Bioacoustics of Pristimantis chinguelas

Distribution, natural history and conservation status. Pristimantis chinguelas sp. nov. is only known from the type locality, in Cerro Chinguelas, at 2849 m a. s. l. The type locality is a steep, rocky, open area on the cliff side of the Sapalache – El Carmen road (Fig. 7 A ). The vegetation here consists of scattered bushes, montane bamboo ( Chusquea spp ), some herbs and grass. All individuals were collected at night, calling on leaves, up to 1.8 m . Air temperature was 10 ° C and the humidity was 98 %. During our fieldwork, we heard at least two more groups of calling males, in a steeper area, no more than 100 meters away from the type locality. No other amphibian was recorded in sympatry with the new species. Based on our field data, we estimate the area of occupancy of this species is less than 10 km 2 . Nevertheless, the species might occupy adjacent unexplored areas. Information on its population size is unknown. In view of the scarcity of information, and according to the IUCN Red List guidelines (IUCN, 2019) we suggest that P. chinguelas sp. nov. be included in the Data Deficient (DD) category.

Description of the holotype . An adult male ( CORBIDI 26772 ). Measurements (in mm): SVL 34.9; TL 18.5; FL 17.1; HL 12.6; HW 13.6; ED 4.9; TD 2.1; IOD 3.8; EW 2.9; IND 2.8; EN 3.9; FeL 15.9. Head wider than long, narrower than body; snout subacuminate in dorsal view, rounded in profile, lacking papilla or flaps on the tip of the snout (Fig. 4 E ); cranial crests absent; nostrils slightly protuberant, directed anterolaterally; canthus rostralis slightly concave in dorsal view, rounded in cross section; loreal region concave; upper eyelid lacking tubercles; tympanic annulus present, visible through the skin, its upper and posterolateral edge concealed by thick, prominent supratympanic fold; tympanic membrane not visible; postrictal tubercles absent. Choanae median, ovoid, non-concealed by palatal shelf of maxilla; dentigerous processes of vomers absent; tongue slightly longer than wide, not notched, posterior half free; vocal slits slightly curved, positioned at posterior half of mouth floor in between tongue and margin of jaw; medium sized vocal sac. Dorsal surfaces of body shagreen; dorsolateral enlarged tubercles present, going from the posterior edge of the upper eyelid to the groin; skin on flanks bearing a row of enlarged tubercles going parallel to the dorsolateral tubercle, below numerous enlarged tubercles cover the rest of the flank; skin on chest and belly areolate, that on throat shagreen, ventral surfaces of limbs smooth, ventral surfaces of thighs coarsely areolate; discoidal fold present, thoracic fold absent. Ulnar tubercles absent; nuptial pads absent; outer palmar tubercle bifid low, as large as ovoid thenar tubercle; subarticular tubercles low, rounded; large supernumerary tubercles at base of fingers, distinct; fingers bearing lateral fringes; Finger I shorter than Finger II; discs on fingers expanded and rounded; pads on fingers surrounded by circumferential grooves on all fingers (Fig. 4 C ). Hindlimbs slender; dorsal surfaces of hindlimbs shagreen; posterior surfaces of thighs smooth, ventral surfaces of thighs coarsely areolate; heel lacking tubercle; outer and inner edge of tarsus lacking tubercles; inner metatarsal tubercle elliptical, elevated, twice the size of oval outer metatarsal tubercle; plantar surface with small, low and rounded supernumerary tubercles; subarticular tubercles prominent, rounded; toes bearing lateral fringes; basal webbing between toes III and IV, and IV and V; discs on toes smaller than those on fingers, expanded and rounded; all toes having pads surrounded by circumferential grooves; relative lengths of toes: I <II <III <V <IV; Toe V longer than Toe III (disc on Toe III reaches the distal edge of penultimate subarticular tubercle on Toe IV, disc on Toe V reaches the distal edge of distal subarticular tubercle on Toe IV; Fig. 4 D ). Coloration of holotype in life (Fig. 3 A – D ). Based on photographs taken in the field. Dorsal surfaces of body and flanks duff yellow covered, skin spaces between tubercles chocolate brown; supratympanic and canthal stripes chocolate brown; groins and anterior surface of thighs creamy yellow with dark flecks; posterior surfaces of thighs, shanks and tarsus orange yellow, some dark flecks present on posterior surface of thighs; venter creamy yellow covered by dark flecks; chest salmon, throat orange, both suffused with brown flecks; ventral surfaces of thighs, shanks, and tarsus yellow; plantar and palmar surfaces creamy white with dense dark flecks; iris gold with thick black reticulations. Coloration of holotype in preservative (Fig. 4 A – E ). Dorsal surfaces of body and flanks dark brown fading lighter at the edge of the flanks and venter; gray supratympanic and canthal stripes; groins, anterior, and posterior surfaces of thighs, shanks and tarsus tan; venter, belly and throat creamy yellow suffused with dark flecks; ventral surfaces of limbs creamy yellow; ventral surfaces of fingers and toes cream. Variation . Male CORBIDI 26765 (Fig. 5 C, D ) has a single enlarged lateral tubercle instead of a row of tubercles. Skin on dorsum is smoother in males CORBIDI 26766 (Fig. 5 E, F ) and 26768 (Fig. 5 G, H ). Also, the lateral row of enlarged tubercles is shorter in male CORBIDI 26768 , reaching only the middle of the flank. Variation in measurements is given in Table 1 and color variation is shown in Fig. 5 . Females unknown. Advertisement call . (Fig. 6 ) Based on recordings of males CORBIDI 26771 and CORBIDI 26772 , the advertisement call consists of one peep-like note (Fig. 6 ). The average duration of a note is 0.10s (range 0.06– 0.15s ). The fundamental and dominant frequencies of the notes are on average 2200.54 Hz (range 2191.00–2209.82 Hz), without frequency modulation. Descriptive statistics for bioacoustic variables are shown in Table 2 . Call parameters Mean ± SD Range Notes per call n = 3 / 12 1 ± 0.00 - No. harmonics n = 3 / 12 - (4–9) Note length (s) n = 3 / 12 0.10 ± 0.03 (0.06–0.15) Inter-note length (s) - - Inter-call length (s) n = 1 / 4 15.97 ± 2.37 (13.96–18.58) Dominant frequency (Hz) n = 3 / 12 2200.54 ± 6.08 (2191.00–2209.82) Initial frequency (Hz) n = 3 / 12 2208.69 ± 27.96 (2196.39–2296.88) Final frequency (Hz) n = 3 / 12 2208.06 ± 23.64 (2196.39–2282.52) Delta Frequency (Hz) n = 3 / 12 -18.48 ± 357.50 (- 943.16–721.38) 2 nd harmonic frequency (Hz) n = 3 / 12 4286.28 ± 92.24 (4138.39–4410.51)