Eleutherodactylus corrugatus, Duellman, William E., Lehr, Edgar & Venegas, Pablo J., 2006

Duellman, William E., Lehr, Edgar & Venegas, Pablo J., 2006, Two new species of Eleutherodactylus (Anura: Leptodactylidae) from the Andes of northern Peru, Zootaxa 1285, pp. 51-64 : 52-57

Eleutherodactylus corrugatus new species

Holotype: MHNSM 28063, an adult female, from Ullilen, Provincia de Mariscal Cáceres, Departamento de San Martín, Peru (06°50'49" S, 77°41'40" W, 3000 m a.s.l.) obtained on 30 November 2005 by Pablo J. Venegas.

Paratypes: MHNSM 28062, 28064–67, two males, three females, and two juveniles, from Quintecocha (06º51'30" S, 77º42' 00"W, 3130 m a.s.l.) obtained on 20–24 November 2005 by Pablo J. Venegas, an MHNSM 24444, 28068–69, one female and two juveniles, from Laguna El Plomo, (6º51'03.2" S, 77º43'00" W, 3300 m a.s.l.), Provincia de Mariscal Cáceres, Departamento de San Martín, Peru, obtained on 28 November 2005 by Pablo J. Venegas.

Diagnosis

A member of the Eleutherodactylus (Eleutherodactylus) orestes Group having (1) skin on dorsum shagreen to finely tuberculate with irregular longitudinal ridges; skin on venter areolate; discoidal fold not evident; dorsolateral folds absent; (2) tympanic membrane smooth; tympanic annulus distinct, round, its length slightly more than half that of eye; (3) snout short, rounded in dorsal view and profile, bearing low terminal tubercle; lips rounded; (4) upper eyelid bearing prominent conical tubercle, 60–75% IOD; cranial crests absent; (5) dentigerous processes of vomers absent; (6) males having vocal slits and nonspinous nuptial pads; (7) Finger I shorter than II; discs on outer fingers expanded, elliptical, half again width of digit proximal to pad; (8) fingers bearing broad lateral fringes; (9) ulnar tubercles small, elongate; (10) heel bearing conical tubercle; outer edge of tarsus with low, diffuse tubercle; inner tarsal fold barely evident distally; (11) inner metatarsal tubercle broadly ovoid, about 6x elongate outer metatarsal tubercle; supernumerary plantar tubercles present; (12) toes bearing broad lateral fringes; Toe V slightly longer than Toe III; discs slightly smaller than those on fingers; (13) dorsum reddish tan with brown markings; venter creamy orange with brown reticulations and flecks; groin pale orange; (14) SVL 19.5–19.8 mm in males, 25.8–26.2 mm in females.

Among the 10 species assigned to the Eleutherodactylus orestes Group ( Duellman & and Pramuk 1999; this paper), E. corrugatus is unique in having prominent, conical tubercles on the upper eyelids and heels, and by lacking contrasting markings in the groin. Four other species of Eleutherodactylus in northern Peru have prominent conical tubercles on the upper eyelids and heels; in all of these, Toe V is much longer than Toe III. Three of these species ( E. galdi Jiménez de la Espada, E. muscosus Duellman and Pramuk , and E. wiensi Duellman and Wild ) are larger frogs (males to 33 mm and females to 36 mm SVL) that have large, truncate discs. Furthermore, E. galdi differs from E. corrugatus by having an acuminate snout, conical tubercles along the other edges of the forearm and foot, and cranial crests. In E. muscosus , there are two subconical tubercles on the posterior part of the upper eyelid, and the belly and ventral surfaces of the hind limbs are dark brown with creamy­white spots. Eleutherodactylus wiensi lacks a tympanic membrane, and only the ventral part of the tympanic annulus is visible. The fourth species, E. colodactylus Lynch , has short, stocky fingers and a yellow spot in the groin; it lacks vocal slits, a tympanic membrane, and tympanic annulus. The only other species in northern Peru that bear a tubercle on the snout are E. anemerus Duellman and Pramuk , and E. proserpens Lynch. Eleutherodactylus anemerus lacks tubercles on the upper eyelids and heels, and has a uniform orange­red dorsum; E. proserpens has an acuminate snout, prominent dentigerous processes of the vomers, and low, round tubercles on the upper eyelids, and lacks tubercles on the heels.

Description of the holotype

Adult female with robust body; head narrow, not as wide as body, wider than long; head width 38.9% of SVL; head length 35.9% of SVL, 92.2% of head width; snout short with small terminal tubercle barely evident in lateral view; snout rounded in dorsal view, bluntly rounded in profile ( Figs. 1 A and B); diameter of eye slightly greater than eyenostril distance; nostrils distinctly protuberant laterally; canthus rostralis curved in dorsal view, nearly angular in section; loreal region concave; lips rounded; upper eyelid bearing prominent, conical tubercle; width of upper eyelid 74% of IOD; tympanic annulus round, its posterodorsal part obscured by laterally projecting supratympanic fold; diameter of tympanum 55.6% of diameter of eye, separated from eye by distance slightly less than diameter of tympanum; two subconical postrictal tubercles. Choanae small, ovoid, not concealed by palatal shelf of maxillae; vomers lacking visible dentigerous processes; tongue cordiform, as wide as long, shallowly notched posteriorly, free behind for about half of its length.

Skin on dorsum shagreen, becoming finely tuberculate laterally, with low irregular paravertebral and scapular ridges, longitudinally sinusoidal ridge on upper flank, and low ridges and subconical tubercles on limbs; skin on flanks finely tuberculate above, tubercles becoming larger ventrally; skin on throat, chest, belly, and ventral surfaces of thighs coarsely areolate; other ventral surfaces smooth; discoidal and thoracic folds not evident; cloacal sheath short; ornamentation in cloacal region absent.

Single, low, elongate ulnar tubercle on each forearm; palmar tubercle elevated, bifid, about twice as large as elliptical thenar tubercle; subarticular tubercles prominent, round, and subconical in section; supernumerary tubercles low, round, about half size of subarticular tubercles; fingers short, bearing broad lateral fringes ( Fig. 1 C); Finger I shorter than Finger II; disc on Finger I slightly expanded; those on Fingers II–IV expanded, elliptical, half again as wide as digit proximal to disc; ventral digital pads well defined by circumferential grooves, weakest on Finger I.

Hind limbs moderately robust; tibia length 45.0% of SVL; foot length 45.4% of SVL; heel bearing distinct conical tubercle; outer edge of tarsus with three, low, subconical tubercles; inner tarsal fold barely evident distally; inner metatarsal tubercle elevated, ovoid, about 6x elongate outer metatarsal tubercle; toes unwebbed, bearing broad lateral fringes ( Fig. 1 D); discs on toes about as large as those on fingers; all toes having ventral pads well defined by circumferential grooves; relative lengths of toes 1<2<3<5<4; Toe V slightly longer than Toe III; disc on Toe III not reaching distal subarticular tubercle on Toe IV; disc on Toe V extending to proximal border of distal subarticular tubercle on Toe IV.

Coloration of holotype in preservative: Dorsum grayish brown with brownish­black markings consisting of interocular bar with broad extension posteromedially to occiput, shallow W­shaped mark in scapular region, small diffuse spots on head and body, three faint diagonal marks on each flank, diffuse canthal stripe, two irregular labial bars on each upper lip, well­defined crescent­shaped mark below supratympanic fold, one elongate diagonal bar and one transverse bar on each thigh, and irregular transverse bars on limbs (4 on shank, 3 on tarsus, 3 on forearm). Broad creamy­tan transverse mark on top of head anterior to interocular bar and with posterolateral corners on supraocular tubercles; groin pale tan; posterior surfaces of thighs dark brown with bold, cream mottling. Throat, chest, belly, and ventral surfaces of limbs creamy tan with brown flecks, most dense on margin of chin; ventral surfaces of outer two fingers and toes brown; ventral surfaces of other digits yellowish tan; dorsal surfaces of Fingers I and II and Toes I–III cream with brown spots.

Coloration of holotype in life: Dorsum reddish tan with dark brown markings, including labial bars, interocular bar, diagonal bars on flanks, transverse bars on limbs, and with broad cream band across top of head and upper eyelids ( Fig. 2 ); venter dull pale orange with brown flecks and reticulations; iris reddish tan dorsally, grayish bronze below narrow median black triangular marks.

Measurements of holotype in mm: SVL 26.2, tibia length, 11.8, foot length 11.6, head length 9.4, head width 10.2, IOD 2.7, width of upper eyelid 2.0; eye–nostril distance 2.3; diameter of eye 2.7, diameter of tympanum 1.5.

Va r i a t i o n

Conical tubercles are present on the eyelids and heels of all specimens, but those on the eyelid are not as well developed in juveniles as in adults. Also, a tubercle on the snout is not evident in the two juveniles (MHNSM 23066, 23068), one male (MHNSM 23069), and one female (MHNSM 23065). The degree of tuberculation and development of dermal ridges on the dorsum and flanks in two females (MHNSM 23062, 23065) and one male (MHNSM 23067) is equivalent to that in the female holotype, whereas the dorsal part of the flank is shagreen in two females (MHNSM 23064, 24444) and one male (MHNSM 23069). The skin on the dorsum is simply shagreen in the two juveniles. Males have vocal slits and weakly spinous, unpigmented nuptial pads on the dorsomedial surface of the base of Finger I.

Males are smaller than females and have proportionately longer legs, narrower IODs, and smaller tympani. The ranges and means (in parentheses) of measurements (in mm) of five females are followed by the ranges of two males: SVL 24.3–26.2 (25.7), 19.5–19.8; tibia length 11.0–11.9 (11.5), 9.4–9.5; foot length 11.6–12.0 (11.8), 9.6–9.7; head length 8.9–9.8 (9.3), 6.5–6.8; head width 9.3–10.5 (9.9), 7.2; IOD 2.6–2.9 (2.8), 2.2–2.4; width of upper eyelid 1.8–2.2 (2.0), 1.5–1.6; eye–nostril distance 1.9–2.4 (2.2), 1.8–1.9; diameter of eye 2.4–3.0 (2.7), 2.2–2.3; diameter of tympanum 1.5–1.7 (1.6). The ranges of proportions (as percentages) in five females is followed by those of two males: tibia/SVL 43.5–46.1, 48.0–48.2; foot/SVL 44.8–47.7, 47.5–47.7; head length/SVL 34.0–39.1, 32.8–34.9; head width/SVL 36.0–40.2, 36.4–36.9; upper eyelid/IOD 69.2–75.9, 66.7–68.1; eye–nostril distance/eye 79.2–85.2, 81.8–82.6; tympanum/eye 55.6–66.7, 47.8–50.0. Two juveniles have SVLs of 13.0 and 16.0 mm.

In preservative, only one specimen (a juvenile, MHNSM 23066) resembles the holotype in having a broad, pale transverse band on the head; this juvenile also has a brown venter with a median cream line. The other juvenile (MHNSM 23068) has dense brown pigment on the throat and belly. The dorsum in one male (MHNSM 23069) is tan with dark brown middorsal and dorsolateral stripes. In all specimens, the groin is pale tan to cream, and the posterior surfaces of the thighs are brown with varying amounts of cream mottling.

Distribution and ecology

Eleutherodactylus corrugatus is known from three localities at elevations of 3000–3300 m in the northern part of the Cordillera Central in northern Peru. All individuals were found on leaves of low bushes, 30–150 cm above ground at night. At Ullilen and Quintecocha the frogs were found in very humid montane forest, and at Laguna El Plomo individuals were in patches of elfin forest. Sympatric species at Ullilen include Colostethus sp., Eleutherodactylus wagteri Venegas, and Gastrotheca ossilaginis Duellman and Venegas. The other species found at Laguna de Quintecocha are Bufo arborescandens Duellman and Schulte , Centrolene lemniscatus Duellman and Schulte , Eleutherodactylus , bromeliaceus Lynch, E. rufioculis Duellman and Pramuk , E. schultei Duellman , E. stictoboubonus new species, Gastrotheca ossilaginis and Telmatbius atahualpai Wiens , whereas the latter was the only other species found at Laguna El Plomo.

Etymology

The specific epithet is a Latin adjective meaning wrinkled or ridged; the name alludes to the texture of the skin on the dorsal surfaces of this species.

Figures

FIGURE 1. Holotype of Eleutherodactylus corrugatus, MHNSM 28063. Lateral (A) and dorsal (B) views of head. C. Palmar view of hand. D. Plantar view of foot.

FIGURE 2. Holotype of Eleutherodactylus corrugatus in life, MHNSM 28063, 26.2 mm SVL. Photo by P. Venegas.