Pristimantis erythroinguinis Catenazzi & Lehr 2018, sp. n.

Pristimantis erythroinguinis sp. n.

Holotype (Figs 10–11, Table 2). Adult female, CORBIDI 16778, from near Raychulloc, 1150 m a.s.l. (coordinates 13°2´6.25´´S; 71°30´46.62´´W, WGS84), along the Paucartambo-Pilcopata road, Distrito Kosñipata, Provincia Paucartambo, Región Cusco, Peru, collected by A. Catenazzi on 8 August 2013.

Paratypes (Fig. 12). Six total (five adult males, 1 adult female): four adult males CORBIDI 16240, 16776, 16777 and 16779, and one adult female, CORBIDI 16780, collected at the type locality along with the holotype; an adult male MUSM 30468, from near Santa Isabel (13°2´38.65´´S; 71°31´51.20´´W), 1255 m a.s.l., collected by A. Catenazzi on 28 January 2009; all from the Paucartambo-Pilcopata road, Distrito Kosñipata, Provincia Paucartambo, Región Cusco, Peru.

Diagnosis. A species of Pristimantis characterized by (1) skin texture on dorsum variable, shagreen with few or numerous small spicules; skin on venter areolate, discoidal fold not visible, dorsolateral folds absent; (2) tympanic membrane not differentiated, tympanic annulus absent; (3) snout short, bluntly rounded in dorsal view, rounded in profile; (4) upper eyelid bearing 2 large tubercles, and 2–4 small tubercles, narrower than IOD; cranial crests absent; (5) dentigerous processes of vomers small; (6) vocal sac, vocal slits and nuptial pads absent; (7) Finger I shorter than Finger II; tips of digits broadly expanded, rounded bearing circumferential grooves; (8) fingers lacking lateral fringes; (9) ulnar and tarsal tubercles present; (10) heel bearing one or two tubercles; inner tarsal fold absent; (11) inner metatarsal tubercle prominent, elliptical, of higher relief and about twice the size of ovoid, outer metatarsal tubercle; supernumerary plantar tubercles few, low; (12) toes lacking lateral fringes; webbing absent; Toe V longer than Toe III; tips of digits expanded, rounded bearing circumferential grooves; (13) dorsal coloration highly variable, from light brown, green-olive, copper to dark brown with darker markings; interorbital bar dark brown; throat brown to black with few light spots; chest, venter and ventral parts of arms and legs dark brown to black with creamy spots; palmar and plantar surfaces dark brown to black, tips of digits and discs yellowish; groin and hidden portions of thighs and legs dark brown with large red markings surrounded by smaller red marks; iris bronze or gold with fine black reticulations, crossed horizontally by a broad copper band, and vertically by a narrow black streak across pupil; (14) SVL 12.0– 16.2 in males (n = 10), 17.5–21.2 in females (n = 5).

Comparisons. The new species differs from most described species in the genus except P. antisuyu sp. n. and P. cruciocularis by the combination of lack of a tympanic annulus and membrane, by having the iris with a cruciform mark, and the bright red coloration on groin and hind limbs. It differs from both species in the relative lengths of fingers II and IV (Finger IV longer than Finger II in P. antisuyu sp. n. and P. cruciocularis, approximately equal in P. erythroinguinis sp. n.) and of toes V and III (much longer in P. antisuyu sp. n. and P. cruciocularis, longer in P. erythroinguinis sp. n.), in having an inner metatarsal tubercle twice the size of outer metatarsal tubercle (three times as long in P. antisuyu sp. n.), and in lacking yellow coloration (found in all P. antisuyu sp. n., and some specimens of P. cruciocularis). Pristimantis erythroinguinis sp. n. further differs from P. antisuyu sp. n. (characters in parenthesis) by its groin coloration with large, bright red markings (smaller, yellow marks), dark interorbital bar (yellow), and absence of middorsal yellow line (present in some specimens). Pristimantis erythroinguinis sp. n. further differs from P. cruciocularis (characters in parenthesis) by having darker ventral coloration (dark gray with pale cream spots), no middorsal line (present in several specimens), and no yellow or cream spots on flanks and surrounding red marks (yellow or cream spots present).

Description of holotype. Adult female (17.7 mm SVL); head narrower than body, its length 38% of SVL; head longer than wide, head length 114% of head width; head width 33% of SVL; snout short, bluntly rounded in dorsal view, rounded in lateral view, eye diameter 37% of head length, its diameter nearly 1.5 times as large as its distance from the nostril; nostrils protuberant, directed dorsolaterally; canthus rostralis slightly curved in dorsal view, rounded in profile; loreal region slightly concave; lips rounded; upper eyelids with 2 larger tubercles and 2–4 small tubercles; upper eyelid width 100% of interorbital distance; interorbital region flat, lacking cranial crests; supratympanic fold, tympanic annulus and tympanic membrane absent; enlarged postrictal tubercles absent. Vocal sac and vocal slits absent. Choanae ovoid, small, not concealed by palatal sheath of maxilla; dentigerous processes of vomers and vomerine teeth minute; tongue large, ovoid, not notched.

Skin on dorsum shagreen with many minute spicules; dorsolateral folds absent, but a faint, discontinuous dorsolateral ridge visible in the anterior half of body; skin on flanks, chest and venter areolate; pectoral and discoidal folds not visible; cloaca not protuberant, cloacal region without tubercles. Ulnar tubercles and tarsal tubercles present, low; palmar tubercle slightly elevated, bifid, approximately twice the width of elongate, thenar tubercle; supernumerary palmar tubercles weakly defined, low, round, and much smaller than subarticular tubercles; subarticular tubercles prominent, round in ventral view, subconical in lateral view, approximately equal in size; fingers lacking lateral fringes; finger I shorter than Finger II; relative lengths of fingers 3> 4 ~ 2> 1 (Fig. 3); discs on fingers expanded, most prominent on Fingers III–IV, rounded terminally; disc on Finger I only slightly expanded; all fingers with ventral pads well defined by circumferential grooves.

Hindlimbs slender, tibia length 53% of SVL; foot length 42% of SVL; upper and posterior surfaces of hindlimbs smooth; posterior and ventral surfaces of thighs areolate; heel bearing one round tubercle; tarsus with row of small, low tubercles; tarsal fold absent; inner metatarsal tubercle elevated, elliptical, about twice the size of subconical, outer metatarsal tubercle; few, low plantar supernumerary tubercles; subarticular tubercles well defined, round in dorsal view and subconical in lateral view; toes lacking lateral fringes, not webbed; discs on toes about equal in size to those on fingers, most prominent on toes IV and V, toe discs well defined by circumferential grooves; relative lengths of toes 4> 5> 3> 2> 1 (Fig. 3), Toe V 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 border of distal subarticular tubercle on Toe IV).

Measurements of holotype (in mm): SVL 17.7, TL 9.4, FL 7.4, HL 6.7, HW 5.9, ED 2.5, IOD 1.8, EW 1.8, IND 1.3, E–N 1.7.

Coloration of holotype in alcohol. Dorsal surfaces of head, body, and fore limbs grayish brown with light brown marks and darker spots; interorbital bar faint and discontinuous, dark tan. Faint thin light line extending longitudinally from interorbital bar to scapular region, corresponding to ridge of tubercles. Dorsal hind limbs reddish brown anteriorly, grayish brown posteriorly, and gray near feet; dark transverse bars present. Loreal region grayish brown, nostrils surrounded by dark tan spot; two subocular dark tan spots present. Iris light gray with cruciform pattern visible. Throat dark tan with minute light flecks; chest tan; belly tan turning black posteriorly around large, red inguinal marks. Ventral surfaces of hind limbs tan; anterior surfaces with large red mark surrounded by black on thighs, smaller spots elsewhere; posterior surfaces tan. Plantar and palmar surfaces tan; tips of fingers and toes yellowish orange.

Coloration of holotype in life. Similar to coloration in preservative, but dorsal coloration brown with darker spots copper, fading into grayish brown on flanks. Iris bronze with horizontal tan streak and narrower than vertical stripe forming a cruciform pattern.

Variation. There is considerable variation in dorsal and ventral coloration, shape and color of inguinal red marks, dorsal skin texture and number of tubercles on eyelids. Dorsal coloration varies from light brown, reddish brown (e.g., MUSM 30468, CORBIDI 16780) to dark tan (e.g., CORBIDI 11854); ventral coloration varies from dark brown (e.g., MUSM 30468) with or without light flecks to uniformly black (e.g., CORBIDI 16780). The shape and size of red marks varies from having one large mark extending from belly to limb, interrupted only at limb insertion (e.g., the holotype and CORBIDI 16780), to having several, smaller red marks (e.g., MUSM 30468). Some individuals (e.g., MUSM 30468, CORBIDI 16780) have finely shagreen, nearly smooth dorsal skin with two eyelid tubercles, whereas other individuals (e.g., the holotype and CORBIDI 11854) have shagreened skin with numerous small spicules and 4–6 small tubercles on eyelids.

The summary of measurements of all types is reported in Table 2. Figure 2B is the histogram of the frequency distribution of SVL for all vouchered and unvouchered specimens.

Etymology. The name erythroinguinis is derived from the Greek erythros meaning red and the Latin inguen meaning groin in reference to the red groin of the new species.

Distribution, natural history and threats. The species is known to occur from 930–1255 m a.s.l. at the foothills of the Andes in the Kosñipata valley (Figs. 8–9), but is likely to occur over a larger geographic area, possibly restricted to similar elevations. Individuals of these species have been found during both the dry (August) and wet (March) seasons, perched on low herbaceous vegetation and shrubs at heights of 20–90 cm above ground. Sympatric species of Pristimantis include P. altamazonicus, P. cf. carvalhoi, P. cf. diadematus, P. cosnipatae (not seen since 1999; (Catenazzi et al. 2011), P. fenestratus, P. ockendeni, P. olivaceus, P. pluvialis, P. reichlei, P. salaputium, and P. toftae.