Hylophorbus maculatus, Ferreira & Kraus & Richards & Oliver & Günther & Trilaksono & Arida & Hamidy & Riyanto & Tjaturadi & Ŋébaud & Gaucher & Fouquet, 2024

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, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 202 (2), pp. 1-22 : 16-18

Hylophorbus maculatus sp.nov.

( Fig. 7 )

Holotype: MZB.Amph.24 339 (field number EAA357), adult male, collected by Antoine Fouquet and Philippe Gaucher, near Lobo village on Lamansiere Mountain, in the Lengguru foldbelt , Triton Bay, Kaimana Regency, West Papua province, Indonesia (−3.7291, 134.0617; 1021 m a.s.l.), 27 October 2014.

Paratypes: One adult male, MZB.Amph.24 340 (EAA358), collected with the holotype .

Etymology: The specific epithet is a Latin masculine adjective meaning ‘speckled’ or ‘spotted’, in reference to the overall spotted pattern on the ventral surfaces and flanks of this species.

Diagnosis: A Hylophorbus species recognizable by the following unique combination of characters: (i) small size (male SV = 23.4–24.2 mm, mean = 23.8 mm); (ii) strongly developed basal subarticular tubercle on F3–F4 (male 3sf =.80–. 82 mm; male 4sf =.77–. 83 mm), T3 (male 3st =.70–. 92 mm), and T4 (male 4st =.81–. 92 mm) (Supporting Information, Fig. S6B ); (iii) a thenar tubercle and two palmar tubercles, inner palmar tubercle at centre of palm; (iv) short, dark brown lateral stripe extending from the posterolateral edge of the eye to middle region of the flank ( Fig. 7E, G ); (v) dark brown lumbar ocellus; (vi) yellow groin; (vii) overall whitish ground coloration on ventral surfaces; (viii) discontinuous dark line extending from dorsal edge of lumbar ocellus to posterior lateral edge of eye, above short lateral stripe ( Fig. 7E, G ); (ix) conspicuous dark blotches on the posterior dorsal thighs and flank between short lateral stripe and lumbar ocellus; and (x) dark brown mottling on the ventral thighs, medial feet, and anterior abdomen.

Description of the holotype: Adult male (for measurements, see Supporting Information, Table S7). Head slightly longer than wide (HL/HW = 1.15); 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 =.84); snout acute in lateral view, truncate in dorsal view. Eye moderately large (EY/ SV =.14). Tympanum large (TY/SV =.08, TY/EY =.58), supratympanic fold inconspicuous. Skin slightly granular on all dorsal surfaces, with several small tubercles on dorsum, finely granular on ventral surfaces. Fingers unwebbed, relative lengths 3> 2> 1> 4; tips with slightly expanded truncate discs, all with circum-marginal grooves. Subarticular tubercles on all fingers, well developed; thenar tubercle well developed, ovoid; palmar tubercles more elongated; inner palmar tubercle at centre of palm. Toes unwebbed, relative lengths 4> 3> 5> 2> 1; discs on T1 and T5 slightly expanded, ~1.5 times wider than penultimate phalanges, discs larger on T2–T4, ~2 times wider than penultimate phalanges, all with circum-marginal grooves. Subarticular tubercles well developed on T1–T4, especially on T3 (3st =. 92 mm), basal subarticular tubercles poorly developed on T5 (5st =. 51 mm), inner metatarsal tubercle ovoid, well developed (MTL = 1.55 mm), others lacking.

Dorsum from head to shanks yellowish brown, with scattered brown spots on suprascapular region and top of thighs ( Fig. 7E ). Lumbar ocellus dark brown, margined posteroventrally with bright yellow; groin bright yellow. Flank overall reddish grey, separated from dorsum by one discontinuous dark brown line extending from dorsal edge of lumbar ocellus to posteriolateral edge of eye. Small red, white, and brown speckles from anterior flank to anterior abdomen. Short black lateral stripe running from anterior edge of tympanum (which it overlays) to middle of flank, margined ventrally with white, separated from lumbar ocellus by grey coloration containing small black blotches ( Fig. 7E ). Dorsal surfaces of F3–F4, lateral surfaces of feet, dorsal T4– T5, and posterodorsal surfaces of forelimb red (more intense on upper arm). Dorsally, F1–F2 and T1–T3 grey, with dark brown irregular spots on all fingers; dark brown blotch between base of F2 and F3; ventral surface of hands and feet brown. Chin, throat, chest, and anterior half of abdomen with inconsistent dark brown mottling; distinct dark brown blotch on each side of posterior submandibular region ( Fig. 7F, H ). Ventral surfaces overall whitish ( Fig. 7F ), ventral surfaces of legs with dark brown mottling. Red pigmentation above tip of urostyle, margined in black posterolaterally. Black colour around naris and eye in contact. Iris golden–copper, with dark brown vertical line crossing pupil; pupil margined with bright orange.

Variation: Assessment of variation is based on only two specimens (Supporting Information, Table S 7). Longest basal subarticular tubercle on the hand either 2sf or 4sf, and 3st or 4st on the foot. Mostly, variation in the size of the 3st (3st/SV =.05 and.07; 3st =.70 and. 92 mm) (Supporting Information, Fig. S6B ). The shape of the palmar tubercles varies between specimens (rounder on MZB. Amph. 24 340), but their positioning relative to the palm remains the same (centred; Supporting Information, Fig. S 10). Colour pattern in life or in preservative of the two available specimens is similar, with the exception of the chin and throat mottling, which are pronounced and consistent in the paratype ( MZB. Amph. 24 340), and the dorsal colour is light brown in the paratype vs. yellowish brown in the holotype. The red pigmentation on the upper arm and hand of the paratype is also less conspicuous than on the holotype, but it remains conspicuous on the foot.

Call: Unknown.

Distribution and ecological notes: Hylophorbus maculatus is known only from the type locality, a pristine lower montane forest at ~ 1000 m a.s.l. Interestingly, specimens of H. lengguru have been sampled in the same locality (specimens MZB. Amph.24 333–8), but non-syntopically (occurring at 300–400 m a.s.l.), suggesting that these species might not overlap in their ecologies and along the elevation gradient, as discussed above.

Comparisons with other species: Hylophorbus maculatus can be distinguished immediately from H. rainerguentheri , H. richardsi , H. sextus , H. tetraphonus , H. wondiwoi , H. proekes , H. infulatus , H. atrifasciatus , H. nigrinus , H. monophonus , and H. lengguru by the presence of a short lateral stripe (extending from the posterolateral edge of the eye to the middle region of the flank); and from H. extimus and H. myopicus by its much smaller size (23.4–24.2 mm in H. maculatus vs. 40.0–49.0 mm). Hylophorbus maculatus resembles H. picoides and H. sigridae , which also exhibit a short lateral stripe, but can be distinguished from them by the presence of a black line extending from the dorsal edge of the lumbar ocellus to the eye, and by the presence of dark brown blotches on the flank, between the posterior end of the short lateral stripe and the lumbar ocellus. Finally, because of the ambiguity surrounding H. rufescens sensu Macleay (1878) , we cannot compare their morphology explicitly. However, their habitat type differs (lower montane rainforest at ~ 1000 m a.s.l. for H. maculatus vs. seasonal woodland and mangroves for H. rufescens ), and their type localities are> 1000 km apart, making their conspecificity highly unlikely.

Figures

Figure 6. Hylophorbus lengguru holotype MZB.Amph.24 334. A, dorsal view in preservative.B, ventral view in preservative. C, lateral view in preservative. D, sonograms and their corresponding oscillograms of a call and a single note (left and right, respectively).E, palm of the hand and sole of the foot in preservative.F–H, holotype in life in dorsolateral view (F), dorsal view of the thigh (G), and ventral view (H). Photographs in preservative by A. Riyanto; photographs in life by A. Fouquet.

Figure 7. Hylophorbus maculatus holotype MZB.Amph.24 339. A, dorsal view in preservative. B, ventral view in preservative.C, palm of the hand in preservative.D, sole of the foot in preservative. E, F, holotype in life in dorsolateral view (E) and ventral view (F). G, H, paratype MZB.Amph.24 340 in life in dorsolateral view (G) and ventral view (H). Photographs in preservative by A. Riyanto; photographs in life by A. Fouquet.