SAMA R71648 (SJR 14203), adult male, from Rentoul River, Western Province, Papua New Guinea (6.4355°S, 142.5615°E; 380 m a.s.l.), collected on 10-08-2014 by S.J. Richards.

SAMA R71647 (SJR10389), female with ripe eggs, ZMB 91129 (SJR10417) male, Camp 2, upper Strickland River basin, Western Province, Papua New Guinea (5.9018°S, 142.4360°E; 950 m a.s.l.), collected by S.J. Richards on 18-02-2008 and 20-02-2008, respectively; ZMB 91130 (SJR10466) male, Camp 1, upper Strickland River basin, Western Province, Papua New Guinea (5.8078°S, 142.3083°E; 215 m a.s.l.), collected by S.J. Richards on 26-03-2008; SAMA R65069 (SJR10902) and R65070 (SJR10949), males, R65071 (SJR10963), (subadult?) female with scarcely developed eggs and R65072 (SJR10985), juvenile, Gugusu Camp, Muller Range, Western Province (5.7290°S, 142.2630°E; 515 m a.s.l.), all collected by S.J. Richards and C. Dahl between 7–9-09-2009.

SAMA R71649, R71650 (SJR2577, 2582), PNGNM (SJR2571), adult males, Herowana, Eastern Highlands Province, Papua New Guinea (6.6220°S, 145.1962°E; 1,400 m a.s.l.), collected by S.J. Richards between 20 and 24-11-2001.

This species of Xenorhina is characterised by the unique combination of: medium size (SUL of five males 34.5–41.0 mm); vomeropalatines each with one long and acuminate spike; legs moderately long (TL/SUL 0.42–0.46); all fingers without and all toes with expanded discs; eye-naris distance greater than internarial distance (END/IND 1.18–1.48); tympanum diameter smaller than or equal to that of eye (TyD/ED 0.75–1.00); dorsal surfaces in life different tones of brown or blue or a mixture of these colours; ventral surfaces different tones of orange with irregular whitish spots or mouse grey (RAL 7005) with whitish spots and reticulations; advertisement calls uttered in series containing 7–12 single, mournful “hoots” separated by long intervals of about five seconds.

Measurements are summarised in Table 1, a dorsolateral view in life is shown in Fig. 1a and ventral surfaces in life in Fig. 1b. Head broader than long (HL/HW 0.74); snout acuminate from above and below, distinctly protruding in profile; tongue very broad, only its lateral and posterior edges free; prepharyngeal ridge with five roundish denticles; left vomerine spike very well developed, right spike present, but malformed; loreal region oblique, no canthus rostralis; nostrils near tip of snout, directed more lateral than dorsal, visible from above, but not from below; eye-naris distance greater than internarial distance (END/IND 1.18); tympanum visible in life and preservative, its diameter slightly less than that of eye (TyD/ED 0.87); supratympanic fold weakly expressed, extending from behind eye to insertion of fore leg; shank short (TL/SUL 0.42); fingers moderately short, not webbed; tips of all fingers with circum-marginal grooves, all not wider than penultimate phalanges; relative lengths of fingers 3 > 4 = 1 = 2 (Fig. 1c); all toe tips with circum-marginal grooves and wider than penultimate phalanges; toes not webbed, relative lengths 4 > 3 > 5 > 2 > 1 (Fig. 1d); plantar and palmar tubercles (with exception of prominent, oval inner metatarsal tubercle; Fig. 1d), as well as subarticular tubercles scarcely visible. Body laterally with numerous distinct tubercles in life, less prominent in preservative; dorsal surfaces of limbs and middle of dorsum with fewer tubercles, all ventral surfaces smooth; tip of snout with several tiny elevations (especially on underside).

Figure 1. 

Holotype (SAMA R71648) of Xenorhina lacrimosa sp. nov. in life: (a) Dorsolateral view; (b) Ventral view; (c) Volar view of right hand; (d) Thenar view of right foot.

In life, dorsal surfaces of head and anterior portion of body and fore limbs, uniform bluish-brown; remaining dorsal surfaces and flanks a mixture of saffron-yellow (RAL 1017) and blue-grey; tubercles with brown bases and whitish apices concentrated on flanks; body dorsally with light yellow mid-dorsal line that continues on to hind legs; lumbar region with light yellow semi-circular spot (Fig. 1a); vent and adjacent region enclosed within dark brown triangular patch; iris blackish with barely visible golden reticulation; plantar and ventral surfaces of toes predominantly brown, palms and ventral surfaces of fingers predominantly grey and cream; throat, chest, abdomen and ventral surfaces of extremities deep orange (RAL 2011), with some whitish spots (Fig. 1b).

In preservative, dorsal surfaces of head, anterior back and fore limbs signal brown (RAL 8002); other dorsal surfaces ivory with diffuse brownish smears, tubercles with terra brown (RAL 8028) bases and whitish apices; ventral surfaces light ivory (RAL 1015); ivory lumbar spot on left side more clearly pronounced than on right.

Measurements and proportions of most paratypes show limited variation (Table 1). An exception is a juvenile (SAMA R65072) measuring 16.6 mm SUL that exhibits some major deviations in proportions from the remainder of the type series. As these differences are almost certainly due to allometry, measurements of this specimen are disregarded in Table 1. Males and females have the same body size, although some ratios of the adult female (SAMA R71647 differ to a negligible degree (Table 1). The smallest specimen in the series is the just-mentioned adult female with an SUL of “only” 34.3 mm that contains ripe ovarian eggs; the largest specimen in the series is a male (ZMB 91130) with an SUL of 41.0 mm.

Colour of paratypes in life varies considerably. Dorsal surfaces may be uniform blue-brown (SAMA R65070, Fig. 2a), uniform light red-orange similar to RAL 2008 (ZMB 91129, Fig. 2b), bluish on head and lower flanks, but reddish-brown on back and dorsal extremities (ZMB 91130, Fig. 2c) or dark brown with bluish hue on head, body and thighs, but beige on fore limbs, shanks and tarsi (SAMA R71647, Fig. 2d). Colour of ventral surfaces is also highly variable. Some specimens are uniform deep orange or traffic orange (RAL 2009) interspersed with scattered irregular whitish spots (SAMA R65070, Fig. 2e); others are more extensively spotted (ZMB 91129, Fig. 2f) or exhibit a mixture of whitish, orange and brown spots, but with throat and thighs more or less uniform traffic orange (SAMA R65071, Fig. 2g); others exhibit grey-brown ground colour with many irregular whitish spots, some of them interspersed with small irregular red patches (SAMA R71647, Fig. 2h) .

Figure 2. 

Xenorhina lacrimosa sp. nov. paratypes in life. Dorsolateral views: (a) SAMA R65070; (b) ZMB 91129; (c) ZMB 91130; (d) SAMA R71647. Ventral views: (e) SAMA R65070S; (f) ZMB 91129; (g) SAMA R65071; (h) SAMA R71647.

In preservative dorsal surfaces of three specimens predominantly violet, of two specimens copper brown, of one specimen beige and of the juvenile specimen beige-brown; ventral surfaces of three specimens almost completely light ivory, of the four other specimens a light ivory ground colour with a brown-beige pattern of various extent. All paratypes, except SAMA R71647, have a light ivory mid-dorsal line and all specimens including the juvenile have a greyish snout tip. None of the paratypes has a clearly pronounced lumbar spot in life or in preservative.

Most records of Xenorhina lacrimosa sp. nov. are from lowland and foothill forest in south-central Papua New Guinea (Fig. 8), where this species appears to have a broad distribution at altitudes ranging from near sea level around Kopi to at least 950 m a.s.l. We also refer several specimens from Herowana Village at 1,400 m a.s.l. (the most easterly location in Fig. 8) to this species pending confirmation of genetic relationships. Males called at night, normally after rain, either from within the leaf litter on the forest floor or down to several centimetres depth in the humus layer beneath the litter.

One call series from SAMA R71648 (holotype), one from ZMB 91129 (paratype), one from SAMA R65069 (paratype) and four from ZMB 91130 (paratype) recorded at air temperatures of 21.2–25.5 °C were analysed. Each call is a single, unpulsed mournful note that is always produced in a series, during which both volume and pitch increase gradually between first and last call (Fig. 3a). Despite some variation in recording temperature, all recorded calls are extremely similar, so they were pooled for analyses. Call series last 26.4–60.4 s (mean 40.0 ± 11.8 s, n = 7), with 7–12 calls/series (mean 9.0 ± 2.2, n = 7) produced at a rate of 0.20–0.27 calls/s (mean 0.23 ± 0.02). Call length is 141–231 ms (mean 193.5 ± 19.1 ms, n = 63) and first and last call in a series are often the shortest; inter-call interval length is 2.8–8.0 s. (mean 4.8 ± 1.0 s, n = 56). Calls start abruptly at high amplitude that rises quickly to a maximum, then decreases gradually until termination of call (Fig. 3b). All calls have 5–7 harmonics (Fig. 3c and 3d)). Dominant frequency may be carried by a second harmonic (i.e. first two calls of series from holotype, with peak at 1.2 kHz) or by first harmonic (all other calls, with peaks increasing from 0.7 kHz in third call to 0.8 kHz in last call in the series. Frequency declines at end of each call in second half of series (Fig. 3c).

Figure 3. 

(a) Oscillogram of a complete advertisement call series with seven calls from the holotype of Xenorhina lacrimosa sp. nov.; (b) oscillogram and (c) spectrogram of the penultimate call of the call series shown on Fig. 3a; (d) amplitude spectrum of the call on (b.) and (c.).

The specific epithet lacrimosa is a Latin adjective in female gender; translated literally it means “tearful”, but it is also translated as “lamentable voice” and refers to the mournful sounding advertisement call of the new species.

We compare Xenorhina lacrimosa sp. nov. with all congeners of a similar size (SUL 30–43 mm) that have a single spike on each vomeropalatine bone.

Xenorhina fuscigula (Blum & Menzies, 1989) has hind legs shorter (TL/SVL < 0.40 vs. > 0.40 in Xenorhina lacrimosa sp. nov.), eye-naris distance shorter (END/SVL 0.064–0.074 vs. 0.072–0.099), inner metatarsal tubercle absent (vs. present), ventral surfaces black (vs. orange-red or grey-brown) and call consisting of a single long note (vs. a series of 7–12 notes = calls).

Xenorhina huon (Blum & Menzies, 1989) is smaller (SUL to 32 mm vs. 34.3–41.0 mm), with hind legs shorter (TL/SUL < 0.40 vs. > 0.40), internarial distance greater (0.064–0.081 vs. 0.050–0.067), eyes larger (ED/SVL 0.070–0.091 vs. 0.060–0.073) and ventral surfaces with dark flecking (vs. ventral surfaces with no or sparse brownish reticulation).

Xenorhina subcrocea (Menzies & Tyler, 1977) is smaller (SUL 30.5–33.3 mm vs. 34.3–41.0 mm), with hind legs longer (TL/SVL > 0.46 vs. < 0.46 in Xenorhina lacrimosa sp. nov.) and ventral surfaces with dark reticulation (vs. without dark reticulation); call length is shorter 64–69 ms (vs. 141–231 ms), with inter-call interval also much shorter (154–285 ms vs. 2.8–8.0 s).

Xenorhina zweifeli (Kraus & Allison, 2002) is about the same size and has similar body ratios. It differs by having a conspicuous dark brown supratympanic stripe (vs. absent in Xenorhina lacrimosa sp. nov.) and in several aspects of its advertisement calls. Xenorhina zweifeli utters single calls at irregular intervals, with two or three calls sometimes produced in quick succession (Kraus and Allison 2002), during both day and early evening. In contrast, Xenorhina lacrimosa sp. nov. always produces calls in discrete series of at least seven relatively evenly spaced calls of increasing pitch and volume; calls are never produced in quick succession and males always call at night. Other differences include: mean length of calls produced by holotype of X. zweifeli is 310 ms (Kraus and Allison 2002) (vs. mean length of calls from Xenorhina lacrimosa sp. nov. 194 ms); the fundamental frequency of zweifeli calls is at 610 Hz and dominant frequency at 1910 Hz (third harmonic), (vs. fundamental and dominant frequency of Xenorhina lacrimosa sp. nov., both at 800 Hz); amplitude of X. zweifeli calls rises more slowly than that of lacrimosa calls and all harmonics are frequency modulated, with pitch decreasing during entire length of call (vs. frequency modulation only occurring at end of harmonics in Xenorhina lacrimosa sp. nov. calls). Moreover, X. zweifeli occurs only on two mountain ranges in northern Papua New Guinea, while Xenorhina lacrimosa sp. nov. lives predominantly in the lowlands and foothills of southern Papua New Guinea. Therefore, the known distributions of the two species are separated by a major biogeographic barrier, New Guinea’s central cordillera.

SAMA R71645 (SJR 10418), adult male, from Camp 2, upper Strickland River basin, Western Province, Papua New Guinea (5.9018°S, 142.4360°E; 950 m a.s.l.), collected by S.J. Richards on 20-02-2008

This species of Xenorhina is characterised by the unique combination of: very small body size (SUL of the only adult male 16.7 mm); vomeropalatines each with a single triangular spike; legs moderately long (TL/SUL 0.46); all fingers and first toe without and toes 2–5 with expanded discs; eye-naris distance greater than internarial distance (END/IND 1.27); tympanum smaller than eye (TyD/ED 0.77); dorsal surfaces in life beige brown (RAL 8024) with darker areas on upper flanks, in middle of back and on neck; lower flanks with whitish spots and reticulations and some irregular dark brown flecks; supratympanic area with dark brown fleck; ventral surfaces off-white with extensive blackish-brown reticulation. Advertisement calls in series containing about 30 soft “popping” calls of 30–40 ms duration, produced at a rate of 6.8–6.9 calls/s.

Measurements and ratios are presented in Table 2. Body squat (Fig. 4a and b), head broader than long (HL/HW 0.84); snout strongly acuminate from above and below and protruding in profile; tongue broad, only its lateral and posterior edges free; prepharyngeal ridge without denticles; a single triangular spike of moderate size on each vomeropalatine; loreal region oblique, no canthus rostralis; nostrils near tip of snout, directed dorsolaterally, visible from above, but not from below; eye-naris distance greater than internarial distance (END/IND 1.27); greater part of tympanum visible in life and preservative, its diameter smaller than that of eye (TyD/ED 0.77); supratympanic fold short, not contacting posterior edge of eye and not reaching insertion of fore leg; shank of moderate length (TL/SUL 0.46); fingers moderately short, not webbed; tips of fingers not wider than penultimate phalanges, all with circum-marginal grooves that extend along entire length of digits, relative lengths of fingers 3 > 4 > 2 = 1 (Fig. 4c); all toe tips with circum-marginal grooves, all tips, except that of toe 1 wider than penultimate phalanges; toes not webbed, relative lengths 4 > 3 > 5 > 2 > 1 (Fig. 4d); plantar and palmar tubercles (with exception of small, but prominent inner metatarsal tubercle), as well as subarticular tubercles scarcely visible. Dorsal surfaces with only a few tubercles and a raised mid-dorsal ridge, ventral surfaces smooth (Fig. 4b).

Figure 4. 

Holotype (SAMA R71645) of Xenorhina perexigua sp. nov. in life: (a) Dorsolateral view; (b) Ventral view; (c) Volar view of right hand; (d) Thenar view of right foot.

In life, dorsal surfaces beige brown with darker areas on upper flanks, in middle of back and in scapular region (Fig. 4a); lower flanks with whitish spots and whitish reticulations and three (left side of body) or four (right side of body) irregular dark brown flecks which merge with dark brown reticulum of abdomen; supratympanic area with conspicuous dark brown fleck; all ventral surfaces light grey with dense dark brown reticulations (Fig. 4b); lumbar spot absent; vent and adjacent areas of thighs enclosed in large, triangular dark brown patch, borders of which disintegrate ventrally; outer margin of iris blackish, inner margin golden.

In preservative, dorsal surfaces reddish-brown, flanks with dark irregular spots and supratympanic region with large, dark brown fleck; ventral surfaces ivory-white with brown beige (RAL 1011) reticulum; large ivory-white area between eye and insertion of fore-leg present (not evident in life).

Xenorhina perexigua sp. nov. is known only from one locality, in hill forest at an altitude of 950 m a.s.l. in the upper Strickland River basin of south-western Papua New Guinea (Fig. 8). The holotype was calling from within leaf litter on the forest floor at night during rain.

Two call series, produced by the holotype (SAMA R71645) at an air temperature of 21.2 °C, were analysed. Each call is a single soft, unpulsed “pop” note uttered in rapid succession (Fig. 5a). The two series lasted 4.1 s and 4.5 s and contained 28 and 31 calls produced at a rate of 6.8 and 6.9 calls/s. Call length 29–42 ms (mean 34.6 ± 3.6 ms, n = 59) and inter-call interval 101–195 ms (mean 115.0 ± 17.1 ms, n = 57). While calls are of approximately equal length throughout each series, inter-call intervals are slightly longer at the end of call series than at the beginning. Volume of calls increases during course of series, as is typical for many Xenorhina species. Calls start abruptly at high amplitude, which then decreases at an irregular rate until the end of each call (Fig. 5a). The start of each call also has a broad frequency range that drops rapidly to a more narrowly defined, frequency-modulated band (Fig. 5b). Fundamental and dominant frequency peak at 1.4 kHz (Fig. 5c).

Figure 5. 

(a) Oscillogram and (b) Spectrogram of the last six calls of a call series containing 31 calls from the holotype of Xenorhina perexigua sp. nov.; (c) Amplitude spectrum of an advertisement call from the holotype of X. perexigua sp. nov.

The specific epithet perexigua is a Latin adjective of feminine gender, meaning very small (translation of perexiguus, -a, -um in the Dictionarium latino-germanicum means “sehr klein”) and refers to the diminutive size of the new species.

Although this species is represented by only a single specimen, it is an adult male of very small size (16.7 SUL mm) and, given knowledge about the size ranges of congeners, its SUL is unlikely to exceed 25 mm. We, therefore, compare Xenorhina perexigua sp. nov. with all congeners of a similar size (SUL 15–25 mm) that have a single spike on each vomeropalatine.

Xenorhina anorbis (Blum & Menzies, 1989) is larger (holotype is an adult male with SVL of 21.3 mm [range of type series 21.3–23.4 mm but sex of other specimens not specified] vs. SUL 16.7 mm in one male), has hind legs shorter (TL/SVL < 0.38 vs. > 0.38) and discs of fingers and toes not wider than penultimate phalanges (vs. discs on toes 2–5 clearly wider than penultimate phalanges in Xenorhina perexigua sp. nov.).

Xenorhina brachyrhyncha Kraus, 2011 appears to be larger (two adult females with SVL 21.2 and 22.8 mm vs. SUL 16.7 mm in one male), with snout blunt in dorsal and ventral view (vs. strongly acuminate), head wider and longer (HW/SVL 0.35–0.38 vs. 0.32 and HL/SVL 0.30–0.32 vs. 0.28) with much lower ratio of eye-naris distance to internarial distance (END/IND 1.06–1.13 in X. brachyrhyncha vs. 1.27 in Xenorhina perexigua sp. nov.); differences in colour include lack of a dark supratympanic spot in X. brachyrhyncha (vs. present in Xenorhina perexigua sp. nov.) and less pronounced dark reticulation on all ventral surfaces.

Xenorhina lanthanites is larger SUL 21.3–22.4 mm vs. SUL 16.7 mm), with tips of toes wider than penultimate phalanges only on 4^th toe (vs. toes 2–5 with expanded terminal discs); ratio of END/IND lower (0.94–1.20 vs. 1.27); and advertisement call series much longer, lasting up to more than one minute (vs. < 5 s) with average call length of 121 ms (vs. 35 ms in Xenorhina perexigua sp. nov.), dominant frequency of about 1.0 kHz (vs. 1.4 kHz) and call repetition rate of 1–2 calls/s (vs. 6.8–6.9 calls/s).

Although it is known from just one specimen, it is an adult male suggesting that Xenorhina perexigua sp. nov. is amongst the smallest known members of the genus. Only one other species, X. bouwensi, may be smaller than Xenorhina perexigua sp. nov., but it can be immediately distinguished from the new species by its lacking odontoid spikes on the vomeropalatines.

SAMA R71644 (SJR 14202), adult male, from Rentoul River, Western Province, Papua New Guinea (6.4355°S, 142.5615°E; 380 m a.s.l.), collected on 11-08-2014 by S.J. Richards and K. Aplin.

SAMA R60217 (SJR 3223), adult male, Darai Plateau, Gulf Province, Papua New Guinea (7.1295°S, 143.6134°E; 435 m a.s.l.), collected on 1-08-2003 by S.J. Richards.

This species of Xenorhina is characterised by the unique combination of: small size (SUL of two adult males 20.3 and 21.2 mm); vomeropalatines each with a single moderately developed triangular vomerine spike; legs of medium length (TL/SUL 0.44 in both specimens); all fingers without and all toes with, expanded terminal discs; tips of all fingers and toes with circum-marginal grooves, all grooves extending at least partly along digits; head short (HL/SUL 0.26 in both specimens); eye-naris distance greater than internarial distance (END/IND 1.33 in both specimens); dorsal surfaces in life brown-beige (RAL 1011) or grey-brown; ventral surfaces ivory-white with extensive pale brown (RAL 8025) reticulation; mid-dorsal line and lumbar spots absent; advertisement calls uttered in series lasting 4–9 s, containing 10–30 “piping” calls, each 56–93 ms duration with repetition rate of 2.5–3.6 calls/s.

Measurements are summarised in Table 3. Body squat (Fig. 6a and b), head broader than long (HL/HW 0.83); snout short (HL/SUL 0.26), strongly acuminate from above and below, protruding in profile; tongue broad, only its lateral edges and posterior lobes free; prepharyngeal ridge with few tiny denticles; vomerine spikes triangular and of moderate size; loreal region oblique, canthus rostralis absent; nostrils near tip of snout, directed more laterally than dorsally, visible from above, but not from below; eye-naris distance significantly greater than internarial distance (END/IND 1.33); tympanum nearly as large as eye (TyD/ED 0.92); supratympanic fold weakly expressed, not reaching eye or insertion of fore leg; shank moderately long (TL/SUL 0.44); fingers moderately short, not webbed, all fingers without and all toes with expanded terminal discs; circum-marginal grooves on all fingers and all toes, extending at least partly along most digits; head short (HL/SUL 0.26); eye-naris distance greater than internarial distance (END/IND 1.33); tympanum slightly larger than half the size of eye (TyD/ED 0.59); relative lengths of fingers 3 > 4 = 2 = 1 (Fig. 6c); toes not webbed, relative lengths 4 > 3 > 5 > 2 > 1 (Fig. 6d); plantar and palmar tubercles, as well as subarticular tubercles, not clearly demarcated, with the exception of small, but prominently raised inner metatarsal tubercle (Fig. 6d). Dorsolateral surfaces of body and dorsal surfaces of shanks with some tubercles, more conspicuous in life than in preservative; ventral surfaces smooth; tip of snout lighter than surrounding skin, with some tiny depressions.

Figure 6. 

Holotype (SAMA R71644) of X. pohleorum sp. nov. in life: (a) Dorsolateral view; (b) Ventral view; (c) Volar view of right hand; (d) Thenar view of right foot.

In life, dorsal surfaces brown beige (RAL 1011); lumbar spots and mid-dorsal line absent; tubercles with whitish apices concentrated on upper flanks; lower flanks, lateral surfaces of head and anterior hind limbs off-white with conspicuous fawn (RAL 8007) reticulum; snout tip window grey (RAL 7040); iris blackish with few golden specks (Fig. 6a); ventral surfaces pearl-white (RAL 1013) with dusky pink (RAL 3014) reticulum and irregular pearl-white spots; throat dusky pink with only a few whitish spots (Fig. 6b).

In preservative, ground colour of dorsal surfaces of head, back and hind limbs fawn brown (RAL 8007) with some inconspicuous darker areas; head less densely pigmented than adjacent neck; ground colour of dorsal surfaces of fore limbs and anterior hind limbs beige (RAL 1001) with conspicuous terra-brown strikes and reticula; rear of thighs predominantly terra-brown with a few whitish spots below and small blackish area around vent; ventral surfaces fawn-brown with conspicuous pearl-white spots; throat and middle of chest least spotted.

Measurements and body ratios of paratype are similar to holotype (Table 3). Dorsal surfaces more tubercular in life (Fig. 7), but in preservative, lateral surfaces with fewer tubercles; colour of dorsal surfaces in life a mixture of indistinct lighter and darker grey-brown flecks, lower lateral surfaces of body and upper arms beige-brown (RAL 8024) with off-white spots and ventral surfaces beige-brown with off-white spots. Dorsal surfaces in preservative beige with signal brown (RAL 8002) spots, stripes and reticula; ventral surfaces in preservative paler than holotype, light ivory (RAL 1015) with scarcely visible brownish network.

Figure 7. 

Paratype SAMA R60217 of X. pohleorum sp. nov. in life.

Xenorhina pohleorum sp. nov. is known from two localities approximately 140 km apart in the lowland rainforests of Gulf and Western Provinces in south-central Papua New Guinea (Fig. 8), where males called from under the litter or within the humus layer, at night during rain.

Figure 8. 

Map of Papua New Guinea showing the known distributions of X. lacrimosa sp. nov. (blue circles), X. perexigua sp. nov. (yellow triangle) and X. pohleorum sp. nov. (red squares). Arrows indicate the type localities.

Advertisement call is a single short, unpulsed and melodic “piping” note and is always uttered in series. Call length and inter-call interval are variable, but call intervals are always much shorter than the interval between call series. Due to some differences in call features, we analysed five call series from the holotype (SAMA R71644) recorded at an air temperature of 24 °C separately from seven call series produced by the paratype (SAMA R60217) at an air temperature of 22 °C. Call series produced by the holotype last 3.6–8.8 s (mean 5.8 ± 1.8 s) and contain 13–28 calls (mean 18.2 ± 5.6) produced at a rate of 2.55–3.61 calls/s (mean 3.22 ± 0.41, n = 5). Call length is 56–93 ms (mean 74.5 ± 8.5 ms, n = 91) and length of call intervals is 139–528 ms (mean 253.4 ± 71.7 ms, n = 86). Calls start abruptly at maximum or almost maximum amplitude which then decreases at an irregular rate until end of call (Fig. 9a). Fundamental and dominant frequencies are at 1.5 kHz and the only upper harmonic (at 3.0 kHz) has much less energy (Fig. 9b and 9c). Frequency of calls is weakly modulated with a slight increase over the duration of the call. A number of calls were uttered in exact antiphony with calls from an unvouchered specimen (Fig. 9d and 9e).

Figure 9. 

(a) Oscillogram; (b) Spectrogram and (c) Amplitude spectrum of 10 consecutive advertisement calls from a longer series produced by the holotype of Xenorhina pohleorum sp. nov; (d) Oscillogram and (e) Spectrogram of six advertisement calls from the holotype of X. pohleorum sp. nov. (higher volume) are answered in exact antiphony by an unvouchered male (lower volume).

Calls of the paratype (SAMA R60217) are similar to those of the holotype, but call series generally contain fewer calls (10–15, mean 12.9 ± 1.77, n = 7, vs. 13–28 mean 18.2; see above) and so are shorter (3.4–5.4 s, mean 4.6 ± 0.72 s, n = 7 vs. 3.6–8.8 s, mean 5.8 ± 1.8 s), although there is some overlap. Calls of the paratype are also slightly longer (66–98 ms, mean 88.4 ± 4.8 ms, n = 89 vs. 56–93 ms, mean 74.5). Other structural parameters of calls from the paratype fall within the range produced by the holotype: inter-call intervals 234–408 ms (mean 290.0 ± 31.1 ms, n = 83) and mean repetition rate 2.73–3.0 calls/s (mean 2.83 ± 0.10, range, n = 7). Calls of the holotype do not show the typical increase in volume and pitch that is typical of the series produced by the paratype. However, the holotype was calling within a group of closely adjacent males and exhibited antiphonal calling behaviour (Fig. 9d and 9e). It cannot be discounted that the slight differences noted between calls of holotype and paratype were a result of their different calling situations (alone vs. within a chorus).

The specific epithet pohleorum is the Latinised patronymic adjective in genitive plural derived from the family name Pohle. It is to recognise a very long-lasting friendship of the senior author with Sybille and Claus Pohle from Berlin.

We compare Xenorhina pohleorum sp. nov. with all congeners of a similar size (SUL 18–25 mm) that have a single spike on each vomeropalatine.

Xenorhina anorbis has hind legs shorter (TL/SVL < 0.38 vs. > 0.38) and fingers and toes without expanded terminal discs (vs. enlarged discs on all toes in Xenorhina pohleorum sp. nov.).

Xenorhina brachyrhyncha has legs longer (TL/SVL 0.46–0.49 vs. twice 0.44), head longer (HL/SVL 0.30–0.32 vs. twice 0.26) and broader (HW/SVL 0.35–0.38 vs. 0.31–0.32), with END/IND ratio lower (1.06–1.13 vs. 1.31–1.33).

Xenorhina lanthanites has expanded disc only on 4^th toe (vs. on all toes), head broader (HW/SVL 0.35–0.37 vs. 0.31–0.32), eyes larger (ED/SUL 0.071–0.081 vs. 0.057–0.064), END/IND ratio lower (0.94–1.20 vs. 1.31–1.33) and advertisement call series much longer (up to more than one minute vs. less than 10 seconds).

Xenorhina mehelyi appears to be much larger (SVL 20.7–35.2 mm vs. 20.3–21.2 mm); although the sex (or state of maturity) of previously reported specimens is unknown, with a male SUL of 20.3–21.2 mm, it is unlikely that Xenorhina pohleorum sp. nov. of either sex will approach the upper size limit reported for X. mehelyi. Xenorhina mehelyi also has eyes larger (ED/SVL 0.067–0.079 vs. 0.057–0.064) and different advertisement calls. Mean call interval 1.5 s, (vs. 0.25 s) and mean call rate 0.60 calls/s (vs. 3.2 calls/s); calls are also longer (mean 140 ms vs. 74.5 ms) and have a much lower dominant frequency (0.88 kHz vs. 1.5 kHz) (Blum and Menzies 1989).

Xenorhina perexigua is smaller than Xenorhina pohleorum sp. nov. (males 16.7 mm vs. 20.3–21.2 mm SUL). Some body ratios also differ (Tables 2 and 3), but sample sizes are too small for robust comparisons. However, substantial differences in advertisement calls support recognition of Xenorhina pohleorum sp. nov. as a distinct species: calls of Xenorhina perexigua sp. nov. are shorter (29–42 ms vs. 56–93 ms), there are more calls/series (28–31 vs. 10-28 calls) and inter-call intervals are shorter (101–195 ms vs. 139–528 ms), so the call rate is twice as fast in Xenorhina perexigua sp. nov. (6.8–6.9 calls/s vs. 2.6–3.6 calls/s). The substantially greater call rate of Xenorhina perexigua sp. nov. (double that of Xenorhina pohleorum sp. nov.) cannot be attributed to differences in temperature because the recording temperature for the former was lower than that of latter, which should reduce, not increase, the call rate.

Xenorhina schiefenhoeveli (Blum & Menzies, 1989) is larger (SVL 26.7–30.7 mm vs. 20.3–21.2 mm) and its call series lasts more than 100 s (vs. not more than 10 s in Xenorhina pohleorum sp. nov.), with call intervals of more than 700 ms (vs. < 528 ms).

Xenorhina tumulus (Blum & Menzies, 1989) is larger (male SVL more than 26.0 mm vs. less than 22.0 mm), has ventral surfaces of toes with striped pattern (vs. absent) and abdomen partly pink or red (vs. pearl-white with dusky pink reticulum and irregular pearl-white spots); and supratympanic ridge is absent (vs. present). Advertisement calls of X. tumulus differ in, amongst other characters, having a much lower dominant frequency (0.9 kHz vs. 1.5 kHz). Xenorhina tumulus is known only from an elevation of about 1500 m a.s.l. in the Adelbert Range, an isolated mountain range near the north coast of Papua New Guinea, while Xenorhina pohleorum sp. nov. is known only from altitudes of around 400 m on the southern side of New Guinea’s central cordillera.

SAMA R71651 (SJR 209047), adult male, from Ok Menga near Tabubil, Western Province, Papua New Guinea (5.3205°S, 141.3049°E; 620 m a.s.l.), collected by S.J. Richards, M. Cunningham and A. Dennis on 14-11-1994.

ZMB 91131 (SJR 209051), PNGNM (SJR209052), SAMA R71652 (SJR209053), same details as for holotype.

This species of Xenorhina is characterised by the unique combination of: moderately small size (males 20.7–23.5 mm SUL); vomeropalatines each with one moderately developed triangular vomerine spike; legs moderately short (TL/SUL 0.40–0.44); all fingers and first toe without and toes 2–5 with, expanded terminal discs; tips of all fingers and toes with circum-marginal grooves that extend, at least partially, along most digits; head short (HL/SUL 0.26–0.28), eye-naris distance much greater than internarial distance (END/IND 1.36–1.54); tympanum approximately 2/3 size of eye (TyD/ED 0.63–0.69). Dorsal surfaces in life reddish-brown, covered extensively with small, white-tipped tubercles, lower flanks with larger off-white spots; back with faint yellowish mid-dorsal line. Advertisement calls uttered in series containing less than 10 short, extremely soft “piping” calls of 133–162 ms duration, produced at a rate of 2.5–3.0 calls/s.

Measurements are summarised in Table 4, a dorsolateral view in life is shown in Fig. 10a and ventral surfaces in life in Fig. 10b. Head broader than long (HL/HW 0.81); snout short (HL/SUL 0.27), strongly acuminate from above and below, protruding in profile; tongue long, broad, only its lateral and posterior edges free; prepharyngeal ridge with eight small denticles; vomerine spikes triangular and of moderate size; loreal region oblique, no canthus rostralis; nostrils near tip of snout, directed dorsolaterally, visible from above, but not from below; eye-naris distance significantly greater than internarial distance (END/IND 1.46); borders of tympanum poorly defined in life and preservative, its diameter 2/3 that of eye (TyD/ED 0.67); supratympanic fold not reaching posterior edge of eye or insertion of fore-leg; shank short (TL/SUL 0.40); fingers moderately short, not webbed; all fingers and first toe without and toes 2–5 with, expanded terminal discs; circum-marginal grooves on tips of all fingers and toes, extending at least partly along most digits; relative lengths of fingers 3 > 4 = 2 = 1 (Fig. 10c); toes not webbed, relative lengths 4 > 3 > 5 > 2 > 1 (Fig. 10d); plantar and palmar tubercles as well as subarticular tubercles poorly defined. Dorsal surfaces with scattered low tubercles and a slightly raised yellowish mid-dorsal ridge, ventral surfaces smooth.

Figure 10. 

Holotype (SAMA R71651) of Xenorhina thiekeorum sp. nov. (a) Dorsolateral view in life; (b) Ventral view, (c) Volar view of right hand and (d) Thenar view of right foot of preserved specimen.

In life, dorsal surfaces brown beige (RAL 1011) with irregularly shaped, indistinct lighter markings in lumbar region and narrow, pale mid-dorsal line; dorsum with numerous small, white-tipped tubercles; lower flanks and anterior and posterior of tympana with whitish spots; dorsal surfaces of limbs and dorsal edge of tympana with few dark brown spots and/or streaks; iris blackish with scarcely visible golden veins and solid golden inner margin. Colour of ventral surfaces in life was not documented.

In preservative, ground colour of dorsal surfaces reddish-brown; dorsolateral surfaces with conspicuous blackish-brown spots, mostly associated with white-tipped tubercles; extremities and anterior back with lighter brown flecks than those on dorsolateral surfaces; solid reddish-brown areas of back merge on lower flanks into ivory-white ground colour of ventral surfaces, which are covered by a dense orange-brown reticulum.

Measurements of the type series are summarised in Table 4. Ground colour of dorsal surfaces in preservative is the same in all types (including holotype), except SAMA R71652 which is slightly paler; number and intensity of brown dorsal and lateral spots varies slightly. Ventral surfaces and rear of thighs in all frogs show a more or less dense orange brown reticulum on ivory-white ground.

Xenorhina thiekeorum sp. nov. is known only from the type locality adjacent to the Ok Menga (“Ok” = River in the local Min language), at an altitude of 620 m a.s.l. in the foothills of the Hindenburg Range, Ok Tedi headwaters in Western Province, Papua New Guinea (Fig. 16). The frogs were calling from 1–3 cm beneath the soil surface at the base of ginger plants after rain at night. Unlike many Xenorhina species, the distribution of calling males was “clumped”; all four frogs were detected by their calls within an area of approximately 4 m² of wet hill forest, while none was heard calling in apparently suitable adjacent forest.

Three call series from the holotype (SAMA R71651) recorded at an air temperature of 22.5 °C were analysed, but due to poor recording quality, the lengths of calls and length of call intervals could not be measured for one of these series. Calls are a single, unpulsed “piping” notes produced in short series. Calls are extremely soft and were barely audible to the human ear. Call series contain 6–8 calls produced at a rate of 2.5–3.0 calls/s and last 2.0–2.9 s (mean 2.3 s) (Fig. 11a and b). Call length is 133–162 ms (mean 143.4 ± 8.8 ms, n = 14) and length of call intervals is 168–376 ms (mean 250.6 ± 51.8 ms, n = 12). There are four harmonics with frequency peaks at 1.1, 2.2, 3.3 and 4.4 kHz; the third harmonic carries the dominant frequency (Fig. 11c). Volume and pitch of calls both increase marginally during the course of call series.

Figure 11. 

(a) Oscillogram; (b) Spectrogram and (c) amplitude spectrum of a series of six calls from the holotype of Xenorhina thiekeorum sp. nov.

The specific epithet thiekeorum is the Latinised patronymic adjective in genitive plural of the family name Thieke. It is given to recognise a very long-lasting friendship of the senior author with Heidi and Ulrich (Uli) Thieke from Berlin.

We compare Xenorhina thiekeorum sp. nov. with all congeners of a similar size (males with SUL ~ 18–25 mm) that have a single spike on each vomeropalatine.

Xenorhina anorbis has hind legs shorter (TL/SVL < 0.38 vs. > 0.38), digital discs on toes absent (vs. expanded discs present on toes 2–5) and END/IND ratio lower (1.26–1.32 vs. 1.36–1.54).

Xenorhina brachyrhyncha has legs longer (TL/SVL 0.46–0.49 vs. 0.40–0.44), head longer (HL/SVL 0.30–0.32 vs. 0.26–0.28) and broader (HW/SVL 0.35–0.38 vs. 0.32–0.33) and END/IND ratio much lower (1.06–1.13 vs. 1.36–1.54).

Xenorhina lanthanites has legs longer (TL/SUL 0.44–0.46 vs. 0.40–0.44), dilated disc only on 4^th toe (vs. dilated discs on toes 2–5), T4D/F3D ratio higher (1.50–2.0 vs. 1.17–1.40), END/IND ratio lower (0.94–1.20 vs. 1.36–1.54) and advertisement call series much longer (up to more than one minute vs. a few seconds), with call intervals longer (397–896 ms vs. 168–376 ms) and repetition rate lower (1.2–1.8 vs. 2.5–3.0 calls/s).

Xenorhina mehelyi is probably much larger (SVL to > 35 mm vs. males 20.7–23.5 mm), internarial distance greater (IND/SVL 0.061–0.077 vs. 0.055–0.062) and has different advertisement calls: call series of X. mehelyi contain > 10 calls produced at a rate of 0.60 calls/s (vs. < 10 calls produced at a rate of 2.75 calls/s in Xenorhina thiekeorum sp. nov.); and dominant frequency is 0.88 kHz in X. mehelyi (vs. 3.3 kHz in X. thiekeorum).

Xenorhina perexigua is smaller (16.7 mm vs. 20.7–23.5 mm SUL) and many body ratios differ from Xenorhina thiekeorum sp. nov. (Tables 2 and 4), but small sample sizes preclude robust comparisons of body ratios. Advertisement calls differ as follows: Xenorhina perexigua sp. nov. utters calls in series lasting more than 4 s, containing about 30 calls produced at rate of 6.8–6.9 calls/s (vs. call series lasting 2–3 s containing just 6–8 calls produced at rate of 2.5–3.0 calls/s); call length of Xenorhina perexigua sp. nov. is also much shorter (29–42 ms vs. 133–162 ms in Xenorhina thiekeorum sp. nov.).

Xenorhina pohleorum has fingers shorter (F3L/SUL 0.178–0.179 vs. 0.187–0.212), disc on third finger smaller (F3D/SUL 0.019–0.020 vs. 0.022–0.027), T4D/F3D ratio higher (1.75 vs. 1.17–1.40), END/IND ratio lower (1.31–1.33 vs. 1.36–1.54), eyes smaller (ED/SUL 0.057–0.064 vs. 0.068–0.078) and TyD/ED ratio higher (0.75–0.92 vs. 0.63–0.69). Moreover, call length of Xenorhina pohleorum sp. nov. is much shorter (~ 70–90 ms vs. 130–150 ms).

Xenorhina schiefenhoeveli is larger (SVL 26.7–30.7 mm vs. 20.7–23.5 mm), with ratio of END/IND lower (1.04–1.33 vs. 1.36–1.54) and different calls; call series last > 100 s (vs. 2–3 s in Xenorhina thiekeorum sp. nov.), with call intervals > 700 ms (vs. less than 400 ms).

Xenorhina tumulus is larger (SVL > 26.0 mm vs. < 24.0 mm), with internarial distance relatively longer (IND/SVL 0.063–0.069 vs. 0.055–0.062), distance between eye and naris relatively shorter (END/SVL 0.073–0.081 vs. 0.082–0.085), END/IND ratio lower (1.11–1.28 vs. 1.36–1.54) and call length shorter (60–70 ms vs. 133–162 ms).

SAMA R71653 (SJR 10372), adult male, from Baia River, Western Province, Papua New Guinea (6.0205°S, 142.5473°E; 330 m a.s.l.), collected by S.J. Richards on 15-02-2008.

PNGNM (FN SJR10373), adult male, same details as for holotype; SAMA R71654 (FN SJR10400), adult male, from Camp 2, upper Strickland River basin, Western Province, Papua New Guinea (5.9018°S, 142.4360°E; 950 m a.s.l.), collected by S.J. Richards on 19-02-2008; ZMB 91132 (FN SJR14220), adult male, Rentoul River, Western Province, Papua New Guinea (6.4355°S, 142.5615°E; 380 m a.s.l.), collected on 14-08-2014 by S.J. Richards; SAMA R65073 (FN SJR10948), adult male, Gugusu Camp, Muller Range, Western Province (5.7290°S, 142.2630°E; 515 m a.s.l.), collected by S.J. Richards and C. Dahl on 8-09-2009.

This species of Xenorhina is characterised by the unique combination of: medium size (males 32.0–35.7 mm SUL); vomeropalatines each with one strongly developed triangular spike; legs moderately long (TL/SUL 0.44–0.47); all fingers tips without and all toe tips with expanded discs; eye-naris distance greater than internarial distance (END/IND 1.19–1.37); tympanum same size as, or slightly smaller than, eye (TyD/ED 0.80–1.00). Dorsal surfaces in life different shades of grey or brown; ventral surfaces different shades of red or yellow, throat and chest with some darker flecks. Advertisement calls uttered in series lasting 10–20 s and containing 20–40 calls; length of calls 60–100 ms, dominant frequency at 0.5 kHz.

Measurements are summarised in Table 5, a dorsolateral view in life is shown in Fig. 12a and ventral surfaces in life in Fig. 12b. Head broader than long (HL/HW 0.84); snout acuminate from above and below and distinctly protruding in profile; vomerine spikes strongly developed; prepharyngeal ridge clearly expressed with about 14 denticles; tongue long, broad, not bilobed posteriorly; loreal region oblique, no canthus rostralis; nostrils near tip of snout, positioned dorsolaterally, visible from above, but not from below; eye-naris distance greater than internarial distance (END/IND 1.37); tympanic annulus more strongly defined in preservative than in life, its diameter smaller than that of eye (TyD/ED 0.80); well defined supratympanic fold extends from marginally behind eye to insertion of fore leg; shank moderately short (TL/SUL 0.44); fingers moderately short, not webbed, tips of all fingers not wider than penultimate phalanges, but with circum-marginal grooves, relative lengths of fingers 3 > 4 > 2 = 1 (Fig. 12c); all toe tips acuminate, but wider than penultimate phalanges, with circum-marginal grooves; toes not webbed, relative lengths 4 > 3 > 5 > 2 > 1 (Fig. 12d); plantar, palmar and subarticular tubercles barely defined. Body laterally and dorsum of legs partly, with scattered small tubercles in life and in preservative; all ventral surfaces smooth; tip of snout (especially ventrally) with several tiny elevations.

Figure 12. 

Holotype (SAMA R71653) of Xenorhina wiegankorum sp. nov. in life: (a) Dorsolateral view; (b) Ventral view; (c) Volar view of left hand; (d) Thenar view of left foot.

In life, all dorsal surfaces almost uniformly light olive-brown (RAL 8008); lumbar spot absent; back with yellowish mid-dorsal line that continues along hind legs on to tarsus; tubercles with whitish apices concentrated mainly on lateral surfaces of body; large dark triangular spot on posterior of thighs around vent absent; iris blackish with golden speckles; ventral surfaces of toes predominantly signal-grey (RAL 7004), plantar surfaces brown-grey; ventral surfaces of fingers and palms predominantly signal-grey; abdomen and ventral surfaces of thighs, shanks and arms melon-yellow (similar to RAL 1028) with inconspicuous whitish spots; ground colour of throat and chest also melon-yellow, but overlain with dense pattern of beige-grey and off-white spots.

In preservative, all dorsal surfaces pastel-violet (RAL 4009), with only few darker areas and inconspicuous whitish tubercle apices. Melon-yellow ventral surfaces faded to ivory colour in preservative and pattern on chest and throat changed from beige-grey to brown-beige (RAL 1011).

Morphometric data for all paratypes are similar (Table 5). Colour pattern of ZMB 91132 (and probably of PNGNM [SJR 10373]) in life is similar to holotype. Dorsal surfaces of SAMA R71654 are telegrey (RAL 7045) with small whitish spots (Fig. 13) and ventral surfaces predominantly broom-yellow (RAL 1032). Dorsal surfaces of SAMA R65073 are a mixture of stone-grey (RAL 7030) and brown-grey (RAL 7013) reticula interspersed with whitish spots (mainly on lower flanks) and ventral surfaces predominantly zinc-yellow (RAL 1018).

Figure 13. 

Xenorhina wiegankorum sp. nov. paratype SAMA R71654 in dorsolateral view.

In preservative, ground colour of dorsal surfaces of head and back of all specimens is dark shades of pastel-violet (RAL 4009), with dorsal surfaces of extremities light brown with dark brown stripes and spots. Two paratypes with and two without, light mid-dorsal line. Snout tip grey in all specimens. Part of chest, entire abdomen and ventral surfaces of thighs light ivory; throat and part of chest light ivory overlain by more or less expanded brown-beige areas. Rear of thighs in all type specimens predominantly brown, only a small area around vent blackish.

Xenorhina wiegankorum sp. nov. has a known distribution limited to altitudes of 330–950 m a.s.l. in the foothills of the upper Strickland River catchment in Western Province, south-western Papua New Guinea (Fig. 16). Males called at night from under the litter on the forest floor or from slightly beneath the soil surface, during or immediately after heavy rain.

We analysed one call series from the holotype (SAMA R71653) recorded at an air temperature of 23.7 °C, two call series from paratype SJR 10400 recorded at 21.0 °C and one call series of paratype ZMB 91132 recorded at 25.0 °C. Calls are rather deep, unpulsed “popping” notes that, as is typical for many Xenorhina species, increase in volume during the course of the call series. Pitch of calls also increases slightly during the course of each series. Although there is some variation in call length and inter-call interval amongst calls of the three animals recorded, there is high overlap in all call parameters and we have no doubt that all represent the same species. We, therefore, combined the calls for analysis

Calls are of approximately equal length, but inter-call intervals are somewhat variable. A call starts abruptly at high amplitude, which then decreases gradually until end of call (Fig. 14a). There are 2–7 harmonics, though the second is often missing (Fig. 14b and c); fundamental and dominant frequencies are at 0.55 kHz (Fig. 14c). Length of call series is 13.8–18.1 s (mean 15.3 s, n = 4); with 22–39 calls per series (mean 28.8, n = 4); call length is 60–104 ms (mean 87.1 ± 6.7 ms, n = 115); intercall interval length is 286–1073 ms (mean 459.6 ± 137.6 ms, n = 111) with call repetition rate of 1.71–2.15 calls/s (mean 1.86 calls/s).

Figure 14. 

(a) Oscillogram; (b) Spectrogram and (c) Amplitude spectrum of the last five calls from a call series containing 29 calls, produced by paratype ZMB 91132 of Xenorhina wiegankorum sp. nov.

The specific epithet wiegankorum is the Latinised patronymic adjective in genitive plural of the family name Wiegank. It is given to recognise a very long-lasting friendship of the senior author with Ulla and Friedrich-Manfred (Conny) Wiegank from Potsdam.

We compare Xenorhina wiegankorum sp. nov. with all congeners of a similar size (SUL ~ 28–38 mm) that have a single spike on each vomeropalatine bone.

Xenorhina fuscigula has hind legs shorter (TL/SVL < 0.40 vs. > 0.40), eye-naris distance shorter (END/SVL 0.064–0.074 vs. 0.070–0.084) and fourth toe shorter (T4L/SVL 0.34–0.41 vs. 0.45–0.47); advertisement calls of X. fuscigula are produced singly (vs. in a long series containing up to 39 calls).

Xenorhina huon (Blum & Menzies, 1989) has hind legs shorter (TL/SVL < 0.40 vs. > 0.40), eyes larger (ED/SVL 0.070–0.091 vs. 0.062–0.066) and ventral surfaces with dark flecking (vs. ventral surfaces without dark flecking). Xenorhina huon is also known only from mountainous regions 1800–2000 m a.s.l. on the Huon Peninsula, near the north coast of Papua New Guinea (vs. lowlands south of the central cordillera).

Xenorhina lacrimosa exhibits considerable overlap in many morphometric characters, but displays extensive variation in dorsal colouration (vs. predominantly brown or grey); vent enclosed in dark brown patch (vs. patch absent) and ventral surfaces deep orange or occasionally grey-brown, with white spots (vs. ventral surfaces at least partially yellow) (Figs 1–2 vs. 12–13); dorsal surfaces also appear less rugose in life (Figs 1–2 vs. 12–13). Advertisement calls are very different: call series of X. lacrimosa much longer (26–60 s vs. 12–18 s), with fewer calls (7–12 vs. 22–39), repetition rate much slower (0.20–0.27 vs. 1.70–2.15 calls/s), call length longer (141–231 ms vs. 60 to 104 ms) and call interval longer (2.8–8.0 s vs. 286–1073 ms).

Xenorhina subcrocea (Menzies & Tyler, 1977) is smaller (SVL 30.5–33.3 vs. 32.0–35.7), with hind legs longer (TL/SVL > 0.46 vs. < 0.47), ventral surfaces with dark reticulation in preservative (vs. without dark reticulation), call intervals within series shorter (154–285 ms vs. 286–1073 ms), produced at rate of about 4 calls/s (vs. 1.7–2.2 calls/s).

Xenorhina zweifeli has similar body size and ratios. It differs from Xenorhina wiegankorum sp. nov. by having a conspicuous dark brown supratympanic stripe (vs. absent) and greatly different advertisement calls: X. zweifeli utters single calls at long and irregular intervals (Kraus and Allison 2002), with 2–3 calls sometimes uttered in quick succession, during the day and early evening (Kraus and Allison 2002); in contrast, Xenorhina wiegankorum sp. nov. produces calls in discrete series with 22–39 calls produced in rapid succession, only at night.

SAMA R71646 (SJR10249), adult male, from southern edge of Karius Range, Hela Province, Papua New Guinea (5.9911°S, 142.6707°E; 1,368 m a.s.l.), collected on 07-02-2008 by S.J. Richards.

ZMB 91133 (SJR 10311), adult male, same collection details as for holotype.

This species of Xenorhina is characterised by the unique combination of: small to medium-size (males 28.7–30.1 mm SUL); vomeropalatines each with one moderate-sized vomerine spike; legs short (TL/SUL 0.36 in two specimens); all fingers and toe 1 without expanded discs, toes 2–5 with weakly expanded discs (T4D/SUL 0.038–0.040); eye-naris distance smaller than internarial distance (END/IND 0.80–0.91); tympanum slightly larger than eye (TyD/ED 1.11 in two specimens). Dorsal surfaces bluish-brown in life, ventral surfaces dark orange with irregular whitish and greyish spots. Advertisement calls uttered in series lasting 3–5 s, calls per series 13–19, call length 37–84 ms, repetition rate 4.0–4.5 calls/s.

Measurements are summarised in Table 6, a dorsolateral view in life is shown in Fig. 15a and ventral surfaces in life in Fig. 15b. Head broader than long (HL/HW 0.75); snout acuminate from above, protruding in profile; loreal region oblique, no canthus rostralis; nostrils near tip of snout, directed more laterally than dorsally, visible from above, but not from below; eye-naris distance less than internarial distance (END/IND 0.90); tympanum visible in life and preservative, its diameter slightly larger than eye (TyD/ED 1.11); tongue very broad; vomerine spikes triangular, moderately large; prepharyngeal ridge narrow with four denticles; supratympanic fold well-developed, not reaching eye or insertion of fore leg (Fig. 15a); shank short (TL/SUL 0.36); fingers moderately short, not webbed; tips of all fingers with circum-marginal grooves, not or only marginally wider than penultimate phalanges, relative lengths of fingers 3 > 4 > 2 > 1 (Fig. 15c); all toe tips with circum-marginal grooves, those on toes 2–4 clearly wider than penultimate phalanges, those on toe 1 and toe 5 scarcely wider than penultimate phalanges; toes not webbed, relative lengths 4 > 3 > 5 > 2 > 1 (Fig. 15d); plantar, palmar and subarticular tubercles barely visible; body laterally with some distinct tubercles in life, barely visible in preservative; dorsal surfaces of extremities, middle of dorsum and all ventral surfaces smooth; tip of snout with several tiny pimples.

Figure 15. 

Holotype (SAMA R71646) of X. woxvoldi sp. nov. in life: (a) Dorsolateral view; (b) Ventral view; (c) Volar view of right hand; (d) Thenar view of right foot.

In life, dorsal surface of head, body and extremities a mixture of grey-brown and copper-brown (RAL 8004) (Fig. 15a); lower flanks uniform greyish with bluish hue and off-white dots and streaks; semicircular lumbar spot present, but only vaguely defined; a distinct whitish mid-dorsal line extends on to rear of thighs and on shanks and tarsi, then as broken line on to abdomen and chest; dorsal and ventral surfaces of fingers and toes and palmar surfaces orange; plantar surfaces a mixture of irregular light grey, dark grey and orange spots. Ventral surfaces of throat, chest, abdomen and extremities orange-brown (RAL 8023) with irregular light grey spots (Fig. 15b); most tubercles on flanks and extremities with whitish tips; snout tip light grey with tiny dark grey spots; outer margin of iris blackish and inner margin gold-orange, with some integration of colours at their margins.

In preservative, dorsal surfaces changed from copper-brown to mahogany-brown (RAL 8016), that of ventral surfaces from orange-brown to ivory (RAL 1014). Dorsal surfaces of fingers and toes also become ivory coloured. Lumbar spots no longer visible.

All body measurements and body ratios of holotype and paratype are similar (Table 6). In life, dorsal surfaces of paratype a mixture of lighter and darker brown and reddish areas, with reddish components more restricted than in holotype. Colours of flanks and dorsal surfaces of fingers and toes and colour and extent of mid-dorsal line (extending on to hind limbs and abdomen) as for holotype. Ventral surfaces more yellow and light grey spotting more extensive, in paratype. Dorsal surfaces in preservative slightly paler than holotype, ventral surface with more extensive pale brown reticulation.

Xenorhina woxvoldi sp. nov. is known only from one location at an altitude of 1,368 m a.s.l. on the southern fringe of the Karius Range in Hela Province, Papua New Guinea (Fig. 16), where males called from within the humus layer in lower montane rainforest during late afternoon and early evening.

Figure 16. 

Map of Papua New Guinea showing the known distributions of X. thiekeorum sp. nov. (blue circle), X. wiegankorum sp. nov. (yellow triangles) and X. woxvoldi sp. nov. (red square). Arrows indicate the type localities.

Two call series from the holotype (SAMA R71646) and one from the paratype (ZMB 91133), recorded at air temperatures of 18–19.5 °C, were analysed. Call is a single unpulsed, piping note produced in discrete series. Call series last 2.9–4.8 s (mean 3.7 s, n = 3) and contain 13–19 calls (mean 5.7 calls, n = 3) produced at a rate of 4.0–4.5 calls/s (mean 4.3 calls/s, n = 3). Call length is 37–84 ms (mean 75.1 ± 8.3 ms, n = 47) and call intervals last 137–250 ms (mean 172.4 ± 28.4 ms, n = 44). Calls are of approximately equal length throughout a series (first call may be shorter) with approximately equal intervals (intervals between first two and last two calls of a series may be slightly longer). Volume of each call increases during course of call series, but rise in pitch is marginal. Calls start abruptly at maximum amplitude, which then decreases gradually until end of call (Fig. 17a). All calls have harmonic structure with 4–5 harmonics between 0.7 and 3.2 kHz (Fig. 17b). First harmonic clearly dominant, with peak at 0.8 kHz (Fig. 17c). Third harmonic often with more energy than second. Frequency of calls weakly modulated with slight reduction during course of call.

Figure 17. 

(a) Oscillogram, (b) Spectrogram and (c) Amplitude spectrum of the last five calls of a series containing 15 calls from the holotype of Xenorhina woxvoldi sp. nov.

The specific epithet woxvoldi is the Latinised patronymic adjective in genitive singular derived from the family name Woxvold. It is in gratitude of the junior author to Iain Woxvold for the many years of friendship, camaraderie and shared adventures in remotest New Guinea.

We compare Xenorhina woxvoldi sp. nov. with all congeners of a similar size (SUL ~ 25–35 mm) that have a single spike on each vomeropalatine.

Xenorhina fuscigula differs from Xenorhina woxvoldi sp. nov. by having an internarial distance shorter (IND/SVL 0.054–0.064 vs. 0.066–0.070), eye-naris distance greater (END/SVL 0.064–0.074 vs. 0.056–0.060), END/IND ratio higher (1.00–1.36 vs. 0.80–0.90), ventral surfaces pale with dark reticulation (vs. orange with light grey spots) and calls produced singly (vs. produced in rapid series of 13–19 calls).

Xenorhina huon has eye-naris distance greater (0.073–0.103 vs. 0.056–0.060), END/IND ratio higher (1.00–1.27 vs. 0.80–0.90), eyes larger (ED/SVL 0.070–0.091 vs. 0.060–0.066), head wider (HW/SVL 0.35–0.47 vs. 0.30–0.34) and ventral surfaces with dark flecking (vs. ventral surfaces with light flecking in life and pale brown reticulation in preservative).

Xenorhina lacrimosa is larger (SUL 34.3–41.0 mm vs. 28.7–30.1 mm), has shanks longer (TL/SUL 0.42–0.46 vs. 0.36 in both known Xenorhina woxvoldi sp. nov.), fourth toe longer (T4L/SUL 0.42–0.49 vs. 0.41–0.42), head longer (HL/SUL 0.27–0.30 vs. 0.25 in both known Xenorhina woxvoldi sp. nov.), eye-naris distance greater (END/SUL 0.073–0.099 vs. 0.056–0.060) and advertisement calls longer (141–231 ms vs. 37–84 ms) with lower repetition rate (0.20–0.27 vs. 4.0–4.5 calls/s).

Xenorhina mehelyi has hind legs longer (TL/SVL > 0.42 vs. 0.36), eye-naris distance greater (END/SVL 0.076–0.096 vs. 0.056–0.060), END/IND ratio higher (1.12–1.50 vs. 0.80–0.90), eyes larger (ED/SVL 0.067–0.079 vs. 0.060–0.066), ventral surfaces with dark mottling (vs. no dark mottling) and calls longer (on average140 ms vs. 75 ms) with inter-call intervals also longer (on average 1500 ms vs. 172 ms).

Xenorhina schiefenhoeveli has eye-naris distance greater (END/SVL 0.077 vs. 0.056–0.060), END/IND ratio higher (1.16–1.21 vs. 0.80–0.90), eyes larger (ED/SVL 0.071–0.081 vs. 0.060–0.066), ventrum cream, with reticulated brown (vs. orange-red with whitish flecking); calls longer (~ 100 ms vs. mean of 75 ms), uttered in very long series of more than 100 calls (vs. 13–19 calls) with repetition rate about 2 calls/s (vs. 4.0–4.5 calls/s).

Xenorhina subcrocea has hind legs longer (TL/SVL > 0.46 vs. < 0.40), ratio of END/IND much larger (1.26–1.41 vs. 0.80–0.90), ventral surfaces with dark reticulation (vs. with whitish flecking) and mid-dorsal line absent (vs. distinct dorsal line present).

Xenorhina tumulus has eye-naris distance greater (0.073–0.081 vs. 0.056–0.060), END/IND ratio higher (1.11–1.28 vs. 0.80–0.90), ventral surfaces in life pinkish, mottled with brown (vs. orange-brown with no brown mottling) and call intervals within series 300–400 ms (vs. 137–250 ms).

Xenorhina wiegankorum appears to be larger (five males 32.0–35.7 mm vs. two males 28.7–30.1 mm SUL), has hind legs much longer (TL/SUL 0.44–0.47 vs. 0.36 in two specimens), has toes longer (T4L/SUL 0.45–0.47 vs. 0.41–0.42), fingers longer (F3L/SUL 0.188–0.213 vs. 0.174–0.189), END/IND ratio higher (1.19–1.37 vs. 0.80–0.90) and a different advertisement call (see description of X. wiegankorum, this paper).

Xenorhina zweifeli is larger (SVL 33.2–38.0 vs. 28.7–30.1), with internarial distance smaller (IND/SVL 0.052–0.063 vs. 0.066–0.070), eye-naris distance larger (END/SVL 0.071–0.085 vs.0.056–0.060), END/IND ratio higher (1.17–1.47 vs. 0.80–0.90); ventral colour pattern of dark brown flecks on a cream ground in preservative (vs. pale brown flecks on ivory-coloured ground) and call consisting of a single note (vs. 13–19 calls produced in distinct series.