Austrochaperina novaebritanniae, ZWEIFEL, 2000

ZWEIFEL, RICHARD G., 2000, Partition Of The Australopapuan Microhylid Frog Genus Sphenophryne With Descriptions Of New Species, Bulletin of the American Museum of Natural History 2000 (253), pp. 1-130 : 45-48

Austrochaperina novaebritanniae , new species Figure 26

Sphenophryne mehelyi : Tyler, 1967: 188 (initial published reference to A. novaebritanniae ).

HOLOTYPE: AMNH A83058 , collected on August 28, 1969, by Harold Cogger (Alpha Helix Expedition) about 12 miles (19 km) from Rabaul, East New Britain Province, Papua New Guinea, on the road to Keravat.

PARATYPES: All localities in East New Britain Province. AMNH A83053–83057 , A88569 (C&S), AMS R29243 , 29246 , 29251 , 29253–29255 , 29259 , 29266 , 29268 , 29272 , 29279 , 29282 , 29285 , 29286 , 29296 , 29305 , 29313 , 29314 , 29317 , 29318 , 29324 , 29328 , 29329 , 29331 , 29333 , 29334 , 29343– 29346 , 29349 , 29351 , 29352 , 29355 , 29361– 29363 , 29366 , 29368 , 29370–29372 , all with same data as holotype ; AMNH A79870– 79872 , MCZ A73085 , 73086 , BMNH 1968.525 , collected by D. Morgan at Keravat in March and July 1966 ; ZMUC R9151– 9164 , collected on the Noona Dan Expedition (Wolff, 1966), May 10–22, 1962, at Yalom, 1000 m (4°25′S, 151°47.5′E) .

ETYMOLOGY: The species name is a Latin substantive in the genitive, formed from the adjective novus and the noun Britannia, meaning ‘‘of New Britain,’’ and refers to the species’ provenance.

DIAGNOSIS: A small species, males to 19 and females to 21 mm SVL, with finger discs slightly broadened and a dorsal color pattern of tiny white spots on a dark background, the venter similar but with slightly larger spots.

DESCRIPTION OF HOLOTYPE: Adult female, gravid, with the following measurements and proportions: SVL 18.2, HW 6.5, TL 8.5, EY 2.1, EN 1.35, IN 1.9, HD 3.7, FT 7.8, third finger disc 0.45, fourth toe disc 0.70, TY 0.8; TL/SVL 0.467, HW/SVL 0.357, EY/SVL 0.115, EN/SVL 0.074, IN/SVL 0.104, EN/IN 0.710, HD/SVL 0.203, FT/SVL 0.429, TY/ EY 0.405, third finger disc/SVL 0.025, fourth toe disc/SVL 0.036.

Snout bluntly rounded seen from above, rounded and slightly projecting in profile; nostrils lateral, slightly visible from above, widely spaced and closer to tip of snout than to eye, appearing almost terminal in lateral view; loreal region flat with a moderate slope, canthus rostralis rounded, not at all angular; eyes lateral, relatively large, upper lid about 75% of interorbital space; tympanum small, less than one-half eye diameter, outline of annulus scarcely visible. Relative lengths of fingers 3> 2 = 4> 1, first about one-half length of second, all with somewhat pointed, grooved terminal discs slightly broader than the terminal phalanges, subarticular and metacarpal elevations barely indicated (fig. 57B). Toes unwebbed, relative lengths 4> 3> 5> 2> 1, discs larger than those on fingers, slightly pointed and grooved, subarticular elevations barely evident, a small inner but no outer metatarsal elevation (fig. 57B). A brief, weak postocular fold; other dorsal and ventral body surfaces smooth.

A color transparency furnished by Harold Cogger shows a frog with a dark, almost black ground color, an abundance of small white spots, and between these are numerous smaller, brick-red spots.

The dorsal ground color in preservative is tan with no regional differentiation except that the loreal region is slightly duskier. A pattern of tiny pale spots on all the dorsal surfaces, including the legs, is uniform except for greater density on the eyelids. The ventral surfaces are slightly paler with a uniform pattern of pale spots larger and sparser than those of the dorsum.

VARIATION IN TYPE SERIES: Variation in proportions is set forth in table 2, and regression data are in table 3. The largest of 61 specimens I measured is a female, SVL 21.9 mm. Females as small as 18.2 mm are gravid, whereas one at 17.1 mm appears just to be maturing. The largest male measured 19.0 mm. Tyler (1967) reported adult males 15.5–17.2 mm SVL and adult females 17.0– 20.1 mm SVL.

There is little variation in color pattern. The dorsal ground color of preserved specimens may range from light to dark brown with the top of the snout and loreal region even darker, and the light spots may be less abundant medially on the back, snout and eyelids.

ILLUSTRATIONS: 3rd finger terminal phalanx, fig. 71K; premaxilla, fig. 64B; vomer, fig. 65J; hand and foot, fig. 57B.

CALL: The call has not been described.

COMPARISONS WITH OTHER SPECIES: Tyler (1967: 188) characterized the coloration of specimens from Keravat as agreeing ‘‘in all respects with that of the holotype ’’ of Sphenophryne mehelyi , which Parker (1934: 156) described as ‘‘uniformly brown above, the flanks with scattered lighter dots; lower surfaces dirty white, the throat and chest washed with pale brown and irregularly spotted with white.’’ Méhelÿ’s (1901: pl. 12, fig. 3) illustration of the ventral surface of mehelyi (as Chaperina fusca ) agrees with Parker’s description rather than with the light brown, white spotted chin, chest, and abdomen of novaebritanniae . For additional comparison with mehelyi , see the account of that species. A. novaebritanniae and the similar yelaensis are compared the account of the latter.

HABITAT AND HABITS: Tyler (1967) described the Keravat locality as one that three months prior to the collection of the frogs had been cleared of virgin rainforest. Large numbers of frogs were aggregated beneath piles of decomposing vegetation—rotting grass and reeds laid upon ground covered with leaf mould. Numerous frogs were in small depressions, sitting on clumps of five or six eggs. The frogs in attendance were said to be females, although it is not clear whether the collector segregated the associated individual specimens with their egg clutches or if sex was merely assumed.

DISTRIBUTION: The only known localities for this species (see Holotype and Paratypes, above) are at the northern end of New Britain (fig. 30).

Austrochaperina palmipes (Zweifel) , new combination Figure 31F

Sphenophryne palmipes Zweifel, 1956: 15 (type locality, ‘‘north slope of Mt. Dayman , Maneau Range, Territory of Papua [Milne Bay Province, Papua New Guinea], at an elevation of 700 meters’’; holotype AMNH A57331 , collected by G. M. Tate on the Fourth Archbold Expedition to New Guinea, July 16, 1953.

DIAGNOSIS: This species differs from other Austrochaperina in its extensively webbed toes and usually in having a prominent, downward-directed, spikelike projection on each vomer.

MORPHOLOGY: The holotype, an adult male 36.1 mm SVL, is described in detail in Zweifel (1956: 15–17). Size moderately large among Austrochaperina , maximum about 40 to 49 mm SVL, evidently varying among populations (see Variation, below), with many body proportions falling in the midrange for the genus as a whole. Head average in width (HW/SVL, 0.38), narrower than body. Snout obtusely pointed in dorsal view, similar and projecting in profile; loreal region sloping, very shallowly concave, canthus rostralis verging on angular, but not sharply defined; nostrils lateral, barely visible from above, appearing close to end of snout in profile. Eyes large, visible from beneath, EY/SVL about 0.13, rarely equaled and not exceeded in any other Austrochaperina ; eyelid slightly narrower than interorbital space. Tympanum present but no external sign of it or its annulus. Relative lengths of fingers 3> 4> 2> 1, first well developed, each with a prominent disc bearing a terminal groove; disc on third finger about 2.5X width of penultimate phalanx, typically slightly narrower than disc on fourth toe but occasionally equal or a little broader. Relative lengths of toes 4> 3> 5> 2> 1, all with well-developed discs, largest of any Austrochaperina , disc on fourth toe about twice width of penultimate phalanges; toes webbed to base of disc of fifth toe and about to proximal subarticular elevation on both sides of fourth toe. Fingers and toes with low, rounded subarticular elevations; a low, elongate inner metacarpal elevation flanked by a broader, round middle-outer elevation; a low, elongate inner metatarsal elevation but no outer. A narrow, straight, postorbital fold passing diagonally from eye to forearm insertion. Dorsal body surface generally smooth, without conspicuous folds, but with a tendency to develop an elevated network of low ridges; ventral surfaces smooth. Males lack vocal sac openings.

There are no maxillary or premaxillary teeth. Near its medial end each vomer typically possesses a bony spike (fig. 65O) projecting from the roof of the mouth. This structure is not always so spikelike as illustrated. It may be more broadly buttressed, or less often is represented by a mere nubbin scarcely evident in the preserved specimen.

COLOR AND PATTERN: Color in preservative is dull gray-brown dorsally with vague dark- er markings rarely well enough defined to be called a pattern. A narrow dark line follows the lower edge of the postorbital fold and below that a broader pale streak. The dorsolateral area of the body may be somewhat darker than the middle of the back, and the lateral area is slightly mottled. In some specimens there is a pattern associated with the dorsal fold network mentioned above. The ventral ground color is pale tan, with conspicuous darker mottling on the throat, a variable scattering of melanophores on the chest and abdomen, and a dusky shade to the undersides of the hind limbs. Occasional individuals are dark beneath on all ventral body surfaces, with coarse light mottling. There is no conspicuous patterning to the groin or thighs.

The dorsal color in life is brown or a mixture of brown and green. Menzies (1976, pl. 11c) published a color photo. My field notes mention ‘‘brown without any distinct pattern... faint light interocular bar.... Greenish brown with obscure darker markings... Wshaped scapular mark.... Dark brown with light green flecks.... greenish brown with... darker brown mottling.’’ The undersurfaces are gray or greenish gray with darker gray or brown spotting and mottling on the chin, with this pattern being fainter on or entirely absent from the chest and abdomen. There are no flash colors in the groin or on the thighs. The iris is dark, much the same as the dorsal ground color, with the horizontally elliptical pupil narrowly margined with gold.

VARIATION IN SIZE AND PROPORTIONS: Adult A. palmipes have sexual dimorphism in the shape and color of the snout. In males the snout is slightly more projecting and is pale, almost white, in larger individuals, whereas females retain a less projecting snout, with the darker ground color common to juveniles of both sexes. Male palmipes lack a vocal sac, so my usual criterion of male maturity, presence of vocal slits, is inapplicable. Hence, I have used the presence of a distinctly pale snout as indication of sexual maturity in males.

There is geographic variation in maximum size and size at sexual maturity, with frogs on Normanby Island attaining a larger size than those elsewhere. Seven adult females measure 43 to 49 mm SVL (six of them 45 mm or greater), whereas the largest in any other sample is only 44 mm. Males are smaller than females in all samples, but again those from Normanby are the largest: three from Normanby are 36 to 38 mm, contrasted to a maximum of 37 mm in all other samples. The smallest frogs are those of the Huon Peninsula, where adult females (N = 21) measure from 32 to 40 mm and adult males from 28 to 33 mm (N = 7). Samples intermediate between these extremes, but not necessarily identical among themselves, include those from Goodenough Island, Mt. Dayman, the Wau-Garaina area, and Simbu Province.

Visual comparison of regression lines for several proportions in four samples of palmipes shows little geographic variation. Only in the case of slightly larger eyes in the Normanby Island sample does one line stand out much from the rest. Regression and proportion statistics are in tables 2 and 3.

ILLUSTRATIONS: 3rd finger terminal phalanx, fig. 71P; premaxilla, fig. 64G; sacral region, fig. 73C; vomer, fig. 65O; finger disc, fig. 51; hand and foot, fig. 56D. Kuramoto and Allison (1989) illustrated the karyotype.

CALL: Menzies (1976: 55) mentioned ‘‘a quiet clicking noise which I believed was made by a palmipes by the side of a forest stream.’’ Verification that palmipes calls (though lacking vocal slits) is needed.

COMPARISONS WITH OTHER SPECIES: Within its geographic range there is no Austrochaperina species with which palmipes could readily be confused, as the combination of extensive toe webbing and relatively large digital discs is unique. The closely related species rivularis, macrorhyncha , and basipalmata are allopatric to palmipes , so far as is known, and either lack or have only slight toe webbing.

HABITAT AND HABITS: This is a riparian species of foothill and lower montane rainforest, ranging in elevation from less than 100 m to at least 1700 m. I have found these frogs by day under streamside rocks and at night on mossy rocks in small streams. Menzies (1976: 55) reported that frogs ‘‘were clinging to wet rocks, especially near waterfalls.... When disturbed, they dived into the water and reappeared a little distance away.’’ For descriptive accounts of areas where this species occurs, see Brass, 1956 (Mt. Dayman and Goodenough Island) and 1959 (Normanby Island).

Although it probably is the most aquatic of the New Guinean microhylids, A. palmipes still must resort to land for breeding. Dr. Allen Allison (personal commun.) reports an individual attending eggs ‘‘in a depression under leaf litter along the bank of a small stream.’’ A female about 35 mm SVL contained 19 ova each of which was 3 mm in diameter.

DISTRIBUTION: This species occupies the Huon Peninsula, the northeast slopes of the mountains from the Huon Gulf to the eastern tip of New Guinea, and the D’Entrecasteaux Islands (not yet recorded from Fergusson Island). In addition, there is an apparently isolated population on the west side of the central ranges in the Purari River drainage of Gulf and Simbu Provinces (fig. 29). This isolated area is more than 200 km from the nearest locality for the species to the east in Morobe Province. Additional collecting may be expected to narrow the gap, but there are few passes as low as the maximum elevation that palmipes is known to attain. It is likely that the populations truly are disjunct. A similar apparent range disjunction occurs in another microhylid frog, Cophixalus cheesmanae (Zweifel: 1979, fig. 8). Records range in elevation from 60 to 1750 m.

LOCALITY RECORDS AND SPECIMENS EXAMINED: PAPUA NEW GUINEA: Gulf Prov.: Camp III, Nimi River, 13.5 km S, 1 km E Soliabedo, 425 m ( AMNH A79973 ; MCZ A111901–111914 ). Simbu Prov.: Camp I, 13.5 km S, 2 km E Karimui , 1070 m ( MCZ A111918 ) ; Soliabedo , 550 m ( MCZ A111916 , 111917 ) ; Camp II, Pio River , 6.5 km S, 1 km E Soliabedo, 300 m ( MCZ A111919–111922 ) ; between Camp II, 6.5 km S, 1 km E Soliabedo, and Weiana, 8 km S, 1 km E Soliabedo , 430–730 m ( MCZ A133017 ) ; Haia Village , 720 m, 145°00′, 6°42′( AM 32257 ) ; Haia Bush Camp , 880 m, 145°01′, 6°40′ ( AMS R32443 , R32450 , R32451 , R32471–32476 ). Morobe Prov.: Ulap, 800–1100 m ( BPBM 5322 ) ; Boana , 880 m ( MCZ A111874–111895 ) ; Areganang ( AMNH A81200–81209 ) ; Gang Ck. , 1340 m ( AMNH A75048–75053 [75050 and 75053 dry skeletons], A76038–76047) ; near Zangaren , 1370 m ( AMNH A76031 , A76032 ) ; Masba Ck. ( AMNH A76033 ) ; Numbut , 1220 m ( AMNH A76034–76037 ) ; Tewep, 1350 m, 11 km E, 8 km N Boana ( BPBM 1048 ) ; Finschhafen ( SAM 5684 [8 specimens]) ; Rari Village, Mt. Shungol , 1250 m ( BPBM 5157 , 5167 ) ; Mt. Missim , about 10 km NE Wau, 1600 m ( BPBM 6409–6416 , 6494 , 6495 ; 9352) ; Black Cat Gap, Mt. Missim , 1700–1750 m ( BPBM 4142 , 4153 ) ; Coldwater Ck., 1055 m, Mt. Missim ( BPBM 9645 ) ; Wau , 1700 m ( BPBM 3054 ) ; Kunai Ck. , 1350 m, 2 km W Wau ( AMNH A81219 , A81220 , A130550 ) ; 3 km E, 5 km S Wau , 1400 m ( AMNH A81218 , A83067 , A83068 ; YPM 5316 ) ; Garaina , 700 m ( AMNH A83059 , A83060 , 83064–83066; YPM 5315 ) ; Gapaia Ck., 1360 m, 1 km N Saureli ( AMNH A81213 ). Northern Prov.: Kokoda , 370 m ( AMNH A75047 ). Milne Bay Prov.: North slope Mt. Dayman , 700 m ( AMNH A56602–56604 , A57062 , A57066 , A57074– 57076 , A57079 , A57104 , A57105 , A57115 , A57122–57124 , A57131–57134 , A57146– 57148 , A57162–57164 , A57168–57170 , A57213–57215 , A57232–57236 , A57331 holotype, A57335, A57339, A57340) ; Goodenough Island , 900 m ( AMNH A56885 , A56893 , A57343–57346 ) ; Goodenough Island , 1600 m ( AMNH A56586–56594 , A56895–56901 , A56948–56955 , A56959 , A56961–56963 , A56968–56970 , A56974 , A56975 , A56977–56983 , A56985 , A56987– 56996 , A57055 , A57056 ) ; Normanby Island, Mt. Pabinama , 820 m ( AMNH A60172– 60181 , A92805–92807 (C&S), A135370– 135396) ; Alotau, 60–150 m (Tyler and Menzies , 1971: 81) .

Figures

Fig. 26. Austrochaperina novaebritanniae, AMS specimen, not individually identified. Harold Cogger photo.

Fig. 31. Examples of Austrochaperina, Liophryne, and Sphenophryne. A. S. cornuta, AMNH A130544, adult. B. A. brevipes, AMNH A130534, SVL 21.9 mm. C. A. guttata, QM J67256, SVL 43.2 mm. D. A. macrorhyncha, MZB 3564, SVL 36.8 mm. E. A. rivularis, holotype, AMNH A130551, SVL 49.0 mm. F. A. palmipes, AMNH A130550, adult. G. L. similis, AMNH A130564, SVL 40.0 mm. H. A. derongo, MZB 3563, SVL 36.7 mm. Photos C, D, and H by S. Richards.