Oxydactyla coggeri, 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 : 80-84

Oxydactyla coggeri , new species

Sphenophryne brevicrus : Bulmer and Tyler, 1968: 342. Menzies and Tyler, 1977: 457.

HOLOTYPE: AMS R22851 , obtained by Papuan collectors for Harold G. Cogger in the vicinity of Fungoi, Kaironk Valley , 2000 m elevation, about 3 km north, 6 km west of Simbai, Madang Province, Papua New Guinea, between Dec. 15, 1963, and Jan. 2, 1964.

PARATYPES: All specimens from Papua New Guinea. Madang Prov.: AMNH A140871–140874 (the last C&S), same data as holotype ; AMS R22647 , R22815–22817 , 22819–22821, 22823–22837, 22839–22850, R22852–22857, R22860, R22861, R22863– 22880, R23121, R23182–23184, R23207, same data as holotype ; AMS 32116–23118 , Bismarck Range, 2200 m, north of Fungoi , collected by H. G. Cogger, Dec. 28, 1963 ; UPNG 837 , 838 , collected by J. Menzies, Aug. 30, 1969 at Kaironk, Schrader Range, 2300 m. Southern Highlands Prov.: UPNG 5559 , collected by J. Menzies, July 9, 1976, at 16 km north of Mendi , 2400 m .

ETYMOLOGY: This species is named for Dr. Harold Cogger of the Australian Museum in recognition of his important contributions to Australasian herpetology, among them collecting the initial specimens of the species.

DIAGNOSIS: Distinguished from other Oxydactyla except O. crassa in that the fingertips are rounded to slightly flattened but not clearly disclike, and the toe tips are disclike with terminal grooves but not or scarcely broader than the penultimate phalanges. The vocalizations of crassa and coggeri differ, the former having a single-note call, the latter a call of similar quality but with several notes uttered in rapid succession. See Comparisons for other morphological differences.

DESCRIPTION OF HOLOTYPE: Adult male (vocal slits present) with the following measurements and proportions: SVL 23.5, HW 9.4, TL 8.4, EY 2.65, EN 1.65, IN 2.2, HD 4.6, FT 8.6, tip of third finger 0.55 (penultimate phalanx 0.525), disc of fourth toe 0.7 (0.65); HW/SVL 0.400, TL/SVL 0.357, EY/ SVL 0.113, EN/SVL 0.070, IN/SVL 0.094, EN/IN 0.750, HD/SVL 0.196, FT/SVL 0.366, third finger tip/SVL 0.023, fourth toe disc/SVL 0.030

Head slightly narrower than body. Snout rounded viewed from above, rounded and scarcely projecting in lateral view; nostrils visible from above; loreal region a flat, gentle slope, canthus rostralis not well defined. Eyes relatively large, corneal outline visible in ventral view, eyelid almost as wide as interorbital space. Tympanic annulus inconspicuous. Relative lengths of fingers 3> 4> 2> 1, first about one-half length of second; tips of fingers rounded to slightly flattened, not clearly disclike, minutely broader than penultimate phalanges, only third with faint terminal groove (fig. 53D); subarticular and metacarpal elevations low, rounded, inconspicuous. Toes unwebbed, relative lengths 4> 3> 5> 2> 1, first short, its tip barely reaching to subarticular elevation of second; tips of second to fourth flattened with terminal grooves but little or no wider than penultimate phalanges, first and fifth less flattened, fifth sometimes weakly grooved (fig. 53D); subarticular elevations low, rounded, inner metatarsal elevation low, elongate, rounded. Dorsal region with many small, inconspicuous tubercles but no folds; a weak postocular-supratympanic fold curving downward behind ear; venter smooth.

The color in preservative is various shades of brown. The facial region is purple-brown, being more concentrated in the canthal area. The area behind the eye is dark, bordered above on a diagonal line directed to the insertion of the arm. A dark postocular streak extends posterior from the eye as a dark band passing above the foreleg and then discontinuously to the groin. The region beneath this band is vaguely mottled brown, paler than the postocular streak. A pale vertebral hairline passes from the snout to just anterior to the cloaca, where it divides and runs along the rear of the thigh and weakly onto the shank. On the back, a narrow streak of dark brown borders the hairline and is in turn bordered by a wider swath of lighter brown, slightly darker than the side of the body below the dark dorsolateral streak. A prominent black spot lies just anterior to the cloaca. The upper sides of the legs are brown with darker spotting, and the back of the thigh below the light line is indistinctly mottled dark and light brown. The chin and chest bear dense, even melanic stippling, which gives way abruptly on the abdomen to a sparser stipple, often with scattered dark spots.

VARIATION IN TYPE SERIES: See table 10 for variation in proportions and table 11 for regression data. The largest specimen is a female, 28.2 mm SVL. The size of females at maturity is about 20–21 mm, as three frogs 19.3–20.6 mm appear to be immature, whereas two at 20.6 mm are gravid. The range in size of mature males (vocal slits present) is 19.0– 26.7 mm SVL.

The back may be unicolor, may have small dark spots, and may have, as does the holotype, a light, midvertebral hairline. Nearly half the specimens tabulated (15 of 38) show at least a trace of the vertebral hairline, which is not always as well developed as described for the holotype.

ILLUSTRATIONS: 3rd finger terminal phalanx, fig. 71D; premaxilla, fig. 63C; sacral region, fig. 72C; vomer, fig. 65C; skull, fig. 67B; hand and foot, fig. 53D.

CALL: James I. Menzies recorded this species at an elevation of 2300 m at Kaironk where the frog (UPNG 837) called from the leaf litter at noon. The two recorded calls each have 11 pure-toned, unpulsed musical notes given over about 2.3 sec at a rate 4.4– 4.5 notes per second (fig. 78B). Notes are 0.04–0.05 sec long and are slightly frequency modulated, dropping about 50 Hz from an initial 900 Hz. Menzies and Tyler (1977) published an audiospectrogram of part of one of these calls in connection with a discussion of vocalization of burrowing microhylids.

COMPARISONS WITH OTHER SPECIES: Oxydactyla coggeri is distinguished from the other species of Oxydactyla known in the same general area of New Guinea — alpestris and stenodactyla —in possessing toe discs. Similar in morphology, although widely separated geographically, coggeri and crassa differ in advertisement calls and sufficiently in certain proportions to permit correct assignment of a large majority of specimens in a mixed sample without reference to geography (fig. 40).

HABITAT AND HABITS: Dr. Harold Cogger (personal commun.) reported finding this species under logs at 2200 m just inside primary rainforest (above grassland).

DISTRIBUTION: Oxydactyla coggeri is known only from two regions. All but one specimen came from the Kaironk Valley– Schrader Mountains area of Madang Province, Papua New Guinea, at the northern edge of the highlands region. A single specimen is from near Mendi, Southern Highlands Province, 120 km to the southwest. Possibly the species may have an extensive range in Enga Province, west of the Schrader Range and north of Mendi, where there has been little collecting (fig. 41). See Holotype and Paratypes for localities and specimens examined.

Oxydactyla crassa (Zweifel) ,

new combination

Sphenophryne crassa Zweifel, 1956: 11 (type locality, ‘‘north slope of Mt. Dayman , Maneau Range, Territory of Papua [Milne Bay Province, Papua New Guinea], at an elevation of 2230 meters’’; holotype, AMNH A56803 , collected by G. M. Tate on the Fourth Archbold Expedition to New Guinea, May 25, 1953).

DIAGNOSIS: Distinguished from other Oxydactyla (except O. coggeri ) in that the fingertips are rounded to slightly flattened but not clearly disclike and the toe tips are disclike with terminal grooves but not (or scarcely) broader than the penultimate phalanges. Differs from coggeri in the advertisement call (see diagnosis of coggeri ) and in certain proportions (see Comparisons with Other Species).

MORPHOLOGY: The holotype, a female with ova 3 mm in diameter, is described in Zweifel (1956); its measurements and proportions are: SVL 28.6, HW 10.7, TL 9.6, EY 3.0, EN 2.2, IN, 2.9, HD 5.5, FT 10.6, FD of 0.6, TD 0.8; TL/SVL O.336, HW/SVL 0.374, HD/SVL 0.210, FT/SVL 0.399, EY/SVL 0.105, EN/SVL 0.077, IN/SVL 0.107, EN/IN 0.722, FD/SVL 0.021, TD/SVL 0.029.

This is a small (up to 30 mm), chunky, short-legged species. Snout bluntly pointed as seen from above, rounded and projecting slightly in profile; nostrils lateral, just visible from above, slightly closer to snout tip than to eye but in lateral view nearly terminal; loreal region flat, moderately steeply sloping, canthus rostralis abrupt but not sharp. Eyes relatively small (EY/SVL 0.109), eyelid width equals about 60% of interorbital distance. Tympanum relatively large (<75% of EY) but scarcely distinct externally. Relative lengths of fingers 4> 3> 5> 2> 1, first more than half length of second; tips not disclike, rounded, equal to or slightly broader than penultimate phalanges, terminal groove not (or but faintly) present; subarticular and metacarpal elevations low, rounded. Toes unwebbed, relative lengths 4> 3> 5> 2> 1, tips flattened and broadened into small but distinct discs with terminal grooves; subarticular and inner metatarsal elevations low, rounded; no outer metatarsal tubercle. A weak, diagonal postocular fold. Back with numerous short skin folds and indistinct rugosities; a><-shaped pair of folds in the scapular region; hind legs somewhat rugose. Ventral surfaces smooth.

COLOR AND PATTERN: In preservative, the dorsum is light brown with indistinct, random, tiny darker spots and some larger spots on the flanks. Lumbar eyespots are more or less evident. The loreal region is slightly duskier than the back. A narrow dark band passes from the tip of the snout through the nostril to the eye and resumes at the posterior corner of the eye, following the postocular fold across the upper edge of the tympanum. This band may terminate anterior to the arm or may continue as a series of spots or as a stripe for a short distance above and past the arm. The venter is pale with relatively large, irregular dark spots, larger on the chin than on the abdomen. The anterior and posterior surfaces of the thighs have dark, splotchy markings, and the posterior surface has an ill-defined, dark triangular seat patch. The undersides of the thighs are pale with obscure dusky markings, whereas the shanks are marked more like the abdomen. The palms are pale with dark markings, the soles the reverse.

Brass (1956: 130) called these frogs ‘‘reddish brown’’; I have not examined living individuals.

VARIATION IN SIZE AND PROPORTIONS: Nothing can be said of geographic variation, as the few specimens all come from the same mountain. The smallest of the 12 specimens (SVL 23.7 mm) is at or close to maturity, as it has ova> 1 mm in diameter; I cannot be sure of the sex of the largest specimen (SVL 30.1 mm). Proportions are summarized in table 10, regression data are presented in table 11.

ILLUSTRATIONS: Hand and foot, fig. 53E.

CALL: Brass (1956: 130) characterized the sound of a chorus of these frogs as ‘‘like concerted cackling in a distant fowl-yard.’’

James Menzies recorded three individuals at Betamin, Mt. Dayman, 2050 m, in July 1984. The note is a soft ‘‘coo’’ lasting about 0.35 sec (0.26–0.41, N = 9; see fig. 77C) and repeated about every 16 sec (13–18, N = 5 intervals). I have recordings of four notes of one frog, three of another, and two of a third. The unpulsed note is finely tuned in all instances and maintained at a frequency of 900 Hz. One individual consistently initiated each of four notes with a brief (0.05 sec) segment at 1050 Hz before dropping to 900 Hz. This was not true of the other frogs.

Menzies (personal commun.) recorded one frog at between noon and 1300 hours, the others at about 2100 hours. One frog was found calling from the ground beneath a leaf, whereas the others were deeper in the substratum and were not captured. Menzies recorded the body temperature of a calling frog as 17°C where the ground was 13.2°C.

COMPARISONS WITH OTHER SPECIES: No other Oxydactyla is known from the area in which crassa occurs. Austrochaperina brevipes , a species of similar size and habitus, occupies much the same habitat in the Owen Stanley Mountains to the northwest. If questionable specimens are captured in an intermediate region and vocalizations are not known, such specimens should be diagnosed especially on the basis of the nature of the Simpson form the core of a highland region somewhat distinct from the main mass of the Owen Stanley Mountains, and O. crassa may prove to be restricted to this area.

LOCALITY RECORDS AND SPECIMENS EXAMINED: PAPUA NEW GUINEA: Milne Bay Prov.: north slope of Mt. Dayman , 2230 m ( AMNH A56803 [holotype], A56805, A56865, A57424, A57425, A57441–57443 [paratypes]; BMNH 1956.1 .1.18 [paratype]; MCZ A28495 [paratype]) ; Betamin, Mt. Dayman , 2050 m ( PNGM 20888 [2 specimens]) .

REMARKS: Tape recordings of this form made by James Menzies that provide good evidence of its specific status were particularly welcome in view of the somewhat equivocal nature of the morphological characters.

fingertips (much more disclike in brevipes ), leg length (longer in brevipes ), and dorsal rugosity (greater in crassa ). See account of O. coggeri for a comparison with that similar but geographically remote species.

HABITAT AND HABITS: Brass (1956: 110) called the vegetation at the type locality ‘‘mossy forest’’ and provided a detailed description and photograph (pl. 16, fig. 1). He stated that ‘‘several specimens were uncovered from under about 10 cm. of loose, somewhat peaty humus in raspberry tangles bordering the forest.’’

DISTRIBUTION: This species is known only from high elevations (2050–2230 m) on Mt. Dayman, whose highest point is on the bor- der between Milne Bay and Central provinces in the southeastern tail of New Guinea (fig. 42). Mt. Suckling, Mt. Dayman and Mt.