(Figs 2–4). MUSM 31097 (GenBank 16S rRNA: KF992151), adult male, collected at Quebrada San Alberto (ca. 10°34'S, 75°23'W) at 1950 m a.s.l., in the buffer zone of the Yanachaga-Chemillén National Park (Sector San Alberto), Distrito de Oxapampa, Provincia de Oxapampa, Región Pasco, Peru, on 15 January 2012 at 18:40h by Edgar Lehr, Jiří Moravec, and Juan Carlos Cusi.

MUSM 31096, NMP6V 74748 (GenBank 16S rRNA: KF992150, KF992152), two adult males, collected with the holotype; MUSM 31148 (Fig. 5), an adult female, same locality as holotype, collected on 3 February 2012 at 18:25h by Edgar Lehr, Jiří Moravec, and Juan Carlos Cusi.

NMP6F 28 (photovoucher), adult male (Fig. 6A), observed on the left bank of the Rio Huancabamba, ca. 5 km W of Oxapampa (10°36'S, 75°30'W) at ca. 1885 m a.s.l. on 5 February 2012 by Edgar Lehr, Jiří Moravec, and Juan Carlos Cusi; IWU 236, an adult female (Fig. 6B), collected in the area of Rio Huatziroki (ca. 11°07'04.2"S, 75°12'05.6"W) at 2075 m a.s.l., in the buffer zone of the Protected Forest Pui Pui, Provincia Chanchamayo, Región Junín, Peru, on 13 June 2013 by Rudolf von May and Juan Carlos Cusi; IWU 235 and IWU 273, subadult specimens, collected in the area of Rio Huatziroki (ca. 11°07'04.2"S, 75°12'05.6"W, and 11°07'40.6"S, 75°11'15.7"W), at 1915 and 2230 m a.s.l., in the buffer zone of the Protected Forest Pui Pui, Provincia Chanchamayo, Región Junín, Peru, on 13 and 16 June 2013 by Edgar Lehr, Jiří Moravec, Rudolf von May, and Juan Carlos Cusi.

A medium-sized species of the Rhinella margaritifera speciesgroup characterized by the presence of cephalic crests, distinct parotoid glands, lateral row of tubercles, dorsal “dead-leaf” pattern, and mtDNA data (see Ávila et al. 2010 and Fig. 1). The new species can be distinguished by the following combination of characters: (1) medium size SVL 57.5–59.5 mm in males (n = 3), 53.5–65.5 mm in females (n = 2); (2) snout slightly pointed in dorsal view, protruding beyond the margin of lip, rounded above and curved posteroventrally in profile; (3) nostrils protuberant, directed dorsolaterally, anterior part exceeding anterior margin of lower jaw; (4) canthal, supraorbital and supratympanic crests continuous, slightly elevated in males, distinctly elevated in female; supratympanic crest moderately expanded dorsolaterally in female; (5) tympanic membrane and tympanic annulus absent; (6) bone protrusion at angle of jaw absent; (7) neural crest of vertebrae absent; (8) parotoid glands elongate, elliptical to subtriangular, slightly protruding laterally, incorporated into lateral row of tubercles; (9) lateral row of tubercles present; tubercles rounded to subconical in males, conical in female; (10) skin on dorsum smooth with scattered flat tubercles in male, tubercles conical in female; (11) skin on dorsal surfaces of limbs smooth with scattered low tubercles in males, spinulose in female; (12) first finger slightly longer than the second in males, both fingers equal in length in single female; (13) palmar tubercle large, ovoid, two to four times size of subtriangular thenar tubercle; (14) inner metatarsal tubercle ovoid, protruding distally, ca. two times size of outer rounded to ovoid subconical metatarsal tubercle; (15) modal webbing on foot: I 0^1/4–0^1/4 II 0^1/4–2^– III 1^––3 IV 3–0^1/4V in males and I 1^––2 II 0^1/3–2^1/2 III 1^––3^1/4 IV 3^1/4–1^– V in the single female; (16) subarticular tubercles prominent, round to oval; supernumerary tubercles round, one half to same size of former; (17) subgular vocal sac and vocal slits absent, and nuptial excrescences present in males; (18) dorsum light yellowish tan to reddish-brown, with irregular brown, dark brown or back markings; whitish or pale yellow middorsal stripe present; venter light orange-tan with irregular dark brown spots, iris silvery greenish with irregular black mottling.

Morphologically, Rhinella yunga differs from all members of the Rhinella margaritifera species group by the absence of tympanum. From the currently recognized species of the Rhinella margaritifera species group occurring in the area of the eastern slopes of the Andes and lowland Western Amazonia, the new species can also be distinguished by following combinations of characters: from Rhinella acutirostris by larger size, absence of bone protrusion at angle of jaw and by coloration (Rhinella acutirostris: SVL up to 47 mm in males [35.3 mm in adult male holotype] and 57 mm in females, weak bone protrusion at angle of jaw, belly cream in holotype; Spix 1824, Hoogmoed 1986, Lötters and Köhler 2000); from Rhinella castaneotica by larger size, presence of lateral rows of enlarged tubercles and absence of bone protrusion at angle of jaw (Rhinella castaneoti ca: SVL 30.9–36.8 mm in males, 33.8–42.6 mm in females, lateral rows of enlarged tubercles absent, weak bone protrusion at angle of jaw present; Caldwell 1991, Köhler and Lötters 1999, Ávila et al. 2010); from Rhinella dapsilis by smaller size, absence of fleshy process in the snout, and tuberculate to spinulose skin (Rhinella dapsilis: SVL 77 mm in female holotype, snout developed in a fleshy proboscis, skin smooth; Myers and Carvalho 1945, Rodrígues and Duellman 1994, Fouquet et al. 2007b); from Rhinella margaritifera by less developed cranial crests, absence of neural crest of vertebrae, and absence of bone protrusion at angle of jaw (Rhinella margaritifera: supraorbital and supratympanic crests hypertrophied, bone protrusion at angle of jaw and vertebral apophyses present; Hoogmoed 1986, Fouquet et al. 2007b, Ávila et al. 2010, type specimen ZISP 257.1 in Milto and Barabanov 2011: fig. 17, Lavilla et al. 2013); from Rhinella proboscidea by less prominent and less pointed snout, distinct parotid glands, tuberculate to spinulose skin, and presence of lateral row of tubercles (Rhinella proboscidea: snout distinctly prominent and pointed, parotid glands indistinct, smooth skin, lateral row of tubercles absent; Spix 1824, Hoogmoed 1986); from Rhinella roqueana by smaller size, less expanded supratympanic crest, absence of bone protrusion at angle of jaw, absence of neural crest of vertebrae, and presence of lateral row of tubercles (Rhinella roqueana: SVL up to 72 mm in males and 81 mm in females, supratympanic crest large, bone protrusion at angle of jaw well developed, crest of vertebrae present, lateral row of tubercles absent; Hoogmoed 1986); from Rhinella stanlaii by larger size, absence of bone protrusion at angle of jaw, and by coloration (Rhinella stanlaii: SVL 39.1–54.1 mm in males and 57.2–59.4 mm in females, well developed bone protrusion at angle of jaw, ventral colors brown and cream; Lötters and Köhler 2000).

Adult male; body robust; SVL 59.5 mm; head wider than long; snout slightly pointed in dorsal view, protruding beyond the margin of lip, rounded above and curved posteroventrally in profile; nostrils protuberant, directed dorsolaterally, anterior part exceeding anterior margin of lower jaw; canthus rostralis concave in lateral view, rounded in profile; loreal region barely concave, horizontal eye diameter larger than distance between nostril and anterior corner of eye; temporal region curved caudomedially; tympanic membrane and tympanic annulus absent; canthal, supraorbital, and supratympanic crests continuous; canthal crest low, barely distinct; supraorbital and supratympanic crests slightly elevated, supratympanic crest slightly expanded laterally, not exceeding markedly outer edge of upper eyelid; bone protrusion at angle of jaw absent; neural crest of vertebrae absent; parotoid glands well developed, elongate, subtriangular, slightly protruding laterally; lateral row of rounded to subconical tubercles from posterior margin of parotoid gland to groin (the first tubercle separated from the gland). Skin on dorsal and lateral surfaces smooth with scattered low to conical tubercles lacking keratinized tips; cranial crests and parotoid glands smooth; loreal and temporal areas smooth with sporadic inconspicuous flat tubercles; upper eyelids with prominent round tubercles; skin on throat and belly coarsely areolate to warty. Forelimb hypertrophied; relative length of fingers II < IV < I < III; palmar tubercle prominent, ovoid; thenar tubercle conspicuously prominent, subtriangular, about one third size of the palmar tubercle; subarticular tubercles large, prominent, distal subarticular tubercle under Finger III bifid; supernumerary tubercles numerous, about half size or less of subarticular tubercles; basal webbing between fingers; nuptial excrescences present on thenar tubercle, dorsal and lateral surfaces of Fingers I–II and inner lateral surface of finger III. Foot longer than tibia; relative length of toes I < II < V < III < IV; inner metatarsal tubercle ovoid, protruding distally; outer metatarsal tubercle ovoid, subconical, about half the size of inner metatarsal tubercle; subarticular tubercles prominent, round to oval; supernumerary tubercles round, about half to same size of subarticular tubercles; toes with moderate webbing, webbing formula I 0^1/4–0^1/4 II 0^1/4–2^– III 1^––3 IV 3–0^1/4V; lateral fringes broad; tips of digits terminating in indistinct discs. Tongue elongate, attached to anterior part of mouth floor; choanae small, oval; vocal slits absent; subgular vocal sac absent.

Measurements of holotype provided in Table 1.

Dorsal surfaces of head, body, and limbs light grey with slightly darker irregular markings forming very inconspicuous “dead-leaf pattern” from between eyes to cloacal region; whitish grey middorsal stripe from snout to cloaca. Middle area of shank, tibia, and tarsus with obscure dark grey spots forming one transverse bar on flexed leg. Dark grey transverse bar on forearm. Ground color of lateral side of head and body light grey. Two inconspicuous oblique darker grey bars below eye, one darker grey bar in temporal area from posterior edge of eye to angle of jaw. Dorsal side of parotoid glands and lateral row of tubercles light grey, sharply contrasting with dark grey to black longitudinal stripe leading from posterior margin of orbit, along lateral side of parotoid gland and below the lateral row of tubercles. Throat, belly, and ventral surfaces of legs whitish with irregular dark grey spots.

General pattern same as in alcohol. Ground color yellow tan dorsally, orange tan ventrally; larger scattered dorsal tubercles light orange.

Iris silvery greenish with irregular black mottling.

For variation in measurements see Table 1. The male paratypes are similar to the holotype in body form and coloration. An uncollected male observed ca. 5 km W of Oxapampa (Fig. 6A) differed in more contrast “dead leaf pattern”. The female paratype (Fig. 5) is larger than the holotype, is more tuberculate (larger tubercles possess keratinized tips), has distinctly elevated cranial crests with supratympanic crest moderately expanded dorsolaterally, and differs in less developed webbing (see Diagnosis). The overall dorsal coloration of the female paratype is darker and the dark spots on the throat and belly are denser than in the holotype. The morphological characters of the three referred specimens from the buffer zone of the Pui Pui Protected Forest correspond, in general, to those of the type series. The referred adult female (IWU 236; Fig. 6B) measured 53.5 mm in SVL and its coloration (in life) is intense reddish-brown.

The specific name yunga is derived from the Quechua expression yungas meaning “warm valley”, which is widely used for an ecoregion of montane rainforests covering the eastern Andean slopes of Peru and Bolivia. The name is used as a noun in apposition and refers to the general habitat of the new species.

Besides from its type locality, Rhinella yunga is also known from the area on the left bank of the Rio Huancabamba (ca. 5 km W of Oxapampa, ca. 1885 m a.s.l.), from Quebrada Yanachaga valley at the settlement Prosoya (10°25.118'S, 75°31.126'W, ca. 1800 m. a.s.l.) and from the area of Rio Huatziroki (elevation 1915–2230 m a.s.l.) lying in the buffer zone of the Pui Pui Protected Forest ca. 60 km straight southeast of the type locality (see the referred material; Fig. 7). To date, Rhinella yunga is known from an altitudinal range 1800–2230 m a.s.l., which represents a contact belt between the transitional montane forest (“Bosque de transición”, 1000–2000 m a.s.l.) and montane cloud forest (“Bosque de neblina”, 2000–3400 m a.s.l.; altitudinal zonation adopted from Milanovich et al. 2006). It is likely that Rhinella yunga is distributed in a wider area of montane forests in the Peruvian regions Pasco and Junín (Selva Central).

All collected and observed specimens were in breeding condition. The female paratype contained numerous small pigmented oviductal eggs. At the type locality, the males were sitting in shallow water of small temporal water bodies along a narrow unpaved road (Fig. 8A). The males entered the water in the late afternoon. The female paratype was collected on the ground in close vicinity of breeding puddles at night. In the vicinity of Huancabamba-Prosoya (Programa Social Yanachaga, former Hacienda Yanachaga) one adult male was observed (not collected) in a small artificial pond at night. The three referred specimens from the area of Rio Huatziroki were found in low dense forest covering a sharp montane ridge (Fig. 8B). Tadpole and call are unknown. Observed sympatric anurans include Rhinella cf. leptoscelis (MUSM 31150, NMP6V 74749), Hypsiboas aguilari Lehr, Faivovich & Jungfer, 2010 (MUSM 31147), Pristimantis cf. bipunctatus (Duellman & Hedges, 2005), and Pristimantis sp. We classify Rhinella yunga as “Data Deficient” according to the IUCN red list criteria and categories (IUCN Standards and Petitions Subcommittee 2013) based on the limited information on its geographic range.