Bioacoustics of Pristimantis munozi

Distribution. Pristimantis munozi is known only from the type locality, Reserva Ecológica Verdecocha, ( 0°5'46.9"S , 78°36'15.3"W ; elevation 2851 m ), located at northwestern flank of the Volcán Pichincha, in the Pichincha province ( Fig. 5 ). Hábitat and natural history. The vegetation of the type locality is described as montane cloud forest ( Valencia et al . 1999 ). The region has a bi-seasonal climatic regime, and present a bimodal pattern of rainfall, with two rainy periods in February-April and September-November (with peaks of maximum rainfall on March-April and October), and two dry periods in June-August and December-January ( Neill & Jørgensen 1999 ). Pristimantis munozi is a nocturnal and secretive frog, apparently associated to bamboo forests ( Chusquea sp.). Even though several types of habitat were intensively sampled at Verdecocha (primary forest, scrubland, secondary forest, grassland and bamboo patches), the new species only was detected in a small patch of bamboo forest at 2851 m ( Fig. 6 ). Numerous males were heard calling between 23:50 and 00:55 h, but due to its cryptic coloration and cryptic behavior (males calling from underneath bamboo leaf litter and mosses, hollows and shelters on the slope of a small seasonal creek) only eight specimens were visually detected and collected. Despite the effort no females were found. At Verdecocha, Pristimantis leoni and P. sirnigeli are sympatric with P. m u n o z i , but none was found syntopically with the new species at the bamboo forest, but in adjacent cloud forest dominated by relatively short trees.

Description of the holotype . Adult male of 17.6 mm SVL. Body short and robust ( Figs. 1 a–b, 2a–b). Head slightly narrower than body, slightly longer than wide ( Figs. 2 a–b, 3a–b); HeL 39.5% of SVL; greatest head width between angles of jaws 38% of SVL; cranial crests absent. Snout short, acuminate in dorsal view ( Fig. 3 a), and rounded in profile ( Fig. 3 c); larger than eye (ETS/ED = 1.5); distance eye-nostril slightly shorter than eye diameter (EN/ED = 0.8). Canthus rostralis weakly concave in dorsal view; nearly angular in cross-section; loreal region slightly concave, sloping outward to lip. Not protruding lips. Nares not protuberant, with dorsolateral orientation, barely visible from the front and completely observable in dorsal view. Upper eyelid wide, narrower than interocular region (UEW/IO = 0.8), with one enlarged and rounded tubercle on each eyelid and few additional low tubercles. Tympanum small (TD/ED = 0.4) but well-defined, slightly higher than long; tympanic membrane differentiated; tympanic annulus prominent anteroventrally, posterodorsally concealed beneath skin, barely visible in dorsal view. Supratympanic fold absent, with several large and conical postrictal tubercles below tympanum. Choanae large, round, not concealed by palatal shelf of maxillary arch; dentigerous processes of vomers low, triangular, slightly smaller than choanae, arranged in V-shape, posterior and medial to choanae, each bearing threeto-four teeth. Tongue oval, longer than wide, posterior 1/4 free, posterior edge feebly notched. Vocal slits present and prominent. Skin of dorsum and upper eyelids shagreen; middorsal raphe present, but low and barely distinguishable; scapular folds present, sinusoidal and prominent, ending posteriorly in a large conical tubercle; dorsolateral folds straight and prominent, extending from posterior end of scapular folds to level of groins; no paravertebral folds ( Fig. 2 a); cloacal sheath absent, small cloacal tubercles present but not conspicuous; flanks and posterior third of dorsum slightly tuberculate; dorsal surface of limbs finely tuberculate. Throat smooth, chest and belly areolate; ventral surface of limbs smooth to slightly areolate ( Fig. 1 b). Two-to-three large ulnar tubercles along outer ventrolateral surface of forearm. Hand length 28.6% of SVL. Relative lengths of adpressed fingers III> IV> II> I; adpressed FI does not reach proximal edge of disc pad of FII; nuptial pads absent; adpresed FIV reaches past distal subarticular tubercle of FIII. Preaxial keels only present on FII and III, very weak and barely visible. Finger disc absent on FI, slightly expanded on FII to IV; digital pad absent on FI, present in all other fingers, rounded, almost longer than wide; circumferential groove of digital pads poorly defined laterally and incomplete proximally; distal edge of discs rounded; disc of FIII about 1.4 times wider than distal end of adjacent phalanx. Subarticular tubercles large, longer than wide, and slightly swollen; palmar tubercle large, slightly swollen, deeply bifid, V-shaped; thenar tubercle large, slightly swollen, elongate; supernumerary tubercles present, relative large (between 1/3–1/2 size of subarticular tubercles) ( Fig. 3 d). Hind limbs relatively long (thigh length 50.5% SVL; shank length 56.3% SVL; foot length 50.5% SVL); heels overlap when shanks are held perpendicular to sagittal plane; relative length of adpressed toes IV> V> III> II> I; several small, low, and rounded tubercles on heel, calcar tubercle absent; four to five fold-like tarsal tubercles aligned on the outer ventrolateral surface of tarsus; inner tarsal fold short, low and straight, extending on the distal fourth of the tarsus. Tip of TV barely extends past distal edge of mid subarticular tubercle of TIV; tip of TIII reaches distal half of mid subarticular tubercle of TIV. Disc of TIV wider than disc of FIII (F3D/T4D = 0.8); all toes with slightly expanded discs and digital pads; circumferential grooves of discs absent. Toes without lateral fringes or keels; webbing absent. Outer metatarsal tubercle large, round, swollen; inner metatarsal tubercle oval, about two times the size of outer metatarsal tubercle. Supernumerary plantar tubercles scarce, small, low, and round. Subarticular tubercles large, round and slightly swollen ( Fig. 3 e). Color of the holotype in life (based on field notes and color digital photographs; Figs. 1 a–b). Dorsal background color grayish brown, with small and irregular black spots scattered on the dorsal surface of head, upper eyelids, and dorsum; several conspicuous black spots flanking externally the scapular fold. All tubercles and folds on dorsum of head and body with reddish brown coloration. Canthus rostralis with a black canthal stripe, extending from tip of snout to anterior corner of eye. Lips with vertical black and brown bars, except for cream bar just below eye. A conspicuous dark supratympanic stripe extends from upper and posterior parts of the tympanum and fails to reach the shoulder; the inferior border of this stripe is also delineated of creamish white. Flank grayish brown, slightly lighter than dorsum, with scattered small black spots and with one or two diffuse diagonal cream stripes. Groin background translucent gray, with several small immaculate white dots. Upper arm light brown; forearm grayish brown with two-to-three irregular blackish brown cross-bands in the distal half, more intensely pigmented the proximal one. Hand and fingers light brown with three-to-four ill-defined pale brown cross-bands; tips of finger discs reddish brown. Hind limbs background grayish brown, becoming paler distally (on feet), with three to four blackish brown cross-bands on thighs, shanks, tarsi and feet; blackish cross-bands on thighs laterally bordered with light lines; background color of the inner surface of thighs translucent gray, densely spotted of black and with scattered small white dots; transversal rows of tubercles on shanks pigmented of reddish brown. Toes pale orange; toe discs dorsally grayish, bordered by reddish brown coloration. Throat white, finely reticulated with black; chest, belly, undersurface forelimbs of thighs and shanks pale orange, finely punctuated of black; tarsi ventrally grayish brown; palms and soles pale orange; subarticular tubercles of feet bright orange. Iris golden with fine black venation and a broad horizontal copper band; pupil ring golden. Color of the holotype in preservative (after sixteen months, June 2013 ; Figs. 2 a–b, 3a–e). Dorsal background almost uniformly gray; reddish brown coloration of dorsal tubercles and folds is replaced by gray and light gray; dorsal and lateral black spots turns more dark and conspicuous. Flanks turn grayish, lighter towards lower portion; diagonal light bands of flanks disappear. Groins and ventral surfaces turn white, with black reticulation. Palms and soles white, with diffuse pink tone and several small black blotches. Fingers and toes with dorsal dark gray, transversal bars, and ventrally colored of white, densely spotted of black. Iris grayish, finely punctuated with black; horizontal copper band turns black. Measurements of the holotype (in mm). SVL: 17.6; ThL: 8.9; SL: 9.9; FL: 8.9; HaL: 5.0; HeL: 6.9; HW: 6.7; InD : 1.9; IOD: 2.1; UEW: 1.7; EN: 1.7; ED: 2.2; ETS: 3.1; TD: 0.9; F3D: 0.6; T4D: 0.8; F1L: 2.6; F2L: 3.3. Variation. Females of Pristimantis munozi are unknown; then, sexual dimorphism is not evaluated. We mention, however, that females of all other species of Pristimantis myersi group are larger than males, and several of them have red blotches on the groins (gender-specific coloration). Thus, we suppose that adult females of P. munozi may be are larger than males and may have red flash coloration on the groins, as other species of the group. Adult males range from 14.9–19.7 (16.7 ±1.6; n = 8). Variation of morphometric characters is shown in Table 1 . Head length ranges from 39.1%–42.3% SVL (40.6% ± 1.1; n = 8), and maximum head width from 35.4%– 42.6% SVL (38.3% ± 2.2; n = 8). Head can be as long as wide, or slightly longer than wide (HeL/HW: 1.0 –1.1[1.1 ± 0.1; n = 8]). The EN/ED ratio is somewhat variable but every eye-naris distance is smaller than eye diameter (0.7–0.9 [0.8 ± 0.1; n = 8]). The width of the upper eyelid is narrower than the interorbital distance, and its ratio ranges from 0.7–0.8 (0.78 ± 0.1; n = 8). The snout length also is slightly variable but always longer than eye diameter (1.2–1.6 [1.4 ± 0.1; n = 8]). Hand length ranges from 26.4–29.7% SVL (28.2% ± 1.2; n = 8). The tympanum is small and its ratio respect to eye has little variation (TD/ED: 0.4–0.5; n = 8). Thigh length ranges from 49.3%–55.0% SVL (51.9% ± 2.2; n = 8); shank length from 53.6–62.1% SVL (58.0% ± 2.8; n = 8), and foot length from 48.5%–54.4% (52.1 ± 2.0; n = 8). In almost all specimens dorsal skin texture is shagreen with scattered tubercles of variable size, except MZUTI 1781, which have dorsal skin nearly smooth, non-tubercular, and with scattered granules on flanks and posterior third of dorsum. Flanks and posterior third of dorsum densely tubercular in MZUTI 1777. Upper eyelid typically with one tubercle; MZUTI 1777 has two tubercles on each upper eyelid. Middorsal raphe absent in MZUTI 1778, but prominent in MZUTI1779. Scapular folds extending anteriorly and reaching tubercles of upper eyelids in MZUTI 1783, nearly straight and continuous with dorsolateral folds in MZUTI 1779 and 1781 . Dorsolateral folds extending to sacral region (MZUTI 1777–1778 , 1784), to groins (MZUTI 1780–1781 ) or inclusively converging above the vent level (MZUTI 1779, 1783). Ulnar tubercles on forearms range from two-to-four; tarsal tubercles in number of four or five. Throat typically smooth, but slightly areolate in some specimens (MZUTI 1777, 1780, 1784). Number of vomerine teeth somewhat variable, from one or two (MZUTI 1777–1778 ) to four (MZUTI 1783), but typically three-to-four (MZUTI 1779–1782 ). In almost all specimens examined, the color pattern is similar to that of the holotype ( Figs. 1 a–b), except specimens MZUTI 1779 and 1781 ( Figs. 1 c–d, 2c–d), which show striking differences. These specimens have a dorsal background pale ocher (pale gray in preservative), extended from the tip of snout to the vent, and medially to the scapular and dorsolateral folds; this area is bordered by a sinuous black stripe that runs from the tip of snout, through nares, canthus , external border of upper eyelid, external flanks of the scapular an dorsolateral folds to upper vent; the middorsal raphe has a light cream coloration and is subtly bordered with pale brown; some small black spots flanking the middorsal raphe in the interorbital and scapular areas. Ventrally, the background color is white, densely spotted with black; a white cross is formed by two thin lines that intersect at chest level, the longitudinal line extends from the chin to the vent, and the transversal one through the chest, undersurfaces of upper arms, and forearms to end at the wrists. Other thin white line extends from the vent through the inner ventrolateral surfaces of thighs, ventral surfaces of shanks and tarsi, to end at the soles; at the level of the articulation between the shank and tarsi, a second line arises from the former and extends to the center of heel ( Fig. 2 d). Morphometric characters SVL Measurements (in mm) X? ± SD 16.7 ± 1.6 Min–Max 14.9–19.7 ThL 8.6 ± 0.5 7.9–9.7 SL 9.7 ± 0.5 9.1–10.5 FL 8.7 ± 0.6 7.7–9.5 HaL 4.7 ± 0.4 4.0–5.2 HeL 6.8 ± 0.5 6.0–7.7 HW 6.4 ± 0.4 5.9–7.0 InD 1.8 ± 0.1 1.7–1.9 UEW 1.6 ± 0.1 1.5–1.8 EN 1.7 ± 0.2 1.5–2.0 ED 2.1 ± 0.3 1.7–2.8 ETS 3.0 ± 0.2 2.7–3.4 TD 1.0 ± 0.2 0.8–1.3 F3D 0.6 ± 0.0 0.5–0.7 T4D 0.7 ± 0.1 0.5–0.8 F1L 2.6 ± 0.2 2.3–2.9 F2L 3.2 ± 0.2 2.9–3.5 Call (adult male, MZUTI 1777; Fig. 4 ). The advertisement call of Pristimantis munozi is composed by a series of calls, each with a duration of 1.589– 2.492 s (mean = 2.160 ± 0.424 s , N = 6) and containing 3–5 calls (mean = 3.833 ± 0.753, N = 6), the first of which is always longer than the remaining calls (length of 1st call = 0.160–0.200, mean = 0.187 ± 0.014 s , N = 6; length of subsequent calls = 0.116–0.153, mean = 0.151 ± 0.027 s , N = 16). Series of calls are produced every 1.589– 18.992 s (mean = 9.870 ± 6.424 s , N = 5). Within a call series, calls are emitted with an interval of 0.501– 0.783 s (mean = 0.608 ± 0.075 s , N = 16). Each call is strongly pulsed, with the first call having more pulsed than the subsequent calls (1st call with 16–20 pulses, mean = 18.667 ± 2.066 s , N = 6; subsequent calls with16–20 pulses, mean = 13.467 ± 1.119 s , N = 16). The dominant frequency (also de fundamental frequency) is at 2198–2248 Hz (mean = 2230 ± 16.3 Hz, N = 21). Finally, the 1st harmonic is at 3776– 4357 Hz (mean = 4143.3 ± 225 Hz, N = 22).