Litoria purpureolata, Oliver, Paul, Richards, Stephen J., Tjaturadi, Burhan & Iskandar, Djoko, 2007

Oliver, Paul, Richards, Stephen J., Tjaturadi, Burhan & Iskandar, Djoko, 2007, A new large green species of Litoria (Anura: Hylidae) from western New Guinea, Zootaxa 1519, pp. 17-26 : 18-24

publication ID	https://doi.org/ 10.5281/zenodo.177396
DOI	https://doi.org/10.5281/zenodo.6246247
persistent identifier	https://treatment.plazi.org/id/EE1087CF-1264-FFFD-FF46-016AB78D1805
treatment provided by	Plazi
scientific name	Litoria purpureolata
status	sp. nov.

Treatment

Litoria purpureolata sp. nov.

( Figs 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 5 )

Litoria sp. nov. 2 nr infrafrenata Richards et al. 2002 a. Litoria sp. 2 Richards et al. 2002b.

Holotype. MZB Amph 12.997 (FN = JCUNQ 5783), adult male, collected at Tiri Camp (3°17'30"S, 138°34'53"E), 4.5 km SW Dabra, Mamberamo Basin, Papua Province, Indonesia, by Stephen Richards, Djoko Iskandar and Burhan Tjaturadi on 9 September 2000.

Paratypes. MZB Amph 12.998– 13.000 (FN = JCUNQ 5800, JCUNQ 5803, JCUNQ 5818 respectively), SAMA R60721–23 (FN = JCUNQ 5798, JCUNQ 5799, JCUNQ 5820 respectively), all adult males from the same locality and obtained by the same collectors of the holotype, between 9 and 12 September 2000.

Diagnosis. A large species of Litoria characterised by: (1) SVL of males 55.7–68.2 mm, (2) dorsum entirely green, (3) dermal ridges on legs and arms white, (4) lateral surfaces and webbing in life with extensive purple pigmentation, (5) finger webbing extending no further than second metacarpal tubercle except on outer edge of digit II, (6) white labial stripe weak and not extending beyond rictus, (7) no parotoid glands, (8) no black mottling on iris, (9) large nuptial pad extending over lateral edge of thumb, with flat anterior edge, and deep triangular ‘extension’ on the lower posterior edge, and (10) advertisement call consisting of monotonously repeated notes produced at a rate of 1.5–1.7 notes s -1 with 32–39 pulses/note at 26.8o C.

Description of holotype. Adult male with following measurements (mm): SVL 63.2, EN 5.7, HW 21.9, EYE 6.6, TL 33.8, IN 5.1, HL 2.4, TYM 4.4, 4TD 3.7, 4TP 2.7, 3FD 3.9, 3FP 2.1. Body slender; head approximately as wide as long (HW/HL 1.023), not wider than body in dorsal view; snout truncate in both dorsal and lateral aspect; labial region very marginally flared; loreal region steeply sloping and marginally concave; canthus rostralis moderately distinct, slightly curved; nares closer to tip of snout than to eyes, oriented laterally but visible in both dorsal and anterior views.

Choanae large, roughly circular, separated by a distance approximately two and a half times their width; vomerine teeth in group along the posterior ridge of two prominent elevations positioned medial to choanae. Eyes moderately small (EYE/SVL 0.10), prominent in both dorsal and lateral views, pupil horizontal. Tympanum moderately large (TYM/SVL 0.07), annulus distinct and raised. Dorsal edge of tympanum obscured by supratympanic fold that extends from posterior edge of eye to above the supra-axillary junction. Dorsally skin smooth but with numerous minute pits on body and legs; ventrally skin smooth on forelimbs and lower hindlimbs, finely granular on posterior half of abdomen, less finely granular on anterior edge of abdomen and on throat and on upper hindlimbs, very coarsely granular on lateral surfaces.

Arms robust; distinct white dermal fold extends from mid-point of finger IV, along fore-arm to elbow; fingers with relative lengths of III>IV>II>I; discs prominent with supramarginal grooves, significantly wider than penultimate phalanx (3PW/3DW 0.538); subarticular tubercles indistinct and rounded, two on digits I and II, three on digits III and IV; supernumerary tubercles low, indistinct, present on proximal phalanx of digits II–IV; prominent palmar tubercle at base of digit I. Nuptial excrescence in single cluster at base of digit I, anterior edge of excrescence straight, posterior edge with elongate triangular projection extending from lower half. Nuptial excrescence (excluding triangular extension) roughly as long as wide. All digits webbed to about second subarticular tubercle, except outer edge of digit II where the webbing extends to approximately first subarticular tubercle; very slight dermal fringes on all phalanges.

Legs moderately long (TL/SVL 0.535) with prominent white dermal fold extending along tarsus from lateral edge of toe V and across heel. Relative lengths of toes IV>V>III>II>I; discs prominent and expanded with circum-marginal grooves, wider than penultimate phalanges (PW4/DW4 0.730); subarticular tubercles prominent and rounded, two on digits I and II, three on digits III and V, and four on digit IV; supranumerary tubercles faintly visible on proximal phalanx of toes II–V; prominent ovoid inner metatarsal tubercle at base of digit I. All digits webbed; webbing extends to distal end of penultimate phalanx on inner edge of digit V and outer edges of digits III, II and I, to approximately halfway up penultimate phalanx on inner edge of digits III and II, and to base of penultimate phalanx on both sides of digit IV. Slight dermal fringes on all digits.

In life, dorsum entirely light green; lateral surfaces light purple with extensive cream blotching concentrated midway between the limbs; indistinct orange-brown stripe extends posteriorly from the rictal region to midway between the limbs; ventral surface of throat yellowish-cream. Brownish horseshoe shaped marking present on the tympanum; indistinct white labial stripe on the lower lip. White ring around the eye, iris orange-brown with faint grey speckling, sclera black. Dorsal surfaces of arms and legs light green; all of upper arm, and lateral surfaces of lower arm and legs purple. Prominent white dermal folds on the legs and arms, bordered ventrally by faint light brown region. Proximal dorsal surface of digits green, distal surfaces orange-brown; webbing largely purple with orange brown margins along the digits.

FIGURE 4. Advertisement calls of Litoria purpureolata sp. nov. holotype (MZB Amph 12.997) recorded at an air temperature of 26.8o C. A. Wave form (upper) and audiospectrogram (lower) of seven consecutive calls in a longer series. B. Wave form (upper) and spectrogram (lower) showing detail of pulses in a single call.

In preservative dorsal surfaces of head, body, arms and legs pale slate blue, with very small, scattered patches of darker blue. Digits and webbing off-white but tending bluish towards the proximal and posterior extremities on both the hands and feet. Ventral surfaces largely off white, with strong brownish tinge just visible on the posterior edge of the thighs and leading into strongly purplish area on the thighs; purplish tinge also apparent on webbing of hand and foot, on lateral surfaces of abdomen, and faintly over ventral surfaces of arms and legs.

Variation. In preservative dorsal colouration of all paratypes is darker than holotype, in some cases considerably so. SAMA R60723 has a few scattered very small white spots dorsally. Dark purplish colouration, of variable intensity, is visible on lateral surfaces of all specimens. Shape of nuptial pad is the same in all specimens, except the smallest specimen (MZB Amph 13.000) which possesses two distinct and relatively small (probably not fully developed) nuptial excrescences on each thumb.

Advertisement call. The advertisement call of this species is a distinctly pulsed note produced in very long series. Twenty consecutive calls of the holotype recorded at an air temperature of 26.8o C were produced at a rate of 1.76 calls s -1. Duration of notes ranged from 0.11– 0.17 s (mean = 0.14, SD = 0.015) and they contained 32–39 pulses (mean = 33.9, SD = 1.9) produced at a rate of 203.7–296.3 pulses s -1 (mean = 246.2, SD = 24.7). The dominant frequency was 1720–1890 kHz (mean = 1814.5, SD = 50.8). Waveforms and audiospectrograms of calls are presented in Fig. 4. Calls of two additional males, SAMA R60721 (n = 36) and SAMA R60722 (n = 44) recorded at the same place and temperature were produced at a rate of 1.5 calls s -1 but these calls were of insufficient quality for detailed analysis.

Distribution and ecology. Litoria purpureolata sp. nov. is known from a singe locality on the Tiri River, a small tributary of the Mamberamo River in the southern Mamberamo Basin, central Papua Province, Indonesia ( Fig. 5 View FIGURE 5 ). The forest at this site has been described in detail by Richards & Suryadi (2002). Males were calling from palm leaves 4–6 metres above the water in a shallow swamp in primary lowland rainforest. Conditions during the survey were extremely dry and activity levels of frogs were generally low. Males of L. purpureolata sp. nov. called strongly despite the dry conditions and all specimens obtained had distinct nuptial excrescences. From this observation it is suggested that the breeding season of the new species may be independent of substantial rainfall.

TABLE 1. Summary of key measurements for the type series of Litoria purpureolata sp. nov. See ‘Materials and methods’ for explanation of abbreviations.

MZB MZB MZB MZB SAMA SAMA SAMA Amph 12.997 Amph 12.998 Amph 12.999 Amph 13.000 R60721 R60722 R60723 Ratio Mean (Range)

EN/SVL 0.10 (0.09–0.11) HW/SVL 0.35 (0.33–0.37) EYE/SVL 0.10 (0.09–0.12) TL/SVL 0.55 (0.52–0.60) IN/EN 0.83 (0.80–0.89) HW/HL 1.03 (1.00–1.07) EAR/SVL 0.08 (0.07–0.08) 4TP/4TD 0.79 (0.69–0.87) 4TD/SVL 0.05 (0.05–0.06) 3FP/3FD 0.58 (0.51–0.79) 3FD/SVL 0.06 (0.05–0.07) Etymology. The species name is an adjective derived from the Latin purpereus (purple) and latus (flank) in reference to the striking purple colouration that characterises the lateral surfaces of this species in life.

Comparison with other species. The combination of large size (> 55 mm SVL) and predominantly green dorsal colouration readily distinguishes L. purpureolata sp. nov. from most congeners. Litoria caerulea , L. gilleni (Spencer) and L. splendida Tyler can be readily distinguished from the new species by the presence of prominent glandular supra-tympanic folds, and in lacking white dermal stripes on the arms and legs. Litoria dux Richards and Oliver , L. graminea , L. hunti Richards, Oliver, Dahl and Tjaturadi , and L. sauroni Richards and Oliver , can all be distinguished by the more extensive webbing on the hands that extends distally beyond the second metacarpal tubercle on digits II and IV. Litoria dux can be further distinguished by its red iris and small rounded nuptial pad. Litoria sauroni has distinct pigment flecking over the eyelid, a red iris with black mottling and a small rounded nuptial pad. Litoria graminea is a more robust frog (HW/SVL 0.325–0.373 vs 0.379–0.404); and L. hunti is generally smaller (SVL 57.9–60.4mm), has a more distinct white labial stripe, and a different call consisting of a long deep guttural growl uttered at much longer intervals (Richards et al. 2006).

Two superficially similar Australian taxa, L. chloris (Boulenger) , and L. xanthomera Davies , McDonald & Adams, lack a white labial stripe and possess indistinct white dermal folds on the arms and legs. These two species also have long, drawn-out rasping calls ( Davies, McDonald & Adams 1986, S. Richards pers. obs.) in contrast to the short, rapidly repeated notes of L. purpureolata sp. nov. Small individuals of the new species could be confused with members of the Litoria gracilenta group [as defined by Günther & Richards (2000): L. aruensis (Horst) , L. auae Menzies & Tyler , L. elkeae Günther & Richards , L. gracilenta (Peters) and L. kumae Menzies & Tyler ]; however these taxa have a distinct canthal stripe running across the eyelid, lack dermal folds and white labial or leg stripes, and have more extensively webbed hands ( Tyler 1968, Gunther & Richards 2000, Menzies & Tyler 2004). Litoria multiplica (Tyler) is also predominately green but can be immediately distinguished by having prominent white raised dermal folds around the vent, a hidden tympanum, some black ventral patterning, and smaller size (SVL of males 32.9–42.0 mm) ( Tyler 1968, Richards & Oliver unpubl.).

Litoria purpureolata sp. nov. is morphologically most similar to L. infrafrenata and L. sanguinolenta . The former species can be differentiated by its much larger adult size (SVL up to 135 mm; Menzies 1976), bolder and far more extensive labial stripe that normally extends to at least the tympanum, and an advertisement call that is a long series of double-notes ( De la Riva et al. 2004) unlike the uniformly pulsed call of L. purpureolata sp. nov. (Fig. 4). Richards et al. (2006) demonstrated that all names synonymised with L. infrafrenata represent that species and these synonyms are not considered further here. Litoria sanguinolenta , known from south of the main cordillera in Papua Province, is smaller (SVL of males <55 mm; Tyler 1968, Richards & Tjaturadi unpubl.), is finely granular laterally (vs very coarsely granular), lacks the distinctive purple lateral colouration of Litoria purpureolata sp. nov. and has a call consisting of 6–8 pulsed notes (vs single notes with> 30 pulses) emitted in rapid succession ( De la Riva et al. 2004).