Liophryne rhododactyla Boulenger

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 : 63-65

Liophryne rhododactyla Boulenger

Liophryne rhododactyla Boulenger, 1897: 11 (type locality, ‘‘ Mount Victoria , Owen Stanley Range, New Guinea ’’; syntypes, BMNH 1947.2 .12.47–49, formerly 1896.10.31.28–30, collected by A. S. Anthony in 1896).

Sphenophryne rhododactyla : Parker, 1934: 156.

TYPE LOCALITY: A quote from Zweifel

(1983: 4) is appropriate here: ‘‘The type locality given in the synonymy is taken from the title of Boulenger’s paper, which provides no other information. Wichmann (1912, p. 608) indicates that Anthony collected on Mt. Victoria between April and June 1896, and as Anthony operated out of Port Moresby, it is likely that collections were made on the western rather than the eastern side of the Owen Stanley Range in what is now the Central Province of Papua New Guinea. The title of a paper by Rothschild and Hartert (1896) treating birds collected by Anthony on the same trip (Wichmann, 1912) includes the phrase ‘mostly at elevations of from 5000 to 7000 feet.’ ’’

DIAGNOSIS: The largest species of Liophryne (adult SVL 48–60 mm), comparable (and possibly identical) in size to L. similis , from which it differs in that the male possesses vocal sac apparatus (slits and sac) and in the advertisement call—a single note rather than a series of rapidly repeated notes.

MORPHOLOGY: Head slightly narrower than the rather flat-sided body. Snout rounded to bluntly pointed seen from above, rounded and scarcely projecting in profile; nostrils lateral, barely visible from above, slightly clos- er to tip of snout than to eye; canthus rostralis angular but not sharp, loreal region nearly vertical, slightly concave. Eyes moderately large, corneal outline visible from below, eyelid about 80% of interorbital span. Tympanum distinct, about 49% of orbit length, closer to eye than its own diameter. Relative lengths of fingers 4> 3> 2> 1, first finger long, greater than half length of second; all fingers with terminally grooved discs, that of first least developed, others barely broader than penultimate phalanges; subarticular and metacarpal elevations rounded, moderately prominent. Toes unwebbed, relative lengths 4> 3> 5> 2> 1, all with terminally grooved discs broader than those of fingers, that of first toe smallest but slightly broader than penultimate phalanx; subarticular elevations rounded, moderately prominent, inner metatarsal elevation rounded, elongate. Skin smooth; indistinct convergent scapular folds sometimes present; a narrow postorbital fold passing across upper edge of tympanum, expanding into a broad, flat region behind tympanum, narrowing again above arm, continuing onto flank as a dorsolateral fold, usually disappearing anterior to groin.

COLOR AND PATTERN: The top of the head and body are moderate to pale brown, sometimes with small, obscure, irregular darker spots. The loreal region, especially near the canthus rostralis, and the area below the postorbital and dorsolateral folds are dark brown, excepting the tympanum, which has the same lighter shade as the dorsum. A thin, pale vertical line on the tip of the snout divides to pass along each canthus rostralis. In some individuals a fairly discrete line continues along the edge of the eyelid, following the postorbital-dorsolateral fold, but in others there is little or no trace of the line posterior to the nostrils. A few specimens have pale eyelids and a swath of the same light pigment between the dorsolateral folds and the remaining light brown of the dorsum. The arms and legs are darker, purplish brown with some light spotting on the arms. The rear of the thigh is unmarked and colored like the middorsal region. The ventral surfaces are brown with numerous small, light irregular spots. In many specimens the light spots are enlarged and coalesce to some extent so that the pale color dominates. The throat and chest are generally somewhat darker than the abdomen.

VARIATION IN SIZE AND PROPORTIONS: The two largest male specimens both measure 52.3 mm SVL; the two largest females are 59.0 and 59.8 mm. Males evidently mature at about 48–49 mm: three measuring 44–47 mm lack vocal slits, whereas two measuring 48.9 mm and four larger specimens have them. Females apparently mature at about the same size as males. A 48.4-mm individual is gravid, as are larger specimens. Body proportions are summarized in table 6, and regression statistics are presented in table 7.

ILLUSTRATIONS: See Boulenger (1897: pl. 2), for illustrations of body form, inside of mouth, and tongue, and Green and Simon (1986) for SEM photographs of the finger discs. For all practical purposes, the illustration of L. similis (fig. 31G) will suffice to illustrate the overall appearance. Terminal phalanx of third finger, fig. 71G; premaxilla, fig. 63F; hyoid, fig. 69C; sacral region, fig. 72F; vomer, fig. 65F; skull, fig. 68B; palatal fold, figs. 58, 59. Kuramoto and Allison (1989) illustrated the karyotype.

CALL: Frogs of the presumably disjunct population in mountains southeast of Wau utter a loud, single-note call, being high-pitched for a frog of its size (fig. 77A). I have a recording made by Allen Allison on the Bulldog Road, 2600 m, about 15 km southeast of Wau, Morobe Province, at about 2000 hours on April 30, 1982, copy on AMNH Herpetology tape reel 244. Six calls (notes) average 0.235 sec long (0.22–0.26), with a mean interval between call initiations of 3.98 sec (3.5–5.1). The notes are unpulsed, with the dominant frequency beginning at about 1300 Hz, rising gradually to about 1700 Hz, and descending slightly to the end.

COMPARISONS WITH OTHER SPECIES: Adults of this large species can be confused only with the sibling Liophryne similis (see the account of that species for comparisons). Juveniles of rhododactyla could be confused with the much smaller but similar sympatric species, Austrochaperina brevipes (see the account of that species for comparisons).

HABITAT AND HABITS: Almost nothing is published specifically referring to the habitat and habits of rhododactyla . Zweifel and Allison (1982: 9, Allison’s observations) referred to rhododactyla as a terrestrial species ‘‘that roams the forest floor at night,’’ and Green and Simon (1986) characterized rhododactyla as terrestrial. Archbold and Rand (1935) described the forest and terrain near the summit of Mt. Tafa, where rhododactyla has been taken.

DISTRIBUTION: Moderately high elevations south of Wau and in the Owen Stanley Mountains (fig. 34). Dr. Allison informed me that he has collected this species as low as 2200 m on Bulldog Road (a World War II supply road, now in disuse, that crossed the divide southwest of Wau), and has heard it at the same elevation south-southeast of Wau. A specimen supposedly from the outskirts of Wau at 1200 m, far below the altitudinal limit otherwise known and in an area where much collecting has produced no other specimens of this species, is almost certainly mislabeled, as presumably is a hylid frog of higher elevations ( Litoria angiana ) bearing the same locality data from the same collector. Undoubtedly the range in the Owen Stanley Mountains, suggested by the area above 2400 m (fig. 34), is much more extensive than the known localities might seem to imply.

LOCALITY RECORDS AND SPECIMENS EXAMINED: PAPUA NEW GUINEA: Central Prov.: Mt. Victoria ( BMNH 1947.2 .12.47–49, syntypes) ; Mt. Tafa , 2600 m ( BMNH 1935 . 3.9.123). Morobe Prov.: Bulldog Road, 15– 17 km S, about 1 km W Wau, ca. 2400–2700 m ( BPBM 6264 , 6265 , 6325 , 6326 , 6344 , 9641–9643 , 9652–9654 , 9662 , 9793 (C&S); UPNG 4119 , 4886 , 4887 , 5329–5335 ) ; Kunai Creek, Wau , 1200 m ( BPBM 5520 , locality questionable; see above) .

REMARKS: Liophryne rhododactyla had remained a little known species for the nearly 100 years since its initial description until the activities of collectors and researchers working out of the Wau Ecology Institute provid- ed a generous sample of specimens. The only specimen additional to those of the type series had been one collected by Evelyn Cheeseman on Mt. Tafa in the mid-1930s and reported by Parker (1936).