Marsupials

Marsupials and their fossil relatives, which collectively comprise Metatheria, have been of scientific interest for centuries, with many aspects of their evolution and systematics subject to intense research and debate. Here, we review progress over the last 25 years, which has included the description of many new species (modern and fossil), and major improvements in understanding of their phylogenetic relationships, as well as the overall evolutionary history and biogeography of Marsupialia (crown-clade) and Metatheria (total-clade). Significant advances have included the deployment of increasingly sophisticated molecular, morphological, and total evidence analyses, which have resolved most previously disputed relationships among and within the modern marsupial orders. A broad systematic consensus is now emerging, although several major areas of contention remain, particularly among fossil metatherians. New modern species continue to be described at an impressive rate, with almost 50 named in the last 25 years, and many more await discovery. There has also been an explosion in the discovery and description of fossil marsupials and non-marsupial metatherians (~270 species), principally from Australasia and the Americas but also from Antarctica, Europe, and Asia. Most are represented by dental specimens only, but some consist of complete and well-preserved material, which has led to major improvements in our understanding of the evolution of cranial and postcranial morphology. Improvements in the fossil record and advances in methods for inferring divergence times have helped clarify when and where key events occurred in metatherian evolution, and the patterns of subclade diversification. We also have improved understanding of biogeographical relationships among metatherians on different landmasses. Despite enormous progress, numerous key uncertainties remain due to major gaps in the fossil record (e.g., Antarctica, Late Cretaceous, and early Paleogene of Australia) and a comparative lack of studies that directly combine molecular and fossil data. Future advances will largely depend on improvements in the fossil record and studies that better integrate neontological and paleontological evidence. Los marsupiales y sus parientes fósiles, que en conjunto forman el grupo Metatheria, han sido de interés científico durante siglos, con muchos aspectos de su evolución y sistemática sujetos a intensas investigaciones y debates. Aquí se resumen los avances alcanzados durante los últimos 25 años, los cuales incluyen la descripción de muchas especies nuevas (tanto fósiles como actuales), una mayor comprensión de relaciones filogenéticas, y también la historia general evolutiva y biogeográfica de Marsupialia (clado corona) y Metatheria (clado completo). Los mayores avances han incluido el uso de análisis moleculares, morfológicos y de evidencia total que son cada vez más sofisticados. Dichos avances ya han resuelto muchas de las relaciones anteriormente disputadas fuera y dentro de los ordenes de marsupiales actuales. Actualmente está surgiendo un amplio consenso general, a pesar de que aún quedan varias áreas importantes de discusión. Se continúa describiendo especies nuevas actuales a una velocidad impresionante, con casi 50 nombradas en los últimos 25 años, y muchas más esperan a ser descubiertas. También ha habido una explosión en el descubrimiento y descripción de especies fósiles de marsupiales y metaterios no-marsupiales (~270 especies), principalmente de Australasia y las Américas, pero

A recent publication in Parasitology Research by (Old et al. Parasitol Res 120:1077-1090, 2021) raises the topical and often controversial issue of the treatment of wildlife by personnel with little or no formal scientific training (e.g. wildlife carers). In a valuable contribution to the subject, Old and colleagues document a wide range of topical (pour-on) application doses and frequencies of moxidectin (Cydectin®) administered in situ to bare-nosed wombats (Vombatus ursinus) by members of the wildlife carer/treater community in southeast Australia to treat sarcoptic mange disease. This treatment occurred under minor use permits issued by the Australian Pesticides and Veterinary Management Authority (APVMA). These permits do not require veterinary supervision, although carers are registered and are expected to comply with the guidelines of this permit. The prevalence and severity of sarcoptic mange in wildlife is influenced by a variety of factors including mite biology, environmental conditions, population density, animal behaviour and immune susceptibility (Browne et al. Bioscience, 2021). In bare-nosed wombats, combinations of these elements play a substantial role in making the treatment of an already difficult disease more complex. (Moroni et al. Parasit Vectors 13:471, 2020) comment that any pharmacological treatment of freeranging wildlife must consider these factors when assessing their feasibility and implications, especially in the context of emerging drug resistance and potential long-term ecological impacts. As individuals with significant interest in sarcoptic mange and representing a range of professional research and veterinary expertise, we see value in providing expert commentary on this issue.

Populations of the common ringtail possum (Pseudocheirus peregrinus) in inland New South Wales have declined or disappeared. Habitat requirements and diet of these populations are poorly understood. Determining the diet of inland ringtail possums is crucial to understanding the factors limiting their survival, and was the focus of this study. Spotlighting surveys were conducted to locate ringtail possums, and scat and vegetation samples were collected for microhistological analysis. Ringtail possums were most frequently observed in red stringybark followed by bundy box and black cypress pine trees, and this correlated with the most common dietary items consumed.

No sul de Minas Gerais há uma grande diversidade de habitats que determinam uma notável alternância de espécies entre diferentes fitofisionomias. A conservação dessas áreas é pertinente para a preservação da fauna associada, principalmente para o grupo dos marsupiais que demonstra potencial para bioindicação e restauração ambiental. O estudo em questão analisou três vertentes na Chapada das Perdizes com diferentes características climáticas e vegetacionais com o objetivo de apresentar uma lista preliminar da composição da comunidade de marsupiais ocorrentes no sul do estado de Minas Gerais.

Nutritional requirements of 12 species of Neotropical opossums (Didelphidae) were inferred through a laboratory food preference experiment. Nutritional contents of experimental diets follow predictions based on field diet data, with more frugivorous species showing high non-structural carbohydrate proportions and more carnivorous species high protein contents in their selected diets. Mouse opossums selected nutritional and fibre proportions that suggested that they may be more frugivorous and less strictly insectivorous than previously thought. The species form a gradient of differential food specialisation from frugivory to car-nivory, and significant differences are found only between extremes of this gradient. Nutritional contents established here are consistent with natural diet patterns and can be used as important complementary data to field diet studies and to prepare diets for captive maintenance of the species.