Oreophryne cameroni, Kraus, Fred, 2013

Kraus, Fred, 2013, Three new species of Oreophryne (Anura, Microhylidae) from Papua New Guinea, ZooKeys 333, pp. 93-121 : 95-101

Oreophryne cameroni sp. n. Figs 1, 2A, B

Holotype.

BPBM 34677 (field tag FK 13704), adult male, collected by F. Kraus at Keki Lodge, Adelbert Mts., 4.7048°S, 145.4042°E, 850 m, Madang Province, Papua New Guinea, 1 October 2009.

Paratypes

(n = 3). BPBM 34678, same data as holotype, except collected 4 October 2009; BPBM 22689, Siruohu, ~3 km SSE Mt. Sapau summit, Torricelli Mts., 3.3908°S, 142.5297°E, 550-700 m, West Sepik Province, Papua New Guinea; AMNH 78139, Mt. Nibo, 19 km NE Lumi, 700-1550 m, West Sepik Province, Papua New Guinea.

Diagnosis.

Oreophryne cameroni can be distinguished from all congeners by its unique combination of small size (adult male SV = 19.5-20.4 mm); cartilaginous connection between the scapula and procoracoid; basal toe webbing; fifth toe longer than third; leg moderately long (TL/SV = 0.49-0.51); snout slightly shorter than broad (EN/IN = 0.94-0.95, IN/SV = 0.097-0.103); head relatively broad (HW/SV = 0.37-0.42); finger discs relatively narrow (3rdF/SV = 0.048-0.068); dorsum brown with scattered pustules, white flecks, and darker lateral blotches; venter heavily stippled with brown; dark-brown subocular blotch; dark-brown iris; and call a series of short peeps delivered at a rate of 2.8-2.9 notes/s with a dominant frequency of around 2900 Hz.

Comparisons with other species.

The new species differs from all other Papuan Oreophryne except Oreophryne idenburghensis , Oreophryne oviprotector , and Oreophryne waira in its unique combination of having a cartilaginous connection between the scapula and procoracoid and basal webbing between the toes. It is easily distinguished from Oreophryne idenburghensis by its much smaller size (SV = 19.5-20.4 mm vs. 43-47 mm in Oreophryne idenburghensis ), longer leg (TL/SV = 0.49-0.51 vs. 0.42-0.44 in Oreophryne idenburghensis ), broader head (HW/SV = 0.37-0.42 vs. 0.34-0.35 in Oreophryne idenburghensis ), broader snout (EN/IN = 0.94-0.95 vs. 0.87-0.91 in Oreophryne idenburghensis , IN/SV = 0.097-0.103 vs. 0.076-0.081 in Oreophryne idenburghensis ), and narrower finger discs (3rdF/SV = 0.048-0.068 vs. 0.077-0.091 in Oreophryne idenburghensis ). It differs from Oreophryne oviprotector in its brown dorsal color with scattered white flecks (lime green, without flecks in Oreophryne oviprotector ), dark-gray ventral coloration (pale translucent gray in Oreophryne oviprotector ), dark-brown subocular blotch (absent in Oreophryne oviprotector ), dark-brown iris (coppery brown around pupil and yellowish distally from pupil in Oreophryne oviprotector ), absence of yellow inguinal and axillary blotches (present in Oreophryne oviprotector ), absence of conspicuous green bar between eyes (present in Oreophryne oviprotector ), absence of a white ring around eye (present in Oreophryne oviprotector ), and call a series of peeps delivered at a rate of 2.8-2.9 notes/s (call a rattle delivered at a rate of 26-28 notes/s in Oreophryne oviprotector ) and with each note of 71-134 ms duration (each note of approximately 12 ms duration in Oreophryne oviprotector ). From Oreophryne waira , the new species differs in having the fifth toe longer than the third (subequal in Oreophryne waira ), longer leg (TL/SV = 0.49-0.51 vs. 0.43-0.46 in Oreophryne waira ), and call a series of peeps of around 2900 Hz and delivered at a rate of 2.8-2.9 notes/s (call a rattle of around 3600 Hz and delivered at a rate of 15-19 notes/s in Oreophryne waira ).

Description of holotype.

An adult male with an incision on right side and left pectoral region dissected. Procoracoid is connected to the scapula by a cartilaginous rod. Head wide (HW/SV = 0.42), with steep, almost vertical loreal region; upper lip inflated. Canthus rostralis rounded, straight when viewed from above (Fig. 1A). Nostrils directed laterally, much closer to tip of snout than to eyes. Internarial distance slightly wider than distance from naris to eye (EN/IN = 0.95, IN/SV = 0.101, EN/SV = 0.096). Snout slightly rounded when viewed from the side (Fig. 1B), shallowly angulate when viewed from above (Fig. 1A). Eyes moderately large (EY/SV = 0.14); eyelid approximately two-thirds width of interorbital distance. Tympanum small (TY/SV = 0.045), but with a distinct annulus. Skin smooth above and below, except abdomen granular. Supratympanic fold absent. Fingers unwebbed, bearing discs with terminal grooves; relative lengths 3>4>2>1 (Fig. 1C). Finger discs approximately twice width of penultimate phalanges (3rdF/SV = 0.066). Subarticular tubercles low but distinct; inner metacarpal tubercle large, low, oval; outer not apparent. Toes with basal webbing between T2-T5, but absent between T1 and T2; bearing discs with terminal grooves; relative lengths 4>5>3>2>1 (Fig. 1D). Toe discs smaller than those of fingers (4thT/SV = 0.060, 3rdF/4thT = 1.10), somewhat less than twice width of penultimate phalanges. Subarticular tubercles low but distinct; inner metatarsal tubercle a narrow oval; outer not apparent. Hind legs moderately long (TL/SV = 0.51).

In preservative, dorsum dark tan, with a dark-brown smudge between the shoulders, flecked with dark brown dorsally and with a series of darker and larger dashes dorsolaterally extending from behind eye to mid-body. Ground color paler tan on snout and sides; pale region on snout sharply demarcated from darker body color along a front extending between eyes (Fig. 1A). Face pale tan, darker below eye, and with elongate dark-brown blotch on canthus (Fig. 1B). Dorsal surfaces of limbs medium brown; rear of thighs with small pale-straw patch of ground color proximally, distal three-fourths uniform medium brown; front of thighs uniformly medium brown. Ventral surfaces pale straw heavily and uniformly stippled with brown punctations throughout; plantar surfaces more densely stippled with brown. A vaguely defined dark-brown blotch present on each wrist, and a dark-brown ring or blotch present on each finger and toe, each followed distally by a pale-straw blotch at the junction of the last two phalanges. Iris dark brown.

Measurements of holotype (in mm).-SV = 19.8, TL = 10.1, HW = 8.4, HL = 7.0, IN = 2.0, EN = 1.9, SN = 3.2, EY = 2.8, TY = 0.9, 3rdF = 1.30, 4thT = 1.18, mass = 0.7 g.

Variation.

Mensural variation is limited (Table 1), as is to be expected from such a small sample. In life, animals have obvious scattered tubercles (Fig. 2A, B), but these become obscure in preservative. Color pattern shows somewhat more variation. The subadult male from the Torricelli Mts. (BPBM 22689) is similar to the holotype in color pattern except that the dorsum is somewhat darker brown, the brown blotch below the eye is more sharply delimited, and the venter is darker brown overall, with the brown punctations more aggregated and less uniformly dispersed than in the holotype. The second specimen from the Adelbert Mts. (BPBM 34678) is also darker dorsally and laterally than the holotype, and it has an irregular pale-straw stripe mid-dorsally that is broadened into one mid-dorsal pale-straw blotch midway along the back and another one in the sacral region. This pale stripe itself is intermittently bisected by a dark-brown vertebral line. In life, this broadening into blotches along the spine was not evident, and the bisecting brown line was continuous (Fig. 2A). The top of the snout in this specimen is also darker than that in the holotype, but the area between the eyes is pale. The venter is as seen in the holotype. The final specimen (AMNH 78139) also has a broad vertebral stripe on a dark-brown ground color; its venter too is like that seen in the holotype.

Color in life.

In life, BPBM 34678 was mottled dark brown on a burnt-orange ground dorsally, with the front and rear of thighs the same. An orange-tan vertebral stripe was bisected by a narrow brown vertebral line, the heels were paler than the remainder of the legs, a pale dash extended posteroventrally from the corner of the eye, and white flecks were scattered thoughout the lateral surfaces (Fig. 2A). The venter was pale yellow, heavily stippled with brown, and under the legs was the same. Iris was brown with a greenish cast on the upper half. The subadult animal from the Torricelli Mts. (BPBM 22689) had a paler ground color and greater contrast with the dark brown blotches (Fig. 2B). Field notes for that animal state: "Dorsum mottled tan and brown with black spots on face and sides. Venter light gray heavily flecked with black and silver-gray. Iris brown with upper edge tan."

Call.

I could identify perches of only two calling animals; both called from hidden locations approximately 2.5-3.5 m above ground. I was able to record two calls from the holotype. The call is a short series of relatively rapid peeps.

Recorded calls comprised series of 8 and 27 peeps emitted at a rate of 2.64-2.75 notes/s; calls ranged from 2.74-9.55 s in duration (Table 2). Each note was brief, with a mean duration of 0.088 s (range 0.071-0.134 s). The interval between notes was approximately three times longer, averaging 0.280 s and ranging from 0.241-0.389 s. The first 1-3 notes in a series were longer than the remainder; as were the first inter-note intervals. In the second call, the terminal three inter-note intervals were also longer than the preceding intervals. Hence, calls begin somewhat slowly, rapidly reach a regular pace, and may also slow down as they approach termination. There was approximately twice as much variation in inter-note duration than in note duration (Table 2). Notes may have a rounded amplitude envelope or may begin at maximum volume and decrease more or less monotonically, creating either a rounded or an approximately triangular amplitude envelope (Fig. 3A). Notes lack harmonic structure, pulsing, and frequency modulation (Fig. 3C). The dominant frequency of calls varied within a very narrow window (Fig. 3B), averaging 2901 Hz and ranging from 2871-2940 Hz.

Etymology.

The name is an honorific for my friend H. Don Cameron, professor emeritus of classical studies at University of Michigan and provider of much etymological and grammatical advice on Greek and Latin over the years.

Range.

Known from the Adelbert Mts., Madang Province, and the Torricelli Mts., West Sepik Province, Papua New Guinea at elevations of 550-850 m (Fig. 4, circles). The species will certainly be found at appropriate elevations in the intervening Prince Alexander Mts. and may, as well, occur in mountain ranges to the west.

Ecological notes.

I collected the subadult male in primary lowland rainforest on a steep slope at 550 m elevation in the Torricelli Mts. Canopy was at approximately 30-35 m; understory was rather open and uncrowded; soil was greasy mud. I collected the two calling animals at 850 m in the Adelbert Mts. perched at night in trees approximately 2.5-3.5 m above the ground. These animals were the nearest to the ground that I heard; all others were calling from higher up in the trees. Forest at this site was a clearing edge in remnant primary rainforest on a ridgetop with gentle slopes and rather open understory; soil was thick, sticky clay.

Mature males were 19.5-20.4 mm SV, but one male was still immature at 15.6 mm SV.

Frogs syntopic with this species include Albericus gudrunae , Austrochaperina basipalmata , Albericus blumi , an undescribed Austrochaperina , Callulops microtis , Callulops personatus , Choerophryne proboscidea , Callulops rostellifer , Cophixalus balbus , Callulops cheesmanae , Callulops pipilans , Copiula fistulans , Copiula tyleri , Hylarana arfaki , Hylarana garritor , Hylarana jimiensis , Hylarana papua , Hylarana volkerjane , Hylophorbus macrops , Hylarana proekes , two undescribed Hylophorbus , Liophryne schlaginhaufeni , Litoria arfakiana , Litoria genimaculata , Litoria wollastoni , Oreophryne biroi , Mantophryne lateralis , Nyctimystes fluviatilis , Nyctimystes pulcher , Platymantis papuensis , Sphenophryne cornuta , Xenorhina obesa , Xenorhina oxycephala , and Xenorhina tumulus .

Remarks.

In their revision of Oreophryne species from the northern coast of New Guinea, Zweifel et al. (2003) pointed out that AMNH 78139 was problematic in its identification, not clearly fitting with the other species discussed. In assigning the specimen to this new species, that problem is resolved.