Oreophryne ampelos, 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 : 54-57

Oreophryne ampelos n. sp.

Figs. 1–2

Type material. Holotype female: Papua New Guinea, Western Province , Imigabip [5.2833°S 141.4833°E], 11 December 1969, collected by F. Parker, AMS 30742 . Paratypes: same data as holotype, AMS 30741, BPBM 35949 (formerly AMS 30743) , AMNH 84535–37 ; same data as holotype except collected 10 December, AMNH 84538–40 ; Finalbin [5.21°S 141.21°E], 27–28 July 1987, collected by R . Zweifel, F. Parker, and L. Penny, AMNH 130500 .

Diagnosis. A large species of Oreophryne (adult male SV = 26.3–31.5 mm, adult female SV = 31.3–35.1 mm) distinguished by its combination of a ligamentous connection of the procoracoid to the scapula, webbing between the toes, fifth toe subequal in length to the third or slightly longer, relatively short leg (TL/SV = 0.40–0.46), relatively long and narrow snout (EN/SV = 0.083 –0.099, IN/SV = 0.074 –0.092, EN/IN = 1.0–1.2), relatively wide head (HW/ SV = 0.37–0.42), relatively small finger discs (3rdF/SV = 0.067 –0.080), and dorsal pattern of brown punctations on a pale straw-yellow ground color which gives an overall appearance of a uniformly light tan, uniformly dark tan, or mottled light and dark tan animal ( Figs. 1–2 ).

Comparisons with other species. The new species differs from all Papuan congeners except Oreophryne albopunctata , O. biroi , O. furu, O. hypsiops , O. insulana , O. kapisa, O. mertoni, and O. unicolor in the combination of having a ligamentous connection between the procoracoids and the scapula, in having the toes webbed, and having the third and fifth toes subequal in length. It is larger than each of these species, which never attain 30 mm SVL. In addition, O. insulana , O. kapisa, and O. unicolor have only basal webbing, whereas that in O. ampelos extends to the penultimate tubercle on the fifth toe and extends up to or slightly below that on the third toe; O. albopunctata , O. hypsiops , and O. mertoni have narrower heads (HW/SL = 0.30–0.37), whereas that of O. ampelos is wider (HW/SV = 0.37–0.42); O. furu has a whitish snout and postocular stripe and dark dorsolateral stripes and interocular bar, all of which are absent in O. ampelos , and it has a wider snout (IN/SV = 0.089 –0.096, mean 0.093 in O. furu vs. IN/SV = 0.074 –0.092, mean 0.081 in O. ampelos ); and O. biroi has the top of the snout light colored and a pale postocular stripe, both lacking in O. ampelos .

Oreophryne ampelos differs from all other members of the genus except O. anthonyi and O. idenburghensis in its large size. It differs from O. idenburghensis in being smaller (SV = 43–47 mm in O. idenburghensis), having a ligamentous (vs. cartilaginous) connection between the procoracoid and scapula, the third and fifth toes subequal in length (T5>T 3 in O. idenburghensis), more toe webbing, a wider head (HW/SV = 0.34–0.35 in O. idenburghensis), longer snout (EN/SV = 0.069 –0.070 in O. idenburghensis), and smaller finger discs (3rdF/SV = 0.077 –0.091 in O. idenburghensis). Oreophryne anthonyi is larger (SV = 30–47 mm) than O. ampelos , has the fifth toe longer than the third, a pair of)(-shaped folds between the scapulae (lacking in O. ampelos ), and has a shorter and broader snout (EN/IN = 0.93–0.97 in O. anthonyi ).

Description (holotype AMS 30742). Adult female with incision on right side. Head wide (HW/SV = 0.37), with steeply oblique, slightly concave loreal region. Canthus rostralis rounded, shallowly concave when viewed from above. Nostrils directed anterolaterally, closer to tip of snout than to eyes. Internarial distance narrower than distance from naris to eye (EN/SV = 0.83, IN/SV = 0.074, EN/IN = 1.12). Snout slightly rounded and protruding when viewed from the side, shallowly angulate when viewed from above. Eyes moderately large (EY/SV = 0.12); eyelid somewhat greater than half width of interorbital distance. Tympanum indistinct and small (TY/SV = 0.034). Dorsal skin smooth; ventral surfaces coarsely granular; supratympanic fold obscure, barely developed. Fingers unwebbed, bearing discs with terminal grooves (3rdF/SV = 0.067); relative lengths 3>4>2>1. Finger discs approximately twice width of penultimate phalanges. Subarticular tubercles well developed; inner metacarpal tubercle oval and well developed; outer absent. Toes webbed, webbing reaching penultimate tubercles on T2 and T5 and almost reaching penultimate tubercle on T3. Toes bearing discs with terminal grooves (4thT/SV = 0.058); relative lengths 4>5=3>2>1. Toe discs smaller than those of fingers (3rdF/4thT = 1.15),

(*) in Western Province, Papua New Guinea.

approximately twice width of penultimate phalanges, except approximately 1.5 times width on T1. Subarticular tubercles distinct; inner metatarsal tubercle low and oval; outer absent. Hind legs rather short (TL/SV = 0.40).

In preservative, dorsum with pale straw-yellow ground color heavily stippled with minute brown punctations; stippling irregular in distribution, producing a mottled impression to the naked eye. Eyelids dark gray-brown; tympanum lighter than surrounding skin; face stippled more darkly than top of head or areas immediately behind. Rear of thighs as for dorsum. Venter pale straw yellow with brown punctations concentrated around lower jaw margin, and with sparse minute punctations scattered throughout chin and throat. Abdomen clear of punctations, and under legs virtually so. Iris black.

Measurements (in mm). SV = 35.1, TL = 14.0, HW = 13.1, HL = 10.6, IN = 2.6, EN = 2.9, SN = 4.5, EY = 4.1, TY = 1.2, 3rd F = 2.35, 4th T = 2.05.

Variation. Mensural variation for the few specimens of the type series is little ( Table 1), and there appear to be no consistent difference between the sexes. The third and fifth toes are usually subequal in length, but a few specimens have the fifth toe slightly longer than the third. Toe webbing typically reaches up to the penultimate tubercle on the fifth toe but may either reach the bottom of the penultimate tubercle on the third toe or lie entirely below it.

Specimens vary in appearance from light tan to dark tan dorsally and are typically unicolor ( Fig. 1 ), but may be mottled ( Fig. 2 ); these differences reflect the degree to which minute dark-brown punctations, which produce the darker appearance, are distributed across the dorsum. Some specimens have stippling limited to the face and top of head; others have it evenly distributed across both dorsum and ventrum. One specimen (BPBM 35949) is very similar in coloration to the holotype but the dorsum is less mottled; the tympanum is not lighter and face not darker than the surrounding skin; and the chin, throat, and chest are more densely stippled with brown. AMNH 130500 too is heavily stippled laterally and dorsolaterally but has the top of head and mid-dorsum with little dark stippling, producing an appearance of a medium-brown frog mottled mid-dorsally with light tan. In life, this animal had a striking pattern of yellow tan and dark brown with pale blue-white flecks scattered across the dorsum and legs ( Fig. 2 ). Two paratypes (AMS 30741 and AMNH 84537) have a wide light-tan vertebral stripe, margined on each side by a slightly narrower dark-brown stripe. In a few animals, the dark stippling is somewhat more concentrated along the canthus, giving the appearance of a vague darker line there. In life, AMNH 130500 had a tan iris with a few black veins ( Fig. 2 ).

Mature males vary from 26.3–31.5 mm SV; mature females from 31.3–35.1 mm; BPBM 35949 is an immature female at 30.2 mm.

Etymology. The species is named, in allusion to its arboreal habits, for one of the hamadryads, demigods of Greek mythology who lived in trees. It is a proper noun in apposition, and the accent occurs on the first syllable.

Distribution. Known only from the type locality in the Hindenburg Range at 1280 m elevation of western Papua New Guinea ( Fig. 3 ) and a second locality c. 30 km to the WNW in the Star Mountains at 840 m.

Figures

Fig. 1.Views of (A) dorsum, (B) ventrum, (C) side of head, (D) right hand, and (E) left foot of holotype (AMS 30742)

Fig. 2. Portrait in life of paratype AMNH 130500 from Finalbin, Western Province. Photo taken by R. Zweifel.

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