Oreophryne parkopanorum, Kraus, Fred, 2013

Kraus, Fred, 2013, Three new species of Oreophryne (Anura, Microhylidae) from Papua New Guinea, ZooKeys 333, pp. 93-121 : 101-106

Oreophryne parkopanorum sp. n. Figs 2C, D, 5

Holotype.

BPBM 22789 (field tag FK 11847), adult female, collected by F. Kraus 1.2 km S Mt. Sapau summit, Torricelli Mts., 3.3773°S, 142.5180°E, 1120-1320 m, West Sepik Province, Papua New Guinea, 27 May 2005.

Paratypes

(n = 4). BPBM 22787-88, PNGNM 24152, same data as holotype; BPBM 22790, 1.6 km SSW Mt. Sapau summit, Torricelli Mts., 3.3807°S, 142.5155°E, 1050 m, West Sepik Province, Papua New Guinea.

Diagnosis.

Oreophryne parkopanorum can be distinguished from all congeners by its unique combination of small size (adult male SV = 17.5-17.7 mm, adult female SV = 20.1 mm); cartilaginous connection between the scapula and procoracoid; unwebbed toes; third toe longer than fifth; leg moderately long (TL/SV = 0.45-0.51); head short (HL/SV = 0.35-0.36, HL/HW = 0.89-0.91), snout long and broad (EN/IN = 0.76-0.89, EN/SV = 0.085-0.097, IN/SV = 0.102-0.120); eye large (EY/SV = 0.14-0.15); finger and toe discs broad (3rdF/SV = 0.048-0.068, 4thT/SV = 0.044-0.053, 3rdF/4thT = 1.08-1.30); longitudinal rows of ridges or pustules on dorsum; dorsum paler mid-dorsally than dorsolaterally; and coppery-brown iris.

Comparisons with other species.

The new species differs from all other Papuan Oreophryne except Oreophryne alticola and Oreophryne habbemensis in its unique combination of having a cartilaginous connection between the scapula and procoracoid, absence of toe webbing, and third toe longer than the fifth. Oreophryne parkopanorum differs from these species in its longer leg (TL/SV = 0.45-0.51 vs. 0.33-0.38 in Oreophryne alticola and Oreophryne habbemensis ), longer and wider snout (EN/SV = 0.085-0.097 vs. 0.064-0.065 in Oreophryne alticola , 0.073-0.081 in Oreophryne habbemensis ; IN/SV = 0.102-0.120 vs. 0.079-0.088 in Oreophryne alticola , 0.082-0.089 in Oreophryne habbemensis ), larger eye (EY/SV = 0.14-0.15 vs. 0.10-0.13 in Oreophryne alticola , 0.12-0.13 in Oreophryne habbemensis ), broader finger discs (3rdF/SV = 0.048-0.068 vs. 0.031-0.040 in Oreophryne alticola , 0.034-0.044 in Oreophryne habbemensis ), and broader toe discs (4thT/SV = 0.044-0.053 vs. 0.026-0.033 in Oreophryne alticola , 0.034-0.038 in Oreophryne habbemensis ).

Several other species also share with Oreoprhyne parkopanorum the combination of a cartilaginous connection between the scapula and procoracoid and absence of toe webbing. Of these, Oreophryne anamiatoi , Oreophryne asplenicola , Oreophryne flava , Oreophryne graminus , Oreophryne notata , Oreophryne pseudasplenicola , and Oreophryne streiffeleri are easily distinguished from Oreoprhyne parkopanorum in having the fifth toe obviously longer than the third. Oreophryne brevicrus , Oreophryne clamata , Oreophryne geminus , and Oreophryne terrestris are somewhat less distinct in this respect in having the third toe subequal to the fifth, instead of distinctly longer. Besides relative toe length, Oreophryne parkopanorum further differs from Oreophryne clamata in its broader snout (IN/SV = 0.102-0.120 vs. 0.091-0.103 in Oreophryne clamata ), lesser relative size of finger discs to toe discs (3rdF/4thT = 1.08-1.30 vs. 1.50-1.63 in Oreophryne clamata ), longer head (HL/SV = 0.35-0.36 vs. 0.28-0.30, HL/HW = 0.89-0.91 vs. 0.70-0.82 in Oreophryne clamata ), and absence of a dark subocular blotch and black spots around arm insertion (both present in Oreophryne clamata ).

Oreophryne brevicrus , Oreophryne geminus , and Oreophryne terrestris are all alpine species instead of mid-elevation forest dwellers. Beyond relative toe length, Oreoprhyne parkopanorum also differs from Oreophryne brevicrus in its longer leg (TL/SV = 0.45-0.51 vs. 0.36-0.42 in Oreophryne brevicrus ), mid-dorsum paler than dorsolateral regions (mid-dorsum darker than dorsolateral regions in Oreophryne brevicrus ), and venter with scattered large brown flecks (venter evenly stippled with brown in Oreophryne brevicrus ); and it differs from Oreophryne geminus and Oreophryne terrestris in its longer leg (TL/SV = 0.45-0.51 vs. 0.32-0.39 in Oreophryne geminus , 0.34-0.44 in Oreophryne terrestris ), broader finger discs (3rdF/SV = 0.048-0.068 vs. 0.030-0.041 in Oreophryne geminus , 0.031-0.042 in Oreophryne terrestris ), and broader toe discs (4thT/SV = 0.044-0.053 vs. 0.025-0.039 in Oreophryne geminus , 0.024-0.042 in Oreophryne terrestris ).

Description of holotype.

An adult female with lateral incision on right side and left pectoral region dissected. Head wide (HW/SV = 0.40), with steeply oblique, slightly concave loreal region; upper lip somewhat inflated. Canthus rostralis rounded, slightly concave when viewed from above (Fig. 5A). Nostrils directed laterally, closer to tip of snout than to eyes. Internarial distance wider than distance from naris to eye (EN/IN = 0.77, IN/SV = 0.109, EN/SV = 0.085). Snout truncate when viewed from the side (Fig. 5B), shallowly angulate when viewed from above (Fig. 5A). Eyes moderately large (EY/SV = 0.14); eyelid approximately two-thirds width of interorbital distance. Tympanum small (TY/SV = 0.050), with distinct annulus, partly covered by surrounding flesh dorsally, projecting ventrally. Dorsum with many raised ridges and series of tubercles, one paired series of tubercles forming an hourglass pattern from behind eyes to posterior of body, each line of warts constricting medially at shoulder and then diverging slightly laterally past this; sides tuberculate; ventral surfaces smooth anteriorly, granular on abdomen. Supratympanic fold absent; few tubercles posterior to tympanum. Fingers unwebbed, bearing discs with terminal grooves; relative lengths 3>4>2>1 (Fig. 5C). Finger discs slightly less than twice width of penultimate phalanges (3rdF/SV = 0.057), except for F1, which is only slightly wider than penultimate phalanx. Subarticular tubercles not obvious; inner metacarpal tubercle oval but low; outer not apparent. Toes unwebbed, bearing discs with terminal grooves; relative lengths 4>3>5>2>1 (Fig. 5D). Toe discs smaller than those of fingers (4thT/SV = 0.044, 3rdF/4thT = 1.32), somewhat less than 1.5 times width of penultimate phalanges on T4 and T5 but wider on T2 and T3. Subarticular tubercles very low or absent; inner metatarsal tubercle large, oval; outer absent. Hind legs moderately long (TL/SV = 0.50).

In preservative, dorsum with pale straw-yellow ground, heavily dusted with brown punctations, with areas having darker dusting and areas lacking dusting arrayed in rows. Pale straw-yellow vertebral stripe; pale straw-yellow blotch above each forearm insertion; pale straw-yellow triangle on top of snout (Fig. 5A). Series of darker-brown flecks dorsolaterally; dark-brown flecks widely scattered laterally; two dark-brown dashes behind eye, one largely superior to the tympanum, the other inferior to it and ending in a brown patch at rictus (Fig. 5B). Face irregularly dusted/mottled with brown, but not as dark as markings on body. Legs, including front and rear of thighs, pale straw yellow with scattered pale-brown flecks. Short, pale straw-yellow stripe on back surface of distal portion of shank and on heel. Irregular brown blotch dorsally on each wrist. Chin and throat evenly dusted with brown punctations except mid-ventrally on chin, where its absence forms a pale line, adjacent to which the brown dusting is more heavily concentrated; abdomen also heavily dusted with brown, but with more irregular distribution than on chin and throat. Palmar and plantar surfaces pale straw yellow evenly dusted with brown punctations. Iris dark brown.

Measurements of holotype (in mm).-SV = 20.1, TL = 10.0, HW = 8.0, HL = 7.3, IN = 2.2, EN = 1.7, SN = 2.9, EY = 2.9, TY = 1.0, 3rdF = 1.14, 4thT = 0.88, mass = 0.8 g.

Variation.

The female is larger than the males and has a slightly larger tympanum and greater disparity in disc widths between the fingers and toes (Table 3). It remains to be determined from a larger sample size whether these represent instances of sexual dimorphism. Otherwise, there is little mensural variation of interest in the small sample.

Snout profile varies from truncate to shallowly angulate when viewed from the side, shallowly angulate to acutely rounded when viewed from above. The female holotype is more heavily tuberculate than the male paratypes, which typically have the hourglass-shaped rows of tubercles well-defined dorsolaterally and also have scattered tubercles on the lateral surfaces, as well as smaller pustules apparent elsewhere, especially posterior to the tympanum.

The holotype is the only specimen with a broad vertebral stripe and heel stripe (Fig. 2D), but two males (BPBM 22790 and PNGNM 24152) have narrower, inter mittent vertebral lines. All specimens have the mid-dorsal region paler than the sides, giving the impression of a paler hourglass-shaped region mid-dorsally. Most specimens are moderately heavily dusted with brown dorsally, as seen in the holotype, but the subadult male (BPBM 22787) is paler overall, with brown dusting less dense dorsally. This specimen also has two rows of dark-brown dashes laterally, extending from near forearm insertion to posterior third of body, the upper row at the level of the dark-brown supratympanic dash, the lower at the level of forearm insertion. BPBM 22790 also has these two rows of dark-brown lateral dashes well defined, but the other three specimens have brown flecking and spotting more irregularly distributed across the lateral surfaces. The snouts of all specimens are paler than the remainder of the head, but brown flecking occurs in this field in some specimens, thereby making the feature less obvious. The males all have an even dusting of brown punctations ventrally, as seen in the holotype, but also have large, darker-brown spots scattered across the ventrum, giving the impression of a pale venter with scattered large brown flecks; these spots are weaker in BPBM 22788 than in the other specimens. In the subadult male, these larger brown spots are arrayed more or less into two rows extending from the chin to the abdomen. None of the males has the pale, brown-bordered, mid-ventral line seen on the chin of the holotype.

Color in life.

Field notes for BPBM 22787 note: "Dorsum light yellow brown with narrow dark-brown lines. Fore and aft of thigh and rear of shank orange-red. Venter pale straw with two rows of dark-gray flecks on chin and throat. Iris light brown." The holotype, BPBM 22789 (Fig. 2D) was similar but had a yellow stripe from chin to abdomen, another across the pectoral region, and an orange mid-dorsal stripe. Brown dorsolateral and postocular markings are more evident in some animals (Fig. 2C) than others (Fig. 2D). Animals are more orangish during the night and yellower during the day. The orange-red on the hidden surfaces of the thighs fades to pale straw in preservative.

Call.

The call is uncertain. I heard two undetermined frog calls at the type locality that are consistent with Oreophryne species from the north-coast ranges. One of these was a rattle call, the other was a series of high-pitched peeps. But I could associate neither call with a particular frog, so the identities of both are undetermined. One of them almost certainly represents Oreoprhyne parkopanorum , but I cannot say which.

Etymology.

The species name is a genetive plural honorific for the people of Parkop Village, whose unflagging help and friendliness made my expedition to the Torricelli Mts. successful and most pleasant.

Range.

Known only from the upper elevations of Mt. Sapau, Torricelli Mts., West Sepik Province, Papua New Guinea at an elevation of 1050-1320 m (Fig. 4, star). It probably occurs in similar habitat elsewhere in the Torricelli Mts. and may occur in the upper elevations of other nearby north-coast ranges.

Ecological notes.

This species inhabits primary mossy cloud forest at 1200-1300 m. We found our specimens active at night on moss-covered tree trunks from 6 cm to 2 m above ground. Forest in this area has a canopy of approximately 20 m height, many epiphytes, and a thick layer of leaf litter and duff.

Mature males were 17.5-17.7 mm in SV, but one male was still immature at 15.8 mm SV.

Syntopic frogs include Albericus brunhildae , Austrochaperina septentrionalis , Choerophryne longirostris , Choerophryne rostellifer , Copiula tyleri , Hylarana jimiensis , Hylarana volkerjane , Hylophorbus sp., Liophryne schlaginhaufeni , Litoria modica , Litoria wollastoni , Nyctimystes pulcher , and Xenorhina arboricola .