Litoria aurifera, Anstis, Marion, Tyler, Michael J., Roberts, Dale, Price, Luke C. & Doughty, Paul, 2010

Anstis, Marion, Tyler, Michael J., Roberts, Dale, Price, Luke C. & Doughty, Paul, 2010, A new species of Litoria (Anura: Hylidae) with a highly distinctive tadpole from the north-western Kimberley region of Western Australia, Zootaxa 2550, pp. 39-57 : 41-43

Litoria aurifera sp. nov.

Kimberley Rockhole Frog

Holotype: WAM R169913, an adult female collected as a tadpole from a creek near Bachsten Creek, Prince Regent River Nature Reserve, Western Australia (elevation 343m; 15º59’18.2”S, 125º19’38.1”E) on 23 January 2007 by J.D. Roberts and P. Doughty and raised to an adult by M. Anstis.

Paratypes (prefixes excluded). Paratypes include a mix of field-collected adults, males with recorded calls, and two adults reared from tadpoles. WAM specimens are all taken from smaller unnamed creeks off Bachsten Creek, Prince Regent River Nature Reserve.

R168004 (female), 168006 (male), 168008 (female), 168009 (male), 168010 (female), 168013–4 (males), 168016–8 (males): elevation 349m, 15°59'22"S, 125°19'36"E; 168059 (male), 168062 (male): elevation 260m, 15°44'54"S, 125°22'25"E; 168095 (male): elevation 232m, 15°25'42"S, 125°18'42"E; 168114 (male), 168116 (male), 168118 (female), 168129 (male), 168134 (female): elevation 46m, 15°35'40"S, 125°11'14"E; 168182–5 (males): elevation 408m, 15°51'34"S, 125°41'47"E.

SAMA specimens were reared from tadpoles collected at 5.1 km ESE of junction of Pitta Creek and Prince Regent River, Western Australia: 63001 and 63002 (male and female): elevation 408m, 15º51’34.6”S, 125º41’47”E.

Diagnosis. Australia has three hylid genera of which Cyclorana is fossorial, Nyctimystes has a vertical pupil and palpebral venation, and Litoria , which has a horizontal pupil and no palpebral venation. The new taxon is assigned to Litoria because of its obvious morphological affinity to Litoria meiriana in body form, size, skin colour and texture and its ability to bounce lightly across the water surface without immersion, an attribute shared only by L. meiriana .

Litoria aurifera is a small (to 22 mm), saxicoline species, characterized by a somewhat dorsoventrally compressed, slight body and numerous scattered tubercles over the dorsal surface. The snout is moderately pointed in dorsal view, canthus rostralis slightly curved, tympanum distinct and toes almost fully webbed. It can be distinguished from L. meiriana primarily by its vividly pigmented gold and black tadpole and by adult call characteristics.

While very similar to L. meiriana , the snout of adult L. aurifera tends to be slightly more pointed in dorsal view ( Figure 1 C), and SVL, TL and HW are slightly greater than the former species.

Description of holotype. Size small (SVL 21.8 mm). Head slightly longer (7.7 cm) than broad (6.4 cm), HL/HW 1.203. Canthus rostralis very slightly curved. Snout moderately pointed when viewed from above; obtusely rounded in profile. Eye prominent, horizontal diameter 2.7 mm. Eye to naris distance greater than internarial span (EN/IN 1.7). Tympanum distinct with sharply defined annulus; horizontal diameter 2.0 mm. Small circular gland at angle of jaws and poorly developed supratympanic fold. Vomerine teeth oblique, slope slightly downwards towards medial corner.

Fingers long and slender, in decreasing order of length 3>4>2>1, with small, transversely oval terminal discs that are distinctly wider than digits; a trace of webbing between third and fourth fingers. Subarticular tubercle at base of terminal phalanx elongate and oval. Palmar tubercle broad and flattened ( Figure 1 E). Tibia length slightly more than one-half SVL (TL/SVL 0.55). Toes long and slender, in decreasing order of length 4>5>3>2>1, discs slightly more rounded than oval and wider than digits. Interdigital webbing extensive, reaching the base of the discs of all digits except the third and fourth ( Figure 1 F). Inner metatarsal tubercle small and elongate; outer metatarsal tubercle extremely small and circular. The dorsum bears numerous scattered slightly raised tubercles, middorsal tubercles more flattened. The throat is smooth; abdomen is weakly granular with granulation larger towards sides of body.

The colour in life of the dorsal surface and limbs is mottled with shades of brown and reddish brown (Pantone 464M to 465M). Dorsal tubercles are surrounded by darker brown (462M), which is also in patches upon the hind limbs. The upper lip is often edged with dark brown and silver-white bars, and the sides of the body have scattered whitish tubercles on a dark brown background. The iris is reddish above and grey-gold below ( Figure 2 C). In ventral view, the submandibular area and throat are warm grey (1M), and the abdomen is white tinged with pale copper-pink ( Figure 2 E). The undersurface of the limbs is dark flesh colour (436M). In preservative, each of the pigments is paler and all red, gold and copper pigment is lost.

Variation. Males (N = 20) range in SVL from 18.2–20.2 mm and females (N = 8) from 20.3–21.6 mm. The TL/SVL range is 0.479 to 0.594 ( Table 1 ). The nasal and maxillary bones are extremely thin and the anterior portion of the skull is therefore subject to distortion by compression. As a result, some specimens were excluded from the analysis because they are slightly distorted rendering measurements unreliable.

snout-vent length; TL = tibia length; HW = head width; HL = head length; IO = interorbital span; IN = internarial span;

ED = horizontal eye diameter; TD = horizontal tympanum diameter; ET = eye to tympanum; EN = distance between eye

and naris.

Colour in life: Two specimens reared in captivity had an iridescent reddish tinge over mottling on the dorsum. Specimens photographed before collection at night in the field were reddish brown to almost translucent beige over the limbs, where faint darker patches were visible beneath ( Figure 2 B). Some others were darker reddish-brown with black mottling over dorsum and limbs (M. Barrett pers. comm.). The throat of calling males was dusky grey. Ventrally, the subgular, pectoral and abdominal regions were white and the limbs faint purple (Pantone 5155M).

Colour in preservative: All iridophore pigment is lost. Ventrally, the limbs fade to the same tone as the remainder of the ventral surfaces.

Etymology. Derived from the latin aureus (gold) and fero (to carry or bear) alluding to the distinctive gold patches characterising the colour of the tadpole.

Distribution and habitat. Figure 3 shows the distributions of L. aurifera and L. meiriana . Adults and tadpoles of L. aurifera were collected from creeks where tadpoles of the new species were found, across an altitudinal range of about 46–408m within about 100 km S. of the Prince Regent River. All sites were first order, fast flowing creeks which collect water from rain on sandstone rock escarpments. Tadpoles were collected from pools within the creeks, but were never found in larger creeks or water that carries silt from flooding (M. Barrett, pers. comm.). Water depth in the pools ranged from a few cm to 1 m and substrate was irregular sandstone rock. In some sites the yellow sandstone rock was covered with patches of black algae, on which tadpoles were well camouflaged.

Figures

FIGURE 1. Head of holotype of Litoria meiriana (SAMA R 9082, female) compared with head of holotype of Litoria aurifera sp. nov. (WAM R 169913, female) and hand and foot of holotype of Litoria aurifera (WAM R 169913, female). A, B = holotype of L. meiriana dorsal and lateral views; C, D = holotype of L. aurifera dorsal and lateral views; E, F = hand and foot of L. aurifera. Bar represents 5 mm.

FIGURE 2. Comparative adult frogs in life: Litoria meiriana and Litoria aurifera sp. nov. A = Litoria meiriana, active by day, Nawurlandja Rock, Kakadu National Park, Northern Territory. B = Litoria aurifera, at night in habitat, Prince Regent Nature Reserve, Western Australia. C = Litoria aurifera, holotype (WAM R 169913, female) dorsolateral view, during daytime, raised from tadpole in captivity. D = Litoria aurifera, holotype (WAM R 169913, female) dorsal view. E = Litoria aurifera, holotype (WAM R 169913, female) ventral view. F = Litoria aurifera, anterior view, at night in habitat, Prince Regent Nature Reserve, Western Australia. Bar represents 5 mm.

FIGURE 3. Distributions of Litoria aurifera sp. nov. and Litoria meiriana in north-western Australia.

Tables

TABLE 1. Morphological measurements of Litoria aurifera sp. nov. and Litoria meiriana. Mean ± S. D. (range). SVL =

Character	Litoria aurifera N = 27	Litoria meiriana N = 27	Statistical Results
SVL	19.9±1.0 (18.2–22.3)	18.8±1.3 (17.1–22.4)	F1,52 = 14.63, P <0.001
TL	11.0±0.7 (10.0–12.7)	10.3±0.5 (9.3–11.8)	F1,52 = 16.00, P <0.001
HW	7.4±0.3 (6.9–7.9)	6.9±0.6 (5.5–8.1)	F1,51 = 7.27, P <0.01 SVL: F1,51 = 4.53, P = 0.038
HL	6.9±0.5 (6.3–8.1)	6.8±0.4 (5.6–7.7)	F1,51 = 0.28, P <0.598 SVL: F1,51 = 5.04, P = 0.029
IO	4.0±0.5 (2.1–4.7)	3.9±0.5 (2.0–4.3)
IN	1.5±0.2 (1.0–1.8)	1.4±0.1 (1.0–1.7)
ED	2.2±0.2 (2.0–2.6)	2.3±0.2 (1.9–2.7)
TD	1.7±0.1 (1.4–2.1)	1.6±0.1 (1.3–1.8)
ET	0.6±0.1 (0.5–0.7)	0.6±0.1 (0.3–0.9)
EN	2.0±0.1 (1.6–2.5)	2.0±0.2 (1.6–2.4)