s, SD 0.51, range 13.5-15.6 notes/s. First note of almost all calls the shortest, and last interval the longest of all inter-note intervals. All notes are composed of many dense pulses. Their amplitude rises rapidly up to maximal level, remains stable on this level over most of the note and then drops gradually to the end of the note. Frequencies scatter from 2.5 to 3.25 kHz with dominant frequency at 2.9 kHz (Fig. 12). Harmonics are very weakly expressed and there is no modulation of frequencies (Fig. 11 below).

Distribution and ecological remarks.

Cophixalus salawatiensis sp. n. is currently known only from one location on Salawati Island in the Raja Ampat Island group off western New Guinea (Fig. 1). It was common in moderately logged lowland rainforest where males called from the surfaces of leaves in low foliage ~30 cm - 1.5 m above the ground after heavy rain at night. Intensive searches on nearby Batanta and Waigeo islands failed to detect this species there despite similar climatic conditions and strong activity of other frogs. This suggests that Cophixalus salawatiensis sp. n. probably does not occur there. A recently collected Cophixalus specimen (NME A2216/15 in the "Naturkundemuseum Erfurt, Germany") represents the first evidence of the genus Cophixalus from Misool Island. The specimen, a male, was collected by D. Telnov on 20 March 2009 from inside a rotten log where it guarded (at least) five rather well developed eggs in a "primeval moist lowland forest, district Misool Utara, Aduwey, valley of River Ifeyo, 01°58 ´41´´ S and 129°55 ´18´´E”. It measures 21.2 mm SUL and is morphologically most similar to Cophixalus salawatiensis but without knowledge of its advertisement calls we refrain from confirming the species’ presence there. However it is biogeographically interesting to confirm that the genus Cophixalus also occurs on Misool. It is not known whether Cophixalus salawatiensis occurs on the nearby New Guinea mainland.

Etymology.

The latinized specific epithet salawatiensis means that the new species occurs on Salawati Island off the western tip of New Guinea.

Comparison with other species

(see species comparison section for Cophixalus rajampatensis for specific size ranges of all congeners discussed below). Cophixalus amabilis , ateles , bewaniensis , desticans , humicola , interruptus , iovaorum , kethuk , linnaeus , melanops , misimae , phaeobalis pictus , pipilans , tagulensis , timidus , tomaiodactylus , tridactylus , variabilis , verecundus , viridis and wempi all have adult male SUL’s of less than 19 mm and so can be immediately distinguished from Cophixalus salawatiensis (SUL 19.6-22.5 mm). With an SVL of 15.7 mm the only known specimen of Cophixalus pictus Kraus is smaller than Cophixalus salawatiensis 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 Cophixalus salawatiensis 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 0.49-0.53 vs. TL/SVL 0.47) and in having a very different ratio of internarial distance to eye-to-naris distance (END/IND 0.76-0.94 vs. 1.08 in Cophixalus pictus ) ( Kraus 2012). Cophixalus balbus , biroi , caverniphilus , cheesmanae , clapporum , cryptotympanum , cupricarenus , kaindiensis , montanus , nubicola , parkeri , riparius and verrucosus ) all have minimum adult male body sizes> 23 mm and so can also be distinguished from Cophixalus salawatiensis sp. n. (SUL 19.6-22.5 mm). From the species of about the same size Cophixalus albolineatus has finger discs smaller than toe discs, while in the new species finger discs are of the same size or larger than toe discs. Cophixalus shellyi has a short, strongly reduced first finger (vs. normal length with moderately large disc in salawatiensis ) and Cophixalus sphagnicola and Cophixalus tenuidactylus , in contrast to Cophixalus salawatiensis , completely lack discs on fingers and toes. Cophixalus daymani and Cophixalus nubicola are distinguished by their very short hind legs (TL/SUL less than 0.48 vs. more than 0.49 in Cophixalus salawatiensis sp. n.). Cophixalus nexipus differs by having basal webbing on toes and advertisement calls consisting of a single, long note lasting more than one second (vs. 6-8 notes). Cophixalus pulchellus Kraus & Allison has a dorsum boldly blotched with black on a light grey background (vs. uniform in Cophixalus salawatiensis ).

In external morphology, Cophixalus tetzlaffi , Cophixalus monosyllabus and the above described Cophixalus rajampatensis exhibit most similarities to Cophixalus salawatiensis sp. n.

Cophixalus tetzlaffi has clearly smaller discs on finger one and toe one than Cophixalus salawatiensis sp. n. - the ratio F1D/SUL in 8 specimens of Cophixalus tetzlaffi is 0.016, SD 0.0016, range 0.014-0.018; mean of the same ratio in 10 specimens of Cophixalus salawatiensis sp. n. is 0.022, SD 0.0031, range 0.018-0.027; mean of the ratio T1D/SUL in Cophixalus tetzlaffi is 0.020, SD 0.0019, range 0.018-0.023 and in Cophixalus salawatiensis sp. n. 0.026, SD 0.0028, range 0.023-0.031. These species also have different advertisement calls - calls of Cophixalus tetzlaffi consist of 3-4 notes with note lengths of more than 300 ms, those of Cophixalus salawatiensis sp n. consist of 6-8 notes with a note length of less than 50 ms.

Cophixalus monosyllabus is morphologically very similar to Cophixalus salawatiensis sp. n. and, although the species differ significantly in body size [mean SUL of the former (n=10 adult males) 22.9 mm, SD 1.04, range 20.6-24.3 mm and of the latter (n=10 adult males) 20.8 mm, SD 0.94, range 19.6-22.5 mm (p=0.001 for comparisons of medians)], there is substantial overlap in SUL. The species also differ significantly in size of disc of third finger - mean ratio F3D/SUL in Cophixalus monosyllabus 0.063, SD 0.004, range 0.055-0.071 and in Cophixalus salawatiensis sp. n. 0.053, SD 0.003, range 0.049-0.058 (p=0.0004 for comparison of medians) but again there is some overlap. However these species have consistently and strikingly different advertisement calls - in Cophixalus monosyllabus these consist of single notes with a duration of more than 140 ms vs. 6-8 notes with note duration not longer than 50 ms in Cophixalus salawatiensis sp. n. and we consider these differences sufficient to warrant their recognition as distinct species.

Cophixalus rajampatensis (n=8) and Cophixalus salawatiensis sp. n. (n=10) have non-overlapping body sizes (17.6-19.5 vs. 19.6-22.5 mm) and further differ in the following body ratios: F1D/SUL 0.010-0.017 (mean 0.014) in the former vs. 0.018-0.027 (mean 0.022) in the latter, (Fig. 13); T1D/SUL 0.016-0.023 (mean 0.021) vs. 0.023-0.031 (mean 0.26), p=0.0005 (Fig. 14); HW/SUL 0.34-0.37 (mean 0.36) vs. 0.37-0.41 (mean 0.38), p=0.0009 (Fig. 15), and T1D/F1D 1.33-1.75 (mean 1.48) vs. 1.00-1.50 (mean 1.22), p=0.002.

Cophixalus rajampatensis and Cophixalus salawatiensis sp. n. also differ in their advertisement calls; calls of the former consist of 2-5 notes per call, note length 142-238 ms, 3.3-4.6 notes/s vs. 6-8 notes per call, note length 32-50 ms, 13.5-15.6 notes/s in the latter.