Pristimantis ventriguttatus, Lehr, Edgar & Köhler, Gunther, 2007

Lehr, Edgar & Köhler, Gunther, 2007, A new species of the Pristimantis orestes Group (Anura: Leptodactylidae) from the Cordillera Occidental in northern Peru, Zootaxa 1621, pp. 45-54 : 46-52

Pristimantis ventriguttatus new species

Holotype: SMF 86413, an adult female ( Fig. 1 ), collected in amplexus with male SMF 86414, from Hacienda Taulis (approx. 6° 50' S, 79° 10' W, 1800 m), Provincia de Santa Cruz, Departamento de Cajamarca, Peru, obtained by H.-W. Koepcke on 2 February 1952.

Paratypes: Three adult males: SMF 86414, collected with the holotype; SMF 86416, SMF 86415, partially desiccated, from Hacienda Taulis (approx. 6° 50 'S, 79° 10' W, 1700 m), Provincia de Santa Cruz, Departamento de Cajamarca, Peru, obtained by H.-W. Koepcke on January 1952.

Diagnosis. A member of the Pristimantis orestes Group having the following combination of characters: (1) skin on dorsum shagreen with small tubercles coalesced into ridges dorsolaterally, forming discontinuous dorsolateral folds; venter areolate; discoidal fold present; (2) tympanic membrane and annulus present, upper margin slightly concealed by supratympanic fold; (3) snout long, acutely rounded in dorsal view, rounded in lateral view; (4) upper eyelid bearing small tubercles; upper eyelid width narrower than IOD; cranial crests absent; (5) dentigerous processes of vomers small, oblique; (6) males with vocal sac and vocal slits, nuptial pads absent; (7) Finger I shorter than Finger II; discs on outer fingers broadly expanded, slightly truncate; (8) fingers with lateral fringes; (9) ulnar and tarsal tubercles present; (10) heel with small tubercles; inner tarsal fold present; (11) inner metatarsal tubercle oval, twice the size of subconical outer metatarsal tubercle, elevated, slightly conical in lateral view; few, low supernumerary plantar tubercles present; (12) toes with lateral fringes; toes webbed basally; Toe V slightly longer than Toe III; toe discs about same size as fingers, slightly truncate; (13) in ethanol, dorsum pale brown with dark brown flecks and narrow, tan middorsal stripe; venter brown with tan blotches and spots; axilla, groin, flanks, anterior and posterior surfaces of thighs, and inner surfaces of shanks, dark brown with tan blotches and spots; iris dark gray; (14) SVL in single female 29.4 mm, in males 17.8–21.8 mm (n = 3).

Pristimantis ventriguttatus is tentatively assigned to the P. o re s t e s Group by having a contrasting pattern of tan blotches and spots on dark brown in the groin, a small SVL of no more than 33 mm ( Duellman et al. 2006), and a robust body.

Pristimantis ventriguttatus is readily distinguished from the other 11 species (see Table 1) currently assigned to the P. o re s t e s Group ( Duellman et al. 2006, Lehr & Duellman 2007a) by having tan blotches and spots on a brown venter, anterior and posterior surfaces of the thighs, and groin, discs on outer fingers broadly expanded, and a long snout with a small terminal tubercle. Pristimantis ventriguttatus shares with P. cordovae and P. vidua dorsolateral folds, dentigerous processes of the vomers, and vocal slits, but male P. v e n - triguttatus and P. v i d u a lack nuptial pads (present in P. cordovae ). Furthermore the digits are broadly expanded and mostly truncate in P. ventriguttatus , whereas narrowly expanded and marginate in P. cordovae . Pristimantis vidua has a short snout without terminal tubercle (snout long with terminal tubercle in P. v e n - triguttatus), and lacks lateral fringes (present in P. ventriguttatus ). Furthermore, dorsolateral folds are usually tan in P. vidua (not distinct from surrounding color or blackish brown in P. ventriguttatus ) and the venter is tan with fine, small brown spots (brown with tan blotches and spots in P. ventriguttatus ).

Pristimantis ventriguttatus and P. pinguis occur syntopically at Hacienda Taulis. Both species are of similar size, have dorsolateral folds, tympanum present and males that have vocal slits present and nuptial pads absent. However, fingers and toes are short in P. pinguis (long in P. ventriguttatus ) without lateral fringes (present in P. ventriguttatus ), with rounded discs (truncate) that are barely wider than digit proximal to it (discs broadly expanded in P. ventriguttatus ), snout short (long), and venter uniformly tan (contrasting pattern consisting of tan blotches and spots on brown). Both Pristimantis cajamarcensis (Barbour and Noble) and P. lymani (Barbour and Noble) are widespread in the western Andes of northern Peru and can easily be distinguished from P. ventriguttatus by having males with nuptial pads (absent in P. ventriguttatus ). Furthermore, P. cajamarcensis has dorsolateral folds and lateral fringes absent (both present in P. ventriguttatus ), and P. l y m a n i are much larger (male SVL to 45.3 mm in P. lymani vs. 21.8 mm in P. ventriguttatus ) and have Finger I> II (Finger I <II in P. ventriguttatus ).

Pristimantis ventriguttatus and P. s i m o n s i i (Boulenger) may occur in sympatry in Departamento de Cajamarca, but P. simonsii lacks a tympanum (present in P. ventriguttatus ) and lacks marginal grooves (present in P. ventriguttatus ).

Other Pristimantis having a distinctive color pattern consisting of tan or white blotches and spots on a brown venter are P. douglasi (Lynch) belonging to the galdi Group from eastern Colombia and Pristimantis phalaroinguinis (Duellman and Lehr) belonging to the conspicillatus Group from the Cordillera Occidental in northern Peru (Departamento de Cajamarca). Both P. ventriguttatus and P. phalaroinguinis have discs on outer fingers broadly expanded and truncate, but P. ventriguttatus has fingers and toes with lateral fringes (absent in P. phalaroinguinis ), is much smaller (SVL in males to 21.8 mm vs. 31.4 mm in P. phalaroinguinis: Duellman & Lehr 2007 a), has areolate skin on the venter (smooth in P. phalaroinguinis ), and has vocal slits (absent in P. phalaroinguinis ). Pristimantis ventriguttatus and P. douglasi are similar in size; both have vocal slits, fingers and toes with lateral fringes, and areolate skin on the venter. Pristimantis ventriguttatus has long dorsolateral folds (extending only to shoulder in P. douglasi ), posterior border of tongue notched (not notched in P. douglasi ), and no nuptial pads in males (present in P. douglasi ). Pristimantis muscosus (Duellman & Pramuk) a member of the unistrigatus Group from the eastern slopes of the Cordillera Central in northern Peru also has an areolate venter with tan spots and fingers and toes with lateral fringes, but P. ventriguttatus has dorsolateral folds (absent in P. muscosus ), tarsal folds (absent in P. muscosus ), and lacks conical heel tubercles (present in P. muscosus ). Furthermore, P. ventriguttatus is much smaller (female SVL 29.4 mm in E. ventriguttatus vs. 46.1 mm in P. m u s c o s u s: Duellman & Pramuk 1999).

Description of the holotype. Head as wide as body and nearly as wide as long; head width 39.1% of SVL; head length 40.1% of SVL; snout long with small terminal tubercle, acutely rounded in dorsal view, rounded in lateral view ( Figs. 2 A, B); eye diameter 91.7% of eye–nostril distance; nostrils slightly protuberant, directed dorsolaterally; canthus rostralis nearly straight in dorsal view, angular in profile; loreal region concave; lips rounded; upper eyelid width 93.3% of interorbital distance, with small tubercles; tympanic annulus round, its upper and posterodorsal part obscured by supratympanic fold, tympanum diameter 48.5% of eye diameter; tympanum-eye distance about equal to tympanum diameter; enlarged postrictal tubercles fused into a ridge on each side of head. Choanae small, oval, not concealed by palatal shelf of maxilla; dentigerous processes of vomers small, narrowly separated medially, situated posteromedial to choanae; tongue 3 × as long as wide, slightly notched posteriorly, posterior half free.

Skin on dorsum shagreen with small tubercles; dorsolateral tubercles forming slender, discontinuous dorsolateral folds, two on each side; skin on flanks tuberculate with tubercles coalescing into ridges; skin on ventral thighs, belly, chest, and throat areolate, skin on other ventral surfaces smooth; discoidal and thoracic folds present; cloacal sheath short; cloacal region without large tubercles. Three small ulnar tubercles on each forearm, round, low; palmar tubercles slightly elevated, outer palmar tubercle bifid, approximately 2 × size of oval, inner palmar tubercle; subarticular tubercles well defined, elongate in ventral view, slightly subconical in lateral view; one supernumerary tubercle at base of each finger except Finger I, round, low, approximately one-fourth size of subarticular tubercles; fingers with lateral fringes; Finger I shorter than Finger II; discs on Fingers I–II slightly expanded, most prominent on Fingers III–IV; discs on Fingers III–IV nearly truncate, discs on Fingers I–II rounded; ventral pads of fingers well defined by circumferential grooves ( Fig. 2 C).

Hind limbs slender, tibia length 53.1% of SVL; foot length 50.3% of SVL; upper surfaces of hind limbs tuberculate; posterior and ventral surfaces of thighs areolate; no distinct tubercles on heel or on outer surface of tarsus; inner tarsal fold extending along distal half of tarsus; inner metatarsal tubercle elevated, ovoid, twice size of subconical outer metatarsal tubercle; one, low plantar supernumerary tubercle at base of Toes II, IV, and V, two supernumerary tubercles at base of Toe III; subarticular tubercles well defined, round in ventral view, subconical in lateral view; toes with lateral fringes; basal webbing between Toes IV and V; discs about equal to those on fingers, most prominent on Toe IV; discs nearly truncate; toes having ventral pads well defined by circumferential grooves; relative lengths of toes: 1 <2 <3 <5 <4 ( Fig. 2 D); Toe V slightly longer than Toe III (disc on Toe III and Toe V not reaching distal subarticular tubercle on Toe IV).

Measurements (in mm) of holotype: SVL 29.4; tibia length 15.6; foot length 14.8; head length 11.8; head width 11.5; eye diameter 3.3; tympanum diameter 1.6; interorbital distance 3.0; upper eyelid width 2.8; internarial distance 2.5; eye-nostril distance 3.6.

Coloration of holotype in preservative ( Fig. 1 ): Dorsum pale brown with brown blotches; a narrow, pale brown middorsal stripe extending from snout to cloaca; blackish-brown dorsolateral folds; forearm with one ill-defined dark brown transverse bar; hind limbs with indistinct, irregularly shaped dark brown transverse bars; sides of head brown; canthal stripe dark brown; upper half of flanks dark brown, lower half dark brown with tan blotches and spots; axilla, groin, anterior and posterior surfaces of thighs, inner and dorsal surfaces of shanks, and flanks dark brown with tan blotches and spots; ventral surfaces brown with tan blotches and spots; irregular, narrow, tan midventral stripe extending from middle of throat to midlength of belly; iris dark gray. Coloration of holotype in life unknown.

Variation. Measurements (in mm) for the three males (SMF 86414, 86416, 86415): SVL 21.3, 21.8, 17.8; tibia length 13.1, 11.1, 7.8; foot length 12.8, 9.4, 7.1; head length 9.3, 8.2, 5.6; head width 9.1, 7.7, 7.9; eye diameter 2.4, 2.5, 2.7; tympanum diameter 1.4, 1.2, 1.1; IOD 2.8, 2.9, 2.8; upper eyelid width 2.8, 1.9, 1.9; inter narial distance 2.3, 1.8, 1.5; eye-nostril distance 2.5, 2.5, 2.3. In one male (SMF 86414), the dorsum and flanks are uniformly dark brown. This individual has fewer tan spots and blotches in the axilla and groin and on the anterior and posterior surfaces of the thighs and the inner surfaces of shanks than the holotype; the venter is tan and brown with few, barely distinct tan blotches and spots. In the other males (SMF 86415, 86416), the dorsum and flanks are brown and tan with blackish-brown flecks dorsolaterally. The groin is pale brown with large tan flecks; anterior surfaces of thighs are dark brown with tan spots, and the posterior surfaces of the thighs are dark brown with elongate, tan blotches. The concealed surfaces of the shanks are pale brown with tan blotches and spots, and the venter is tan with small dark brown spots. All males have nearly straight vocal slits located at posterior half of mouth floor closer to margin of jaw than to tongue.

Distribution and ecology. Pristimantis ventriguttatus is known only from the type locality described as montane forest by H.-W. Koepcke. Sympatric Pristimantis include P. cajamarcensis , P. lymani , and P. pinguis .

Etymology. The specific name ventriguttatus is derived from the Latin noun venter meaning belly and the Latin adjective guttatus meaning spotted. The name refers to the distinct ventral pattern consisting of tan spots and flecks on dark brown coloration.

Remarks. The Pristimantis orestes Group was defined by Lynch and Duellman (1997) and modified by Duellman et al. (2006) and Lehr and Duellman (2007a) as three new species were assigned to the group. With P. ventriguttatus the P. o re s t e s Group contains 12 species and occurs in páramo, puna, and cloud forest at elevations of 1700–4010 m above sea level in the Andes from southern Ecuador to northern Peru. With more intensive exploration of the Cordillera Occidental, the discovery of new species of Pristimantis is likely.

Phylogeny of the orestes Group is unknown. Both members of the orestes Group and Phrynopus are similar in several morphological characters: Phrynopus have narrow digits that lack pads and marginal grooves, whereas members of the Pristimantis orestes Group have narrow digits with pads that have reduced or absent (only in Pristimantis simonsii ) marginal grooves. As in Phrynopus , most of the members of the orestes Group have limited distributional ranges which are restricted to the type locality or its close surroundings.

Sexual male characters such as nuptial pads or vocal slits are useful to distinguish species from each other. Unfortunately these important diagnostic characters are frequently ignored or simply overseen in species descriptions, even if adult males are present. This led to wrong conclusions that Phrynopus lack nuptial pads (see comments by Lehr 2006) or that nuptial pads are intraspecific variable (present or absent) in males. Unlike in bufonids or Telmatobius where males usually develop seasonally dark brown, spinous nuptial pads, nuptial pads in Pristimantis (and Phrynopus ) are more secretive, cream colored usually non spinous and seem to be present permanently, indicating that reproduction may take place throughout the year (Lehr et al. 2006). In none of the thousands observed specimens from different museum collections did the senior author find nuptial pads in adult male Pristimantis (or Phrynopus ) to be seasonally present or intraspecific variable (absent or present). Only slight differences in size and shape of nuptial pads were observed. Thanks to the detailed field notes by H.-W. Koepcke, we know that female holotype and male paratype (SMF 86414) of P. ventriguttatus were found in amplexus, indicating that both were reproductive adults. Despite the long time in preservative, the type series is well preserved.

Figures

FIGURE 1. Pristimantis ventriguttatus (SMF 86413, holotype, SVL 29.4 mm) in dorsal (A) and ventral (B) views. Photos by E. Lehr.

FIGURE 2. Dorsal (A) and ventral (B) views of head, and ventral views of hand (C) and foot (D) of Pristimantis ventriguttatus (SMF 86413).