Bioacoustics of Boulenophrys acuta

Distribution and habits. Currently, M. acuta sp. nov. is known only from the type locality, Heishiding Nature Reserve, and the adjoining Qixing Nature Reserve, Fengkai County, Guangdong Province, China . It inhabits forest floor, leaf litter and the nearby undergrowth mountainous streams surrounded by moist subtropical evergreen broadleaved forests at elevations between 270– 450 m . ( Figure 4 . A) Advertisement calls. We recorded the calls of male holotype SYS a002267 from the bank of the streamlet, and the ambient air temperature which was 26.9°C. The sonograms and waveforms are shown in Figure 5. We define a continuous vocalization with pauses less than one second as a strophe. One strophe consists of a series of syllables of a pulsed structure. The call consists of a few strophes of 3.440– 4.649 s duration (mean 4.202 ± 0.460, N = 4). Each strophe contains 7–9 syllables (mean 8.250 ± 0.829, N = 5). Each syllable has a duration of 0.106– 0.172 s (mean 0.136 ± 0.012, N = 33). The interval between syllables has a duration of 0.335– 0.747 s (mean 0.425 ± 0.092, N = 29). Syllables are repeated in series at a rate of 1.87–2.04 times (mean 1.967 ± 0.066, N = 4) per second. Syllable-intervals gradually increase from the beginning to the end of each strophe. Amplitude modulation within syllables is unapparent, only increasing slightly to a maximum by approximately middle syllable. Calls have a broad frequency range of 1400–6700kHz. (Figure 5).

Remark. M. acuta sp. nov. is most frequently found on leaves, stems or branches at height of 10–20 cm near the streamlets (SYS a001957, 2266–2269 , 2274, 2276 and 2278 ). However, an adult male individual inspected at night on 20 August 2013 , was hidden in soil burrow and called softly. The burrow was located on mud-sandy slopes of the streamlet; the opening of the burrow is small, measuring 10 mm in diameter; posteriorly immediately enlarged a room measuring 100 mm in diameter and 70 mm in depth, connected by two narrow tunnels in opposite directions; 1/3 of the room was filled with water, where the toad was found immersed ( Figure 4 : B, Ba, Bb). When it rained or after raining, they more frequently stayed on dirt roads at a distance of 5–15 m from the stream (SYS a000165, 0 168, 0 169, 0 187, 0 517 and 0521). Adult males call at night and in the daytime throughout the year. They emit advertisement calls in form of a series of short syllables repeated in slightly quick succession from forest floor, leaves, stems, branches of plants or burrows. 15 specimens were collected in early April, May, June, August, and November, respectively. In addition, we also found several individuals in July and September, including two juveniles (not collected) in July; a few males occasionally emit several short syllables in October. Among them, all adult male individuals were found or collected by their calls, except SYS a000165 and 0 169, collected on dirt roads on 2 May ; the male paratype SYS a000165 and 0 169 had fully developed testes in the abdominal cavity, measured 3.0– 3.2 mm in diameter. Specimen SYS a001957, collected on 12 November , also had developed testes; but in the specimens, collected in June and August, testes were atrophied. The gravid female paratypes SYS a000187, 0 168, 0 512 and 0 517, collected from early April to the end of May, with about 30 pure yellowish mature oocytes in each oviduct, measured 1.6 mm in oocyte diameter. Therefore, the breeding season of this species may be from November to early June of the second year. We dissected SYS a001957, SYS a000169 and SYS a000168, and found four, seven and 24 termites in their stomaches, respectively.