A new green , arboreal species of Pristimantis ( Anura : Strabomantidae ) from Amazonian Peru

We describe a new species of Pristimantis from lowland Amazonia of the Region Loreto, northern Peru. The new species is mainly characterized by its size (SVL 26.5 mm in male, 33.0 mm in female), shagreen dorsal skin, absence of dorsolateral folds, slightly areolate venter, presence of discoidal fold, presence of tympanic membrane including tympanic annulus, absence of vocal slits in males, presence of ulnar and tarsal tubercles, bright green to yellow-green dorsal coloration with irregular pattern of small white spots, brown loreal-tympanic region, brown stripe on fl anks sharply outlining dorsal coloration, white to yellow throat, yellow belly, and dark brown palmar and plantar surfaces. The new species is tentatively assigned to the Pristimantis unistrigatus Group. It has an arboreal mode of life and inhabits primary and disturbed Amazonian lowland rainforest.


Material and methods
The format for the description follows Lynch & Duellman (1997) and diagnostic characters of Duellman & Lehr (2009).Specimens were stored in 70% ethanol.Specimens were dissected to examine the gonads.Measurements, which were taken with digital calipers by the senior author and rounded to the nearest 0.1 mm, are: snou-vent length (SVL), tibia length, foot length (distance from proximal margin of inner metatarsal tubercle to tip of Toe IV), head length (obliquely from angle of jaw to tip of snout), head width (at level of angle of jaw), eye diameter, interorbital distance, upper eyelid width, internarial distance, eye-nostril distance (straight line distance between anterior corner of orbit and posterior margin of external nares).Fingers are numbered preaxially to postaxially from I -IV.Comparative lengths of Toes III and V were determined when both were adpressed against Toe IV; lengths of Fingers I and II were estimated when adpressed against each other.Coloration in life descriptions are based on photos taken by J. Moravec, P. Perez Peña and J.J. Lopez Rojas.Comparison with other species.Few species of Pristimantis from the Amazonian lowlands have a green dorsal coloration.These are P. acuminatus, P. olivaceus, P. pseudoacuminatus, and P. tantanti (Table 1).Hind limbs slender, tibia length 48% of SVL; foot length 38% of SVL; upper surfaces of hind limbs shagreen; ventral surfaces of thighs weakly areolate; heel with minute white tubercles; outer surface of tarsus with small white tubercles, slightly elevated, reaching outer margin of Toe V; inner tarsal fold absent; inner metatarsal tubercle elongate (1.8 mm), elevated, more than twice the size of round fl at outer metatarsal tubercle (0.8 mm); supernumerary plantar tubercles indistinct; subarticular tubercles well defi ned, round; toes without lateral fringes; webbing absent; discs broadly expanded, oval, slightly smaller than those on fi ngers, most prominent on Toe IV; toes having ventral pads well defi ned by circumferential grooves; relative lengths of toes: 1 < 2 < 3 < 5 < 4; Toe V subequal to Toe III (Fig. 2 C).Oviducts contain 11 and 8 (left/right) unpigmented eggs, largest approximately 3.8 mm in diameter.

Codes of collections are
tus), acuminated snout (rounded), dark loreal-tympanic region (yellow tan canthal stripe), absence of vocal slits (present), presence of discoidal fold (absent), and by presence of dark brown palmar and plantar surfaces in adults (cream to yellow) (Lynch, 1980; material examined); from P. tantanti (Fig. 3) by larger size (SVL up to 21.9 in males and 29.9 in females in P. tantanti), snout acuminate in dorsal view (acuminate-triangular), presence of tympanic annulus (absent), presence of tympanic membrane (absent), presence of discoidal fold (absent), absence of ulnar and tarsal folds (present, prominent, see Lehr et al., 2007: Fig 2, p. 96), fi ngers with basal lateral fringes (lateral fringes broad, not restricted basally; outer fringe of Finger IV continuing to proximal edge of palm with its shape slightly undulated), toes without lateral fringes (broad lateral fringes present, outer fringe of Toe V contacting outer row of fold of plantar surface with its shape undulated) and without webbing (basal webbing present) and by dark brown palmar and plantar surfaces in adults (yellow to yellowish brown) (Lehr et al., 2007;Lehr, 2009;material examined).
Description of the holotype.Head slightly narrower as body, slightly shorter than wide; head width 36% of SVL; head length 35% of SVL; acuminated in dorsal view, protruding and inclined posteroventrally in lateral view (Fig. 2 A); eye diameter slightly longer (115%) than eye-nostril distance; nostrils directed laterally; canthus rostralis straight in dorsal view, and in profi le; loreal region weakly concave; lips rounded; upper eyelid smooth, upper eyelid width 51% of interorbital distance; tympanic membrane present, round, 37% of eye diameter; tympanic annulus present, best pronounced anteriorly; supratympanic fold moderately developed, covering tympanum dorsally.Choanae small, oval; dentigerous processes of vomers small, horizontally arranged, at posterior margin of choanae, narrowly sepa-

A B
knee area light brown; palmar surfaces brown with fi ne white mottling, plantar surfaces dark brown; iris light reddish brown.
Coloration of holotype in preservative (Fig. 1  C -D). Dorsal coloration of head, body and limbs yellowish white with small irregular gray mottling in the area of snout and upper eye lids, dorsal surfaces of fi ngers and toes light gray to black; loreal-tympanic region dark gray to black with scattered small white dots; mandible with dense melanophores; anterior surface of proximal part of upper arm gray; fl anks with dark gray bar sharply outlined against dorsum, fading ventrally and caudally; throat white with dense melanophores in mental and central area; belly white, translucent caudally; cloacal area gray; ventral surfaces of hind legs white; knee area with dense melanophores; palmar and plantar surfaces dark gray to black; iris dark gray.
Variation.Measurements (in mm) of one adult male (MZUNAP 963) and one subadult male (MZUNAP 957) paratypes are as follows: SVL 26.Coloration of holotype in life (Fig. 1 A -B).By day, dorsal coloration of head, body and limbs yellowgreen with scattered small inconspicuous yellowish white spots; snout and upper eyelids with traces of irregular brown mottling; loreal-tympanic region and mandible brown with scattered small white dots; anterior surface of proximal part of upper arm brown; fl anks with brown bar, starting on tympanic fold, sharply outlining dorsal coloration, bearing minute white dots, fading ventrally and caudally; axilla bright yellow; groin yellow to translucent; dorsal surfaces of fi ngers and toes dark brown with fi ne white mottling; throat white to yellow with dense melanophores distributed along mandible, small group of melanophores in the centre of throat; belly bright yellow, translucent caudally; cloacal area brown with white tubercles; ventral surfaces of hind limbs dull yellow to orange; Tab. 1. Comparisons of Pristimantis padiali sp.n. with other species from the Amazonian lowlands having a dorsal green coloration.Characters were taken from original species description and from the examined material.Presence of a character is indicated by "+", its absence by "-".Buncuya (tributary of río Ucayali), río Nanay, río Tigre and río Pucacuro.Pristimantis padiali has an arboreal mode of life and was encountered in more or less preserved primary lowland forest growing both on sandy and clay substrates.Most records come from non-fl ooded areas, nevertheless, the new species was encountered also in fl ooded forests (río Napo) and palm swamps called "aguajales" (río Tahuayo).
Distribution, ecology and threat status.The documented records of Pristimantis padiali are depicted in the Fig. 4. In general, the new species seems to be distributed in wider surroundings of Iquitos where it was recorded in neighboring aluvial zones of río Napo, río Amazonas, río Itaya, río Tahuayo, río Ucayali, río According to the sparse data available we here classify P. padiali as "Data Defi cient" according to the IUCN red list criteria.
Etymology.The specifi c name is a patronym for our colleague and friend José Manuel Padial in recognition of his important contributions to strabomantid frogs systematics.

Discussion
Pristimantis padiali seems to be closely related to the recently described P. tantanti (Fig. 3).Both species are canopy inhabitants with acuminate snout and bright green dorsum with white spots (Lehr et al., 2007, Duellman & Lehr, 2009).The fact that both adults and juveniles of P. padiali were encountered nearly exclusively on vegetation above ground indicates that also this species has an arboreal mode of life.It appears that also in the case of P. padiali ants form the main part of the food.It is possible that P. padiali can deposit its large unpigmented eggs in bromeliads, moss clumps or other suitable arboreal shelters where they undergo their direct development (typical for Pristimantis) and the frogs need not to descend to the forest fl oor.The mentioned similarity with other arboreal species and a likelihood that most individuals of P. padiali are out of reach in higher forest strata can explain why this species remained overlooked for so long despite its close vicinity of Iquitos.This example supports the presumption that the canopy of tropical forests is one of the least known strata with respect to species diversity (Guayasamin et al., 2006).Therefore, we expect that a thorough investigation of less accessible upper forest strata can result in discoveries of other new species of arboreal frogs even in relatively well-explored area.

Fig. 4 .
Fig. 4. Schematic map of northern and central Peru showing the known distribution of Pristimantis padiali sp.n.Square indicates the type locality.Shaded areas indicate elevations above 500 m a.s.l.