Possum acoustic behaviour is complex and varies substantially, with some species having numerous calls used in various contexts, while other species are limited to one known vocalisation or non-vocal sounds. Here, we report that the first known recording of Sulawesi bear cuscus (Ailurops ursinus, 1824) acoustic behaviour and observations of associated behavioural displays. We observed an animal adopting a raised posture in apparent threat display and audio-recorded the concurrent short, harsh sounds. The animal produced a 'chatter', composed of four notes given at short, regular intervals, followed by a series of 'clicks' given at longer and irregular intervals. We describe the frequency and temporal characteristics of these sounds. Clicks were variable in acoustic structure, possibly falling into three subtypes, and some clicks overlapped in acoustic features with individual chatter notes. Click and chatter notes were broadband and non-tonal, and so appear to be non-vocal sounds, produced by the mouth or tongue rather than larynx. Our observations and recording of A. ursinus contribute to the natural history of this poorly known and enigmatic species, that is currently threatened with extinction from illegal wildlife trade, hunting and deforestation. Abstrak Perilaku akustik possum bersifat kompleks dan sangat bervariasi, dengan beberapa spesies memiliki beragam panggilan yang digunakan dalam berbagai konteks, sementara spesies lain diketauhi terbatas pada satu suara vokalisasi atau non-vokal. Di sini, kami melaporkan rekaman pertama yang diketahui dari perilaku akustik Kuskus beruang Sulawesi (Ailurops ursinus,1824) dan pengamatan dari tampilan perilaku terkait. Kami mengamati seekor hewan yang mengadopsi postur tubuh yang tampak seperti ancaman, dan merekam audio suara yang pendek dan kasar secara bersamaan. Hewan itu mengeluarkan "obrolan", terdiri dari empat nada yang diberikan secara singkat dan teratur, diikuti oleh serangkaian suara decak yang diberikan dengan interval yang lebih panjang dan tidak teratur. Kami menjelaskan frekuensi dan karakteristik temporal suara-suara ini. Suara decak bervariasi dalam struktur akustik, mungkin terbagi dalam tiga sub-jenis, dan beberapa suara decak tumpang tindih dalam fitur akustik dengan catatan obrolan individual. Nada decak dan obrolan adalah nada pita lebar dan non-nada, sehingga tampak seperti suara non-vokal, yang dihasilkan oleh mulut atau lidah daripada laring. Pengamatan dan pencatatan kami terhadap A. ursinus berkontribusi pada sejarah alami spesies yang kurang dikenal dan misterius ini, yang saat ini terancam punah karena perdagangan illegal satwa liar, perburuan dan penggundulan hutan.

Tropical ecosystems are biodiverse and ecologically complex, supporting nearly half of the global herpetofauna. Ecological interactions play a role in the maintenance of species diversity with a range of ecological interactions occurring within and among species in tropical ecosystems. Incidental observations of ecological interactions provide an important contribution to the understanding of the ecology and natural history of species. Here, we report an interspecific interaction between distant taxa, the Four-Clawed Gecko (Gehyra mutilata) utilizing an active communal nesting site and shared nesting resources with two vespid wasp species (Eumeninae and Polistinae), where previous observations documented species utilizing abandoned nesting resources. This is the first known record of three species actively cohabitating in a shared nesting resource. This observation, with one or all species positively benefiting from the ecological interaction, likely indicates a mutualistic or commensal ecological interaction. Incidental observations such as the present study are likely to reveal that interspecific ecological interactions including communal nesting are more widespread than previously thought and the co-utilization of existing nesting resources presents an advantage for taxa. Observations such as these provide the basis for understanding the complex network of ecological interactions occurring in tropical rainforests.

The southern Australian endemic genus Geocrinia Blake 1973 (Anura: Myobatrachidae) currently contains seven species, with five restricted to Western Australia and two in the south-eastern states covering parts of New South Wales, Victoria, Tasmania and South Australia. All species have a modified life history with at least some or all of the larval stage being completed terrestrially. Four of the Western Australian species have terrestrial, non-feeding tadpoles nourished by yolk until metamorphosis. The remaining species have a biphasic development with embryos developing on land followed by an aquatic tadpole stage. The presence of species groups within the Geocrinia has been recognised since the 1970s, with all relevant subsequent studies supporting a model of two groups within the genus, recovered as reciprocally monophyletic in phylogenetic analyses. We examined character traits of the seven recognised Geocrinia species, concluding that distinction of the two monophyletic groups is supported by differences in life history strategy, larval morphology, adult morphology, call structure, breeding season and geographic distribution. The differences between the two groups correspond to phylogenetic structuring for all traits except distribution. Given reciprocal monophyly, and greater variation in traits than present within other myobatrachid genera, we conclude that the two groups should be given generic distinction. We therefore describe a new genus, Anstisia gen. nov., for four Western Australian Geocrinia species, retaining three species in Geocrinia. This increases the number of recognised myobatrachid genera to 14: five are endemic to south-western Australia.