Mammal predation by an ariid catfish in a dryland river of Western Australia

The presence of the spinifex hopping mouse Notomys alexis in the diet of lesser salmon catfish Neoarius graeffei from the Ashburton River, Western Australia, is reported for the first time. The consumption of terrestrial mammals by Australian freshwater fishes is widely considered to be an infrequent occurrence, of limited importance to aquatic food webs. However, remains of N. alexis were present within the stomachs of 44% of N. graeffei sampled, constituting approximately 95% of the total stomach contents. These findings suggest that N. graeffei will consume large quantities of terrestrial vertebrates when available, and may represent a valuable energy source for this ecologically important species in dryland river

Population genomic diversity and structure in the golden bandicoot: a history of isolation, extirpation, and conservation

Published online: 08 October 2023. OnlinePublUsing genetic information to develop and implement conservation programs is vital for maintaining biodiversity and ecosystem resilience. Evaluation of the genetic variability within and among remnant populations can inform management of both natural and translocated populations to maximise species' adaptive potential, mitigate negative impacts of inbreeding, and subsequently minimise risk of extinction. Here we use reduced representation sequencing to undertake a genetic assessment of the golden bandicoot (Isoodon auratus), a threatened marsupial endemic to Australia. The currently recognised taxon consists of three subspecies distributed among multiple natural and translocated populations. After confirming the genetic distinctiveness of I. auratus from two closely related taxa, I. fusciventer and I. macrourus, we identified four genetic clusters within I. auratus. These clusters exhibited substantial genetic differentiation (pairwise FST values ranging from 0.18 to 0.65, pairwise DXY ranging from 0.1 to 0.168), reflecting long-term isolation of some populations on offshore islands and the influence of genetic drift. Mainland natural populations in the Kimberley region had the highest genetic diversity and the largest contribution to overall allelic and gene diversity compared to both natural and translocated island populations. A population translocated to Guluwuru Island in the Northern Territory had the lowest genetic diversity. Our data suggest that island populations can appear genetically unique due to genetic drift and this needs to be taken into account when considering genetic diversity in conservation efforts to maintain overall genetic diversity of the species. We effectively demonstrate how genomic information can guide practical conservation planning, especially when declining species are represented by multiple isolated populations.Kate Rick, Margaret Byrne, Skye Cameron, Steve J. B. Cooper, Judy Dunlop, Brydie Hill, Cheryl Lohr, Nicola J. Mitchell, Craig Moritz, Kenny J. Travouillon, Brenton von Takach and Kym Ottewel

The biology and palaeontology of the Peramelemorphia: a review of current knowledge and future research directions

Bandicoots and bilbies (Marsupialia : Peramelemorphia) represent the dominant omnivorous clade of Australasian marsupials and, as ground-dwelling, small- to medium-sized mammals, have not fared well in the 200 years since European settlement. Unlike large or charismatic marsupial species, the cryptic nature of bandicoots and bilbies tends to keep them out of the public eye, at a time when public interest plays a significant role in conservation efforts. The inconspicuous ‘rat-like’ appearance of many bandicoots and a generalist ecological strategy belie a complex biology of adaptive traits and evolutionary diversity. For a few species these biological traits have enabled them to make use of urban environments. In the main, however, peramelemorphians are facing ongoing pressure from introduced predators and human impacts. Basic biological information for many species, particularly those from New Guinea, is still lacking. In this review, we examine advances in the knowledge of the biology of this group over the past 25 years including anatomical, physiological and ecological studies. We also provide a comprehensive review of the fossil records of bandicoots in order to provide an up-to-date platform for future studies. From this work, it is clear that there is still much to be done regarding the taxonomy and biology of these animals before a more detailed understanding of the evolutionary history of this group can be elucidated

Keeping an ear out: Size relationship of the tympanic bullae and pinnae in bandicoots and bilbies (Marsupialia: Peramelemorphia)

Bandicoots and bilbies (Order Peramelemorphia) occupy a broad range of habitats across Australia and New Guinea, from open, arid deserts to dense forests. This once diverse group has been particularly vulnerable to habitat loss and introduced eutherian predators, and numerous species extinctions and range retractions have occurred. Understanding reasons for this loss requires greater understanding of their biology. Morphology of the pinnae and tympanic bullae varies markedly among species. As hearing is important for both predator avoidance and prey location, the variability in ear morphology could reflect specialization and adaptation to specific environments, and therefore be of conservation relevance. We measured 798 museum specimens representing 29 species of Peramelemorphia. Controlling for phylogenetic relatedness and head length, pinna surface area was weakly negatively correlated with average precipitation (rainfall being our surrogate measure of vegetation productivity/complexity), and there were no environmental correlates with effective diameter (pinna width). Controlling for phylogenetic relatedness and skull length, tympanic bulla volume was negatively correlated with precipitation. Species that inhabited drier habitats, which would be open and allow sound to carry further with less obstruction, had relatively larger pinnae and tympanic bullae. In contrast, species from higher rainfall habitats, where sounds would be attenuated and diffused by dense vegetation, had the smallest pinnae and bullae, suggesting that low-frequency hearing is not as important in these habitats. Associations with temperature did not reach statistical significance. These findings highlight linkages between hearing traits and habitat that can inform conservation and management strategies for threatened species

Mechanical similarity across ontogeny of digging muscles in an Australian marsupial (Isoodon fusciventer)

Many mammals dig, either during foraging to access subsurface food resources, or in creating burrows for shelter. Digging requires large forces produced by muscles and transmitted to the soil via the skeletal system; thus fossorial mammals tend to have characteristic modifications of the musculoskeletal system that reflect their digging ability. Bandicoots (Marsupialia: Peramelidae) scratch‐dig mainly to source food, searching for subterranean food items including invertebrates, seeds, and fungi. They have musculoskeletal features for digging, including shortened, robust forelimb bones, large muscles, and enlarged muscle attachment areas. Here, we compared changes in the ontogenetic development of muscles associated with digging in the Quenda (Isoodon fusciventer). We measured muscle mass (m m), pennation angle, and fiber length (FL) to calculate physiological cross‐sectional area (PCSA; a proxy of maximum isometric force) as well as estimate the maximum isometric force (Fmax) for 34 individuals ranging in body size from 124 to 2,390 g. Males grow larger than females in this bandicoot species, however, we found negligible sex differences in mass‐specific m m, PCSA or FL for our sample. Majority of the forelimb muscles PCSA showed a positive allometric relationship with total body mass, while m m and FL in the majority of forelimb muscles showed isometry. Mechanical similarity was tested, and two thirds of forelimb muscles maximum isometric forces (Fmax) scaled with isometry; therefore the forelimb is primarily mechanical similar throughout ontogeny. PCSA showed a significant difference between scaling slopes between main movers in the power stroke, and main movers of the recovery stroke of scratch‐digging. This suggests that some forelimb muscles grow with positive allometry, specially these associated with the power stroke of digging. Intraspecific variation in PCSA is rarely considered in the literature, and thus this is an important study quantifying changes in muscle architectural properties with growth in a mammalian model of scratch‐digging

Review of the methods used for calculating physiological cross‐sectional area (PCSA) for ecological questions

This review examines literature that used physiological cross‐sectional area (PCSA) as a representative measure of an individual muscle's maximal isometric force production. PCSA is used to understand the muscle architecture and how a trade‐off between muscle force and muscle contractile velocity reflect adaptations of the musculoskeletal system as a reflection of functional demands. Over the decades, methods have been developed to measure muscle volume, fascicle lengths, and pennation angle to calculate PCSA. The advantages and limitations of these methods (especially the inclusion/elimination of pennation angle) are discussed frequently; however, these method descriptions are scattered throughout the literature. Here, we reviewed and summarised the different approaches to collecting and recording muscle architectural properties to subsequently calculate PCSA. By critically discussing the advantages and limitations of each methodology, we aim to provide readers with an overview of repeatable methods to assess muscle architecture. This review may serve as a guide to facilitate readers searching for the appropriate techniques to calculate PCSA and measure muscle architecture to be applied in ecomorphology research

<i>Kutjamarcoot brevirostrum</i> gen. et sp. nov., a new short-snouted, early Miocene bandicoot (Marsupialia: Peramelemorphia) from the Kutjamarpu Local Fauna (Wipajiri Formation) in South Australia

<p>Chamberlain, P.M., Travouillon, K.J., Archer, M. & Hand, S.J., November 2015. <i>Kutjamarcoot brevirostrum</i> gen. et sp. nov., a new short-snouted, early Miocene bandicoot (Marsupialia: Peramelemorphia) from the Kutjamarpu Local Fauna (Wipajiri Formation) in South Australia. <i>Alcheringa 40</i>, XX–XX. ISSN 0311-5518.</p> <p>A new bandicoot species, <i>Kutjamarcoot brevirostrum</i> gen. et sp. nov. (Peramelemorphia), is described here from the Leaf Locality, Kutjamarpu Local Fauna (LF), Wipajiri Formation (South Australia). The age of the fossil deposit is interpreted as early Miocene on the basis of biocorrelation between multiple species in the Kutjamarpu LF and local faunas from the Riversleigh World Heritage Area (WHA). <i>Kutjamarcoot brevirostrum</i> is represented by isolated teeth and three partial dentaries and appears to have been short-snouted with an estimated mass of 920 g. Phylogenetic analyses place <i>K. brevirostrum</i> in a clade with extant Australian bandicoots and the extinct <i>Madju</i>, but potentially exclude the extant New Guinean bandicoots. Morphometric analysis infers close similarity between <i>K. brevirostrum</i> and species of <i>Galadi</i> in both size and rostral length. They, thus, potentially occupied compatible ecological niches with competitive exclusion perhaps explaining geographical segregation between these broadly coeval lineages.</p> <p><i>Philippa M. Chamberlain [</i>[email protected]<i>], School of Earth Sciences, University of Queensland, St Lucia, Queensland 4072, Australia; Kenny J. Travouillon [</i>[email protected]<i>;</i>[email protected]<i>], Western Australian Museum, Locked Bag 49, Welshpool DC, WA, 6986, and School of Earth Sciences, University of Queensland, St Lucia, Queensland, 4072, Australia; Michael Archer [</i>[email protected]<i>] and Suzanne J. Hand [</i>[email protected]<i>], School of Biological, Earth and Environmental Sciences, University of New South Wales, New South Wales, 2052, Australia.</i></p

Hidden in plain sight: reassessment of the pig-footed bandicoot, Chaeropus ecaudatus (Peramelemorphia, Chaeropodidae), with a description of a new species from central Australia, and use of the fossil record to trace its past distribution

The Pig-footed Bandicoot, Chaeropus ecaudatus, an extinct arid-adapted bandicoot, was named in 1838 based on a specimen without a tail from the Murray River in New South Wales. Two additional species were later named, C. castanotis and C. occidentalis, which have since been synonymised with C. ecaudatus. Taxonomic research on the genus is rather difficult because of the limited material available for study. Aside from the types of C. castanotis and C. occidentalis housed at the Natural History Museum in London, and the type of C. ecaudatus at the Australian Museum in Sydney, there are fewer than 30 other modern specimens in other collections scattered around the world. Examining skeletal and dental characters for several specimens, and using a combination of traditional morphology, morphometrics, palaeontology and molecular phylogenetics, we have identified two distinct species, C. ecaudatus and C. yirratji sp. nov., with C. ecaudatus having two distinct subspecies, C. e. ecaudatus and C. e. occidentalis. We use palaeontological data to reconstruct the pre-European distribution of the two species, and review the ecological information known about these extinct taxa.Kenny J. Travouillon, Bruno F. Simões, Roberto Portela Miguez, Selina Brace, Philippa Brewer, David Stemmer, Gilbert J. Price, Jonathan Cramb, Julien Louy