Xenorhina brachyrhyncha, Kraus, 2011

Kraus, Fred, 2011, New Frogs (Anura: Microhylidae) from the Mountains of Western Papua New Guinea, Records of the Australian Museum 63 (1), pp. 53-60 : 57-59

Xenorhina brachyrhyncha n. sp.

Fig. 4

Type material. Holotype female: Papua New Guinea, West Sepik Province, Telefomin [5.123° S, 141.637° E], 24 November 1956, collected by D. McMichael, AMS 15021 . Paratype: same data as holotype except collected 26 November, BPBM 31889 (formerly AMS 15021) .

Diagnosis. A small species of Xenorhina (adult female SV = 21.2–22.8 mm) with a single odontoid spike, slightly expanded discs with circum-marginal grooves on all toes except T1, inflated lores, relatively long legs (TL fold /SV = 0.40–0.43, TL knee /SV = 0.46–0.49), relatively short and broad head (HL/SV = 0.30–0.32, HW/SV = 0.35–0.38, HL/ HW = 0.85–0.86), relatively short and broad snout (EN/IN = 1.06–1.13), abdomen straw with reticulation of brown flecks ( Fig. 4 ), no dark loreal stripe, no dark supratympanic stripe, no white vertebral line, and rear of thighs brown with scattered straw flecks but with no white line or stripe.

Comparisons with other species. The single odontoid spike and very small size of the new species distinguish it from all congeners except Xenorhina anorbis and X. lanthanites . It is distinguished from X. anorbis by its longer legs (TL fold /SV = 0.40–0.43 vs. 0.29–0.32 in X. anorbis ), shorter snout (EN/ IN = 1.06–1.13 vs. 1.26–1.32 in X. anorbis ), presence on the toes of discs bearing terminal grooves (discs and grooves absent in X. anorbis ), and abdomen straw with reticulum of dark flecks (uniformly light in X. anorbis ). X. brachyrhyncha is distinguished from X. lanthanites in having an inflated (vs. concave) loreal region ( Fig. 5 ), shorter and broader snout (EN/IN = 1.06–1.13 vs. 1.13–1.21 in X. lanthanites ), slightly longer leg (TL knee /SV = 0.46–0.49 vs. 0.42–0.46 in X. lanthanites ), smaller and more obscure tympanum (TY/SV = 0.057 vs. 0.066 –0.070 in X. lanthanites ), larger foot (FootL/ SV = 0.48–0.51 vs. 0.42–0.45 in X. lanthanites ), absence (vs. presence) of a circum-marginal groove on first toe; absence (vs. presence) of a broad white dorsal stripe on the rear of the thigh, absence (vs. presence) of a dark loreal stripe, and absence (vs. presence) of a dark stripe curving above and behind the tympanum. Female X. brachyrhyncha are the same size as male X. lanthanites ; hence, because females are the larger sex in most asterophryines, X. brachyrhyncha probably also differs in being of smaller body size than X. lanthanites .

Xenorhina brachyrhyncha is also similar to small specimens of X. mehelyi but is distinguished from that species by its smaller size (SV up to 37.0 mm in female X. mehelyi ), shorter and broader snout (EN/IN = 1.06–1.13 vs. 1.29–1.61 in X. mehelyi ), in lacking a circum-marginal groove on first toe (present in X. mehelyi ), and lacking a white vertebral line and white line on the rear of each thigh.

Description of holotype. Adult female with right-lateral incision. Vomeropalatines each with a single enlarged odontoid spike. Head wide (HW/SV = 0.38), merging with body with no constriction at neck. Loreal region oblique, inflated; canthus rostralis absent; nostrils dorsoventrally compressed, directed anterolaterally, much closer to tip of snout than to eyes. Internarial distance much less than distance from naris to eye (EN/IN = 1.06, IN/SV = 0.075, EN/ SV = 0.080). Snout inflated, slightly rounded when viewed from above, rounded when viewed from side. Eyes small (EY/SV = 0.075); eyelid less than half width of interorbital distance. Tympanum very indistinct but large (TY/SV = 0.057). Dorsal, lateral, and ventral surfaces smooth; supratympanic fold slight. Fingers unwebbed, tips slightly flattened into discs on F2–F4 (3rdF/SV = 0.025), but only F3 with terminal groove; relative lengths 3>4>2>1. Finger discs barely wider than penultimate phalanges. Subarticular tubercles absent; inner metacarpal tubercle low and oval; outer low and rounded. Toes unwebbed, bearing discs with terminal grooves (4thT/SV = 0.039) except on T1; relative lengths 4>3>5>2>1. Toe discs larger than those of fingers (3rdF/4thT = 0.64), little wider than widths of penultimate phalanges. Neither subarticular tubercles nor metatarsal tubercles obvious. Hind legs rather short (TL knee /SV = 0.49).

In preservative, dorsum uniformly medium brown; eyelids darker. Face and sides straw yellow heavily flecked with brown. Straw-yellow postocular stripe extending through tympanum, heavily flecked with brown and, hence, somewhat obscure. Rear of thigh straw-yellow heavily flecked with brown, imparting the general appearance of being brown with a few pale-straw markings. Venter pale straw yellow densely covered with brown flecks from chin through chest, more sparsely flecked on abdomen. Plantar and palmar surfaces brown. Iris brown.

Measurements (in mm). SV = 21.2, TL = 10.3, HW = 8.0, HL = 6.8, IN = 1.6, EN = 1.7, SN = 2.5, EY = 1.6, TY = 1.2, 3rd F = 0.53, 4th T = 0.83.

Variation. The sole paratype is a female with enlarging but still unyolked ova. It is similar to the holotype in color pattern, but has a few obscure pale-straw markings dorsally, has less brown flecking on the abdomen, and has a somewhat more distinct pale postocular stripe. Its measurements are: SV = 22.8, TL = 10.5, HW = 8.0, HL = 6.9, IN = 1.5, EN = 1.7, SN = 2.4, EY = 1.8, TY = 1.3, 3rd F = 0.56, 4th T = 0.80. Etymology. The species name is a latinized feminine combinatorial adjective derived from the Greek words “brachys”, meaning “short” and “rhynchos”, meaning “snout”, in reference to the feature which distinguishes this species from its most similar congeners.

Range. Known only from the type locality at approximately 1500 m in the Star Mountains of western Papua New Guinea ( Fig. 3 ) .

ACKNOWLEDGMENTS. I thank Ross Sadlier (AMS), Darrel Frost and Dave Kizirian (AMNH), Ronald Vonk (ZMA), Mark-Oliver Rödel (ZMB), and Rose Singadan and Paulus Kei (UPNG) for loan of specimens; Ross Sadlier (AMS) and Mark Wilkinson (BMNH) for graciously hosting research at their institutions; Pumehana Imada for collections assistance at BPBM; Richard Zweifel for providing the photo of Oreophryne ampelos in life; Shep Myers for producing the figures; Brad Evans for help in producing the map; and Don Cameron for confirming correct nomenclatural grammar. This research was supported by National Science Foundation grant DEB-0743890 and by grant #020954 from the Global Biodiversity Information Facility Secretariat. This is contribution 2011-004 from the Pacific Biological Survey at the Bishop Museum.

Figures

Fig. 4. Xenorhina brachyrhyncha, views of (A) dorsum, (B) ventrum, (C) side of head, (D) right hand, and (E) right foot of holotype (AMS 15021) of X. brachyrhyncha. Scale bars = 5 mm (A–C) and 2 mm (D–E).

Fig. 5. Snouts of (A) Xenorhina lanthanites (ZMB 69557), and (B) X. brachyrhyncha (AMS 15021) showing difference in shape of loreal region. Scale bar = 2 mm.

Fig. 3. Locality records for Oreophryne ampelos (• = type locality, O = other locality) and Xenorhina brachyrhyncha