Description. Summary measurements and ratios for samples from four disjunct groups of sites are given in Table 1. Body very slender and elongate, tibia approximately half length of body; head wider than body in dorsal profile, clearly distinct from neck. Snout rounded in dorsal view and truncate in lateral view. Rostral spike in males extending from tip of upper jaw; mean spikelength varies among populations sampled from different localities (see Table 1). Canthus rostralis moderately well defined, slightly curved; loreal region concave. Nares closer to tip of snout (excluding spike) than to eye, oriented laterally. Eyes moderately large, protruding in both dorsal and lateral views; pupil horizontal. Upper jaw protruding marginally beyond lower jaw. Tympanum small with distinct to indistinct annulus, bordered dorsally by a fleshy supratympanic fold extending to the superior edge of the insertion of the upper arm. Choanae small and circular, situated close to anterior and lateral edge of palate; no vomerine teeth visible; tongue fleshy and ovoid and usually with a slightly indented posterior edge. Vocal slits present. Dorsal skin tuberculate; ventral skin finely to coarsely granular on throat, abdomen and tibia; remaining ventral surfaces of limbs smooth; additional tubercles also present in clusters around the vent, and to a variable extent on sides of ankles and upper forearms. Fingers with relative lengths III> IV> II> I; fleshy, whitish to translucent webbing between all digits, forming a narrow basal strip between I and II, extending to disc on distal edge of II and proximal edge of IV, and to penultimate phalanx on both sides on III. Terminal finger discs expanded (narrower in the six samples from Timika: see Table 1), wider than toe discs and with distinct circum-marginal grooves. Nuptial pads dark brown, roughly tear-shaped with point of tear oriented in posteroventral direction. Indistinct unpigmented bifid subarticular tubercles usually visible at base of penultimate phalanx on all fingers, further indistinct unpigmented subarticular tubercles in series on finger IV, indistinct proximal metacarpal tubercles at base of I, and small distal metacarpal tubercles at base of III and IV. Toes moderately long, relative lengths IV> III> V> II> I. All digits with extensive fleshy, opaque webbing, basal between I and II, extending to anterior end of penultimate phalanx on distal edge of II and III and proximal edge of V, to halfway along penultimate phalanx on proximal edge of III and IV, and base of penultimate tubercle on distal edge of IV. Terminal discs slightly expanded (narrower in the six samples from Timika: see Table 1), narrower than finger discs and with distinct circum-marginal grooves. Indistinct unpigmented subarticular tubercles on penultimate phalanx of all toes, single on I-III, bifid on IV and V. No other tubercles clearly apparent. Small, indistinct unpigmented metatarsal tubercle at base of I. In preservative, ground colour of all dorsal surfaces medium brown, with extensive blueish green and darker brown flecking, maculations, vermiculations and / or blotches across all dorsal surfaces, blueish pattern elements sometimes coalesce into three indistinct transverse blotches, overall darker pigmentation elements tend to be densest on body, and less concentrated and more finely reticulated towards distal extremities of limbs (Fig. 2). Rostral spike light brown, with extensive darker brown flecking at base, tending towards unpatterned at tip. White patches often, but not always, present on either side of head, extending from posterolateral edge of eye, below tympanum and around axilla. Venter predominantly buff, internal organs sometimes visible, throat sometimes offwhite, and / or with two clusters of dark brown maculations laterally, tubercles around vent and sometimes those along outer edge of limbs, off-white. Appearance in life. The following description is based on photographs of specimens from Papua New Guinea; Tabubil (Western Province) (Fig. 1 A – B), Gobe (Gulf Province), Agogo (Southern Highlands Province) (Fig. 1 C), Crater Mountain (Chimbu Province), and Indonesia; Timika (Fig. 1 D) and the Bomberai Peninsula. Dorsal base colouration light to dark brown, with variable amounts of green and darker brown spotting, mottling or banding on body, limbs and head. Dorsal and lateral tubercles on torso and limbs often, but not always, green and contrasting against brown base colouration. Head brown, often with extensive green pigmentation, usually including a ring around the eyes, and more variably a green transverse band between the eyes. Dense clusters of dark-brown to almost black maculations extend to a variable degree across the limbs, lateral portions of torso, and in patches across the back. Off-white patches sometimes present below tympanum and on exposed surfaces of lower hindlimbs. Iris pattern complex; base colouration light brownish, with extensive darker brown vermiculations; rim of pupil orange. Hidden regions of axilla and groin orange. Comparisons with other species. The combination of small adult size (<35 mm), slender build, and males with a rostral spike that is rounded in cross-section will distinguish L. pronimia from all other previously recognised Melanesian Litoria except L. havina, L. mareku and L. mucro. Litoria pronimia differs from L. havina in having a complex brown and green dorsal pattern (vs uniform green or brown) and orange groin colouration (vs red); from L. mareku in its larger size (male SVL 26.9 – 30.4 mm vs 25.5 – 26.5 mm), long erectile rostral spike in males (vs effectively a short stub that is wider than long), and light to medium-brown base colouration on dorsum (vs at least some regions of very dark chocolate brown); and from L. mucro by its more complex dorsal colour pattern including extensive green flecking and banding (vs predominantly olive-green to brown dorsum with at most a small amount of light-green flecking). Males of L. havina and L. mucro tend to have rostral spikes shorter than L. pronimia (<1.5 mm vs> 1.5 mm), however as noted above the length of the rostral spike may vary between populations and samples of L. pronimia, reducing the utility of this character. Even though there are relatively few diagnostic characters seperating L. mucro and L. pronimia, genetic data also indicate that they are deeply divergent (Oliver et al. accepted). Four other species of Litoria from New Guinea have a rostral spike: L. chrisdahli Richards, L. hilli Hiaso and Richards, L. humboldtorum Günther, and L. prora Menzies. In addition to their larger size (male SVL between 37.0 – 49.4 mm) these species can be diagnosed from L. pronimia by an array of characters largely summarised by Kraus (2007): fleshy rostral spike present in both sexes, moderate to extensive dermal crenulations along the distal edge of the limbs and fourth finger, fully webbed hands, papillae along the chin margin, and posterior abdomen and ventral surfaces of thighs dark purplish with white pustules. Range. Litoria pronimia is now known from a broad band of lowland and foothill forest spanning over 1000 km along the the southern edge of the Central Cordillera from the Crater Mountain Wildlife Management Area in the east, to at least as far west as Timika in Papua Indonesia, with a further (potentially disjunct) population in the Fakfak Mountains (Fig. 3). Ecological notes. Litoria pronimia is known from lowland, hill and lower montane forests at elevations between ~ 200 – 1150 m a. s. l. where it forms breeding choruses around ponds or other waterbodies in disturbed or primary rainforest. One of the authors (R. Günther) found a small gelatinous egg cluster containing less than 10 white eggs on a leaf approximately 150 cm above a roadside ditch, at 800 m a. s. l. in the Fakfak Mountains on the 7 th September 2008. According to investigations of mitochondrial 12 S genes these eggs belong to L. pronimia, with sequences the same as ZMB 85620 – 21 (R. Günther, unpublished). At the same site calling males of Litoria christianbergmanni and L. havina were found, in addition to many eggs and larvae of the latter species. Litoria pronimia occurs in sympatry with, and uses the same breeding sites as L. havina across much of its range. Conservation status. Litoria pronimia is currently listed as Least Concern by the IUCN based on an assessment in 2004. Subsequent records extend its known distribution 1000 kilometres to the west, including large areas of relatively little-disturbed and continuous forest at suitable elevations.
