Cophixalus desticans, Kraus, Fred & Allison, Allen, 2009

Kraus, Fred & Allison, Allen, 2009, New species of Cophixalus (Anura: Microhylidae) from Papua New Guinea, Zootaxa 2128, pp. 1-38 : 11-15

Cophixalus desticans , sp. nov.

Fig. 1 E, F

Holotype. BPBM 16436 (field tag FK 6754), adult male, collected by F. Kraus at Saidowai, 9.9580166ºS, 150.9505333ºE, 5 m, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, Papua New Guinea, 1 October 2002.

Paratypes (n = 37). BPBM 15703, PNGNM 24057, Duabo, Pini Range, 10.4184333ºS, 150.3068333ºE, 300 m, Milne Bay Province, 1 May 2002; BPBM 15704–05, PNGNM 24058–59, same data as BPBM 15703 except collected 2 May 2002; BPBM 15706, S slope Mt. Pekopekowana, 10.2805555ºS, 150.1686111ºE, 590 m, Owen Stanley Mts., Milne Bay Province, 6 May 2002; BPBM 15708, S slope Mt. Pekopekowana, 10.2806306ºS, 150.1721461ºE, 430 m, Owen Stanley Mts., Milne Bay Province, 17 May 2002; BPBM 16434–35, S end Sewa Bay, 10.0559166ºS, 150.9767123ºE, 100 m, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, 28 September 2002; PNGNM 24060–61, S end Sewa Bay, 10.0516304ºS, 150.9716895ºE, 50–65 m, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, 28 September 2002; BPBM 17437, Duabo, Pini Range, 10.4179833ºS, 150.3046ºE, 220 m, Milne Bay Province, 5 October 2002; BPBM 20235, SE slope Mt. Pekopekowana, 10.2850666ºS, 150.1821666ºE, 330 m, Owen Stanley Mts., Milne Bay Province, 24 May 2004; BPBM 20236–43, SE of Sewa Bay, 10.0407608ºS, 150.9771689ºE, 80 m, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, 26 May 2004; BPBM 20244–54, PNGNM 24062–65, near Sibonai, S end Sewa Bay, 10.0326086ºS, 150.9753424ºE, 40–80 m, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, 27 May 2004.

Diagnosis. A small species (male SV = 13.1–16.2 mm, female SV = 13.7–19.1 mm) with finger discs smaller than toe discs (3rdF/4thT = 0.52–0.65); first finger reduced in size, of recognizable form, lacking a disc with circum-marginal groove; dorsum with many parallel narrow dermal ridges; irregular dark lateral band extending to midbody; and advertisement call a slow series of 5–25 squeaking peeps.

Comparisons with other species. The new species differs from all other Papuan Cophixalus except C. bewaniensis , C. humicola , C. iovaorum , C. kethuk , C. pipilans , C. shellyi , and C. tridactylus in having the combination of a reduced first finger lacking a disc with circum-marginal groove and the finger discs distinctly smaller than the toe discs. From C. bewaniensis , C. humicola , and C. tridactylus the new species differs in still retaining a recognizable first finger instead of a nub. From the other four species, C. desticans differs in having many parallel narrow dermal ridges on the dorsum and in having an irregular dark lateral band extending to midbody. It further differs from C. iovaorum and C. kethuk in lacking dark hourglassshaped markings on the dorsum, and in having a much slower and higher-pitched peeping call. Cophixalus desticans typically has a pair of dark, forward-pointing dorsal chevrons, one in the scapular region, one at midbody. These chevrons can be reduced to obscure smudges (or occasionally be lacking entirely) and, therefore, sometimes be hard to detect. However, when present, this pattern element is shared only with another species described below.

Description of holotype. An adult male with vocal slits. Head moderately wide (HW/SV = 0.37), with steeply oblique loreal region; canthus rostralis rounded, slightly inflated when viewed from above; nostrils directed laterally, closer to tip of snout than to eyes; internarial distance considerably larger than distance from naris to eye (EN/IN = 0.61, IN/SV = 0.12, EN/SV = 0.076); snout rounded and projecting when viewed from the side, gently angulate when viewed from above; eyes moderately large (EY/SV = 0.13); eyelid slightly more than half width of interorbital distance; tympanum distinct and small (TY/SV = 0.062), with a clear annulus. Dorsum with narrow vertebral ridge and series of pustules and wrinkles parallel to this, with largest pustules arrayed in two paravertebral series; sides smooth; venter smooth. Supratympanic fold absent. Fingers unwebbed, relative lengths 3>4>2>1; first finger somewhat reduced in size and lacking disc with circummarginal groove; F2–F4 with discs bearing terminal grooves. Finger discs approximately twice widths of penultimate phalanges. Articular tubercles low and rounded; inner metacarpal tubercle oval, outer larger and round. Toes unwebbed, bearing discs with terminal grooves; relative lengths 4>3>5>2>1. Toe discs larger than those of fingers (3rd F/4thT = 0.62); disc of fourth toe approximately twice width of penultimate phalanx; disc of first toe slightly wider than penultimate phalanx. Subarticular tubercles well developed, rounded; inner metatarsal tubercle oval, outer lacking. Hind legs moderately long (TL/SV = 0.54).

Dorsum medium brown, vaguely clouded with darker brown, this clouding most distinct in a blotch between and posterior to the eyes and in a vague chevron in the suprascapular region. Sides medium brown with dark-brown band extending from rear of eye to mid-body; behind and below this sides flecked with dirty white. Tympanum light brown; face, margin of mandible, and area below tympanum dark brown with scattered white flecks. Arms tan boldly spotted with dark brown, with a dark-brown band at wrist; legs medium brown irregularly mottled with darker brown; rear of thighs uniformly and heavily stippled with brown on a dirty-white ground. Venter dirty white, heavily stippled with brown on chin, throat, and chest; sparsely stippled with brown on abdomen. Dark-brown bar along anterior face of upper arm; dark-brown spot on each side of pectoral region. Palmar and plantar surfaces brown. Iris black, minutely stippled with bronze; rim of pupil silver.

Measurements (in mm). SV = 14.5, TL= 7.9, HW = 5.3, HL = 5.0, IN = 1.8, EN = 1.1, SN = 2.1, EY = 1.9, TY = 0.9, 3rd F = 0.61, 4th T = 0.98.

Variation. Mensural variation for the type series is shown in Table 6 . The dorsal ridges and pustules that help characterize this species vary from evident to apparently absent in preserved material, with the latter condition presumably a preservation artifact. Color pattern in this species is quite variable. Dorsum may vary from uniform light tan with no dark markings, to tan with one or two dark, medial chevrons, to darker brown with clear dark flecks or obscure dark mottling, as in the holotype. The dark mid-dorsal chevrons are typically obvious, especially so in light animals, but they are frequently reduced to dark smudges in the darker animals and may be absent entirely. Three specimens have a narrow light-tan vertebral line. The dark lateral band is usually well developed in the darker animals but may be reduced to a field of dark-brown blotches and flecks in some of the lighter animals; it is absent in the smallest juvenile (8.8 mm SV), so appears to develop late in ontogenesis. The dark wrist band is always bold and obvious. Brown stippling on venter varies from sparse to heavy, but the abdomen is invariably less stippled than the chin, throat, and chest, imparting a two-toned appearance to the venter. The abdomen has silver-white flecks in most of the paratypes.

Color in life. As just noted, color pattern elements in this species are quite variable. BPBM 15703: “Dorsum tan with two black chevrons, black face and suprascapular band. Legs gray with few burnt-orange tubercles; rear of thighs chocolate brown. Venter light gray with dark-gray flecks on chin/throat, fading posteriorly and replaced by scattered gray-white flecks on chest. Belly appears rose because liver shows through. Iris reddish brown.” BPBM 15706 had a dark-tan dorsum with irregular dark brown blotches middorsally; legs same, with small dark-brown blotches; dark chocolate-brown lateral stripe from eye to midbody; face and lower jaw dark brown; iris red-brown; venter gray flecked with light gray and heavily suffused with black punctations on chin and throat. BPBM 16434 had a light-brown dorsum with a reddish cast, a vague dark line between the eyes, and a vague dark-brown blotch between forearms; black face mask continuing halfway down side; burnt-orange forearm banded with black/dark brown; top of thighs as for dorsum, but front and rear of thighs plain sepia; shanks with a few white tubercles; chin, throat, and chest purple-gray, darker anteriorly, heavily speckled with light-gray flecks; belly light yellow-gray with a few smaller light-gray flecks; two black pectoral spots; under legs maculated with dark-gray dusting; iris orange. BPBM 16435 had two dark chevrons like BPBM 15703, but was also heavily freckled with dark brown and with dark-brown shanks and an orange spot in the groin. BPBM 16437 was uniform orange-brown dorsally with no dark chevrons; mask on face and dark lateral band obscure and broken, not well defined; venter very light. BPBM 20235 was light brown with a tan vertebral stripe and irregular black markings, especially on sides and limbs, tan stripe on back of each shank; ventral ground unpigmented, dusted with dark gray on chin and throat and flecked with light gray on belly; iris brown. BPBM 20243 was brown speckled with black; face and anterior sides black except between tympanum and forearm insertion; chin dark gray with light graycream flecks; chest and belly light gray-cream; front of thighs with light gray-cream flecks; groin and back of shanks with yellow-orange wash; iris dark brown.

Call. Animals call at night perched on leaf litter or on sticks or low vegetation within ~ 50 cm of the ground. The call sounds like a drawn-out, high-pitched squeak.

We recorded six calls from four individuals ( Table 7 ). These recordings include four complete calls which ranged from 5–25 notes and, respectively, 14.08– 82.61 s in duration. The duration of notes (complete calls only) averaged 0.3291 s (range 0.1800–0.3640). The interval between notes was more than eight times the duration of the notes, averaging 2.838 s (range 2.1026–5.1832). This produced a noticeably slow repetition rate that averaged 0.4 notes/s with essentially no variation between calls. The call note is unpulsed and begins at close to maximum amplitude and remains at this amplitude until termination ( Fig. 10 A). The mean dominant frequency (all calls) was 6110 Hz (range 5940–6370) ( Fig. 10 B). The notes are frequency modulated, starting at about 400 Hz below maximum frequency and quickly reaching maximum frequency ( Fig. 10 C).

Total Mean Mean

Call Note Internote Repetition Dominant Etymology. The name is a Latin present participle meaning “squeaking” and is in reference to the advertisement call of the species.

Range. Known from the southeasternmost tip of New Guinea and from Normanby Island, D’Entrecasteaux Islands, Milne Bay Province, Papua New Guinea ( Fig. 4 ).

Ecological notes. Animals were found in both primary and secondary lowland rainforest from sea level to 600 m. The species seems fairly tolerant of habitat disturbance, being commonly found in heavily disturbed forest patches near lowland villages. Where we found it in undisturbed primary forest at higher elevations the species did not appear as common. It calls from either the forest floor or perched on leaves or fallen stems within 30 cm of the floor.

Figures

FIGURE 1. Photos in life of (A) holotype of Cophixalus cupricarenus (BPBM 20223), (B) paratype of Cophixalus cupricarenus (BPBM 20208), (C) paratype of Cophixalus kethuk (BPBM 20202), (D) paratype of Cophixalus iovaorum (BPBM 19280), (E) paratype of Cophixalus desticans (BPBM 15703), and (F) paratype of Cophixalus desticans (BPBM 16434).

FIGURE 4. Map showing known distributions for Cophixalus cupricarenus (inverted triangles), C. desticans (circles), C. iovaorum (triangle), C. melanops (star), and C. tomaiodactylus (squares). Filled symbols are type localities; open symbols are additional localities, as relevant.

FIGURE 10. (A) Waveform, (B) power spectrum, and (C) spectrogram of call “ A ” (see Table 7) of holotype of Cophixalus desticans (BPBM 16436) recorded by F. Kraus at Saidowai, 5 m elevation, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, Papua New Guinea on 1 October 2002. Time was not noted; air temperature 24.3 ° C.

Tables

TABLE 6. Mensural data for type series of Cophixalus desticans sp. nov. Data include only adult animals. * = n of 1. Character Males (n = 32) Females (n = 2)

	mean	range	mean	range
SV (mm)	14.6	13.1–16.2	18.4	17.6–19.1
TL/SV	0.53	0.50–0.58	0.50	0.48–0.52
EN/SV	0.079	0.068–0.086	0.076	0.073–0.080
IN/SV	0.12	0.11–0.13	0.11	0.11–0.11
SN/SV	0.14	0.13–0.15	0.13	0.13–0.13
TY/SV	0.060	0.050–0.070	0.068	0.068–0.068
EY/SV	0.13	0.12–0.15	0.12	0.12–0.13
HW/SV	0.36	0.34–0.40	0.36	0.33–0.38
HL/SV	0.34	0.31–0.40	0.32	0.31–0.34
3rdF/SV	0.036	0.032–0.042	0.037	0.037*
4thT/SV	0.056	0.048–0.068	0.057	0.057*
EN/IN	0.67	0.58–0.76	0.68	0.67–0.70
3rd F/4th T	0.64	0.58–0.71	0.66	0.66*
HL/HW	0.93	0.82–1.16	0.91	0.88–0.94

TABLE 7. Call characteristics of four individuals of Cophixalus desticans recorded by F. Kraus at Saidowai, 5 m elevation, Normanby Island, D’Entrecasteaux Archipelago, Milne Bay Province, Papua New Guinea. Calls “ A ” from BPBM 16436 and Upcaptured- 2 are incomplete. All were recorded on 0 1 October 2002 except for BPBM 16437, which was recorded on 0 5 October 2002.

Specimen	Call Temp	Total	Duration	Duration	Duration	Rate	Frequency
No.	No. °C	Notes	s	s	s	notes/s	Hz
BPBM 16436	A 24.3	3	6.04	0.3364	2.5149	0.6	6370
"	B "	25	82.61	0.3425	3.0854	0.3	6200
Uncaptured - 1	A 24.3	21	57.86	0.3016	2.5762	0.4	6110
Uncaptured - 2	A 24.3	1	-	0.3370	-	-	6020
"	B "	5	14.08	0.3484	3.0850	0.4	6020
BPBM 16437	A 23.0	17	47.19	0.3237	2.6053	0.4	5940