Xenorhina lacrimosa, Günther & Richards, 2021
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publication ID |
https://dx.doi.org/10.3897/zse.97.59696 |
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publication LSID |
lsid:zoobank.org:pub:FB92F5DF-7FC7-4F01-A1DD-8E85B6F5FE67 |
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persistent identifier |
https://treatment.plazi.org/id/D78F9340-1032-4D34-976A-B91C7001CC1C |
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taxon LSID |
lsid:zoobank.org:act:D78F9340-1032-4D34-976A-B91C7001CC1C |
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treatment provided by |
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scientific name |
Xenorhina lacrimosa |
| status |
sp. nov. |
Xenorhina lacrimosa sp. nov.
Holotype.
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.
Paratypes.
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.
Referred specimens.
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.
Diagnosis.
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.
Description of the holotype.
Measurements are summarised in Table 1 View Table 1 , a dorsolateral view in life is shown in Fig. 1a View Figure 1 and ventral surfaces in life in Fig. 1b View Figure 1 . 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 View Figure 1 ); all toe tips with circum-marginal grooves and wider than penultimate phalanges; toes not webbed, relative lengths 4> 3> 5> 2> 1 (Fig. 1d View Figure 1 ); plantar and palmar tubercles (with exception of prominent, oval inner metatarsal tubercle; Fig. 1d View Figure 1 ), 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).
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 View Figure 1 ); 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 View Figure 1 ).
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.
Morphological variation.
Measurements and proportions of most paratypes show limited variation (Table 1 View 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 View 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 View 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 View Figure 2 ), uniform light red-orange similar to RAL 2008 (ZMB 91129, Fig. 2b View Figure 2 ), bluish on head and lower flanks, but reddish-brown on back and dorsal extremities (ZMB 91130, Fig. 2c View Figure 2 ) or dark brown with bluish hue on head, body and thighs, but beige on fore limbs, shanks and tarsi (SAMA R71647, Fig. 2d View Figure 2 ). 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 View Figure 2 ); others are more extensively spotted (ZMB 91129, Fig. 2f View Figure 2 ) 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 View Figure 2 ); others exhibit grey-brown ground colour with many irregular whitish spots, some of them interspersed with small irregular red patches (SAMA R71647, Fig. 2h View Figure 2 ).
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.
Distribution and ecological notes.
Most records of Xenorhina lacrimosa sp. nov. are from lowland and foothill forest in south-central Papua New Guinea (Fig. 8 View Figure 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 View Figure 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.
Vocalisation.
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 View Figure 3 ). 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 View Figure 3 ). All calls have 5-7 harmonics (Fig. 3c View Figure 3 and 3d View Figure 3 )). 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 View Figure 3 ).
Etymology.
The specific epithet Xenorhina 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.
Comparisons with other 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 Xenorhina 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 Xenorhina 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.
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