Pristimantis lucasi, Duellman, William E. & Chaparro, Juan Carlos, 2008

Duellman, William E. & Chaparro, Juan Carlos, 2008, Two distinctive new species of Pristimantis (Anura: Strabomantidae) from the Cordillera Oriental with a distributional synopsis of strabomantids in Central Peru, Zootaxa 1918, pp. 13-25 : 14-18

Pristimantis lucasi new species

Holotype: KU 311454–55, MHNC 6475, an adult female, from Abra Esperanza, 2790 m, Distrito Oxapampa, Provincia Oxapampa, Departamento Pasco, Peru (10°31' 54.4" S, 75°20' 58.5" W) one of a series collected on 4 September 2007 by Juan Carlos Chaparro, Aaron Quiroz, and David Salcedo.

Paratopotypes: KU 311454–C55, MHNC 6476, 6478, 6494, 6500, 6504–05, 6526, 6536, and 6565, seven males and five females, collected on 4–10 September 2007 by the same persons, and MHNC 7155, a male, obtained by Juan Carlos Chaparro on 15 May 2008.

Diagnosis. The new species is placed in the Pristimantis (Pristimantis) unistrigatus Group (as defined by Hedges et al., 2008a) because it has expanded digital discs supported by T-shaped terminal phalanges, Finger I shorter than Finger II, and Toe V much longer than Toe III. It has: (1) skin on dorsum smooth with scattered subconical tubercles; that on venter weakly areolate with scattered rounded tubercles; discoidal fold not evident; dorsolateral folds absent; (2) tympanic membrane not differentiated; tympanic annulus absent; (3) snout rounded in dorsal view, bluntly rounded in profile; (4) upper eyelid bearing two large, conical tubercles, slightly less than one half IOD; cranial crests absent; (5) dentigerous processes of vomers absent; (6) males having vocal slits; nuptial pads absent; (7) Finger I shorter than Finger II; discs expanded, truncate, about twice as wide as digits proximal to pads; (8) fingers bearing lateral fringes; (9) ulnar tubercles conical; (10) heel bearing single subconical tubercle; outer edge of tarsus bearing two or three conical tubercles; inner tarsal fold absent; (11) inner metatarsal tubercle elongately elliptical, elevated; no discrete outer metatarsal tubercle; supernumerary plantar tubercles numerous, rounded; (12) toes bearing lateral fringes; webbing absent; Toe V much longer than Toe III; discs equal in size to those on fingers; (13) dorsum with or without bold transverse or longitudinal dark brown markings; venter pale gray with irregular brown or black markings; (14) SVL 15.5–19.1 mm in males, 20.9–23.7 mm in females.

Only five other species of Pristimantis in Peru have conical tubercles on the upper eyelid and heel and do not have a differentiated tympanic membrane and tympanic annulus. Two of these species, P. altamazonicus (Barbour and Dunn) and P. flavobracatus (Lehr, Lundberg, Aguilar, and von May) differ from P. l u c a s i by lacking lateral fringes on the fingers and toes; moreover, the former also differs from P. l u c a s i by lacking ulnar tubercles and having red and black mottling in the groin and on the posterior surfaces of the thighs, whereas P. flavobracatus further differs from P. l u c a s i by having a bright yellow groin. Pristimantis colodactylus (Lynch) differs from P. l u c a s i by having short fingers with broadly rounded terminal discs, no ulnar tubercles, and no labial bars. Pristimantis vilcabambae Lehr differs from P. l u c a s i by having a rostral papilla, and H-shaped scapular fold, and a brown groin with cream spots (in preservative). The equally sized P. leucorrhinus Boano, Mazzotti , and Sindaco from an elevation of 2500 m in the Parque Nacional Yanachaga-Chemillén is the species that is most like P. lucasi , especially in having numerous tubercles on the belly. However, P. leucorrhinus differs by having several conical and subconical tubercles on the eyelid; one of these is notably larger than the tubercles on P. l u c a s i and is curved terminally. Furthermore in P. leucorrhinus the throat, groin, and anterior surfaces of the thighs are black, and there is a pair of large white spots on the anteroventral surfaces of the thighs. For comparative character states in strabomantids in the region of the known distribution of P. l u c a s i, see Table 1 .

Description of holotype. An adult female with head about as wide as body; head width 32.7% of SVL; head length 31.4% of SVL; snout rounded in dorsal view, bluntly rounded in profile, barely protruding beyond margin of lower jaw; eye-nostril distance 69.6% of diameter of eye; nostrils not protuberant, directed slightly anterolaterally at level just behind anterior edge of lower jaw. Canthus rostralis curved, rounded in section, not elevated; loreal region concave; lips rounded; internarial region slightly depresssed; top of head flat; upper eyelid bearing two large, conical tubercles an a few small tubercles; its width 45.5% of IOD; supratympanic fold barely evident, only just posterior to orbit; tympanic membrane not differentiated, tympanic annulus absent; no enlarged postrictal tubercles. Choanae small, nearly round, not obscured by palatal shelf; dentigerous processes of vomers not evident; tongue small about twice as long as wide, not notched behind, barely free posteriorly.

Skin on dorsum smooth with scattered small, conical tubercles; skin on flanks smooth; skin on belly weakly areolate with many scattered rounded tubercles; skin on posteroventral surfaces of thighs coarsely areolate; other ventral surfaces smooth; discoid fold not evident; dorsolateral folds absent; cloacal sheath short, no tubercles in cloacal region. Ulnar tubercles conical, three on each forearm; thenar tubercle elongately elliptical, elevated; palmar tubercle small, deeply bifid; subarticular tubercles large, rounded; supernumerary tubercles prominent, numerous; fingers lacking lateral fringes; relative lengths of fingers I <II <IV <III; Finger I shorter than Finger II; discs on outer fingers expanded, almost truncate, about twice width of digit proximal to disc; all fingers having terminal ventral pads well defined by circumferential grooves ( Fig. 1A ). Hind limbs moderately robust; when hind limbs flexed perpendicular to axis of body, heels barely overlap; tibia length 48.9% of SVL; foot length 45.4% of SVL; heel bearing one subconical tubercle; outer edge of tarsus bearing conical tubercles (two on right; three on left); tarsal fold absent; inner metatarsal tubercle elongately elliptical, elevated, outer metatarsal tubercle absent; toes slender, bearing lateral fringes and elliptical terminal discs about same size as those on fingers; webbing absent; relative lengths of toes I <II <III <V <IV; Toe III much shorter than Toe V; Toe III extending to proximal base of antepenultimate subarticular tubercle on Toe IV; Toe V extending to proximal base of penultimate subarticular tubercle on Toe IV; subarticular tubercles large, rounded; supernumerary tubercles rounded, numerous on proximal segments of digits ( Fig. 1 B).

Coloration in preservative: Dorsum pale gray with dark grayish brown markings, those on head consisting of large spot on top of head anterior to orbits, broad canthal stripe, two diagonal labial bars, narrow postorbital stripe, broad interorbital bar. Body with three broad transverse marks, one in scapular region, one on sacral region, and one postsacrally; first two continue as diagonal marks on flanks. Broad transverse brown bar on forearm; narrower bar on wrist; diagonal bars on hind limbs—two on thigh, two or three on shanks, two on tarsus, one on foot; groin and posterior surfaces of thighs pale greenish yellow with black subcloacal triangle. Venter pale grayish white with irregular black marks, largest on chin and anterolaterally on belly.

Coloration in life: Dorsum pale tan with large dark reddish brown markings—spot anterior to eyes, broad interorbital bar, labial and postorbital bars, broad transverse marks on body (scapular and sacral regions and postsacrally) extending diagonally onto flanks, and diagonal bars on hind limbs ( Fig. 2 A); groin, posterior surfaces of thighs, and ventral surfaces of shanks pale greenish tan. Throat and belly dull yellowish tan with brown tubercles and lateral blotches on belly and reddish brown marks on throat; palmar and plantar surfaces brown ( Fig. 2 B); iris pale bronze with reddish brown flecks and narrow streaks.

Measurements of holotype in mm: SVL 22.3, tibia length 10.9, foot length 9.5, head length 7.0, head width 7.3, IOD 4.4, internarial distance 1.9, width of upper eyelid 2.0, diameter of eye 2.3, eye-nostril distance 1.6.

Variation.— Females are slightly larger than males ( Table 1 ). Males have proportionately larger heads and longer shanks than females; otherwise the proportions greatly overlap. All specimens are alike in having two conical tubercles on the upper eyelid and in the anterior tubercle larger than the posterior one. There are two or three conical ulnar tubercles and two or three conical tubercles on the outer edge of the tarsus. Three specimens have a second, somewhat smaller conical tubercle of the heel ( Table 2 ).

Photographs of living individuals and examination of preserved specimens revealed three color patterns. Eight individuals (four males, four females) have essentially the pattern described for the holotype, that is, transverse marks on the dorsum; in two males and one female the markings are narrower than those in the holotype. Three males have an irregular longitudinal dark mark on the body ( Fig. 2 C), and two others essentially lack markings on the body ( Fig. 2 E). The ventral coloration varies from the irregular black marks displayed by the holotype to dark brown reticulations ( Fig. 2 D) or solely dark brown tubercles on the belly ( Fig. 2 F).

*Also small tubercles on eyelids.

Distribution and ecology. This species inhabits an area of humid elfin montane forest just below the crest of the Abra Esperanza (± 3000 m). All individuals were on low vegetation 30–100 cm above the ground at night during the dry season. Other sympatric strabomantid frogs are Phrynopus auriculatus Duellman and Hedges , and five species of Pristimantis—P. bromeliaceus (Lynch) , P. mendax (Duellman) , P. rhabdocnemus (Duellman and Hedges) , P. sagittulus (Lehr, Aguilar and Duellman) , and P. stictogaster (Duellman and Hedges) .

Etymology. The specific name is a patronym for Lucas Morciniec, who has supported field studies in Peru.

Remarks. With the full realization that the Pristimantis unistrigatus Group is a paraphyletic assemblage ( Hedges et al., 2008a; Lynch & Duellman, 1997), we assign this new species to that group, because it does not “conveniently” fit in any other group in the genus. Pristimantis lucasi and P. leucorrhinus are unique among Peruvian members of the genus in having areolate skin on the venter that is bedecked with many prominent, round tubercles. These seem to be cryptic species, like two other pairs in the Cordillera Yanachaga named by Duellman and Hedges (2005, 2008)— P. adiastolus and P. bipunctatus ; P. albertus and P. stictogaster .

Figures

FIGURE 2. Pristimantis lucasi— A and B. Dorsal and ventral views of the holotype, MHNC 6475, female, 22.3 mm SVL. C and D. Dorsal and ventral views of a paratype, MHNC 6494, male, 17.0 mm SVL. E and F. Dorsal and ventral views of paratype, MHNC 7155, male, 18.4 mm SVL.

FIGURE 1. A and B. Hand and foot of Pristimantis lucasi. C and D. Hand and foot of Pristimantis spectabilis. Scale bars = 3 mm.

Tables

TABLE 1. Measurements (in mm) and proportions with means in parentheses in Pristimantis lucasi.

Character	Eight males	Five females
Snout-vent length	15.5–19.1 (17.03)	20.9–23.3 (22.38)
Tibia length	8.1–9.5 (8.84)	10.2–11.2 (10.82)
Foot length	6.6–8.7 (7.66)	9.4–10.4 (9.94)
Head length	5.0–6.5 (5.65)	6.1–7.3 (6.90)
Head width	5.4–6.5 (5.94)	7.1–7.9 (7.44)
Diameter of eye	1.6–2.0 (1.88)	2.0–2.7 (2.36)
Interorbital distance	3.2–3.8 (3.50)	3.5–4.4 (4.00)
Width of eyelid	1.3–1.8 (1.50)	1.6–2.0 (1.86)
Internarial distance	1.2–1.7 (1.46)	1.6–1.9 (1.76)
Eye–nostril distance	1.1–1.4 (1.24)	1.3–1.7 (1.54)
Head length/SVL	31.3–35.3 (33.15)	28.1–33.5 (30.86)
Head width/SVL	33.5–36.8 (34.91)	32.7–34.4 (33.22)
Width eyelid/IOD	33.5–51.4 (43.04)	43.9–50.0 (46.50)
Eye-nostril/eye	61.1–70.0 (65.98)	61.5–69.6 (65.46)
Tibia length/SVL	50/6–55.5 (52.30)	47.2–49.3 (48.36)
Foot length/SVL	42.6–47.4 (44.99)	42.6–46.1 (44.44)

TABLE 2. Characteristics of strabomantid frogs in the vicinity of Parque Nacional Yanachaga-Chemillén, Departamento Pasco, Peru. Generic abbreviations are: Hyp. = Hypodactylus, Nob. = Noblella, Phr. = Phrynopus, Pri. = Pristimantis. In the column Lateral fringes, F = fingers, T = toes. Conditions are those by Duellman and Hedges (2005, 2007, 2008), Lehr et al. (2004 a, b, 2006), and personal observations.

Species Hyp. lundbergi	Tympanic membrane Yes	Eyelid tubercles No	Skin on venter Smooth	Fingers I=II	Toes V=III	Lateral fringes F,T	Maximum SVL males;females 39.7; 48.8	Range of elevation 1800–2760
Nob. duellmani	No	Small	Smooth	I<II	V<III	–,–	—; 20.0	2900
Phr. auriculatus Phr. bracki	Yes No	No Small	Smooth Smooth	I<II I<II	V>III V>III	–,– F,–	13.4; 14.5 16.2; 19.8	2600 2600
Phr. bufoides	No	No	Areolate	I<II	V>III	–.–	23.9; 33.6	3850–4100
Phr. miroslawae Phr. nicoleae	No No	Small Small	Areolate Areolate	I<II I=II	V=III V<III	–,– –,–	—; 29.1 —; 21.2	3360 3589
Phr. paucari	No	No	Areolate	I<II	V>III	–,–	—; 23.8	3600
Phr. pesantesi Phr. tribulosus	No No	No Small	Areolate Smooth	I<II I=II	V>III V=III	–,– –,–	25.5; 32.7 15.2; 14.6	4280–4390 2600–2700
Pri. aniptopalmatus	Yes	1 round	Smooth	I<II	V>III	F,–	23.2; 22.0	2300–2600
Pri. bipunctatus Pri. bromeliaceus	Yes Yes	No Small	Areolate Areolate	I=II I<II	V>III V>>III	–,– F,T	28.8; 41.5 26.0; 32.8	1240–2320 2200–2600
Pri. flavobracatus	No	2 round	Areolate	I<II	V>>III	–,–	19.6; 23.4	1770
Pri. leucorrhinus * Pri. lucasi	No No	1 conical 2 conical	Areolate Areolate	I<II I<II	V>>III V>>III	F,T F,T	21.1; — 19.1; 23.7	2500 2790
Pri. mendax	Yes	No	Areolate	I<II	V>>III	F,T	23.3; 28.0	1700–3325
Pri. ornatus Pri. pardalinus*	Yes Yes	No 1 round	Smooth Areolate	I<II I<II	V>III V>III	–,– F,T	20.5; 27.3 26.7; 34.1	2400–3000 2640
Pri. platydactylus	Yes	Small	Areolate	I<II	V>>III	F,T	23.8; 35.3	930–3470
Pri. rhabdocnemus Pri. sagittulus	No Yes	No No	Areolate Areolate	1<II I<II	V>>III V>>III	F,T F,T	21.2; 27.0 25.7–29.9	230–2900 1970–2750
Pri. spectabilis	Yes	No	Smooth	I<II	V>>III	–,–	—; 22.7	3300
Pri. stictogaster	Yes	Small	Areolate	I<II	V>>III	F,–	17.7; 23.9	1470–2790