Callulops bicolor, Kraus, 2019

Kraus, Fred, 2019, A revision of Callulops doriae (Anura: Microhylidae), with descriptions of four new species, Zootaxa 4612 (1), pp. 1-28 : 12-15

Callulops bicolor , sp. nov.

Fig. 1D , 5

urn:lsid:zoobank.org:act:83504BE1-C8EA-487E-AE34-AE813BD6147C

Xenorhina doriae (part) Zweifel, 1972: 53.

Phrynomantis doriae Burton, 1986: 415 [by implication].

Callulops doriae Dubois, 1988: 3 [by implication].

Holotype. BPBM 38834 (field tag FK 15778), adult male, obtained by native collectors on N slope Mt. Dayman , 9.6980° S, 149.2610° E, 900 m a.s.l., Milne Bay Province, Papua New Guinea, 7 April 2011.

Paratypes (n = 10). NW slope Mt. Obree , 9.4434° S, 148.0073° E, 1560 m a.s.l., Central Province, Papua New Guinea, F. Kraus, J. Anamiato, and B. Iova, 31 January 2004 ( BPBM 19236 ) ; Mondo , Central Province, Papua New Guinea, E. Cheesman ( BMNH 1935.3.9.116–120); Astrolabe, Central Province, Papua New Guinea ( BMNH 1932.10.2.97); Mt. Lamington, 8.56° S, 148.10° E, Oro Province, Papua New Guinea, C.T. McNamara, 19 October 1928 ( AMS R9603 , 9605–06 ) .

Diagnosis. Callulops bicolor sp. nov. is distinguished from all other members of the genus by its unique combination of moderately large size (adult male SV = 61.7–75.5 mm); narrowly expanded finger and toe discs (3rdF/SV = 0.021 –0.034, 4thT/SV = 0.026 –0.037); circum-marginal grooves absent on fingers and toes, but larger toes may have shallow terminal puckerings at tips; short leg (TL/SV = 0.38–0.43); pustulose dorsum; EN less than IN (EN/ SV = 0.051 –0.064, IN/SV = 0.066 –0.078, EN/IN = 0.68–0.89); loreal region with a greatly swollen protuberance anterior to eye; small eye (EY/SV = 0.064 –0.082, EY/SN = 0.53–0.72); thick fingers; basal subarticular tubercle of 4th toe absent or poorly developed; dorsum yellow or brownish yellow with black-rimmed white ocelli; limbs and sides black with small white spots, including under thighs and shanks; groin, and hidden surfaces of legs blotched with yellow or orange, blotches largely absent from front of thighs; venter black minutely flecked with blue white; and a long (4.14– 9.68 s) multi-note call with relatively short notes (0.301 – 0.383 s), long internote intervals (0.810 – 1.501 s), and a slow repetition rate (0.64–0.74 notes/s).

Comparisons with other species. Callulops bicolor sp. nov. differs from all other species of the genus except C. doriae , C. neuhaussi , and C. argus sp. nov. in its dark-spotted dorsum and large yellow or orange blotches in the groin and on the hidden surfaces of the thighs. From C. doriae it differs in lacking well-developed circum-marginal grooves on toes (vs. toes with well-developed grooves in C. doriae ), in having a loreal region with a greatly swollen protuberance (vs. shallow swelling in C. doriae ), a yellow dorsum with dark-edged white ocelli (vs. yellow with many irregular brown or black spots in C. doriae ), sides and limbs black with minute blue-white flecks (vs. brown yellow with brown or black spots in C. doriae ), black ventral surfaces with minute blue-white flecks (vs. dirty white, heavily dusted or flecked with gray or brown from chin to chest and with orange or yellow blotches under shanks in C. doriae ), and longer (4.14– 9.68 s vs. 1.58– 1.62 s in C. doriae ) call with more (4–7 vs. 2 in C. doriae ) and shorter (0.301 – 0.383 s vs. 0.445 – 0.682 s in C. doriae ) notes. Callulops bicolor sp. nov. differs from both C. neuhaussi and C. argus sp. nov. in its distinctively two-toned appearance comprised of a yellow or brownish-yellow dorsum and black limbs and sides (vs. dorsum, limbs, and sides brown in C. neuhaussi and C. argus sp. nov., although the limbs of C. neuhaussi are darker brown than the dorsum) and its black venter (vs. brownish yellow or pale brown in C. neuhaussi and C. argus sp. nov.). Callulops bicolor sp. nov. further differs from C. neuhaussi in its shorter leg (TL/SV = 0.38–0.43 vs. 0.46 in C. neuhaussi ), shorter EN (EN/SV = 0.051–0.64 vs. 0.074 in C. neuhaussi , EN/IN = 0.68–0.89 vs. 1.02 in C. neuhaussi ), and prominent boss in front of the eye (vs. shallowly inflated in front of the eye in C. neuhaussi ); it further differs from C. argus sp. nov. in its larger eye (EY/SV = 0.064 –0.082 vs. 0.057 in C. argus sp. nov., EY/SN = 0.66–0.98 vs. 0.60 in C. argus sp. nov.), wider head (HW/SV = 0.32–0.38 vs. 0.30 in C. argus sp. nov., HL/HW = 0.69–0.85 vs. 0.88 in C. argus sp. nov.), and smaller relative size of the white portions of each ocellus (cf. Fig. 1C vs. 1D).

Description of holotype. An adult male with right-lateral incision, liver removed. Head wide (HW/SV = 0.35), wider than long (HL/HW = 0.82), with swollen loreal region, highly inflated immediately anterior to eye, concave posterior to naris; upper lip inflated; canthus absent; nostrils horizontally compressed, directed laterally but slightly dorsally too, closer to tip of snout than to eyes; internarial distance considerably more than distance from naris to eye (EN/IN = 0.68; IN/SV = 0.75; EN/SV = 0.51); snout slightly rounded, almost truncate when viewed from side, shallowly angulate when viewed from above; eyes small (EY/SV = 0.064); eyelid slightly more than half width of interorbital distance; tympanum distinct, sunken, smaller than eye (TY/EY = 0.82; TY/SV = 0.052), annulus overlain or bordered posteriorly and dorsally by heavy supratympanic fold that extends from behind eye to posterior of tympanum, where it bends sharply to end in front of forearm insertion at approximately level of jaw; supratympanic fold a clearly demarcated ridge ventrally but smoothly continuous with dorsal skin, continuing medially to form shallow transverse fold behind head. Dorsum and sides slightly rugose to obviously pustulose and heavily glandular, clearly pustulose in life ( Fig. 1D ); ventral surfaces smooth anteriorly, weakly granular on abdomen. Fingers unwebbed, thick, all bearing discs lacking terminal grooves; relative lengths 3>4≈2>1. Finger discs slightly wider than penultimate phalanges (3rdF/SV = 0.034). Subarticular tubercles low, large, better developed on F1 and F2; inner metacarpal tubercle low, large, oval; outer narrow, shallow oval skin thickening; medial metacarpal skin thickening absent. Toes unwebbed, all bearing discs without terminal grooves; relative lengths 4>3>5>2>1. Toe discs barely wider than penultimate phalanges (4thT/SV = 0.035), equivalent in width to those of fingers (3rdF/4thT = 0.97). Subarticular tubercles well developed, rounded, only two on fourth toe, none present at junction of metatarsal and proximate phalanx on fourth toe; inner metatarsal tubercle a large, prominent oval; outer only a vague, slightly whitened skin thickening. Legs short (TL/SV = 0.41).

In preservative, dorsal ground color mustard yellow with many scattered black warts tipped with white. Limbs, lower sides, venter, sides of face, and top of snout black; sides, venter, forelimbs, and face flecked with white. Thighs with large yellow and white blotches dorsally and posteriorly, with white flecks ventrally, with white flecks and two or three small white blotches anteriorly. Shanks largely flecked with white, but also with large mustard-yellow marbling dorsally. Digits black above, largely gray beneath. Groin with one large yellow blotch on left side, two on right; axilla with large yellow blotch on left side, none on right. All yellow dorsal areas highly glandular. Circle of small white blotchs bordering anus. Iris black.

Measurements of holotype (in mm). —SV = 70.6, TL = 28.8, HW = 24.7, HL = 20.2, IN = 5.3, EN = 3.6, SN = 6.8, EY = 4.5, TY = 3.7; 3rdF = 2.38, 4thT = 2.46, mass = 46.3 g.

Variation. Mensural variation is rather large for such a small sample of specimens ( Table 3 , Appendix II), and this may in part reflect the old and hardened nature of some of them. Few characters suggest meaningful differences between the sexes, and the large standard deviations among the few that have larger average differences (EY/SN, TY/EY, 3rdF/4thT) suggest that apparent differences may only be artifacts of the small sample sizes. Only paratype BPBM 19236 is sufficiently fresh to provide useful comparison with the holotype in other features of morphology. This specimen has thicker skin between the metacarpal tubercles. The smallest mature male has a SV length of 61.7 mm, the smallest mature female a slightly larger size of 67.6 mm.

Color pattern exhibits some important variation. Paratype BPBM 19236 has a slightly oranger cast to the dorsum than the holotype but is otherwise very similar in dorsal color pattern; it also has only one small white blotch on the anterior face of the left thigh, and no white blotches around the anus or in the axilla. The specimens from Mondo, Mt. Lamington, and the Astrolabe Range have a greater degree of black coloration around the dorsal and lateral ocelli than do the specimens from Mt. Dayman and Mt. Obree, and this black color is often irregularly shaped instead of comprising a simple circular margin to each ocellus. This encroachment is most extensively developed in the population from Mondo ( Fig. 5 ), which is the northernmost. Furthermore, the smallest specimen of this series (BMNH 1935.3.9.120, SV = 61.7 mm) has the greatest amount of black dorsally, appearing black overall to the naked eye, although small patches of yellow color show through this under magnification ( Fig. 5E ). The largest specimen of this series (BMNH 1935.3.9.116, SV = 75.5 mm) has the greatest extent of yellow dorsally ( Fig. 5A ) and is relatively similar to the specimens from Mt. Dayman and Mt. Obree ( Fig. 1D ) though with more black on the posterior dorsum. The other three members of this series ( Fig. 5 B–D) clearly have yellow backs but intermediate amounts of black pigmentation around the ocelli to those seen in these two extremes. The Mondo specimens also exhibit many small yellow spots on the hidden surfaces of the rear of the thighs instead of the larger blotches seen in the other specimens, and they have many small, discrete, yellow spots on the tops of the legs ( Fig. 5 ) instead of the more extensive blotches of ochre seen in other specimens (e.g., Fig. 1D ).

Color in life. The color pattern of the holotype in life was recorded as “Dorsum mustard yellow with black warts each having a white center. Limbs, face, and venter black with white spots; legs with paler mustard-yellow blotches”. The paratype from Mt. Obree was noted to be ochre above, and the flecks on the black surfaces of sides, limbs, and venter were blue-white ( Fig. 1D ).

Call. The call is a short series of deep-voiced grunts delivered at long intervals. I was able to record six calls from a single individual (the holotype). Calls comprised a series of 4–7 notes emitted at a rate of 0.64–0.74 notes/s; calls ranged from 4.14– 9.68 s in duration, with a mean of 7.02 s ( Table 2 , Fig. 3D, F ). Each note was relatively brief, with a mean of 0.347 s (range 0.301 – 0.383 s). The interval between notes was much longer, with a mean of 1.156 s and a range from 0.810 – 1.501 s. Notes were highly pulsed, with a rounded amplitude envelope ( Fig. 3D ) and without frequency modulation ( Fig. 3F ). The dominant frequency of calls did not vary greatly ( Fig. 3E ), with a mean of 406 Hz and a range from 378–454 Hz.

Etymology. The name is a single-ending compound adjective from the Latin bi -, meaning two, and color, whose meaning is obvious, in reference to the contrast in color pattern between the dorsum versus the limbs and sides.

Range. Known from 900–1560 m a.s.l. at three localities in the southern and central Owen Stanley Range, from an unknown elevation on the outlying Mt. Lamington to the east, and from an unknown elevation in the outlying Astrolabe Range to the west ( Fig. 4 ). The elevational range may be greater than what is indicated here, but only the two specimens I collected had elevation recorded.

Ecological notes. Both animals I obtained came from primary lower montane rainforest, with the paratype living in rather open forest with deep leaf litter and a tall canopy overtopped by gigantic conifers.

Remarks. Kinghorn (1929) referred specimens of this species to Hylophorbus sp., noting the dorsal color to be brown. Kinghorn had six specimens available, of which three (AMS R9603, 9605, 9606) are paratypes of C. bicolor sp. nov. The others are an uncertain species of Callulops (see Discussion).

Figures

FIGURE 1. Portraits in life of (A) adult Callulops doriae, BPBM 38833, Egiaba, Normanby Island, Milne Bay Province, SV = 77.0 mm; (B) juvenile C. doriae, UMMZ 245247, Suau, Milne Bay Province, SV = 18.1 mm; (C) holotype of C. argus sp. nov., AMNH 82886, Garaina, Morobe Province, SV = 81.0 mm, photo by R.G. Zweifel; (D) paratype of C. bicolor sp. nov., BPBM 19236, NW slope Mt. Obree, Central Province, SV = 70.7 mm; (E) paratype of C. stellatus sp. nov., BPBM 37122, SE slope Mt. Victory, Oro Province, SV = 63.6 mm; (F) holotype of C. stellatus sp. nov., BPBM 39980, S slope Mt. Trafalgar, Oro Province, SV = 63.5 mm; (G) adult paratype of C. taxispilotus sp. nov., MCZ 59898, Bomai, Tive Plateau, Chimbu Province, SV = 79.7 mm, photo by F. Parker; and (H) juvenile paratype of C. taxispilotus sp. nov., MCZ 60804, Bomai, Tive Plateau, Chimbu Province, SV = 37.0 mm, photo by F. Parker.

FIGURE 3. Calls of members of the Callulops doriae group. (A) Waveform, (B) amplitude spectrum, and (C) spectrogram of 2-note call of Callulops doriae (BPBM 20141) recorded on S slope Mt. Pekopekowana, 330 m a.s.l., Owen Stanley Mts., Milne Bay Province, 24 May 2004, air temperature 23.6 ˚C, analyzed with fast-Fourier transform of 256 points; (D) waveform, (E) amplitude spectrum, and (F) spectrogram of a 7-note call of the holotype of Callulops bicolor sp. nov. (BPBM 38834) recorded on N slope Mt. Dayman, Milne Bay Province, 7 April 2011, air temperature 25.0–25.9 ˚C, analyzed with fast-Fourier transform of 1024 points; and (G) waveform, (H) amplitude spectrum, and (I) spectrogram of a 5-note call of the holotype of Callulops stellatus sp. nov. (BPBM 39980) recorded on S slope Mt. Trafalgar, 7 November 2011, air temperature 24.3 ˚C, analyzed with fast-Fourier transform of 512 points.

FIGURE 4. Map of southeastern New Guinea showing collecting localities for Callulops argus sp. nov. (diamond), C. bicolor sp. nov. (squares), C. doriae (triangles), C. neuhaussi (X), C. stellatus sp. nov. (stars), and C. taxispilota sp. nov. (circles). Type localities are solids; additional localities are open symbols.

FIGURE 5. Ontogenetic variation in dorsal color pattern in Callulops bicolor sp. nov. (A) BMNH 1935.8.9.116, SV = 75.5 mm; (B) BMNH 1935.8.9.117, SV = 67.6 mm; (C) BMNH 1935.8.9.118, SV = 68.5 mm; (D) BMNH 1935.8.9.119, SV = 67.6 mm; (E) BMNH 1935.8.9.120, SV = 61.7 mm.