Pristimantis leucorrhinus sp. nov.

Holotype. MHNSM 19996 (Fig. 1), a single female from the cloud forest surrounding the Refugio El Cedro (10°32.7’S, 75°21.4’W) at m 2500, collected on 11.XI.2006, Distrito de Chontabamba, Provincia de Oxapampa, Departamento de Pasco, Peru, by G. Boano, S. Mazzotti and R. Sindaco.

Diagnosis. A member of the Pristimantis unistrigatus group having: (1) skin on dorsum shagreen, skin on venter areolate (mostly anteriorly), discoidal fold absent, dorsolateral folds in the scapular region only; (2) tympanic membrane and tympanic annulus absent; (3) snout short, rounded in dorsal and lateral views, swollen in the nostril region and slightly depressed between nostrils; (4) upper eyelid with many small tubercles and one large, horn-like tubercle (Fig. 1, inset b), eyelid slightly narrower than interorbital distance, cranial crests absent; (5) vomerine teeth small; (6) condition of vocal slits and nuptial excrescences unknown; (7) Finger I shorter than Finger II, discs on outer fingers broadly expanded, rounded; (8) fingers without lateral fringes; (9) ulnar tubercles present; (10) heel with single tubercle (Fig. 1, inset a), tarsal tubercles present; inner tarsal fold absent; (11) inner metatarsal tubercle rather large, ovoid, about 3x rounded outer metatarsal tubercle, few supernumerary plantar tubercles, low, diffuse; (12) toes with lateral fringes, webbing absent, Toe V longer than Toe III (condition “C” according to Duellman & Pramuk 1999), discs on toes slightly smaller than those on fingers; (13) dorsum cream and brown with dark brown markings, top of snout creamy white, venter brownish-grey with small black turbercles and a few white spots; black throat, black groin with two irregular white spots on the anterior surfaces of the thighs (Fig. 2); (14) snout to vent length (thereafter SVL) 21.1mm in the only known specimen.

Pristimantis leucorrhinus is readily distinguished from all other species known from Peru by the combination of prominent, horn-like supraocular tubercles, a distinctive black and white pattern of the groin and a brownish iris with darker reticulations. Thirteen other Peruvian species ( P. altamazonicus, colodactylus, coronatus, cruciocularis, flavobracatus, imitatrix, lirellus, martiae, quaquaversus, rhabdocnemus, simonsii, tantanti, and ventrimarmoratus) lack a differentiated tympanic membrane and annulus. None of these has a hornlike supraocular tubercle, and none has a color pattern like that of P. leucorrhinus . In particular, the very similar P. flavobracatus (Lehr et al. 2006) differs also by the colour (yellow) and pattern on groin and thighs, and by the colour of the iris, gold with fine black reticulations, with a broad dark-brown horizontal streak across pupil, and a narrow black vertical streak from pupil to lower margin of eye forming a “T”.

Description of the holotype. Head almost as wide as body, slightly wider than longer; head width 39,3 % of SVL; head length 33.2 % SVL; snout short, rounded in dorsal and lateral views, swollen in nostril region with internarial region depressed; distance between eye and nostril 90% of eye diameter; nostrils directed dorsolaterally; canthus rostralis curved downwards in dorsal view, straight in profile; loreal region slightly concave; lips rounded; upper eyelid bearing many tubercles, five of them prominent, apical one more than twice as large as others; upper eyelid width 92% of interorbital distance; supratympanic fold weak, tympanic annulus and tympanic membrane absent; enlarged postrictal tubercles absent. Choanae small, rounded; vomerine teeth small; tongue rounded, 1.14 times as wide as long (length 4.2 mm, width at midlength of tongue 4.8 mm), not notched posteriorly, posterior three-fourths free.

Skin on dorsum shagreen; dorsolateral folds present in the scapular region only; skin on flanks smooth with few, scattered spicules; skin on belly and chest areolate (mostly so anteriorly); discoidal fold absent; large tubercles in cloacal region on proximal half of posterodorsal surfaces of thighs. Forelimbs with low ulnar tubercles; palmar tubercles slightly elevated, outer tubercle approximately twice size of inner one; supernumerary tubercles below Fingers II–IV round, low, subequal in size to subarticular tubercles well defined, round in ventral view and subconical in lateral view, most prominent on base of Finger I; fingers with lateral fringes; relative length of fingers I <II <IV <III; discs on fingers expanded, largest on Fingers III–IV, rounded; all fingers having pads well defined by circumferential grooves (Fig. 3 a). Hind limbs slender, tibia length 52.6% of SVL; foot length 40.8% of SVL; upper surfaces of hind limbs smooth; posterior and ventral surfaces of thighs areolate; heel bearing single, strongly elevated, flat, subtriangular tubercle (less developed on left leg); tarsus with two small, elongate, low tubercles; tarsal fold absent; inner metatarsal tubercle low, elliptical, about twice size of outer metatarsal tubercle; some low plantar supernumerary tubercles; subarticular tubercles well defined, round in ventral view, subconical in lateral view; toes with lateral fringes, not webbed; discs on toes slightly smaller than those on fingers, most prominent on Toes IV–V, well defined by circumferential grooves; relative length of toes is I = II <III <V <IV; Toe V much longer than Toe III (disc on Toe III not reaching distal subarticular tubercle on Toe IV, tip of the disc on Toe V extending to distal bor- der of distal subarticular tubercle on Toe IV) (Fig. 3 b).