SPHENOPHRYNE - American Museum of Natural History

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46 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 253 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.’’ Méhely¨’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
2000 ZWEIFEL: PARTITION OF SPHENOPHRYNE 47 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 2.5 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 darker 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 dor- solateral 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
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SPHENOPHRYNE - American Museum of Natural History

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