Oreophryne purari Günther, Nagombi & Richards, 2025, sp. nov.

Oreophryne purari sp. nov. urn:lsid:zoobank.org:act: F83C1881-C37C-4B72-B7E6-629D2FC01DE4 Figs 4A–F, 5 Holotype. SAMA R72179 (Field Number: SJR 15129), adult male, Papua New Guinea, Gulf Province, Purari River Basin, Total PLNG Site 4 (7.3518°S, 145.1904°E; 30 m a.s.l.), collected by S.J. Richards and E. Nagombi on 13 February 2016. Paratypes. None Diagnosis. The new species is assigned to Oreophryne on the basis of the following combination of characters: jaws eleutherognathine; procoracoids present; and clavicles present but not extending to scapulae. We follow Frost (2024) in not accepting the recommendation of Dubois et al. (2021) to synonymise the genus name Oreophryne with Asterophrys. A medium-sized species of Oreophryne (SUL 24.0 mm in the only male) distinguished from congeners by the following unique combination of characters: procoracoid cartilaginous, extending from middle of chest to scapula; head short (HL/SUL 0.27); tympanum small (TyD/ED 0.24); internarial distance about same as eye-naris distance; legs short (TL/SUL 0.38); third and fifth toe same length; terminal disc of third finger about same size as that of fourth toe; toes 2–5 with basal webbing; ventral surfaces in life white with sparse tiny dark grey (RAL 9007) dots; dorsal and lateral surfaces covered with conspicuous pattern of large beige (RAL 1001) and beige-brown (RAL 8024) longitudinal bands; loreal region not black. Advertisement calls last 3–5 s and consist of 6–9 honking notes each with 40–50 pulses; note length 140–190 ms with a dominant frequency of 3.1 kHz. Description of the holotype (Fig. 4A–F). Body slender (Fig. 4A). Head much broader than long (HL/HW 0.76); canthus rostralis rounded; loreal region oblique; snout tip protruding slightly in profile, roundish in dorsal and ventral view; nostrils close to canthus rostralis and near to tip of snout (Fig. 4A); eye diameter longer than eye-naris distance (ED/END 1.45); tympanum small (TyD/ED 0.24), poorly defined; internarial distance approximately same length as eye-naris distance (END/IND 1.05); tongue long and wide, free laterally and posteriorly, posterior margin notched; prepharyngeal ridge wide, with indistinct dermal denticles; vocal slits on both sides of tongue short. Dorsal surfaces smooth with few small, irregularly distributed white-capped tubercles, these visible in life and in preservative. Ventral surfaces slightly granular (Fig. 4B). Legs short (TL/SUL 0.38); fingers without webbing but toes 2–5 with basal webbing; terminal disc on finger 3 slightly wider than that on toe 4 (T4D/F3D 0.93); all discs on fingers and toes with circum-marginal grooves; relative lengths of fingers 3> 4> 2> 1 (Fig. 4E); third toe same length as fifth, relative length of toes 4> 3 = 5> 2> 1 (Fig. 4F); subarticular tubercles on fingers and toes and inner metatarsal tubercle weakly developed. Body measurements and ratios: SUL 24.0; TL 9.2; TaL 6.1; FtL 9.1; T4D 1.4; T1D 0.85; HdL 6.2; F3D 1.5; F1D 1.0; HL 6.5; HW 8.6; END 2.0; IND 1.9; SL 3.4; EST 2.8; ED 2.9; TyD 0.7; TL/SUL 0.38; TaL/SUL 0.25; FtL/ SUL 0.38; T4D/SUL 0.058; T1D/SUL 0.035; HdL/SUL 0.26; F3D/SUL 0.063; F1D/SUL 0.042; T4D/F3D 0.93; T1D/F1D 0.85; HL/SUL 0.27; HW/SUL 0.36; HL/HW 0.76; END/SUL 0.083; IND/SUL 0.079; END/IND 1.05; ED/SUL 0.121; TyD/SUL 0.029; TyD/ED 0.24; SL/SUL 0.142; EST/SUL 0.117. Colour in life. Iris light ivory dorsally and ventrally, yellow-orange (RAL 2000) anteriorly and posteriorly; entire iris with very sparse dark brown veining. Dorsal surfaces predominantly beige-brown; paravertebral surfaces with beige longitudinal bands forming X-shaped figure; a beige, partly interrupted longitudinal band present on flank; tympanum with light ivory spot; inguinal region and posterior thigh orange brown (RAL 8023). Ventral surfaces white covered by sparse tiny dark grey dots (Fig. 4B). Colour in preservative. Dorsal surfaces predominantly clay brown (RAL 8003), light bands and spots ivory (Fig. 4C). Ventral surfaces ivory, dark dots orange brown (RAL 8023), much larger and more numerous in preservative than in life (Fig. 4D). Vocalization. The advertisement call of Oreophryne purari sp. nov. is a series of honking notes (sensu Kraus 2016) (Fig. 5A, B). Two calls of an unvouchered male recorded at an air temperature of 27.7°C at Total PLNG Site 8 (Fig. 5, yellow star; 7.7892°S, 145.2664°E; 5 m a.s.l.) on 12 July 2016 contained 7 notes and one contained 6 notes. Call length varied from 3.17 to 3.97 s, mean 3.58 s. Because of insufficient quality, the note length of one call could not be measured. The length of 13 notes varied from 147–193 ms, mean 165.8 ms, SD 15.0. The length of 11 inter-note intervals varied from 352–572 ms, mean 425.2, SD 73.6 ms. Pulses were sufficiently well defined to count in only 7 notes, with the mean number of pulses per note 42.9, SD 2.2, range 40–46 (corresponding to 238–272 pulses/s). Note repetition rate in three calls varied from 1.76–1.94, mean 1.86 notes/s. All notes start with pulses of low amplitude and longer inter-pulse intervals; their amplitude gradually increases to maximum then drops rapidly towards the end. Terminal pulse intervals are shorter than those at the beginning of the note. The spectrogram shows five pseudoharmonic bands (Fig. 5B) with the dominant band at 3.1 kHz (Fig. 5C). Three additional, unvouchered calls of rather poor quality recorded at the type locality were very similar to the ear to these analysed calls and contained 7, 8 and 9 notes produced at a rate of 1.35–1.75 notes/s lasting a total of 4.2– 5.1 s. One of the calls analysed above has been uploaded to Xeno-Canto (XC964726). Distribution, habitats and habits. Oreophryne purari sp. nov. is known with certainty only from three sites in the Purari River Basin in south-central Papua New Guinea (Fig. 6) where males called at night from perches> 5 m high in lowland alluvial rainforest (Fig. 7). This species appeared to occur at low densities with calling males usually separated by at least 50 m and often by several hundreds of metres, although 2–3 calling males were sometimes ‘clumped’ within a small area (S. Richards, personal observation). Allison et al. (1998) reported an undescribed Oreophryne species (Oreophryne sp. 3) similar to O. loriae from the Lakekamu Basin, approximately 130 km to the southeast of the type locality (Fig. 6) that may also represents this species, but we have been unable to examine that material. The holotype was calling from a Pandanus frond but its position on or in the frond could not be determined. Nothing else is known about this species’ ecology or behaviour. Oreophryne purari sp. nov. occurs in sympatry with at least 14 other microhylid frogs at sites where it was documented in the Purari Basin: Asterophrys slateri, Callulops marmoratus, Ca. taxispilotus, Cophixalus flavopunctatus sp. nov., Coph. hannahae, Copiula derongo, Copi. guttata, Copi. sp. (probably mosbyae), two undescribed Hylophorbus species, Mantophryne lateralis, Oreophryne oviprotector, O.pseudunicolor, Sphenophryne cornuta and Xenorhina lacrimosa. Etymology. The specific epithet is a proper noun in nominative and refers to the Purari River Basin, Gulf Province of Papua New Guinea, where the holotype of the new species was collected. Comparison with other species. Oreophryne purari sp. nov. differs from all other congeners for which calls are known except O. anser Kraus, 2016, O. lemur Kraus, 2016, O. loriae, and O. philosylleptoris Kraus, 2016 by having a “honk” call (sensu Kraus 2016). It can be distinguished from these four species by having a cartilaginous procoracoid extending from the middle of the chest to the scapula (vs. ligamentous connection) and by having shorter shanks (TL/SUL 0.38 vs. TL/SVL 0.40–0.48) and having fifth and third toes of equal length (vs. fifth toe longer than third). Below we further compare the new species with congeners of a similar size that have a cartilaginous procoracoid extending from the middle of the chest to the scapula. Oreophryne purari sp. nov. can be distinguished from O. alticola Zweifel, Cogger & Richards, 2005, O. brevicrus Zweifel, 1956, O. brevirostris Zweifel, Cogger & Richards, 2005, O. geminus Zweifel, Cogger & Richards, 2005, O. habbemensis Zweifel, Cogger & Richards, 2005, and O. terrestris Zweifel, Cogger & Richards, 2005 by its moderately long shanks and well-developed digital discs (vs. very short limbs and poorly-developed digital discs), and arboreal (vs. terrestrial) habits. These six species also have restricted distributions in alpine meadow habitats (Zweifel et al. 2005). It differs from Oreophryne anamiatoi Kraus & Allison, 2009 by lacking (vs. having) a dark face mask, having (vs. lacking) webbing between the toes and that species has a harsh ‘rattling’ call; it is larger than O. asplenicola Günther, 2003, O. notata Zweifel, 2003, O. pseudasplenicola Günther, 2003, and O. streiffeleri Günther & Richards, 2012 (male SUL 24.0 mm vs. male SUL <22.5 mm), and lacks a conspicuous inverted white U- or O-shaped mark on the snout (vs. present), and all of these species have calls comprising a note train of un-pulsed peeping notes; it differs from O. clamata Günther, 2003 in its larger size (male SUL 24.0 mm vs. <21 mm), having webbing between the toes (vs. absent) and that species has calls comprising loud rattling notes; it has shorter shanks than O. crucifer (van Kampen, 1913) (TL/SUL 0.38 vs.0.45) and has light longitudinal bands on the dorsum (vs. absent); The new species has shorter shanks than O. flava Parker, 1934 (TL/SUL 0.38 vs. 0.43–0.45), wider discs on the fourth toe (T4D/SUL 0.058 vs. 0.038 –0.042), a shorter head (HL/SUL 0.27 vs. 0.31–0.34), a shorter internarial distance (IND/SUL 0.079 vs. 0.097 –0.106) and has light bands on the dorsum (vs. absent); it is larger than O. gagneorum Kraus, 2013 (male SUL 24.0 mm vs. SVL 16.3–20.0 mm) with shorter shanks (TL/SUL 0.38 vs. TL/ SVL 0.46–0.59). It differs substantially from the holotype of O.