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Severe flooding in early 2020 and 2021 necessitated major desedimentation works at the iconic Blue Lake in the Jenolan Karst Conservation Reserve (JKCR). Movements and behaviour of platypuses were monitored before, during and after these works, using direct observations, remote cameras and environmental DNA (eDNA) sampling. Platypuses were observed along a 3 km reach of the Jenolan River, including the areas where works occurred, although in low numbers. In their use of the available waterways, platypuses negotiated artificial barriers, including a 10 m high dam, two smaller weirs and natural waterfalls and cascades. Overland movements were detected through vegetation tunnels, drainage pipes and culverts, and individuals were seen entering the cave system, where eDNA was also detected. Platypuses responded to the works activity by foraging outside the affected areas but also continued to traverse these areas from time to time. We describe movements around and through instream infrastructure and past natural barriers and report on other species detected by remote cameras. These observations could help planning and deployment of bypasses suitable for movement of platypuses around anthropogenic barriers and provide insights into impediments to dispersal and gene flow within stream systems. Because of their cryptic nature and being active predominately at night, movement of wild platypuses is poorly documented. Our studies of their movements in the upper Jenolan River showed them moving around and through natural and artificial instream structures, including across weirs, through culverts, around waterfalls and entering caves. This research is important to the management and conservation of the species in relation to human activities in rivers. Photograph by Anne Musser. [ABSTRACT FROM AUTHOR]

Genetic mutations resulting in abnormal colouration occur across all vertebrate groups but are considered rare, especially in mammals. Hypo-pigmentary conditions can be separated into albinism, leucism and piebaldism. The impact of colour variation on an animal's risk of predation and its ability to blend with its surroundings is widely recognised. We report our observations of a white platypus (Ornithorhynchus anatinus) in a tributary of the Gwydir River in the upper reaches of the Murray Darling Basin, New South Wales, Australia. We describe our observations in the context of historical platypus records since 1835. [ABSTRACT FROM AUTHOR]

The platypus (Ornithorhynchus anatinus) is a semi-aquatic monotreme that occupies a high trophic position in the freshwater ecosystems of eastern mainland Australia and Tasmania. Platypuses are continuously exposed to anthropogenic contaminants including perfluorooctane sulfonate (PFOS). This study examined PFOS concentrations in the livers of deceased platypuses (eight wild; one captive) that were opportunistically collected across NSW over a two- and a half-year period. There was a large variation in PFOS concentrations, ranging from < 1 µg/kg to 1200 µg/kg. This study presents the first report of PFOS contamination in platypuses, revealing their PFOS levels are broadly similar to those found in river otters (Lutra canadensis) and lower than those in American mink (Mustela vison), both which occupy similar ecological niches in freshwater systems. This study raises concerns about the impact of PFOS on platypus health., (© 2024. The Author(s).)

The occurrence of biofluorescence across Mammalia is an area of active study. We examined three specimens of the platypus (Ornithorhynchus anatinus) from Tasmania and New South Wales, Australia, housed in the Field Museum of Natural History (Chicago, Illinois, USA) and the University of Nebraska State Museum (Lincoln, Nebraska, USA) under visible light and ultraviolet (UV) light. The pelage of the animals appeared uniformly brown under visible light and green or cyan under UV light, due to fluoresced wavelengths that peaked around 500 nm. Our observations are the first report of biofluorescence in a monotreme mammal. [ABSTRACT FROM AUTHOR]

The diet of the platypus Ornithorhynchus anatinus was studied by examination of material collected from the cheek pouches of animals captured while foraging in streams in Kangaroo Valley, NSW, Australia. Platypuses consumed benthic invertebrates from 55 families in 16 orders, with virtually no prey being derived from the terrestrial environment. We also sampled invertebrates in pool, riffle and stream edge habitats to identify where prey were obtained. Invertebrates in the diet were most similar to those collected along stream edges and in pools compared with the faster-flowing riffles, suggesting that platypuses focused their foraging activities largely in these deeper water habitats. Although there was no seasonality in the assemblage structure of macroinvertebrates, the diet of platypuses varied between seasons, notably between winter and summer, suggesting that some dietary selectivity is seasonal. Dietary differences between the sexes were not detected. Overall, our results suggest that some dietary selection occurs in the platypus with respect to both foraging habitat and season. Seasonal selectivity may reflect different metabolic demands on platypuses at different times of the year. In contrast, habitat selectivity may reflect difficulty of prey access and risk of prey escape in fast-flowing riffles, higher energy costs and risk of predation associated with exploiting this habitat, and prey avoidance responses that are more rapid in the shallow riffles than in the deeper water pools and stream edges. These alternatives await evaluation by future research. [ABSTRACT FROM AUTHOR]

Population genetics is a powerful tool to increase the understanding of animals that may otherwise be difficult to study, such as the platypus (Ornithorhynchus anatinus). Focusing on two adjacent river systems in New South Wales, we used 12 polymorphic microsatellite loci to investigate the population dynamics of the platypus. We found that individual river systems acted as discrete population units. Evidence of migration, presumably overland, between systems explains how these units remain connected. This establishes an isolation-by-distance pattern that maintains species continuity across most of the mainland distribution. This improved understanding of population structure will be a valuable contribution to designing accurate management plans for the long-term conservation of this unique Australian animal. [ABSTRACT FROM AUTHOR]

Investigates feeding in the platypus by identifying material found in the cheek pouches of animals trapped in nets in a study area on the upper Shoalhaven River in New South Wales. Benthic samples taken in the rapids and pools of the river; Relationship between the relative abundance of food items available and the food found in the platypus cheek pouches; Implications on studies of ecology.

We identified and optimized 10 microsatellite loci for the platypus, Ornithorhynchus anatinus (Monotremata: Ornithorhynchidae), and screened 21 individuals from the southern tablelands area of New South Wales, Australia. Each polymorphic locus possessed between two and 12 alleles with observed heterozygosities between 0.118 and 0.950. The intent of this effort was to provide informative loci for studies on the population genetics of this species. [ABSTRACT FROM AUTHOR]

Case Report: The clinical and laboratory findings in an orphaned juvenile female platypus (Ornithorhynchus anatinus) that presented with a severe anaemia and tick infestation are reported. The animal developed a terminal septicaemia and died. Antemortem clinical pathology, postmortem histopathology and 18S rDNA sequencing supported a diagnosis of extravascular haemolytic anaemia secondary to Theileria ornithorhynchi infection., Conclusion: Although T. ornithorhynchi infection is common in the platypus, this is the first case in which it has been shown to cause a haemolytic anaemia in this species and molecular characterisation of the organism has been described. A review of the previous literature concerning T. ornithorhynchi and possible treatment options for future cases are discussed., (© 2014 Australian Veterinary Association.)