Hylophorbus monophonus Ferreira, Kraus, Richards, Oliver, Günther, Trilaksono, Arida, Hamidy, Riyanto, Tjaturadi, Thébaud, Gaucher & Fouquet, 2023, sp.nov.
Creators: name: Ferreira, Flavien
name: Kraus, Fred
name: Richards, Stephen
name: Oliver, Paul
name: Günther, Rainer
name: Trilaksono, Wahyu
name: Arida, Evy Ayu
name: Hamidy, Amir
name: Riyanto, Awal
name: Tjaturadi, Burhan
name: Thébaud, Christophe
name: Gaucher, Philippe
name: Fouquet, Antoine
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Microhylidae
Hylophorbus
Hylophorbus monophonus

description: Hylophorbus monophonus sp.nov.
(Fig. 4)
Holotype: MZB.Amph.24 348 (field number EAA514), adult male, collected by Antoine Fouquet and Philippe Gaucher, southern slopes of Kumawa Mountains, Bomberai Peninsula, West Papua province, Indonesia (−4.0365, 133.0703; 400 m a.s.l.), 12 November 2014.
Paratypes: One adult male, MZB.Amph.24 346 (EAA510), and two adult females, MZB.Amph.24 347 (EAA511) and MZB. Amph.24 351 (EAA549), collected with the holotype.
Etymology: The specific epithet ‘monophonus’ is a Latinized masculine compound adjective formed from the Greek adjective ‘monos’ (alone) and Greek noun ‘phone’ (sound, voice), as a reference to the single-note calls of this species. The name indicates a character that is diagnostic compared with Hylophorbus tetraphonus Günther 2001, a species that displays similar size and colour pattern.
Diagnosis: A Hylophorbus species recognizable by the following unique combination of characters: (i) medium size (male SV = 26.0– 28.2 mm; female SV = 27.5–27.7 mm); (ii) poorly developed basal subarticular tubercle on T4 and T5 (male 4st =.53–. 59 mm; female 4st =.44–. 49 mm; male 5st =.52–. 66 mm; female 5st =.42–. 43 mm); (iii) a thenar tubercle and two palmar tubercles, ovoid, at proximal edge of hand; (iv) absence of lateral stripe (Fig. 4F); (v) dark brown or black lumbar ocellus, with pale orange anterodorsal margin (Fig. 4G); (vi) dark brown pigmentation on anterodorsal flank, forming various shapes, ranging from dark brown irregular blotches to a well-defined ‘crescent’ shape (Figs 4F, 5A, B); (vii) bright yellow coloration on axilla, groin, and from anterodorsal side of thigh extending to ventral edge of flank (Fig. 4F, G); (viii) overall pale yellow coloration on the ventral surfaces (Fig. 4H); and (ix) single-pulse, single-note calls, with slight frequency modulation and dominant frequency at ~1.3 kHz (Fig. 4D).
Description of the holotype: Adult male (for measurements, see Supporting Information, Table S7). Head as wide as long (HL/ HW =.98); nares directed laterally, closer to tip of snout than to eye, internarial distance larger than distance from nostril to anterior edge of eye (EN/IN =.55); snout acute in lateral view, almost truncate in dorsal view. Eye moderately large (EY/ SV =.14). Tympanum large (TY/SV =.11, TY/EY =.74), supratympanic fold inconspicuous, outlined in dark brown. Skin finely granular on dorsal surfaces, with sparse flat tubercles, smooth on ventral surfaces. Fingers unwebbed, relative lengths 3> 4> 2> 1, nearly the same for F1, F2, and F4; finger-tips with slightly expanded discs, truncate, all with circum-marginal grooves. Basal subarticular tubercles on F1–F3 more developed (1–3sf =.68–. 79 mm) than on F4 (4sf =. 60 mm); thenar tubercle and two palmar tubercles present, ovoid, well developed, located at proximal edge of palm, with inner palmar tubercle slightly more anterior. Toes unwebbed, relative lengths 4> 3> 5> 2> 1; disc almost lacking on T1, slightly expanded on T5, and much larger on T2–T4 (twice width of penultimate phalanges), all with circum-marginal grooves. Subarticular tubercles best developed on T1–T3 (1–3st =.60–. 75 mm), basal subarticular tubercles on T4–T5 indistinct; inner metatarsal tubercle ovoid, well developed (MTL = 1.00 mm), others lacking.
Dorsum, suprascapular region, posterodorsal surface of thigh, and dorsal surface of shank light brown, with several scattered small, dark brown blotches; very thin vertebral skin ridge extending from tip of snout to urostyle. Anterior region of flanks with pale grey and dark brown irregular blotches (Fig. 4F), white speckles extending under axilla to anterior abdomen (Fig. 4H). Posterodorsal surface of forelimbs and dorsal surfaces of F3–F4 light reddish brown; brown blotch consistently present between base of F2 and F3; outer side of foot and dorsal surfaces of T4– T5 light reddish brown (Fig. 4F); dorsal surfaces of all fingers and toes with brown blotches. Dorsal and lateral surface of head light reddish brown; dorsal tip of snout, under eye, and margin of naris heavily pigmented with dark brown. Chin, throat, chest, and anterior portion of abdomen mottled with brown and having pale yellow flecks (Fig. 4H). Abdomen, ventral surfaces of thigh, and shank overall pale yellow, fading to translucent skin on anteroventral forelimbs (Fig. 4H). Axilla, groin and anterodorsal thigh to ventral edge of flank bright yellow (Fig. 4G, H). Ventral surface of hands and feet light brown. Pale red blotch above tip of urostyle, margined in black posterolaterally. Iris silver, with dark brown vertical line crossing pupil; pupil margined with incandescent orange.
Variation: Only four specimens are available to assess variation within the sample (Supporting Information, Table S 7). Relative size of subarticular tubercles varies between individuals, such that the longest ones on the hand are on F1–F3, and on the foot on T2 – T3. The relative position of palmar tubercles is consistent between individuals (proximal; Supporting Information, Fig. S 10). Little variation is visible in colour patterns among preserved specimens. The two females exhibit a stronger contrast between dorsal and lateral coloration, in addition to a dark brown ‘crescent’ shape on the flanks. They also exhibit four welldistinguished dorsal tubercles in the lumbar region, anterior to the lumbar ocellus. Information on colour in life for MZB. Amph. 24 351 is not available; therefore, only the colour in life of MZB. Amph. 24 346 and MZB. Amph. 24 347 is discussed (Fig. 5A, B). Overall, colour pattern as is described for the holotype, with variation observed on the flanks and dorsal coloration. The male MZB.Amph.24 346 dorsum mixes red and dark brown coloration and displays a dark brown blotch with irregular edges on the anterior flank. The female MZB.Amph.24 347 harbours a well-defined dark brown ‘crescent’ blotch on the anterior flank; the flanks are pale grey (slightly pinkish) from the posterolateral edge of eye to the lumbar ocellus.
Call: We analysed a total of 70 calls from three males (Table 1; Supporting Information, Table S3). The analysed files are deposited in the sound collection of ‘La Sonothèque du Muséum National d’Histoire Naturelle’ (Supporting Information, Table S3; Guilbert and Loret 2018). The advertisement call consists of a short single note, mean duration 131 ms, range 108–153 ms (Fig. 4D). The dominant frequency is 1.27 kHz (range 1.20–1.32 kHz). Notes can exhibit one harmonic, at a frequency of ~1.90 kHz. Most of the calls (notes) within a call series display similar amplitude and frequency.However, the species sometimes emits a second type of note with two pulses (Supporting Information, Fig. S5C). Mean inter-note duration is 1570 ms (range 635–2395 ms).
Distribution and ecological notes: Hylophorbus monophonus is known only from the type locality. The species inhabits the leaf litter of pristine lowland rainforest between 300 and 400 m a.s.l. Very little is known about its ecology. Interestingly, specimens of H. picoides have been sampled at the same locality (MZB. Amph.24 349 and MZB.Amph.24 350), but not syntopically (1100 m a.s.l.), suggesting that these species might not overlap in their ecology, occupying distinct elevational ranges. Such a pattern of distribution has also been documented in the Wondiwoi Mountains by Günther (2001), where Hylophorbus wondiwoi Günther 2001 and H. tetraphonus mainly occupy different altitudes.
Comparisons with other species: Hylophorbus monophonus can be distinguished immediately from Hylophorbus nigrinus Günther 2001, H. picoides Günther 2001, H. atrifasciatus, H. infulatus, and H. sigridae by the absence of a lateral stripe (Zweifel 1972, Günther 2001, Kraus 2013, Günther et al. 2014); from H. extimus Zweifel 1972 and H. myopicus Zweifel 1972 by smaller body size (26.0– 28.2 mm in H. monophonus vs. 40.0–49.0 mm); from H. proekes Kraus & Allison 2009 and Hylophorbus sextus Günther 2001 by its yellow ventral coloration and its single-note calls; and from H. wondiwoi by its smaller body size (>32.0 mm in H. wondiwoi) and its single-note calls. Colour patterns of H. tetraphonus (Bird’s Neck species, West Papua, Indonesia), H. richardsi (Hela Province, Papua New Guinea), and Hylophorbus rainerguentheri Richards & Oliver 2007 (Huon Peninsula, Papua New Guinea) most resemble H. monophonus. However, H. monophonus is larger (26.0– 28.2 mm) than H. richardsi (21.3– 22.6 mm), its abdomen is yellowish (vs. whitish for H. richardsi), and notes are longer (131 ms vs. ~60.5 ms); H. monophonus has a ventral–lateral and axillary yellow coloration, in addition to a conspicuous dark brown pattern on the flanks, lacking in H. rainerguentheri; H. monophonus has single-note calls, vs. one to five notes in H. tetraphonus. Finally, because of the ambiguity surrounding H. rufescens sensu Macleay (1878), we cannot compare their morphology explicitly. However, their habitat type differs (lowland rainforest at 300–400 m a.s.l. for H. monophonus vs. seasonal woodland and mangroves for H. rufescens), and their type localities are> 1000 km apart, making their conspecificity highly unlikely.
description: Published as part of Ferreira, Flavien, Kraus, Fred, Richards, Stephen, Oliver, Paul, Günther, Rainer, Trilaksono, Wahyu, Arida, Evy Ayu, Hamidy, Amir, Riyanto, Awal, Tjaturadi, Burhan, Thébaud, Christophe, Gaucher, Philippe & Fouquet, Antoine, 2023, Species delimitation and phylogenetic analyses of a New Guinean frog genus (Microhylidae: Hylophorbus) reveal many undescribed species and a complex diversification history driven by late Miocene events, pp. 1-22 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) (Zool. J. Linn. Soc.) 202 (2) on pages 11-14, DOI: 10.1093/zoolinnean/zlad168, http://zenodo.org/record/14542157