Bioacoustics of Ischnocnema nigriventris

vizottoi , I. melanopygia , I. gehrti , I. lactea , I. paranaensis , I. spanios , and I. randorum ); in life, bright yellow or orange mottling or as blotches in the inguinal region and hidden areas of hind limbs (no bright coloration in these areas occur in I. concolor , I. vizottoi , and I. paranaensis ; the coloration in life is unknown for I. lactea and I. gehrti ; I holti presents red or orange coloration in the inguinal region but not mottled or as blotches); iris silver with a ventral yellowish copper band (iris green in I. holti , dorsally bluish in I. spanios , golden to lemon yellow in I. randorum , I. melanopygia , I. concolor , and I vizottoi , and dark violet in I. lactea ; not reported for I. gehrti and I. paranaensis ); snout nearly rounded in dorsal view (truncate in I. gehrti , the others are also nearly rounded, rounded or sub-acuminate with no substantial difference; head wider than long (head longer than wide in I. melanopygia , I. randorum , and I. spanios ). Ischnocnema nigriventris differs from species in the I. guentheri species series by having a tibia length shorter than 55% of SVL; snout nearly rounded in dorsal view; disks expanded and emarginated; translucent glandular nuptial pads. ( I. guentheri species series: legs with tibia length> 60% SVL; acuminate snout in dorsal view; disks usually small or slightly expanded, large only in I. hoehnei and I. vinhai ; and conspicuous white glandular nuptial pads, unknown in I. vinhai ; see Heyer, 1984; Hedges et al. 2008; Canedo et al. 2010). Ischnocnema nigriventris differs from species in the I. parva species series by its shagreen dorsum with tubercles. Finger I smaller than Finger II; disks expanded and emarginated; and translucent and glandular nuptial pads. ( I. parva species series: smooth dorsum; Finger I as long as Finger II; small and pointed disks; and conspicuous white glandular nuptial pads [contra Hedges et al. 2008]). Ischnocnema nigriventris differs from the I. verrucosa species series by its rounded snout in dorsal view; Finger I shorter than II; and expanded disks. ( I. verrucosa species series: snout sub acuminate in dorsal view; Finger I as long as II; and small disks, Hedges et al. 2008; Canedo et al. 2010). Ischnocnema nigriventris differs from I. manezinho and I. sambaqui , recently removed from the I. lactea species series and not allocated to any series (Canedo and Haddad, 2012), by its smaller size, males 18–20 mm ; presence of nuptial pads; and bright coloration in hidden areas in life (bigger size, I. sambaqui males 32–40 mm , and I. manezinho males 22–28 mm ; absence of nuptial pads and bright colors in hidden areas in life). Measurements Males (n=16) Females (n=3) SVL 19.0 ± 0.6, 18.2–20.2 24.6 ± 0.1, 24.5–24.7 HL 6.6 ± 0.4, 6.2–7.4 8.1 ± 0.3, 7.7–8.4 HW 6.9 ± 0.2, 6.4–7.2 8.6 ± 0.1, 8.4–8.7 ED 2.6 ± 0.2, 2.3–3.1 3 ± 0.0, 3.0–3.1 END 1.9 ± 0.2, 1.1–2.1 2.5 ± 0.0, 2.5–2.6 AMD 3.6 ± 0.2, 3.3–3.8 4.5 ± 0.0, 4.4–4.5 IND 1.9 ± 0.10, 1.7–2.0 2.4 ± 0.1, 2.3–2.6 NSD 1.1 ± 0.1, 1.0–1.4 1.4 ± 0.1, 1.4–1.5 THL 9.5 ± 0.4, 8.9–10.4 11.5 ± 0.3, 11.2–11.9 TBL 10 ± 0.4, 9.3–10.5 11.9 ± 0.2, 11.6–12.2 FL 9.7 ± 0.5, 8.8–10.5 12.2 ± 0.3, 11.8–12.6 Vocalization. Two calls were recorded for two specimens of Ischnocnema nigriventris . The first (considered a territorial call due to continuous and high emission rate) consists of a single, non-pulsed note emitted at regular intervals of 2.8–3.3 seconds ( Figure 4 ). Note duration is 30–41 ms (36.1 ± 3.8 ms, n = 8 calls of two individuals). The frequency spectrum is 2004–3685 Hz and the peak frequency (= dominant frequency) is 2928–3014 Hz (2965 ± 46.0, n = 8 calls of two individuals). The second call ( Figure 5 ), considered here as the advertisement call, shows two to four non-pulsed notes, emitted after long irregular intervals. The duration of the call is 194–565 ms, the frequency spectrum is 1955–3932 Hz, and the peak frequency is 2756–2928 Hz (n = 19 calls of three individuals). The first note differs from the others by its lower intensity (the amplitude of the first note is about 11–33% lower than the others) and lower frequency range (the first note ranged from 2151–2774 Hz). Note duration is similar, the first note is 30–89 ms (54.2 ± 2.0 ms) and the others are 28–88 ms (41.7 ± 2.0 ms). The interval between the notes is 113–157 ms (132 ± 12 ms). The major differences in call with respect to other Ischnocnema from I. lactea series (sensu Canedo and Haddad, 2012) and I. manezinho and I. sambaqui (former I. lactea series and unassigned to species series in Canedo and Haddad, 2012) are shown in Table 2 . I. nigriventris I. nigriventris I. randorum Call 1 Call 2 (advertissment call) (Heyer et al. 1990) Natural history. Ischnocnema nigriventris starts its vocalization activity just before dusk, with its territorial call. The males are usually found perching on trees or shrubs. On some occasions we found males calling from about three meters above the ground. On others, a couple in amplexus was observed moving on the leaf litter. Individuals were found active all year round, even during the dry season (June), although they were more abundant in September during the early stages of the rainy season when the forest was very humid. Two dissected females contained large, unpigmented ovarian ovules. One (CFBH23478) with 20 ovules, nine in the left ovary and eleven in the right, and the second (MZUSP136724) with 18 ovules in total. Ovule diameter: 2.5–3.2 ( x = 2.8mm ).

Diagnosis. Ischnocnema nigriventris can be distinguished from other Ischnocnema by the following combination of character states: (1) snout short and nearly rounded in dorsal view and rounded in profile view; (2) head wider than long; (3) prominent conical tubercles on the upper eyelid; (4) first finger shorter than second; (5) disks on fingers II–IV expanded and emarginated, with ungual flap notched in dorsal view; (6) translucent, double glandular nuptial pad on the thumbs of males; (7) vomerine teeth present; (8) single vocal sac not expanded externally; (9) skin on dorsum shagreen with tubercles or warts, flanks, belly and posterior portion of thighs areolate (10) prominent calcar on the heel; tibia length <55% SVL; (11) In life, iris silver with a ventral yellowish copper band; inguinal region and hidden areas of hind limbs with yellow mottling in males and orange mottling in females; (12) advertisement call composed of two to four non-pulsed notes with the first one differentiated by its lower intensity and frequency. Comparison with other species of Ischnocnema . Ischnocnema nigriventris is distinguished from all other species of the I. lactea species as follows (character states for other members of the series in parenthesis): upper eyelid tubercles large, conical (absent, or present as low and small rounded granules); expanded disks in fingers II– IV (Finger IV with no expanded disk in I. concolor and I. vizottoi ); nuptial pads present (absent in, I. melanopygia , and I. spanios ; not reported in I. paranaensis ; I. lactea is only known from its female holotype ; the condition is unknown for the poorly preserved male holotype of I. gehrti ; not reported in the original description of I. vizottoi but observable as a translucent inconspicuous glandular pad); well-developed calcar tubercles (absent in I. concolor , and I. paranaensis ; unknown in I. lactea , and I. gerhti whose type specimens are in bad condition); vomerine teeth present (absent in I. randorum and I. paranaensis ); palmar tubercles inconspicuous but present (indistinct in I. spanios and I. paranaensis ); dorsum shagreen with tubercles or warts (smooth in I. concolor , I.