Uperoleia micromeles Tyler, Davies, and Martin, 1981

Catullo, Renee A., Doughty, Paul, Roberts, Dale & Keogh, Scott, 2011, Multi-locus phylogeny and taxonomic revision of Uperoleia toadlets (Anura: Myobatrachidae) from the western arid zone of Australia, with a description of a new species, Zootaxa 2902, pp. 1-43 : 17-19

Uperoleia micromeles Tyler, Davies, and Martin, 1981

Tanami Toadlet

Uperoleia micromeles Tyler, Davies, and Martin, 1981 Aust. J. Zool., Suppl. Ser. 79: 46–49.

Holotype. SAMA R17175, an adult female collected in the Tanami Desert, Northern Territory, on 18 January 1978 by M. Gillam and I. Andrews. In the original description Tyler et al. (1981) note the coordinates as 28º38’S; 130º25’E. However, these coordinates contained a typo and the correct coordinates are 20º38’S; 130º25’E (M.J. Tyler, per. comm.).

Paratypes. There are five paratypes, one adult male and four adult females NTM R31199 (previously Central Australian Museum ( CAMA) 140); SAMA R17176–78, R17221. All paratypes share the same collection details as the holotype.

Diagnosis. Distinguished from congeners by a combination of large body size (males 24.2–31.1 mm, females 22.2–37.6 mm SUL) with short to moderate length limbs (TL/SUL 0.36±0.01 [0.33–0.38]), very broad snout (EN/ IN 0.87±0.09 [0.70–0.98]), absence of maxillary teeth, narrowly exposed frontoparietal fontanelle, scattered pale or reddish tubercles on dorsum, pale tubercles conspicuous on side of snout and above eyes, dull brown dorsal surface with irregular-shaped rich dark brown and red blotches, usually a vertebral row of orange tubercles from snout to urostyle, well developed parotoid and subarticular glands, inguinal and coccygeal glands moderately developed and restricted to rear of body. Toes basally webbed ( Fig. 2 a), and thin exceptionally large and projecting inner and outer metatarsal tubercles.

Description. Body large, squat, rotund, and thick. Head wide with small eyes. When viewed laterally, thick snout with little slope and squarish tip; when viewed from above, the sides of the snout slope minimally and end in a wide square tip. Canthus rostralis not defined; loreal region sloping and moderately concave. Rounded medial projection (synthesis of mentomeckelian bones) on lower jaw that matches notch on upper jaw. Nostrils directed upwards; nares with moderate rim. Anterior corner of eye moderately covered by flap of skin; at dorsal terminus the skin overlaps the skin of the brow above the eye. Posterior edge of brow projects slightly over skin on side of head. Tympana covered by skin and parotoid glands. Tongue oval and elongate. Maxillary and vomerine teeth absent. Frontoparietal fontanelle narrowly exposed ( Tyler et al. 1981). EN less than IN (EN/IN 0.87±0.09 [0.70– 0.98]).

Arms and hands thickly built. Arms are short (ArmL/SUL 0.39±0.02 [0.35–0.43]) and fingers are poorly fringed and unwebbed. Finger length 3>4=2>1. Tubercles under fingers moderately developed; one on first and second, two on third and fourth. Large outer palmar tubercle on distal portion of wrist. Nuptial pad of males on inner portion of first finger (beginning halfway down finger), extending to base of wrist (¼ along forearm) and slightly encroaching on palmar surface.

Figure 7: Photos in Life. Top row from left to right: Uperoleia glandulosa from Tabba Tabba Ck (M. Anstis), U. micromeles from South Headland (H. Cook), and U. russelli from Gascoyne River Crossing (M. Anstis). Bottow Row from left to right: U. saxatilis sp. nov. from Mt. Brockman (WAM R162771, P. Doughty), U. saxatilis sp. nov. from Mt. Brockman (WAM R162774, P. Doughty), and U. talpa from Tabba Tabba Ck (M. Anstis).

Legs short (TL/SUL 0.36±0.01 [0.33–0.38]) with thickly muscled tibia. Toe length 4>3>5>2>1. Tubercles under toes moderately developed; one on first and second, two on third and fifth, three on fourth. First toe extremely reduced and fifth toe very narrow (½ the width of the third toe). Toes basally webbed ( Fig. 2 a) and moderately to strongly fringed. Inner and outer metatarsal tubercles extremely large and spatulate, oriented perpendicular to the foot.

Dorsum with scattered tubercles, with a raised mid-vertebral stripe. Large pale tubercles present along snout above mouth. Ventral surface slightly granular. Parotoid gland well developed; inguinal and coccygeal glands moderately developed. Mandibular gland well developed, discrete and prominent posterior to angle of jaw.

Coloration. The dorsal surface is a pale dull brown, with irregularly connected dark brown and red blotches. A vertebral row of crimson tubercles runs from snout to cloaca, with scattered red tubercles on the eye, hind limbs, and glands. Scattered white tubercles occur above the mouth on the side of the snout. The parotoid glands are suffused with metallic gold (Fig. 7). Ventral and femoral coloration is unknown. Males have a darkly pigmented chin.

Advertisement call. Unknown.

Habitat. Occurs in sandridge deserts with Spinifex. Several specimens collected under rocks adjacent to creeks or pools. Known to burrow up to 2 m down in deserts during the dry season ( Thompson et al. 2005).

Distribution. Widely distributed across the Tanami Desert of the Northern Territory and the Great and Little Sandy Deserts in Western Australia, extending to the north-eastern edge of the Pilbara craton near Port Hedland (Fig. 8b).

Etymology. micromeles is derived from the Greek micros (small) and melos (limb) referring to the short limbs of this species.

Comparisons with other species. Uperoleia micromeles is easily distinguished from all other Uperoleia species by the very broadly spaced nares. It is the only species where the internarial span is greater than the eye-naris distance (EN/IN 0.87±0.09 [0.70–0.98], all others EN/IN <1). The basal toe webbing and pale spots on the side of the snout also serve as strong distinguishing characters when used in combination with the broadly spaced nares, as no other arid zone Uperoleia share these characteristics.

Remarks. The ability of this species to live within some of the driest and hottest areas in Australia is remarkable, and distributional information is potentially limited by the difficulty surveying sand dunes and remote locations during the monsoonal wet season when frogs may be active. This species may also be more extensively distributed in the Gibson Desert as it forms part of the Great Sandy Desert drainage ( Beard & Webb 1974).

Figures

FIGURE 2. Extent of webbing relative to tubercle position on the fourth toe. a) basal webbing, b) webbing extends to the first proximal tubercle, c) webbing extends to halfway between the first and second proximal tubercles, d) webbing extends to the second proximal tubercle.