Bioacoustics of Cophixalus kulakula

Measurements of holotype . QMJ88540, female; SVL 43.0 mm; TL 21.5 mm ; FL 10.5; HW 15.8 mm ; HL 11.7 mm ; ED 3.7 mm ; EN 3.4 mm ; IN 3.6 mm ; 3DW 2.9 mm ; 3FL 8.1 mm ; 4TL 11.3 mm . Description of type series. Data presented as range followed by mean in brackets. Adult measurements (mm): SVL 39.8–48.0 (43.1); TL 19.5–22.8 (20.7); FL 9.8–11.8 (10.6); HW 14.5–17.5 (15.9); HL 10.1–11.7 (11.0); ED 3.7–4.7 (4.2); EN 3.2–3.8 (3.5); IN 3.2–4.2 (3.6); 3DW 2.3–3.1 (2.7); 3FL 7.0–8.1 (7.4); 4TL 9.3–11.9 (10.5). Adult proportions : TL/SVL 0.45–0.52 (0.48); FL/SVL 0.23–0.27 (0.25); FL/TL 0.48–0.58 (0.51); HW/ SVL 0.34–0.41 (0.37); HL/SVL 0.24–0.27 (0.25); HW/HL 1.34–1.55 (1.45); ED/SVL 0.08–0.11 (0.10); EN/IN 0.86–1.11 (0.99); EN/ED 0.71–0.93 (0.84); 3DW/SVL 0.054–0.068 (0.062); 3FL/SVL 0.16–0.19 (0.17); 4TL/SVL 0.22–0.27 (0.24). Comparison of sexes: Females are on average larger than males (SVL 43.7 vs. 42.5) but the ranges overlap substantially (females: 39.8–48.0 mm, males 40.5–44.8 mm ). No differences in proportions were detected between the sexes. Juvenile measurements (mm): SVL 24.2; TL 12.2; FL 5.5; HW 9.1; HL 7.0; ED 2.5; EN 2.2; IN 2.0; 3DW 1.5; 3FL 4.2; 4TL 5.8. Juvenile proportions : TL/SVL 0.50; FL/SVL 0.23; FL/TL 0.45; HW/ SVL 0.38; HL/SVL 0.29; HW/HL 1.31; ED/SVL 0.10; EN/IN 1.14; EN/ED 0.88; 3DW/SVL 0.060; 3FL/SVL 0.18; 4TL/SVL 0.24. Compared to adults, the juvenile has a proportionally longer head and shorter forearms. Head: Narrower than body, triangular in dorsal view; snout truncated at the nares, noticeably projecting in profile; canthus rostralis angular, loreal region steep; nares much closer to tip of snout than to eye, nares anterolateral on tip of snout; eyes large; eye diameter greater than eye to naris distance; internarial distance about equal to distance from eye to naris; tympanum large (approximately half to greater than half diameter of eye) but indistinct beneath overlying skin, bordered dorsally by supra-tympanic fold. Body: Rotund. Limbs: Hindlimbs and forearms relatively long; fingers and toes unwebbed; relative finger length 3>4>2>1; fingers 2, 3 and 4 long and slender with very large and obviously truncated discs, first finger short with disc expanded but small and rounded; low, ovoid inner and larger, rounded outer palmar tubercles; subarticular tubercles low, moderately prominent; relative length of toes 4>3>5>2>1, toe 4 very long and slender; large, truncated discs on toes 2, 3 and 4, discs smaller and more rounded on toes 1 and 5; low, rounded inner metatarsal tubercle, no outer metatarsal tubercle; subarticular tubercles low and rounded, moderately prominent; discs on longest fingers larger than discs on longest toes. Skin: Ventral surface smooth; dorsal surface of head and limbs covered in very fine tubercles, back covered with scattered low tubercles; distinct supra-tympanic fold. Colour pattern in preservative: All dorsal surfaces uniformly dark brown. Tympanum tawny brown with darker centre. White patches at the base of the finger and toe discs. Dark brown dorsal colouration merges to lighter brown on flanks. Ventral surface of head and body light grey-brown. Ventral surfaces of limbs brown; discs and tubercles grey. The orange seen in life in the groin, posterior thigh and on the calf appears as white patches in preserved specimens. Measurements of live individuals. Two adults were measured in the field: female, SVL 44.3 mm , WT 8.1 g ; male 42.4 mm , 6.1 g . Colour pattern in life ( Fig. 3 ). Adults . No sexual dimorphism in colour pattern evident. Dorsal colour variable. Some individuals emerging from rock crevices were dark brown ( Fig. 3 B) and most individuals changed to this colouration in bags following capture. Individuals active on the surface of the rocks or in associated vegetation were even light brown, uneven grey-brown ( Fig. 3 C) or a fairly uniform pale putty colour ( Fig. 3 A). Diffuse, pale lumbar ocelli are present on some individuals. There is a dark canthal band from the nare to the eye, through the iris, and along the supra-tympanic fold. The upper iris is heavily speckled with gold or copper; speckling is present but less intense in the lower iris. Most individuals have a paler brown or yellowish forehead triangle and similar colouration on the eyelids. The darker dorsal colouration merges with the paler ventral colouration on the flanks. The ventral surfaces are uniformly white on some individuals, while on others they are pale with heavy grey mottling on the chin, throat, chest and forearms ( Fig. 3 D). The palms are dark. Reddish orange markings are present in the hidden parts of the hindlimbs (in the groin and on the posterior thigh and inner calf) ( Figs 3 C, 3D). The brightness and extent of these markings varies between individuals, from very bright and discrete to more diffuse. Juveniles . Greyish brown to yellowish colour with darker mottling on the back, arms and legs. There is a yellowish brown forehead triangle, a dark canthal streak and dark markings on the loreal region, above the tympanum and on the anterior flank. Yellow lumbar ocelli are evident. The flanks and ventral surfaces are mottled grey, and the groin, posterior thigh and calf are orange. Call. Calls were only obtained for a single individual, which was not collected. No obvious differences were heard between the calls of this individual and those calling around it. The mating call of C. kulakula sp. nov. is a short, wavering ‘bleat’ of the following mean characteristics: dominant frequency 1.97 kHz (1.95–1.99), duration 0.38 s (0.35–0.41), pulses per call 155 (140–167), and pulse rate 411 pulses/s (381–448). Calls are uttered at an interval of approximately 8 seconds. Air temperature at the time of recording was approximately 28 ºC. Figure 4 displays a single representative call. The call is distinct from that of other Australian Cophixalus (although the calls of C. pakayakulangun sp. nov. and C. zweifeli are not known). It is obviously different to the tapping calls of most Australian Cophixalus (including C. saxatilis ) and is most similar to the ‘bleat’ of C. ornatus . The call of C. ornatus is a loud, ‘clean’, highpitched ‘beep’, whereas that of C. kulakula sp. nov. is relatively soft, deeper in pitch and has a wavering, ‘scratchy’ quality to it. The call is of higher dominant frequency than would be expected for body size, compared to the relationship seen across other Cophixalus and Australian frogs in general ( Hoskin et al. 2009 ). Comparison. Cophixalus kulakula sp. nov. does not co-occur with any other Cophixalus . It could only be confused with the other three boulder-adapted Cophixalus : C. pakayakulangun sp. nov. (Stanley Hill region, 30 km to the north), C. zweifeli (Cape Melville, 210 km south-east) and C. saxatilis (Black Mountain, 390 km south-east). These four species can be distinguished as follows. Cophixalus saxatilis differs from the other species in that females are bright yellow ( Fig. 1 A) and males are heavily mottled and relatively small ( 29–35 mm ) ( Fig. 1 B). Cophixalus zweifeli ( Figs 1 C, 1D) and C. kulakula sp. nov. have red/orange in the groin and on the posterior thigh, whereas this is at most a faint wash on adult C. pakayakulangun sp. nov. . Cophixalus zweifeli differs from C. kulakula sp. nov. in that it also has red/orange in the axilla (absent in C. kulakula sp. nov. ) and dark blotching on the anterior half of the flanks (i.e. above the axilla) ( Figs 1 C, 1D), whereas the flanks of C. kulakula sp. nov. are generally unmarked ( Fig. 3 ). Additional differences between C. pakayakulangun sp. nov. and C. kulakula sp. nov. are that C. pakayakulangun sp. nov. females are larger (SVL 49–53 mm vs. 40–48 mm ), there is generally an obvious gold tinge to the eyelids and forehead of C. pakayakulangun sp. nov. ( Figs 6 A, 5B) whereas this is faint or absent on C. kulakula sp. nov. ( Figs 3 A–C), and the juveniles of C. pakayakulangun sp. nov. are blotched with dark markings ( Fig. 6 D) whereas those of C. kulakula sp. nov. are mottled with darker markings but not obviously blotched. Genetics. There is substantial sequence divergence (for 944 bp 12S and 16S rRNA) between C. kulakula sp. nov. and all other Australian Cophixalus (average = 12.1%, range = 8.3–14.7%) (Hoskin et al. unpublished). Phylogenetic analyses suggest that Cophixalus kulakula sp. nov. is most closely related to C. pakayakulangun sp. nov. , and these two species are allied to C. ornatus (Hoskin et al. unpublished). Sequence divergence between C. kulakula sp. nov. and C. pakayakulangun sp. nov. is high (8.3%) compared to that between some sister-species of north Queensland Cophixalus (e.g., 4.2% between C. concinnus Tyler, 1979 and C. monticola Richards, Dennis, Trenerry & Werren, 1994 ; 5.1% between C. aenigma Hoskin, 2004 and C. exiguus Zweifel & Parker, 1969 ). A 16S sequence for C. kulakula sp. nov. was deposited in GenBank (accession number JN208371 ).