Oreophryne wolterstorffi (Werner)

ZWEIFEL, RICHARD G., MENZIES, JAMES I. & PRICE, DAVID, 2003, Systematics of Microhylid Frogs, Genus Oreophryne, from the North Coast Region of New Guinea, American Museum Novitates 3415, pp. 1-32 : 27-28

Oreophryne wolterstorffi (Werner)

Hylella wolterstorffi Werner, 1901: 613 (type locality ‘‘German New Guinea’’; holotype ZMB 16853, collected by Ernst Tappenbeck in 1896 or 1898; see Type Locality).

Hyla wolterstorffi: Van Kampen, 1923: 40 . Loveridge, 1948: 323.

Oreophryne wolterstorffi: Tyler, 1964b: 676 .

TYPE LOCALITY: The type locality of wolterstorffi is indefinite. Dr. Rainer Günther (personal commun.) advised us that the Berlin Museum has no data accompanying the holotype other than ‘‘Neu Guinea’’ and ‘‘Tappenbeck’’. The collector, Ernst Tappenbeck, explored in 1896 westward from the coastal region of Astrolabe Bay (south of Madang) as far as the upper reaches of the Ramu River, and in 1898 traveled upstream (south) from the mouth of the Ramu more than 300 km, overlapping a segment of the river he had previously explored from the south ( Wichmann, 1912: 643–644; Souter, 1963: 76–78); see figure 9 for the combined routes. We cannot even approximate where or on which of these routes the type specimen may have been taken.

DEFINITION AND DIAGNOSIS: A small Oreophryne , probably with a ligamentous connection of procoracoid and scapula ( Tyler, 1964b: 676), and with relatively large eyes, narrow head, short eye–naris span, unwebbed fingers, fifth toe longer than third, and scant toe webbing. These and other characters in combination provide a tentative diagnosis distinguishing wolterstorffi from other species in the north coast region. See Comparisons with Other Species.

MORPHOLOGY: The holotype (sole specimen) has the following measurements and proportions 8: SVL 22.6, HW 8.0, TL 10.4, EY 3.0, EN 1.85, IN 1.75, HD 6.2, FT 9.0, FD 1.3 (penultimate phalanx 0.5), TD 1.15 (0.4), TY 0.75; HW/SVL 0.354, TL/SVL 0.460, EY/SVL 0.133, EN/SVL 0.082, IN/ SVL 0.077, HD/SVL 0.274, FT/SVL 0.398, FD/SVL 0.058, TD/SVL 0.051.

8 Measured by R.G.Z. in 1997; there are minor differences from data in Tyler (1964b).

Head slightly narrower than body; canthus rostralis rounded, loreal region moderately steep, slightly concave; snout narrowly rounded seen from above, vertical in profile; interorbit 3.1 mm, eyelid 2.0 mm; tympanic ring scarcely visible. Fingers 3> 2> 4> 1, 1st longer than one­half of 2nd, all with broad disks, no webbing; toes 4> 5 = 3> 2> 1, all with well­developed disks, webbed to subarticular elevation between toes 4 and 5, to anterior edge of subarticular elevation between 3 and 4.

COLOR AND PATTERN: The faded dorsal color and pattern are now pale yellowish brown with white dorsolateral streaks and white on top of snout and loreal region. Werner (1901: 613) stated: ‘‘Upperside brownish white, gray spotted. A dark brown stripe passes horizontally from the posterior corner of the eye to above the eardrum, but not beyond the head. Snout and face pale to between the eyes, posterior of head dark brown, the two colors sharply separated from oneanother. Limbs indistinctly flecked with brown.’’ Abdomen and undersides of thighs marbled white and pale brown.

VARIATION IN SIZE AND PROPORTIONS: Not known.

COMPARISONS WITH OTHER SPECIES: O. wolterstorffi and O. geislerorum are similar, but as seen in regression plots the TL of wolterstorffi is longer than in geislerorum (out of range), and its short EN and IN are at the edge of the geislerorum ranges. See following Discussion.

Oreophryne brachypus of New Britain is closely similar to geislerorum in most aspects of morphology; wolterstorffi differs in its greater TL and absence of hand webbing.

Oreophryne hypsiops occurs on the route of Tappenbeck’s 1896 expedition south of Madang (fig. 9). Although resembling hypsiops in its narrow head width, wolterstorffi has a larger EY, broader IN, and a shorter EN (though matched by one specimen of hypsiops ). Both FD and TD are narrower in wolterstorffi .

Oreophryne biroi differs from wolterstorffi in its greater HW and, especially, greater EN and IN. This is true both of the sample from Madang Province and of the larger sample that also includes specimens from East and West Sepik provinces and Papua.

Oreophryne parkeri has much shorter TL, narrower HW, larger EY, and smaller IN than does wolterstorffi .

ADVERTISEMENT CALL: Not known.

HABITAT AND HABITS: Not known.

DISTRIBUTION: The species is known only from the indefinite type locality, ‘‘German New Guinea’’ (see above); the approximate path followed by the collector is indicated in figure 9.

LOCALITY RECORDS AND SPECIMENS EXAM­ INED: German New Guinea ( ZMB 16853, holotype) .

DISCUSSION: We are unable to associate the holotype of wolterstorffi with any species described from New Guinea nor with any undescribed species of which we are aware. The first of Tappenbeck’s expeditions may have taken him to within 200 km of the known range of geislerorum in the Markham River drainage northwest of Lae. O. geislerorum may range northwest of its present known limit, if not in the relatively dry Markham­Ramu trough, then in adjacent uplands that have not been well collected for frogs. Given the large size of the geislerorum regression sample (48 specimens), it would be remarkable if one additional individual would be at the edge of the range of variation or well out of it (TL) in three proportions. Also, the differences deviate in opposite directions with respect to the size of wolterstorffi , which has the TL of a much larger geislerorum and the IN of a smaller one. Synonymization of wolterstorffi under geislerorum does not appear justified, though if the latter should be discovered within the area traversed by Tappenbeck, and if no additional typical wolterstorffi are found, the issue may be reopened.

The smaller eye and narrower internarial span of Oreophryne parkeri seem to rule out identity with wolterstorffi . The poor condition of the parkeri types must be kept in mind, but the distinctive narrow internarial span of parkeri is not likely to have been significantly modified. Also, the distance between the localities for parkeri and the closest point at which wolterstorffi may have been collected—the mouth of the Ramu Riv­ er in Papua New Guinea, about 660 km — argues against conspecificity.

For the present, Oreophryne wolterstorffi remains a species of indefinite provenance whose validity remains to be established.