Description

Diagnosis: Small body size (males 12.4-13.5 mm SVL; females 13.2-15.0 mm SVL); finger discs smaller than toe discs; first finger is distinct and lacks a disc; toes with basal webbing; narrow head with wide snout; smooth dorsum; wide, dark hourglass-shaped marking on dorsolateral surface; side of face dark but with light speckling; venter stippling in mottled pattern rather than evenly; call sounds like a marble bouncing on a hard surface and coming to rest, with 12-13 notes coming more rapidly toward the end (Kraus and Allison 2009).

Description: Adult males measure 12.4-13.5 mm SVL. Adult females measure 13.2-15.0 mm SVL. Narrow head with a wide snout, rounded canthus rostralis, and oblique loreal region. Laterally directed nostrils close to the tip of the rounded snout. Eyes large. Tympanum small; annulus has indistinct posterior and dorsal margins. Supratympanic fold absent. Fingers unwebbed. Finger I somewhat reduced and lacks a disc. Fingers II-IV have discs with circum-marginal grooves; discs are barely wider than penultimate phalanges. Fingers have low indistinct subarticular tubercles. Distinct metacarpal tubercles (round inner, elongate outer) on palm. Hind legs are moderately long. Basally webbed toes have discs with terminal grooves. Toe discs are much larger than finger discs; toe discs are 1.5x the width of the penultimate phalanx, except for that of Toe I, which is only slightly wider than the penultimate phalanx. Inner metatarsal tubercle is oval-shaped; the outer metatarsal tubercle is absent. Skin smooth dorsally and ventrally (Kraus and Allison 2009).

Brown to orange-brown dorsum that may be mottled with gray. Two broad dark brown dorsolateral stripes that constrict into an hourglass in the scapular region, or gray mottling may form an hourglass if dorsolateral stripes are not present. Dark brown face with white specks. Sides of the face are dark, but have light speckles. Dark V-shaped interocular blotch just posterior to the eyes. Tympanum dark brown. Iris dark brown or black with a red ring around the pupil. Ventral surfaces of body, including thighs, range from almost white in some individuals to dark brown with scattered white specks. (Kraus and Allison 2009).

This species appears to undergo metachrosis, as several specimens were lighter at night (light orange-brown dorsally and grayish-white ventrally) (Kraus and Allison 2009).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Papua New Guinea

View distribution map in BerkeleyMapper.

Endemic to Papua New Guinea. Found in primary and advanced secondary rainforests on Rossel Island, Milne Bay Province from sea level to 640 m ASL; has been heard at 750 m ASL (Kraus and Allison 2009).

Life History, Abundance, Activity, and Special Behaviors
Calls at dawn and for an hour before nightfall. It has also been heard at night in the higher part of the range (750 m). Generally calls from under leaf litter, under brush piles, under rocks near surface of deep rockpiles, and under boulders. Call series of 12-13 notes, sounded at intervals of 7-17 seconds. Described as sounding like pebbles hitting each other or like a marble bouncing on a hard surface and coming to rest (becoming more rapid towards the end). Dominant frequency averages 4530 Hz, with a range of 4400-4800 Hz (Kraus and Allison 2009).

Trends and Threats
Common but difficult to locate due to its habit of calling from under objects (Kraus and Allison 2009).

Comments
The specific epithet kethuk refers to a Javanese word for a gamelan instrument which gives a sound similar to the advertisement call for this species. The word is pronounced “kĕ-tú”, with the accent on the second syllable and the "k" being a glottal stop (Kraus and Allison 2009).

References

Kraus, F., and Allison, A. (2009). ''New species of Cophixalus (Anura: Microhylidae) from Papua New Guinea.'' Zootaxa, 2128, 1-38.

Species Account Citation: AmphibiaWeb 2010 Cophixalus kethuk <https://amphibiaweb.org/species/7339> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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