Xenorhina zweifeli (Kraus & Allison 2002)

Xenobatrachus zweifeli is a medium sized (33.2-38.0 mm SVL length) microhylid frog belonging to the X. rostratus group (Blum and Menzies 1988). From Kraus and Allison (2002), X. zweifeli differs from X. arfakianus, X. giganteus, X. macrops, X. multisica, X. obesus, X. rostratus, and X. scheepstrai in its smaller adult body size (41.1-90.2 mm); from X. anorbis, X. bidens, X. ophiodon, X. schiefenhoeveli, X. subcroceus, and X. tumulus in its larger adult body size (others range from 21.3-33.3 mm); from X. bidens, X. giganteus, X. multisica, and X. ophidion in having one, instead of two, odontoid spikes on each vomeropalatine; from X. mehelyi, X. obesus, X. ophiodon, X. scheepstrai, and X. subcroceus in shorter hind legs (TL/SVL = 0.32-0.38 in X. zweifeli, 0.23-0.34 in others). Calls are also different (see below). X. zweifeli can be distinguished from X. rostratus by its smaller adult body size, larger eyes, nostril closer to snout tip, somewhat larger foot, and a ventral coloration of sparsely scattered dark brown flecks on a cream ground color (a few light flecks on a dark brown ground color in X. rostratus). Head is moderately wide (HW/SVL = 0.28), same width as body and has no neck constrictions; oblique loreal region, no canthus rostralis; internarial distance less than distance from external naris to eye; snout truncate in dorsal and lateral view; eyes are small (EY/SVL = 0.063), eye-lid one-half the width of the interorbital distance; tympanic ring indistinct. Finger relative length formula: 3>4>2>1. Toe relative length formula: 4>3>5>2>1. Neither toes or fingers webbed; both have the presence of thickenings, but not high enough to form tubercles. Finger discs are lacking, though tips of fingers are slightly expanded; toe tips have expanded discs and are only slightly wider than penultimate phalanx. There is one enlarged spike on each vomeropalatine. Coloration in life, as recorded for the paratypes, is as follows: mainly a light chocolate-brown coloration; anterior regions are darker. Vertebral stripe is yellow. Dorsolateral surfaces of the body and legs have prominent, raised tubercles. There is an irregular black blotch between tympanum and forelimb. Venter is salmon colored and sides of face are white. Some individuals were heavily mottled with tan and brown blotches overlaid with black specks and small black blotches, some even lacked a vertebral stripe.

X. zweifeli is found in primary forest ranging from 900-1900 m. Vegetation is low; trees in the upper part of its range are shorter and more heavily covered with moss. Known only from the Bewani and Hunstein Mts. in the north coast of Papua New Guinea.

This species is a fossorial frog and is found in the leaf litter and upper layers of the soil (< 10 cm). Males may call in clusters where they are distributed within ~5 m of one another. The length of the call of the holotype was 310 ms. (see fig. 2 in Kraus and Allison, 2002). The mean fundamental frequency was 610 Hz; the third harmonic at approximately 1910 Hz was dominant, but was only slightly higher than the first and second.

Xenorhina zweifeli is a species of frog in the family Microhylidae. It is endemic to New Guinea and is only known from the Bewani and Hunstein Mountains in northern Papua New Guinea. The species is named for American herpetologist Richard G. Zweifel, a specialist in New Guinean herpetology and microhylid frogs; he is also said to share "characteristically terse vocalizations" with this frog.