Oreophryne biroi, : van Kampen, 1923

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 : 5-17

Oreophryne biroi (Méhely¨)

Figure 1

Sphenophryne biroi Méhely ¨, 1897: 4006 (type locality, ‘‘from near Friedrich­ Wilhelmshafen’ ’ [= Madang, Madang Province, Papua New Guinea]; the two syntypes, MNH 2126 B/3 [fide Parker, 1934: 170], collected by Lewis Biro´, were destroyed in the Hungarian uprising of 1956; see Designation of Neotype, below).

Méhelyia lineata Wandolleck, 1911: 7 (type locality ‘‘Sacksackhütte’’, Torricelli Mountains, West Sepik Province, Papua New Guinea; 10 syntypes under MTKD D2213, 9 destroyed in World War II [ Obst, 1977], one remains as

6 This publication consists of a text in Hungarian followed by the same text in English, where the account of Sphenophryne biroi commences on p. 411.

BMNH 1947.2.12.63, all collected by O. Schlaginhaufen).

Méhelyia affinis Wandolleck, 1911: 8 (type locality not specifically stated, but presumably the same as that of Mehelyia lineata : ‘‘Sacksackhütte’’, Torricelli Mountains, West Sepik Province, Papua New Guinea [so given by Obst, 1977: 174]; syntypes a ‘‘not exactly ascertainable number of specimens under MTKD D2214’’ [ Obst, 1977: 174, specimens destroyed in World War II], also BMNH 1947.2.12.61–62 and NMW 19826, all collected by O. Schlaginhaufen).

Oreophryne biroi: van Kampen, 1923: 118 (part, first use of combination). Parker, 1934: 170 (part, ‘‘cotypes’’ of Sphenophryne biroi only).

TYPE SPECIMENS AND TYPE LOCALITIES: Méhelÿ (1897) based his description of S. biroi on two specimens from the type locality. In a later publication (Méhely¨, 1901: 252) he referred ‘‘Zahlreiche Exemplare vom Sattleberg’’ to this species. Specimens collected by Biró at Sattelberg (a mission station near the tip of the Huon Peninsula of Papua New Guinea) and present in at least two museums have been thought to be syntypes of S. biroi . Turin University has a specimen ( MZUT An567) donated by the Budapest Museum that is cited as a syntype (Gavetti and Andreone, 1993: 114). Similarly, the Naturhis­ torisches Museum, Vienna, has a specimen ( NMW 19825) received on exchange from Budapest that is listed as a syntype of S. biroi ( Häupl et al., 1994: 34) . Not only were these specimens not included in the material contributing to Méhelÿ’s species description (and hence are not syntypes), but they belong to another species, Oreophryne geislerorum . Iskandar and Colijn (2000: 51) included BMNH 1901.3.9.2 along with the MZUT and NMW specimens in listing types of O. biroi , but the BMNH specimen is a Cophixalus biroi ‘‘juv. in egg’’ from Sattelberg ( Parker, 1934: 175).

The type locality of affinis and lineata does not appear on maps available to us, but a map in Schlaginhaufen (1914) indicated that his anthropological fieldwork in the Torricelli Mountains took place south of Paup, a coastal village 29 km east­southeast of Aitape.

DIAGNOSIS: A species of Oreophryne with a maximum SVL of about 29 mm, ligamentous connection of procoracoid and scapula, third and fifth toes approximately equal in length, fourth toe about one­third webbed, and the following average proportions: HW/ SVL 0.391, TL/SVL 0.474, EY/SVL 0.134, EN/SVL 0.100, and IN/SVL 0.092. No other described Oreophryne from the New Guinea region possesses this combination of characters. The advertisement call is unique among those of the few species whose calls are known.

MORPHOLOGY: Head somewhat narrower than body; canthus rostralis distinct but rounded, loreal region a steep, slightly concave slope; nostrils visible from above; interorbital space about 1.3–1.4× eyelid width; tympanum small, annulus obscured by overlying skin; no postocular skin fold. Relative lengths of fingers 3> 2 = 4> 1, 1st finger> one­half length of 2nd, all fingers with broad terminal disks, no webbing, subarticular elevations low, rounded (fig. 2A); relative lengths of toes 4> 5 = 3> 2> 1, all with broad terminal disks, that of the 4th toe slightly narrower than that of 3rd finger or rarely the two equal, webbing reaching to proximal subarticular elevations, subarticular elevations low, rounded (fig. 2A).

The figure of the pectoral girdle ( Méhelÿ, 1897: pl. 10, fig. 6) confirms the generic placement in Oreophryne .

COLOR AND PATTERN: In preserved specimens, the dorsum has fine, light brown mottling on a paler background and indistinct, convergent, lighter dorsolateral bands, sometimes emphasized by indistinct darker borders. The top of the snout usually is paler than the middorsal region and may be abruptly demarcated at a transverse boundary between the eyes (fig. 1). There is a pale, indistinct, diagonal postocular stripe, and lumbar ocelli are only faintly indicated. The loreal region from the tip of the snout to beneath the eye is darker and more densely and evenly pigmented than the dorsum or the top of the snout. The groin and anterior surface of the thighs are pale and virtually unmarked, the posterior of the thighs similar. The upper sides of the legs are largely brown with lighter areas in no definite pattern, whereas the undersides are largely unmarked. The chin, throat, chest, and abdomen have a sparse scattering of melanophores, most concentrat­ ed near the jaw symphysis and posteriorly on the abdomen.

In life, two specimens (UPNG 7355, 7356) had the dorsum fawn and the top of the snout to midocular region conspicuously paler. The concealed sides of the thighs were orange, the venter pale with glistening white blotches, and the iris red­gold. One of the specimens had a thin middorsal stripe (J. Menzies, field notes).

VARIATION IN SIZE AND PROPORTIONS: Two adult females are 27.4 and 27.5 mm SVL, and a probable female (not sexed) is 28.5 mm. Adult males range from 22.1 to 24.0 mm SVL.

Ten specimens from East Sepik Province differ slightly from the Madang Province sample in some average proportions while being identical or nearly so in others (tables 1,2; figs. 3, 4). The East Sepik specimens have smaller average HW/SVL and IN/SVL ratios than those from Madang Province, though both sets of data overlap. If the two datasets are considered together, a good segregation of samples is evident (fig. 5). A specimen from West Sepik Province and an­ other from the Cyclops Mountains of extreme eastern Papua show no significant differences from those from more easterly localities. Our assignment of the samples from outside of Madang Province to biroi is tentative; sibling species may be present (the name lineata is available). Acquisition of advertisement calls from East Sepik localities could play an important part in resolving the question.

COMPARISONS WITH OTHER SPECIES: From its sympatric congener O. hypsiops (a new species described below), O. biroi differs most conspicuously in its broader head, greater eye diameter, and wider internarial span; the third finger disk is narrower, but the difference is less marked (figs. 6, 7). See Discussion for additional comparisons.

HABITAT AND HABITS: Specimens have been taken in forests. Menzies (field notes) found two ‘‘in much degraded bush on the slopes of Nobanob Hill’’ (Mt. Hanseman, Madang Prov.). The lectotype was ‘‘calling from the axil of a Pandanus frond not more than a meter above the ground’’ (documentation on recording tape).

ADVERTISEMENT CALL: This is a loud, harsh rattle (fig. 8 A, table 3). The single recorded sample lasts 3.7 sec and contains 67 brief notes with a duration of 0.014 –0.025 sec, each note with two or three pulses. The note repetition rate is 18.1 per second at an air temperature of 25.0°C, the dominant frequency about 2450 Hz. There is a harmonic at 4900 Hz with almost as much energy as the dominant. J. Menzies made the recording at Kowat in the Adelbert Mountains ; voucher specimen UPNG 8134 .

DISTRIBUTION: The north coast of New Guinea from the vicinity of Madang, Madang Province, Papua New Guinea, north and west at least to the Cyclops Mountains near Jayapura , Papua, Indonesia. The range in elevation is from sea level to at least 1000 m (fig. 9) .

LOCALITY RECORDS AND SPECIMENS EXAM­ INED: INDONESIA: Papua: Mt. Cyclops, 900–l 200 m (BMNH 1935.6.5.90). PAPUA NEW GUINEA: West Sepik Prov.: Sacksackhütte, Torricelli Mtns. (BMNH 1947.2.12.61–63, NMH 19826 [syntypes of M. affinis ], BMNH 1947.2.12.63 [syntype of M. lineata ]), Rauit, 520 m, 53 km S, 11 km

TABLE 1 Body Proportions in Six Species of Oreophryne

W Aitape ( UPNG 4088 ) , Mt. Somoro , 11 km NE Lumi, 730–1400 m ( AMNH A­78143 ) . East Sepik Prov.: Passam , S of Wewak ( AMS R31031–31035 ) ; Maprik ( MCZ A 92801 , 92802 ) ; Kairuru Island , N of Wewak ( AMNH A­103192 , MCZ A 97247, 97248 ) . Madang Prov.: Madang, 5 m ( AMNH A­ 84512 ) ; Nobanob , 7 km N, 5 km W Madang ( UPNG 7355 , 7356 ) ; Kowat, Adelbert Mtns. , 1000 m, 42 km N, 50 km W Madang ( UPNG 8133 , 8134 , last is neotype) ; Wanuma, Adelbert Mtns. , 670 m, 35 km N, 54 km W Madang ( AMNH A­83041 ) ; near Wanuma, Adelbert Mtns. , 975 m, ( AMNH A­83042 ) ;

TABLE 2 Regression Statistics for Five Species of Oreophryne

2.2 km W, 1.0 km N Alexishafen, sea level (YPM 5610).

DISCUSSION: Parker (1934) applied the name biroi to specimens collected over much of New Guinea from the neck of the Vogelkop Peninsula in Papua to the southeastern tip of Papua New Guinea, a distance of some 1900 km, including localities in both north and south drainages of the island. Although his sample of 52 specimens might at first be thought adequate, more than half came from a single locality (Sattelberg on the Huon Peninsula) and the remainder included some juveniles. Given the conservative morphology of most Oreophryne , it is not astonishing that Parker chose to recognize only a single species in this assemblage, synonymizing three names junior to biroi . It is now apparent that he subsumed several species in biroi , and it is essential to determine if the name can reasonably be associated, either as a junior synonym or as a valid species name, with a diagnosable natural population represented in the area of the type locality.

The two syntypes were a tiny juvenile of 8.5 mm and an ‘‘adult’’ of 17 mm. Neither Méhelÿ nor Parker gave the sex of the ‘‘adult’’, so use of the term may merely have emphasized its greater size. That the larger syntype was immature is likely, for among our mixed species sample of about 100 Oreophryne from the whole north coast region, there are only two adult male specimens (vocal slits present) with SVL as short as 19.6 and 19.7 mm; all others are greater than 20 mm SVL, and a male biroi of 18.4 mm lacks vocal slits.

Méhelÿ’s (1897) description is thorough by the standards of the time, but unfortunately lacks all measurements except ‘‘ 17 mm. long’’, probably approximately equiva­ lent to SVL. Several aspects of morphology in the original description are not of diagnostic use, being either common to many species or not given in a sufficiently quantitative fashion. Assuming that the illustration (Méhely¨, 1897: pl. 10, fig. 3, presumably the larger syntype) depicts proportions accurately, one can estimate a TL 8.7 and a HW of 6.9 mm. The search for the identity of biroi is best directed to comparisons of relative tibia length and head width with species of known or possible occurrence in the region of the type locality. Méhelÿ’s statement (1897: 412) that the interspace between the nostrils is about equal to that between the latter and the orbit also is important.

Oreophryne geislerorum has been found no closer than about 220 km to the Madang area but it must be considered as it has been confused with biroi in the literature and may occur closer to Madang. Both the estimated HW and TL of biroi lie well above the extrapolated regression lines for geislerorum (fig. 10). The sample of geislerorum is large and well distributed by size (giving confidence in the regression data), so it is unlikely that the deviation seen in biroi can be explained as variation within geislerorum . A combination of HW/SVL and TL/SVL (fig. 11) distinguishes most specimens of these two species. Hence, we conclude that biroi is not a junior synonym of geislerorum .

We have found two quite distinct species of Oreophryne in the vicinity of Madang. The first of these (for convenience, species A) is represented by eight specimens from Madang Province as well as several others tentatively assigned to species A from sites to the northwest. These are relatively broadheaded frogs, and the estimated head width (fig. 6) and tibia length of biroi fall on the regression lines for species A. The relative eye–naris and internarial measurements (mean EN/IN, 1.07) are similar to the near equality of EN and IN stated for biroi .

The second species (B), represented by eight specimens from Madang Province with others from East and West Sepik provinces tentatively assigned to species B, is sympatric with species A and distinct in both morphology and vocalization. The head width of biroi falls above the regression line for the narrow­headed species B (fig. 6). The tibia length regressions for species A and B have different slopes but converge at the small size of the larger syntype of biroi , so tibia length does not distinguish biroi from species B. The internarial span of species B is narrow, noticeably less than the eye–naris distance (mean EN/IN, 1.32), another difference from biroi . It is unlikely that species B is equivalent to biroi .

Two problematic species are Mehelyia affinis and Mehelyia lineata , described by

TABLE 3 Advertisement Call Statistics for Five Species of Oreophryne

Wandolleck (1911) from the Torricelli Mountains some 500 km northwest of Madang and treated by Parker (1934) as junior synonyms of his composite biroi . Wandolleck based his two species on relatively large series of specimens (at least 27 of the former and ten of the latter) from one locality. He noted their great morphological similarity but stated that they differed in the shape of the pterygoid and in features of the ventral pectoral girdle. He considered that the presence of a middorsal stripe in lineata distinguished it externally from affinis . Parker (1934: 170) dismissed the supposed differences in the pectoral girdle as ‘‘probably due to individual or sexual variation’’, but he did not comment on the color pattern.

The near lack of objective measurements in Wandolleck’s descriptions (only maximum body lengths of 24 and 27 mm are mentioned), the loss of most of the syntype specimens in World War II ( Obst, 1977), and the poor condition of the few remaining syntypes hinder determination of the status of the two species. Only one syntype of lineata exists ( BMNH 1947.2.12.63). 7 Upon examining it

7 Obst (1977: 174) stated that a paratype had been given to the Berlin Museum in 1935. However, Dr. Rainer Günther (personal commun.) has advised us that no such specimen is now in the collection.

in 1986, R.G.Z. noted ‘‘in very poor condition—toes falling off, right arm off, legs dangling by skin only.’’ There are two extant syntypes of affinis ( BMNH 1947.2.12.61– 62) for which we have a complete set of measurements, and one ( NMW 19826) with an incomplete set. Their condition, too, is less than perfect .

Measurements of lineata (TL not taken) with one exception fall close to the regression line for biroi as here conceived and well within the scatter of points. The exception is EY (3.7 mm), which is unusually large for an Oreophryne the size of lineata (ca. 22.3 mm SVL)—larger, in fact, than for any other specimen of its approximate size among several species examined. Considering the poor condition of the specimen (with implications for accuracy of measurement), we do not think that this aberrant measurement disqualifies lineata as a synonym of biroi . The specimens of affinis present essentially the same picture as does the single lineata , largely conforming to the measurements of biroi . Again, one specimen has an EY above the scatter of biroi points, but another is on the regression line. One of the specimens we assign to biroi for which we have color pattern notes has the middorsal pale line described for lineata . This particular feature of color pattern is polymorphic in some other species of Oreophryne and is a tenuous attribute on which to diagnose a species. However, it is curious that it appeared in a large proportion (at least 27%) of the original combined sample of lineata and affinis .

With the information available, we do not find it possible to distinguish lineata and affinis as different species, nor can they be separated from biroi . Hence, we maintain their status as junior synonyms of biroi . This conclusion could be verified or reversed by the acquisition of recordings of advertisement calls from biroi ­like frogs from the Torricelli Mountains.

The enigmatic Oreophryne wolterstorffi presumably came from within the general range of O. biroi but cannot be identified with that species (see species account of O. wolterstorffi ).

In summary, geislerorum is the least likely to be the same as Oreophryne biroi , while affinis and lineata are best left in the syn­ onymy of biroi pending new information to the contrary. Between species A and B, species A is a better fit to biroi than is species B. The remaining alternative—that biroi is a species as yet not rediscovered at its type locality—is the least parsimonious explanation. Therefore, we equate species A with Sphenophryne biroi and describe B as new a new species, O. hypsiops . There is a practical aspect to this decision; that is, with the syntypes of biroi destroyed, a neotype may be designated that conserves the species name and provides for a functional diagnosis of the species. Such a designation conforms to the ‘‘Qualifying conditions’’ in the International Code of Zoological Nomenclature ( International Commission on Zoological Nomenclature, 1999: 84–85).

DESIGNATION OF NEOTYPE FOR SPHENOPHRY­ NE BIROI MÉHELŸ, 1897 : Stabilization of the nomenclature of this species dictates designation of a neotype to replace the destroyed syntypes. We designate UPNG 8134 , a male collected by James Menzies (see Locality Records and Specimens Examined ). The locality for this specimen falls broadly within the original type locality, ‘‘near Friedrich­ Wilhelmshafen’’ (= Madang) in an area that was under German colonial development. The specimen is particularly appropriate in that it as yet is the only one with a tape recording of the diagnostic advertisement call.

ERRONEOUS LITERATURE REFERENCES TO OREOPHRYNE BIROI: Parker (1934, 1936 ), with his broad concept of the range of O. biroi , identified as that species a number of specimens that are unlikely to be biroi as here defined. Some of these are Oreophryne geislerorum (see species account); others we deal with here.

A specimen from Mt. Tafa , 8500 ft, in Northern Province, Papua New Guinea ( BMNH 1935.3.9.24; Parker, 1936: 72) , is a juvenile Oreophryne anthonyi (Boulenger) , a relatively large species of high elevations known from Mt. Tafa ( Zweifel, 1956: 19) .

Four specimens from Fergusson Island, Milne Bay Province, Papua New Guinea (BMNH 1904.11.62–65; Parker, 1934: 170) agree well with Oreophryne insulana Zweifel (1956) , described from nearby Goodenough Island. A mainland specimen from Milne Bay (BMNH 1903.4.30.21; Parker, 1934: 170) is best referred to Oreophryne sp. , pending resolution of the relationship of Oreophryne of this region to Oreophryne loriae in the Port Moresby area ( Menzies, 1976: 62).

Single specimens identified by Parker (1934: 170) as O. biroi from Katow, Western Province, Papua New Guinea (BMNH 1883.10.23.2), Wendessi, Papua (BMNH 1909.10.30.23), and Setakwa River, Papua (BMNH 1913.11.1.132) each differ from biroi in at least two significant proportions as well as being from sites remote from the known range of biroi . These are best left as Oreophryne sp. until the Oreophryne of western Papua New Guinea and Papua are better understood.

Parker (1934: 169) included Oreophryne mertoni (Roux) of the Aru Islands, Indonesia, in the synonymy of Oreophryne biroi , but with question (he had not examined any specimens from that locality). Forcart (1946: 134) compared the holotype of mertoni (NMBA 2731) with three specimens of ‘‘ Or. biroi vom Sattelberg’’ (NMBA 2268–2270) and considered Parker’s uncertain synonymy of the two species confirmed. But the specimens from Sattelberg must be O. geislerorum , which again points up the confusing morphological similarity among various Oreophryne . The meager known frog fauna of the Aru Islands comprises eight common lowland species of New Guinea and a supposed endemic genus and species, Microbatrachus pusillus Roux , that Zweifel (2000) considered to be unidentifiable. Geographic considerations alone rule out conspecificity of O. mertoni and O. biroi , and it is likely that O. mertoni is an insular representative of a mainland species. Which species cannot at present be said.

Since Parker defined Oreophryne biroi , remarkably few literature references to the species have appeared. Loveridge (1948: 423) recorded several specimens as O. biroi : a British Museum exchange specimen from Fergusson Island (possibly Oreophryne insulana , see above), five specimens from Aitape, West Sepik Province, and one from Gusiko, Morobe Province. The last must be O. geislerorum ; we discuss the Aitape specimens in the section on Specimens Not Identified to Species. Menzies (1976: 50) used the name biroi for what is geislerorum (at this time the latter species was still considered to be a Cophixalus ) and mistakenly indicated that the species ranges as far northwest as Madang.

Zweifel (1956: 22) identified four specimens from Mt. Dayman, Milne Bay Prov., as O. biroi . These bear a considerable similarity to Oreophryne inornata of Goodenough Island, but evidently represent a much smaller species, probably undescribed. References to biroi in checklists (e.g. Allison, 1993; Iskandar and Colijn, 2000; Scott et al., 1977; Zweifel, 1985; Zweifel and Tyler, 1982) now have no currency.

Figures

Fig. 1. Oreophryne biroi. Left, UPNG 7355, SVL 20.5, from Nobanob (Mt. Hanseman), Madang Prov., Papua New Guinea (J. Menzies photo). Right, specimen from series AMS R31031–31035, not measured, from Passam, E. Sepik Prov., Papua New Guinea (H. Cogger photo).