Pristimantis bambu Arteaga-Navarro & Guayasamin, new species
Creators: name: Arteaga-Navarro, Alejandro F.
name: Guayasamin, Juan M.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Strabomantidae
Pristimantis
Pristimantis bambu

description: Pristimantis bambu Arteaga-Navarro & Guayasamin, new species
Holotype. QCAZ 46740, an adult male (Figs. 1–3) obtained by Alejandro F. Arteaga-Navarro on January 0 7, 2010, at La Libertad, Reserva Mazar (02.54804 S, 78.69741 W; 2976 m.a.s.l.), Cantón Azogues, Provincia Cañar, Ecuador; airline distance from Rivera is 6.6 km.
Paratypes. All 24 paratypes (Figs. 4 A, B) were collected by Alejandro F. Arteaga-Navarro on January and March 2010 at the Reserva Mazar, southern Sangay National Park, east of Pallcayacu river, within the Cantón Azogues, Provincia Cañar, Ecuador. From these, 16 are adult males (QCAZ 46704, 46706–7, 46710–12, 46724– 27, 46741–42, 47555, 47558, 47556–57); 6 are adult females (QCAZ 46705, 46708, 46739, 46743–44, 7559); and 2 are juvenile females (QCAZ 46713–14).
Diagnosis. The new species is placed in the genus Pristimatis, as diagnosed by Hedges et al. (2008), because of the presence of the following traits: cranial crests absent, dentigerous process of the vomers present, and Tshaped terminal phalanges. Pristimantis bambu is diagnosed by having: (1) skin texture of dorsum shagreen with few widely interspersed low tubercles; middorsal fold barely noticeable and fragmented when present (Fig. 1 A); dorsolateral folds ill-defined and incomplete, sometimes absent; venter areolate, lacking discoidal or thoracic folds (Fig. 1 B); (2) tympanic membrane absent; tympanic annulus present, 40–71% of eye length in females and 42– 65% in males, with upper rim obscured by supratympanic fold; (3) snout short, acuminate in dorsal view and rounded in profile; (4) upper eyelid lacking enlarged tubercles; when present, tubercles are low and almost undistinguishable from surrounding skin texture; upper eyelid width 49–83% of interorbital distance; cranial crests absent; (5) dentigerous process of vomers well developed, oblique in outline, positioned posterior to level of choanae and separated medially by distance less than width of odontophore, each process bearing 4–10 teeth; (6) males with a small subgular vocal sac; vocal slits present; nuptial pads absent; (7) first finger shorter than the second; discs on fingers expanded and rounded to slightly truncated (Fig. 2 A), except for Finger I that is only barely expanded; (8) fingers bearing narrow lateral fringes; outer palmar tubercle divided at least distally, inner portion larger and elliptical and outer portion smaller and round; supernumerary tubercles round (Fig. 2 A); (9) ulnar tubercles coalesced into fold; (10) no heel or tarsal tubercles; (11) toes bearing narrow fringes; webbing absent; Toe V slightly longer than Toe III; toe discs expanded, rounded to slightly truncated (Fig. 2 B); (12) inner metatarsal tubercle elliptical, about 1.2–2 times the size of outer, rounded and enlarged metatarsal tubercle; supernumerary plantar tubercles round and weakly developed (Fig. 2 B); (13) in ethanol, dorsum pale brownish gray in males (blackish or slate gray in females), with minute dark spots on the scapular and sacral region (Fig. 3), and faint barring on the dorsal surfaces of limbs (absent in females); dark postocular stripe and faint supralabial bars present; flanks with some localized rusty tinge on the axilla, groin and hidden surfaces of hind limbs; pale cream spots enclosed by blackish pigment may be present on the groin and posterior surfaces of the thigh (bolder and invariably present in females); ventral surfaces uniformly grayish tan with very fine, dark, localized mottling on throat. In life (Fig. 3), dorsal surfaces of males tan, with or without dark symmetrical markings overall (uniformly blackish olive drab in females); dark transverse bars on the hind limbs poorly marked if present (absent in females); black postocular blotch present; in males, background color of throat, belly and ventrolateral surfaces khaki, with or without a yellowish tint on the throat that may shift to orange-red on the belly; rest of underparts, grayish brown to rosy brown; in females, all ventral surfaces uniform gray or deep purplish brown; a rusty tinge on the hidden surfaces of hind limbs is present in both males and females, almost always surrounding one or several amber to orange blotches in the axilla, groin and posterior surfaces of the thigh; these marks may be enclosed by black pigment; upper half of the iris pale goldenrod yellow; lower half, deep coppery brown; (14) SVL in females 24.6–26.4 (mean = 25.3 ± 0.6, n = 5), in males 17.4–20.1 (mean = 19.2 ± 0.7, n = 13); (15) body mass in living females 0.9–1.6 g, in males 0.5– 0.8 g.
Similar species. Pristimantis bambu differs from all other members of the P. o re s t e s group (i.e., P. a t r a b r a - chus, P. chimu, P. cordovae, P. corrugatus, P. melanogaster, P. orestes, P. pataikos, P. pinguis, P. seorsus, P. simonbolivari, P. simonsii, P. stictoboubonus, P. vetriguttatus, P. vidua; sensu Hedges et al. 2008) by having slightly expanded, rounded to slightly truncate finger pads. Pristimantis corrugatus (Duellman & Lehr 2009) may as well have expanded discs, but these are elliptical and wider than those of P. bambu. The new species may be further distinguished from all other species in the group (Table 1), except from P. c h i m u, P. pinguis, P. seorsus and P. s i m o n s i i (Duellman & Lehr 2009), by having ulnar tubercles coalesced into a low fold. Pristimantis chimu, P. seorsus and P. simonsii differ from P. b a m b u by lacking vocal slits; P. pinguis differs by having a differentiated tympanic membrane. From those species in the group bearing small eyelid tubercles (P. c h i m u, P. cordovae, P. o re s t e s, and P. v e n - triguttatus: Duellman & Lehr 2009; Lynch 1979), it differs by lacking a distinct discoidal fold. Finally, in life, P.
bambu is unique among the species assigned to the P. ore s te s group on the basis of the rusty pigment of the hidden surfaces of the hind limbs and the bold, black-bordered amber blotches on the groin and posterior surface of the thighs.
Description of the holotype. Adult male (QCAZ 46740; Figs. 1–3). Head slightly narrower than body, slightly longer than wide; upper eyelid bearing several, feebly visible tubercles; head width 35% of SVL; head length 36% of SVL; snout relatively short (snout to eye distance 17% of SVL), acuminate in dorsal view (Fig. 1 A) and rounded in profile; tongue longer than wide, posterior half notched and not adherent to floor of mouth; eye diameter slightly larger than eye–nostril distance; nostrils not protuberant, directed anterolaterally; canthus rostralis weakly concave in profile; loreal region slightly concave; upper eyelid width 58% of interorbital distance; cranial crests absent; tympanic annulus distinct, round; tympanic membrane absent; two enlarged postrictal tubercles, situated posteroventrally to tympanic annulus; choanae round, not concealed by palatal shelf of maxillary; vomerine odontophores posteromedial to choanae, oblique in outline, about the same size of choana, separated medially by distance less than width of odontophore, each bearing 5 teeth; vocal slits and median, subgular vocal sac present; skin on dorsum shagreen with widely interspersed low tubercles; dorsolateral fold visible on either side but only on anterior half of the body; middorsal fold fragmented, barely noticeable (Fig. 1 A); skin on venter areolate with no discoidal or thoracic folds (Fig. 1 B); cloacal sheath absent; cloacal region bordered ventrally by small, closely packed warts; ulnar tubercles coalesced into fold, continuous throughout forearm; outer palmar tubercle divided, inner portion larger and elliptical, outer portion smaller and round (Fig. 2 A); subarticular tubercles round in section; supernumerary palmar tubercles low and rounded, much lower than subarticular tubercles; fingers bearing narrow lateral fringes; Finger I shorter than Finger II; disc of Finger I barely expanded; all other discs expanded, rounded to slightly truncate (Fig. 2 A); ventral pads well defined by circumferential grooves; nuptial pads absent.
Tibia length 47% of SVL; foot length 45% of SVL; inner metatarsal tubercle present, about the same size of the outer, rounded and enlarged tubercle; subarticular tubercles round in section; plantar supernumerary tubercles indistinct; toes bearing narrow lateral fringes; webbing absent; discs of Toe I barely expanded; all other toe discs expanded, rounded to slightly truncated; toes with ventral pads well defined by circumferential grooves; relative length of toes: I <II <III <V <IV; Toe V slightly longer than Toe III (Fig. 2 B).
Measurements of holotype (in mm). SVL 20.04; tibia length 9.4; foot length 9.0; head length 4.5; head width 7.2; eye diameter 2.3; interorbital distance 2.6; upper eyelid width 1.5; internarial distance 2.0; eye-nostril distance 1.8.
Coloration of holotype in preservative. Dorsal surfaces pale brownish gray, with minute dark dots on the scapular and sacral region, distributed symmetrically on each half of the body, and with faint, dark transverse bars on the hind limbs (Fig. 1 A); upper lip with dark brown bars below eyes; dark brown supratympanic stripe present; background color of ventral surfaces khaki with a localized rusty tinge on the hidden surfaces of the hind limbs, which is also present but much fainter on the lower belly, palms and axillary region (Fig. 1 B).
Coloration of holotype in life (based on observations in the field and photographs; Figs. 3 A, B). Dorsal surfaces light orangish brown, with faint, dark transverse bars on the hind limbs; flanks with same coloration as dorsum, with a dark brown postocular stripe accompanied by faint vertical supralabial stripes; background color of ventral surfaces khaki, finely mottled with dark pigment on the throat and strongly tinged with yellow on the throat and upper chest; palms, soles, ventral surfaces of hind limbs and groin intensely tinged with rusty to yellow, which becomes deep saffron on the belly as it fuses with the yellowish pigment of the throat; upper half of iris light goldenrod, lower half coppery brown.
Variation. Meristic variation is presented in Tables 2 and 3. Some paratypes have two eyelid tubercles (QCAZ 46705, 46714, 46712, 46739, 46711, 26724), and others have only one (QCAZ 46725, 46704, 41444, 41606, 41616, 41620, 41672, 41694, 41738; Figs. 4, 5 B); several paratypes have no visible dorsolateral fold (QCAZ 46706, 46714, 46725, 46711, 46742, 46724) nor middorsal fold (QCAZ 46725, 46711, 46742, 46724). In ethanol, the dorsum of one paratype is densely covered throughout with symmetrically distributed dark marks (QCAZ 46742; Fig. 6 A), another one has a pale gray middorsal spot (QCAZ 46714), and yet another one (QCAZ 46710) has a light drab frontal patch. The dorsal background color of three paratypes is darker than the holotype (QCAZ 47555, 47556, 47557; Fig. 6 D) or completely dark grayish brown altogether (QCAZ 46707); three male paratypes (QCAZ 46712,47555, 47557) have no localized rusty to light reddish brown pigment on the groin, axilla and hidden surfaces of the hind limbs. Most male paratypes (QCAZ 47555, 46726, 47556, 47558, 47557, 46711, 46712, 46714 46725, 46713, 46724, 46727, 46706, 46742) have pale cream spots on the groin and posterior surface of the thighs. Throat mottling is much more extensive in two male paratypes (QCAZ 46706, 46707). In preservative, the dorsal color becomes grayer and the rusty and yellowish tinge of the ventral surfaces is extensively lost. Specimens in life have well-defined tubercles and folds on the dorsum and legs, but those skin marks are much fainter in preservative.
Vocalization. The advertisement call of QCAZ 47558 (an adult male recorded on Reserva Mazar on 11 March 2010 at 22:08 h, temperature not recorded) can be characterized as a series of short, indistinctly pulsed, non-modulated notes in amplitud. The dominant frequency ranges between 2.50 and 2.56 kHz (maximum energy is 122.54 ± 1.74 dB; n = 20). The note repetition rate is 54.42 notes per minute, and the note length ranges between 0.005 and 0.006 s (Fig. 5). Internote intervals range between 0.816 and 1.782 s (mean = 1.195 ± 0.310 s; n= 20). Out of six recordings, call duration ranged between 12 and 103 s, with significant variation among note repetition rate. Vocalizing males decreased note intensity when approached by an observer. This is the first call described for a species in the P. o re s t e s group.
Etymology. This specific epithet bambu refers to the habitat preference of the new species, which is found in bamboo-dominated montane forests (Chusquea sp). The epithet is a noun in apposition.
Distribution and natural history. Pristimantis bambu is known only from La Libertad, Reserva Mazar, (S2.54804, W78.69741), at elevations between 2876 and 2989 m.a.s.l (Fig. 6). This site, a family-owed alpaca ranch, is located in the eastern mountain range of Ecuador, on the southern edge of Sangay National Park, Cañar province. The area is a patchwork of native evergreen montane forest (Valencia et al. 1999), shrub, secondary forest and pastures (FCT 2008). Average temperatures at La Libertad are 18ºC and precipitation is 1200 mm per year. There are two distinct seasons: the dry season (Oct/Nov – Jan/Feb) and the wet season (FCT 2008). Individuals of P. bambu were active during night on leaf litter and vegetation (20–155 cm above ground) within regrowth montane forest where bamboo (Chusquea sp) is dominant. Individuals were seen active under overcast and cloudy nights, even under light drizzle, but not under heavy showers. During early morning, P. bambu was found active on the leaf litter, later during the day, individuals were found hidden in the leaf litter. Two individuals were hidden under piled up eucalyptus lumber and dead leaves far from the forest border, in pastures. Pristimantis bambu was found both near rivers and far from significant watercourses; but it was never found within primary forest. The species appears to be closely associated with secondary forests where the canopy cover is not complete, a habitat composed mainly of small trees, shrubs and bamboo. The species was also found on the forest border.
Females Males
(n = 5) (n = 13)
SVL 24.6–26.4 (25.3 ± 0.6) 17.4–20.1 (19.2 ± 0.7) Tibia length 11.9–12.4 (12.1 ± 0.2) 8.7–9.8 (9.3 ± 0.3) Foot length 11.3–11.7 (11.5 ± 0.2) 7.5–9.1 (8.4 ± 0.4) Head length 8.3–9.0 (8.6 ± 0.3) 6.1–7.2 (6.7 ± 0.3) Head width 8.4–9.3 (8.7 ± 0.3) 6.2–7.1 (6.6 ± 0.3) Interorbital distance 3.0–3.3 (3.1 ± 0.1) 2.2–2.6 (2.4 ± 0.1) Upper eyelid width 1.6–2.1 (1.9 ± 0.2) 1.5–2.0 (1.7 ± 0.1) Radioulna lenght 5.4–6.3 (5.8 ± 0.3) 4.2–4.7 (4.5 ± 0.1) Eye to nostril distance 2.2–2.4 (2.3 ± 0.1) 1.5–1.9 (1.7 ± 0.1) Snout to eye distance 4.0–4.3 (4.1 ± 0.1) 3.0–3.6 (3.3 ± 0.2) Eye diameter 2.5–2.7 (2.6 ± 0.1) 2.1–2.4 (2.2 ± 0.1) Tympanum diameter 1.0–1.5 (1.3 ± 0.2) 0.7–1.3 (1.1 ± 0.2) Hand lenght 6.1–6.4 (6.2 ± 0.1) 4.3–5.2 (4.9 ± 0.2) Finger I lenght 3.6–4.0 (3.7 ± 0.2) 2.6–3.1 (2.9 ± 0.2)
Females Males
During March 2010, a vocalizing male was heard. When searching it, a female Pristimantis bambu was found, presumably attracted by the male's vocalization. They were both bagged together and began amplexus 72 min afterwards. During the wet season, five males were heard vocalizing simultaneously along with another species (Pristimantis pycnodermis). A gravid female released 30 unfertilized eggs inside a plastic collecting bag. Sympatric species of P. b a m b u include, P. pycnodermis, P. gagliardoi, P. riveti, and two undescribed Pristimantis species.
During night, P. bambu remains still when approached by an observer; calling males may continue to vocalize even when approached, though some individuals may stop calling or foraging, even jumping away at times. At night, most individuals were found by standing 0.4–1.8 m from the vegetation and carefully scanning thin (2–10 mm in diameter) twigs, ferns, and leafs.
Discussion. The most recent comprehensive phylogeny of strabomantids includes four species assigned to the Pristimantis orestes group; two of them, P. o re s t e s and P. simonbolivari, cluster together, but the other species (P. simonsii and P. melanogaster) do not (Hedges et al. 2008). Two scenarios explain the observed pattern: (i) the molecular phylogeny is accurate and the shared morphologies of the species included in the Pristimantis orestes group represent convergent evolution to cope with similar habitats (Hedges et al. 2008), or (ii) the molecular phylogeny is not congruent with the evolutionary history of the these amphibians, and the Pristimantis orestes group is monophyletic. Since only a molecular phylogeny is at hand at the moment, we favor the first scenario. Both morphology and molecules support the lineage distinctiveness of P. b a m b u. Given our taxon sampling, P. bambu is most closely related to Pristimantis sp. (Fig. 7; corrected genetic distance = 5.9–6.8%), P. simonbolivari (corrected genetic distance = 7.7–7.8%), and P. o re s t e s (corrected genetic distance = 8.9%; Fig. 7).
description: Published as part of Arteaga-Navarro, Alejandro F. & Guayasamin, Juan M., 2011, A new frog of the genus Pristimantis (Amphibia: Strabomantidae) from the high Andes of Southeastern Ecuador, discovered using morphological and molecular data, pp. 17-29 in Zootaxa 2876 on pages 19-27, DOI: 10.5281/zenodo.205032