Bioacoustics of Bokermannohyla diamantina

Bokermannohyla diamantina (SVL 46.7–51.7 mm ) is larger than B. astartea , B. feioi , B. ibitipoca , B. nanuzae , B. sazimai (combined species SVL 30.2–44.1 mm ), and B. ravida (SVL 30.1–47.6 mm ), but smaller than B. caramaschii , B. carvalhoi , B. circumdata , B. gouveai , B. luctuosa (combined species SVL 55.2–71.6 mm ), and B. hylax (SVL 51.4–59.6 mm ). The tympanum diameter of B. diamantina (TD/SVL 0.07–0.08) is smaller than in B. caramaschii and B. luctuosa (combined species TD/SVL 0.08–0.10), but larger than in B. astartea , B. sazimai , B. ahenea , B. carvalhoi , B. feioi , B. lucianae (combined species TD/SVL 0.04–0.06), B. nanuzae , B. hylax , and B. ibitipoca (combined species TD/ SVL 0.05–0.07). The shorter head distinguishes B. diamantina (SVL/HL 2.8–2.9) from males of B. astartea , B. hylax , B. izecksohni , B. lucianae , and B. ravida (combined species SVL/HL 2.4–2.7). The narrower head distinguishes B. diamantina (SVL/HW 2.7–2.9) from males of B. ravida (SVL/HW 2.5–2.7). The shorter thigh and tibia lengths distinguish B. diamantina (THL/SVL 0.48–0.52; TL/SVL 0.49–0.51, respectively) from males of B. izecksohni (THL/SVL 0.53–0.55; TL/SVL 0.52–0.55, respectively). Dorsum blackish brown or with weak transverse dark brown stripes in B. diamantina , cream color in B. ibitipoca and B. sazima , the latter with reticulated thin brown stripes and random brown dots over it; also, B. gouveai , B. carvalhoi , B. ahenea , and B. astartea have immaculate dorsa (the two latter with dorsal surfaces golden brown), and B. nanuzae lacks distinct transverse brown bars over it. A dorsolateral blackish brown stripe from tip of snout to inguinal region distinguishes B. feioi from B. diamantina , which lacks such stripe. Flanks, anterior, and posterior surfaces of thighs with dark transverse brown stripes in B. diamantina , they are immaculate in B. nanuzae , B. feioi , and B. lucianae , with thin and fragmented stripes in B. carvalhoi , and with thin brown stripes intercalated with transverse brown bars in B. hylax . The presence of vocal slits in adult males distinguishes B. diamantina from B. caramaschii and B. izecksohni , which lack such structures. The advertisement call distinguishes B. diamantina from all other species of the B. circumdata group for which such data is available (see below).

Color in life Dorsal surfaces dark brown to blackish brown ( Fig. 2 ), with weak transverse dark brown bars on dorsum, flanks, arms, thighs, shanks, tarsus, and feet. Belly and ventral surfaces of chest, throat, and thighs vivid yellow; ventral surfaces of arms, hands, shanks, tarsus, feet, and anterior and posterior surfaces of thighs purple. Color in preservative Dorsal surfaces medium to blackish brown, with weak transverse dark brown bars on dorsum, flanks, arms, thighs, shanks, tarsus, and feet. A weak brown vertebral stripe might be present from the tip of snout to the middle of dorsum. Canthus rostralis delimited by a weak subcanthal dark brown stripe. Flanks pale cream with transverse dark brown bars; anterior and posterior faces of thighs medium brown; ventral surfaces pale cream. nov. from the Municipality of Abaíra, State of Bahia, Brazil . n = number of specimens; X = mean; Min = minimum; Max = maximum; SD = standard deviation. Values in millimeters. Males ( n = 6) Female ( n = 1) X Min Max SD SVL 48.28 46.7 51.7 1.95 49.4 HL 17.03 16.6 17.7 0.43 16.9 HW 17.18 16.0 18.7 0.92 17.2 ED 4.97 4.8 5.5 0.29 4.8 END 4.15 3.9 4.3 0.15 3.9 TD 3.77 3.3 4.3 0.33 3.9 UEW 3.80 3.7 4.0 0.12 4.0 IOD 5.55 5.2 6.0 0.36 5.4 IND 3.30 3.1 3.4 0.13 3.3 NSD 2.77 2.4 3.0 0.24 2.7 THL 24.58 23.2 25.3 0.79 24.4 TL 24.31 23.2 25.5 0.78 23.8 FL 35.50 32.4 35.8 1.21 32.6 3FD 2.22 2.1 2.5 0.17 2.2 4TD 2.07 1.9 2.2 0.11 1.8 SVL/HW 2.81 2.72 2.93 0.08 2.87 SVL/HL 2.83 2.78 2.92 0.04 2.92 HL/SVL 0.35 0.34 0.35 0.00 0.34 ED/TD 1.32 1.27 1.50 0.08 1.23 TD/SVL 0.07 0.07 0.08 0.00 0.07 ED/SVL 0.10 0.09 0.11 0.00 0.09 THL/SVL 0.50 0.48 0.52 0.01 0.49 TL/SVL 0.50 0.49 0.51 0.00 0.48 THL+TL 48.90 47.1 50.8 1.43 48.2 Measurements of holotype SVL 51.7, HL 17.7, HW 18.7, ED 4.8, END 4.3, TD 3.7, UEW 3.7, IOD 6.0, IND 3.4, NSD 2.8, THL 25.3, TL 25.5, FL 35.8, 3FD 2.5, 4TD 2.2. Specimens Sexual dimorphism (not captured) MZUEFS 1785 (CRC 47.00 mm) MZUEFS 1799 (CRC 46.80 mm) Number of calls 21 13 17 Number of notes 3 2.85±0.55 (2–4) 3.41±0.50 (3–4) Note 1 duration 221.20±34.90 (148.32–296.63) 199.31±38.79 (150.04–262.90) 276.66±37.65 (210.23–322.23) Note 2 duration 267.57±20.30 (228.83–307.50) 261.26±41.37 (187.55–350.53) 302.52±27.17 (271.09–381.73) Note 3 duration 277.06±19.56 (235.98–321.80) 262.37±39.89 (175.05–326.71) 360.96±38.19 (309.67–409.40) Note 4 duration ­ 328.62 385.48±17.22 Notes per second 4.16±0.24 (3.70–4.61) 4.25±0.89 (2.77–6.13) 3.28±0.38 (2.77–3.90) Adult males of Bokermannohyla diamantina have hypertrophied forearms, enlarged prepollices, and vocal slits, characteristics absent in females. Advertisement call The following description is based on advertisement calls from three recorded males. Social interactions among males were not noticed. The call (Fig. 4A–D) is composed of 2–4 pulsed notes, usually three notes, and the first note always with lower intensity than the others. The pulses are very close to each other and present side bands, which prevented the accurate count of the pulse number of each note. Therefore, we counted only the pulses with more intensity in the notes (Fig. 4D). In this sense, the pulse number of one note varied from 21–110 pulses ( X = 48.08, n = 59 notes, SD = 23.16). The call duration is 0.63– 1.85 s ( X = 1.16, n = 51, SD = 0.29). The interval between calls is 65.45– 3.79 s ( X = 8.89, n = 48, SD = 9.81). Note duration between 0.14– 0.40 s, with trend to increase the duration from the first to the last note, and note rate between 2.77–6.13 notes per second ( Table 2 ). Two main energetic bandwidths are clearly distinguishable in the audiospectrogram (Fig. 4B), and two peaks of intensity can be observed on the power spectrum (Fig. 4A). Low frequency is 0.22–0.29 kHz ( X = 0.26, n = 51, SD = 0.02) and high frequency 2.08–2.75 kHz ( X = 2.45, n = 51 SD = 0.23). The dominant frequency is 0.39–0.56 kHz ( X = 0.40, n = 49, SD = 0.03), but in one specimen (MZUEFS 1799), two, of a total of 17 calls analyzed, displayed the dominant frequency in the upper bandwidth (1.59 and 1.63 kHz). This alteration in the dominant frequency may correspond to a change between the two peaks of intensity observed in all calls analyzed. The advertisement call of Bokermannohyla diamantina is distinguished from the calls of the other species of the B. circumdata group by the general singular structure and by the lowest dominant frequency (0.39–0.56 kHz; 1.25–2.80 kHz; respectively). Natural history Bokermannohyla diamantina occurs in gallery forests along creeks surrounded by rocky mountain fields called “Campo Rupestre”, a biome typical in Chapada Diamantina (for description of “Campo Rupestre” see Rizzini 1979 ). The three males heard were calling from the central axis of an epiphytic bromeliad, a cavity under a rock on the side of a stream, and on the ground in an open field near the stream, respectively. Two individuals were collected in a gallery forest, and four in the “Campo Rupestre” near a stream, all at night. Only one individual was collected during the day, resting inside the gallery forest.