Bioacoustics of Rawlinsonia sibilus

Etymology. The specific epithet, sibilus , is a masculine Latin 2 nd declension noun meaning whistle or hiss. It is used in apposition to the genus name. Advertisement Call. Call description is based on the calls of six individuals. The advertisement call of Litoria sibilus has a duration of 1.48– 2.34 s (mean 1.78 s ) and comprises 8–11 (mean 9) pulsed notes. Notes are typically short 0.1– 0.28 s (mean 0.17 s ) with the shortest note at the beginning (83.3% of calls) and the longest note at the end (50%). Notes have limited intervals between them and are not distinctly pulsed. In 50% of calls, amplitude rose to a peak in roughly the middle of each note before descending, giving a tent-like appearance ( Fig. 7 ). Dominant frequency had a short range of 2156–2541 Hz (mean 2451 Hz). Comparison with other species. Litoria sibilus is isolated from all other members of the L . ewingii group, separated from the closest species, L. calliscelis , across a 13 km stretch of sea known as the Backstairs Passage, which separates Kangaroo Island from the adjacent mainland. For a description of colour/pattern features potentially useful for identification where collection locality is unknown, see Litoria ewingii and L. calliscelis above.

Ecology and reproduction. The species is uncommonly recorded via FrogID (68 records from 10 November 2017 – 30 June 2022 ), but is often heard calling in disturbed areas, with 6% of FrogID records of the species documented as being in urban habitats and 74% of records in rural areas. Breeding period appears to be extended, with males recorded calling in January–November, with the majority of FrogID submissions from between March– May. Breeding habitat poorly known but appears to include static ephemeral and permanent waterbodies such as dams, ponds, swamps, inundated ditches and streamside ponds and pools. For a detailed description of tadpole development and morphology specific to this taxon, see Anstis (2017) . Conservation status. Litoria sibilus has the most restricted distribution of all species within the Litoria ewingii Group. AOO was calculated for the species at 268 km 2 and EOO 3,743 km 2 . Under criterion B of the IUCN Red List guidelines, these calculations potentially qualify the taxon for Endangered listing (AOO < 500 km 2 ; EOO < 5,000km 2 ). However, given there is a lack of baseline information indicating severe fragmentation, decline or fluctuation in population size, we suggest a conservative listing of Data Deficient to be appropriate for this taxon until further information becomes available. Of particular concern is the potential threat posed by the devastating bushfires that occurred on Kangaroo Island in 2019–2020, which burned through 45.9% the island’s landmass ( Bonney et al. 2020 ). Targeted surveys of Litoria sibilus are required to establish a population baseline and assess post-fire population health and recovery.