Cophixalus albolineatus, Kraus, Fred, 2012

Kraus, Fred, 2012, Papuan frogs of the genus Cophixalus (Anura: Microhylidae): new synonyms, new species, and a dichotomous key, Zootaxa 3559, pp. 1-36 : 19-23

publication ID	https://doi.org/ 10.5281/zenodo.282919
DOI	https://doi.org/10.5281/zenodo.6180278
persistent identifier	https://treatment.plazi.org/id/03C087AC-FF90-FF8C-AB84-FF09FA67CBC4
treatment provided by	Plazi
scientific name	Cophixalus albolineatus
status	sp. nov.

Treatment

Cophixalus albolineatus View in CoL , sp. nov.

Fig. 8 View FIGURE 8 B, 11

Holotype. BPBM 18433 (field tag FK 8479), collected by F. Kraus at NW slope Mt. Shungol, 5.35 km NW of summit, 6.8188º S, 146.6933º E, 780 m, Morobe Province, Papua New Guinea, 21 October 2003.

Paratypes (n = 10). BPBM 18432, 18434–37, same data as holotype; BPBM 18429–30, NW slope Mt. Shungol, 5.6 km NW of summit, 6.8162º S, 146.6915º E, 750 m, 16 October; BPBM 18431, same data as 18429 except collected 20 October; BPBM 18438–39, same data as 18429 except collected 23 October.

Referred specimens. BPBM 13445–49. Papua New Guinea: Morobe Province: Oomsis Forestry Camp, 6.6984º S, 146.8157º E, 500– 530 m.

Diagnosis. A species characterized by its unique combination of small size (male SV = 16.8–20.5 mm, female SV = 20.1–21.0 mm); finger discs smaller than toe discs (3rdF/4thT = 0.65–0.77); first finger of reduced size, but still elongate and functional, lacking a flattened disc and terminal groove; leg relatively long (TL/SV = 0.53–0.61); snout short and broad (EN/IN = 0.71–0.91); skin smooth; face and postocular area black with a white line extending from snout tip, along canthus, and above eye, and another white line extending from behind eye, through tympanum, and down forearm; rear of thighs dark brown; and relatively slow peeping call with a dominant frequency of 1900–2000 Hz.

Comparisons with other species. Cophixalus albolineatus differs from all other members of the genus in having a conspicuous white line extending from the eye down the forearm; it also differs from all other Papuan Cophixalus except for C. ateles , C. desticans , C. iovaorum , C. kethuk , C. pipilans , C. shellyi , and C. tomaiodactylus in the combination of having the finger discs smaller than the toe discs and having a reduced, though functional, first finger that lacks an expanded disc or terminal groove. Cophixalus bewaniensis , C. humicola , and C. tridactylus also have finger discs smaller than toe discs and a reduced first finger, but in those species the first finger is miniaturized to a non-functional nub easily distinguished from the elongate, functional finger of C. albolineatus . From C. ateles and C. tomaiodactylus , C. albolineatus further differs in having a black face and a smooth dorsum (vs. pustulose or with dorsolateral row of pustules). Cophixalus iovaorum and C. kethuk further differ from the new species in having an hourglass pattern dorsally, marked by black dorsolateral lines. Cophixalus iovaorum also differs in its smaller size (SV = 13.2–17.2 mm) and shorter leg (TL/SV = 0.41–0.49), and C. kethuk has webbing between the toes, which is lacking in C. albolineatus . From C. desticans , the new species further differs in its larger size (male SV = 13.1–16.2 mm in C. desticans ) and smooth skin (with dorsal ridges in C. desticans ). Cophixalus albolineatus further differs from C. pipilans in lacking a dark postorbital bar, lacking a black dorsolateral line, and having a slower call with a lower dominant frequency (4900–5300 Hz in C. pipilans ); it further differs from C. shellyi in its longer leg (TL/SV = 0.44–0.53 in C. shellyi ) and having a much slower call with a lower dominant frequency (ca. 5200 Hz in C. shellyi ).

Description of holotype. An adult female with small right-lateral incision. Head rather wide (HW/SV = 0.41), with vertical, slightly concave loreal region; canthus rounded, straight when viewed from above ( Fig. 11 View FIGURE 11 A); nostrils directed laterally, closer to tip of snout than to eyes; internarial distance larger than distance from naris to eye (EN/IN = 0.77, IN/SV = 0.127, EN/SV = 0.098); snout projecting when viewed from the side ( Fig. 11 View FIGURE 11 B), shallowly angulate when viewed from above; eyes of moderate size (EY/SV = 0.12); eyelid slightly more than half width of interorbital distance; tympanum fairly large (TY/SV = 0.078), with a distinct annulus. Dorsal, lateral, and ventral surfaces smooth; supratympanic fold absent. Fingers without webbing; relative lengths 3>4>2>1. First finger small, with rounded tip but no expanded disc or circum-marginal groove; expanded discs and circummarginal grooves on remaining fingers ( Fig. 11 View FIGURE 11 C); third finger disc approximately twice width of penultimate phalanx (3rdF/SV = 0.049). Subarticular and metacarpal tubercles low and poorly developed but distinct. Toes without webbing or fringes, bearing discs with terminal grooves; relative lengths 4>3>5>2>1 ( Fig. 11 View FIGURE 11 D). Toe discs larger than those of fingers (3rdF/4thT = 0.74); disc of fourth toe more than twice width of penultimate phalanx (4thT/SV = 0.066); disc of first toe slightly broader than penultimate phalanx. Subarticular tubercles poorly developed; inner metatarsal tubercle low and elongate, outer lacking. Hind legs long (TL/SV = 0.57).

In preservative, dorsum medium brown with few dark-brown spots; sides pale straw yellow with reticulum of brown; face, lower jaw, and tympanum dark brown with a postocular pale straw-yellow stripe extending from behind eye, through tympanum, and down forearm, subtended on forearm by field of dark brown. Palmar and plantar surfaces dark brown. Ventral surfaces pale straw yellow flecked with brown, flecking denser anteriorly and sparser on abdomen and under legs. Rear of thighs brown flecked with dark brown. Iris black.

Measurements (in mm). —SV = 20.4, TL = 11.7, HW = 8.3, HL = 7.5, IN = 2.6, EN = 2.0, SN = 3.1, EY = 2.5, TY = 1.6, 3rdF = 1.00, 4thT = 1.35.

Variation. Females average slightly larger than males ( Table 7 View TABLE 7 ), and there is some indication that females may have larger discs than males, but sample sizes are insufficient to be certain of this point. Otherwise, mensural variation among the type series is rather slight. Color pattern varies slightly: three juveniles and one adult have a narrow light-tan vertebral line; two adults have more extensive dark-brown mottling dorsally than do the remaining specimens, and they have a dark-brown, backward-pointing triangle between the eyes. The width of the white postocular line varies from half to two-thirds the width of the tympanum. And the rear of the thighs varies from light brown distinctly blotched with dark brown to fairly uniformly dark brown.

Color in life. From field notes for paratype BPBM 18429 ( Fig. 8 View FIGURE 8 B): “Dorsum brown, face and tympanic region black with a white stripe running from snout along canthus and upper eyelid to forearm insertion and down forearm. Chin to chest black, with few white flecks on chest; belly gray with few black and white flecks. Rear of thighs dark brown; tan line above anus. Iris dark brown rimmed with orange around pupil.”

Call. This species calls primarily from 1–2 h before dark to 1–2 h after dark, with the frequency of calling decreasing noticeably after dark. It may call briefly during daytime, especially following rain.

The call is a rapid series of 2–23 raspy chirps emitted at a rate of 0.32–0.95 notes/s (mean = 0.71 notes/s for six call series); calls range from 3–25 s in duration ( Table 8). Each note is brief, with a mean duration of 0.100 s (range 0.076– 0.113 s). The interval between notes was considerably longer, averaging 1.265 s and ranging from 0.517– 4.702 s. There was little variation among individuals in note duration, but internote duration varied considerably ( Table 8). Each note increases sharply to maximum amplitude and decreases at an accelerating rate, creating an approximately semi-lunar amplitude envelope ( Figs. 12 View FIGURE 12 A, 13A). The note has a well-developed harmonic structure and is frequency modulated, with a downward slur of approximately 200–300 Hz ( Fig. 12 View FIGURE 12 C). The dominant frequency of the calls varied within a very narrow window ( Fig. 12 View FIGURE 12 B), averaging 1972 Hz and ranging from 1911–2010 Hz.

Specimen Call Temperature Number Call Note duration Internote Repetition Dominant

series (˚C) of notes duration (s) (s) duration (s) rate (notes/s) frequency (kHz)

BPBM a 22.5 17 18.6 0.094 ± 0.0013 1.043 ± 0.1138 0.92 1.95 ± 0.0027

18432 (0.084–0.101) (0.525–1.992) (1.93–1.97) b “ 3 9.4 0.083 ± 0.0033 4.446 ± 0.2565 0.32 1.92 ± 0.0052 (0.078–0.089) (4.189–4.702) (1.91–1.93) c “ 2 3.6 0.084 ± 0.0075 3.302 0.55 1.92 ± 0.0005 (0.076–0.091) (1.92)

BPBM a “ 23 25.1 0.103 ± 0.0008 1.029 ± 0.1821 0.92 1.98 ± 0.0022

18433 (0.097–0.110) (0.517–3.781) (1.96–2.01) b “ 12 20.0 0.099 ± 0.0012 1.730 ± 0.1498 0.60 1.98 ± 0.0017 (0.090–0.104) (0.916–2.532) (1.97–1.99) c “ 19 20.0 0.106 ± 0.0010 0.998 ± 0.1112 0.95 1.98 ± 0.0023 (0.099–0.113) (0.567–2.476) (1.96–2.00) Etymology. The trivial epithet is a Latin combinatorial adjective from “albus” for “white” and “linea” for “line”. It refers to the two distinctive white lines on the head and extending down the forearm in this species. Range. Known from the northwestern slope of Mt. Shungol, Madang Province, Papua New Guinea, and from Oomsis, approximately 18 km to the NE ( Fig. 2 View FIGURE 2 ).

Ecological notes. This species inhabits leaf litter, from which it begins calling in late afternoon, continuing for the first couple hours of dark. Habitat at the area of collection was medium-crowned lowland hill forest ( Paijmans, 1975, 1976) with a canopy ~ 30 m high and emergents to ~ 50 m. Specimens were collected along the narrow (ca. 30–50 m-wide) valley bottom bounded by the Dunch River and adjacent steep hills. This valley bottom appeared to be a perched, rocky floodplain, had a series of tributary streams and braided rivulets crossing the area, and had a rich soil with a moderately dense understory, especially of urticaceous herbs.

The smallest mature male is 16.0 mm SV; an immature male is 14.0 mm. The smallest mature female is 20.1 mm; one immature female is 14.8 mm.

Syntopic microhylids include Albericus exclamitans , Austrochaperina parkeri , Austrochaperina palmipes , Callulops personata , Cophixalus cheesmanae , Copiula fistulans , Hylophorbus sp., Mantophryne lateralis , and Oreophryne geislerorum .

Remarks. Specimens BPBM 13445–49 were erroneously identified many years ago as Cophixalus pipilans by R. Zweifel, author of that species; they have been catalogued under that name since that time. Identity between this older sample and the type series of C. albolineatus led me to apply the name C. pipilans to this latter sample for several years too. I subsequently used these specimens in diagnosing several new species of Cophixalus from C. pipilans ( Kraus and Allison, 2009) . Because the original identification was in error, those diagnoses vis-à-vis C. pipilans were also sometimes incorrect in particulars. The only newly described species in Kraus and Allison (2009) seriously affected by this error was C. desticans , which is actually more similar to true C. pipilans (subsequently collected by me and verified against the type series, see Appendix) than first presumed. Based on these specimens of C. pipilans and recordings I made for four animals, C. desticans may be correctly diagnosed from C. pipilans in having a dorsum with many parallel dermal ridges (dorsum smooth in C. pipilans ), a broad dark lateral band (vs. a narrow lateral stripe or series of dashes in C. pipilans ), rear of thighs brown (vs. dark orange in C. pipilans ), and a slower advertisement call (0.4 notes/s in C. desticans vs. 1.5–2.0 notes/ in C. pipilans ) with a higher dominant frequency (5900–6400 Hz in C. desticans vs. 4900–5300 Hz in C. pipilans ) and a rounded waveform lacking a spike in amplitude (waveform with a sharp amplitude spike in the first 0.01 s of call in C. pipilans ). None of the other species described by Kraus and Allison (2009) is liable to confusion with C. pipilans .

Character	Males (n = 6) mean range	Females (n = 3) mean range
SV (mm) TL/SV	19.2 16.8–20.5 0.55 0.54–0.57	20.5 20.1–21.0 0.56 0.53–0.57
EN/SV	0.094 0.083–0.101	0.098 0.095–0.100
IN/SV	0.12 0.11–0.12	0.12 0.11–0.13
SN/SV	0.15 0.12–0.16	0.16 0.15–0.16
TY/SV	0.074 0.066–0.078	0.075 0.070–0.078
EY/SV	0.12 0.11–0.13	0.12 0.12–0.12
HW/SV	0.40 0.39–0.42	0.39 0.37–0.41
HL/SV	0.35 0.34–0.37	0.36 0.35–0.37
3rdF/SV	0.039 0.038–0.042	0.044 0.040–0.049
4thT/SV	0.056 0.053–0.058	0.064 0.061–0.066
EN/IN	0.82 0.71–0.90	0.80 0.76–0.88
3rdF/4thT	0.71 0.66–0.77	0.68 0.65–0.74
HL/HW	0.87 0.84–0.94	0.92 0.90–0.95