Bioacoustics of Ptenopus kenkenses

Advertisement call. The advertisement call (Figs 3 , 20E ) consists of 4.6 notes (range 4–5), uttered slowly at a rate of 2.45s - 1 (range 1.99–2.96). Note duration is the longest of all species (92 ms [range 61–154]), the first usually notably longer than those following, with note 1 duration deviance 30 % [range 10–47]. Inter-note intervals are 316 ms (range 269–368) and quite regular, inter-note interval range 23.3 % (range 12–42). Median call density is high, 0.29 (range 0.18–0.48). Call duration is 1.57s (range 1.3–1.9). The basal frequency is ~ 399 Hz (range 366–474), but very soft may be inestimable, with harmonic bands louder towards the dominant frequency at 3.506 kHz (range 3.3–3.8); sometimes a very slight lower frequency peak is evident at around or just below half the dominant frequency (roughly 1.2–1.9 kHz, cannot always be reliably estimated). Frequency appears to modulate down by ~ 0.4 kHz during the course of the note, and (human) perceived pitch also seems to modulate within each note, slightly reminiscent of dripping water. Bandwidth (90 %) is difficult to estimate consistently: approximately 0.5–6.9 kHz. Calling activity for this species commences ~ 30 min before sunset and may continue late into the night if the moon is up. Call period (mean 84 s) varies considerably, but can be as low as 18 seconds during peak chorus activity. Peak calling activity occurs from September to November.

Natural history. Calling (and therefore breeding) activity appears to be seasonal, probably peaking in the austral spring and early summer. This species is seldom found on the surface, except early in the evening during peak chorus activity. Burrow entrances are nearly always sealed after calling ceases, or during the day; the entrance is sealed from the inside, and it is so neatly disguised as to be almost entirely indistinguishable from the surrounding soil surface. The burrow is then re-opened before calling commences. It has been observed consuming large numbers of harvester termites ( Hodotermes mossambicus ), even up to 61 % of its own body-weight, during sporadic events when these termites emerge en masse to forage ( Bauer et al. 1989 ). All adult females collected by Bauer et al. (1989) in early October contained ovarian or unshelled oviductal eggs, suggesting an egg-laying period possibly later than November. One individual of P. kenkenses sp. nov. has been found to be infected by a tapeworm of the genus Mesocestoides ( McAllister et al. 1995 ) . Aggregations of this species are sometimes observed on tarred roads late at night, numbering in the hundreds on a few kilometres of road. The reason for this behaviour is unknown.

Etymology. This species is named after the Nama name for the gecko, “ || en || enses ”, pronounced with two lateral clicks (produced by clicking with one’s tongue on the posterior-lateral roof of one’s mouth, similar to the typical command given for a horse to speed up), in reference to the clicking sound that it makes. The name is usually formed in the Nama female genitive, indicated by the suffix “ s ”, because the animal is small. This gecko occurs throughout the Nama Karoo and various places that were historically, and are currently, occupied by the Nama people. The Nama are highly familiar with its call, and believe the bite of this gecko to be extremely venomous. Nama children are taught to treat it with caution. However, the authors have been bitten by this species, and have survived. We use the specific epithet “ kenkenses ”, a noun in apposition. Since the Nama symbols cannot be included in a scientific name, the phonetically similar letter “ k ” is used instead. However, the use of Nama lateral clicks is recommended in the pronunciation of this name.