Journal articles: 'Dasyurus Genetics'

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Czarny, N. A., K. E. Mate, and J. C. Rodger. "Acrosome stability in the spermatozoa of dasyurid marsupials." Reproduction, Fertility and Development 20, no. 2 (2008): 295. http://dx.doi.org/10.1071/rd07178.

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The spermatozoa of most marsupials lack nuclear stabilising disulfide-bonded protamines found in eutherian mammals. However, disulfide stabilisation has been observed in the acrosome of macropodid (Macropus eugenii) and phalangerid (Trichosurus vulpecula) marsupials. As a result this organelle, which is normally fragile in eutherian mammals, is robust and able to withstand physical and chemical challenge in these marsupials. The present study examined acrosomal characteristics of the spermatozoa of three dasyurid marsupials; the fat-tailed dunnart (Sminthopsis crassicaudata), eastern quoll (Dasyurus viverrinus) and northern quoll (Dasyurus hallucatus). In all species examined Bryan’s staining demonstrated that significant acrosomal loss occurred following physical challenge with osmotic stress, cryopreservation without cryoprotectant and exposure to detergent (Triton-X). Bromobimane staining indicated that the acrosomes of dasyurids lacked stabilising disulfide bonds. As reported for the wallaby and possum, calcium ionophore (A23187) did not induce the acrosome reaction-like exocytosis in dasyurid spermatozoa but treatment with diacylglycerol (DiC8) caused significant acrosome loss at concentrations similar to those effective for other marsupials. The present study found that the spermatozoa of dasyurids are more sensitive to physical challenge than the previously-studied marsupials and we suggest that this is due to the absence of acrosomal stabilising disulfide bonds.

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Dickman, C. R., and R. W. Braithwaite. "Postmating Mortality of Males in the Dasyurid Marsupials, Dasyurus and Parantechinus." Journal of Mammalogy 73, no. 1 (April 14, 1992): 143–47. http://dx.doi.org/10.2307/1381875.

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Czarny, N. A., and J. C. Rodger. "143. THE FIRST EVIDENCE OF HIGH SUSCEPTIBILITY TO COLD SHOCK BY THE SPERMATOZOA OF A MARSUPIAL, THE FAT TAILED DUNNART (SMINTHOPSIS CRASSICAUDATA)." Reproduction, Fertility and Development 21, no. 9 (2009): 61. http://dx.doi.org/10.1071/srb09abs143.

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Carnivorous marsupials are native Australian predators including the highly threatened northern quoll (Dasyurus hallucatus) and Tasmanian devil (Sarcophilus harrisii). These species are currently actively managed in captive populations but assisted reproductive techniques such as gamete banking may also contribute to their conservation. Previous studies on a model dasyurid, the fat tailed dunnart (Sminthopsis crassicaudata), have found that spermatozoa do not survive freezing and thawing using a variety of freezing protocols and cryoprotectants. We have re-examined cold shock to investigate problems with sperm cryopreservation in S. crassicaudata. Epididymal spermatozoa were rapidly cooled to 0.5ºC in a pre-cooled tube held in an iced water slurry and upon re-warming the spermatozoa were non-motile (n=6). The addition of up to 20% egg yolk, which is considered protective to the spermatozoa of cold shock sensitive eutherians, did not improve the outcome (n=6). Similarly when S. crassicaudata spermatozoa were rapidly cooled to 4ºC, just 2% remained motile upon re-warming (n=10). However when spermatozoa were combined with at least 10% egg yolk and rapidly cooled to 4ºC only small reductions in motility were observed upon rewarming (n≥8). In order to achieve motile spermatozoa at 0ºC, controlled rate cooling at 0.5ºC/minute was examined. In the absence of egg yolk there was a decline in the percentage of motile spermatozoa below 4ºC (n=6). However if spermatozoa were combined with at least 10% egg yolk there was no significant loss of motility at temperatures as low as 0ºC (n=6). This study has revealed that at least one species of marsupial is highly susceptible to cold shock. These paradigm shifting findings give direction to future experiments aiming to develop a robust technique for sperm preservation in endangered dasyurids.

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Degen, A. A., and M. Kam. "Water Intake in Two Coexisting Desert Rodents, Acomys cahirinus and Gerbillus dasyurus." Journal of Mammalogy 73, no. 1 (April 14, 1992): 201–6. http://dx.doi.org/10.2307/1381883.

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Hohnen, Rosemary, Katherine D. Tuft, Sarah Legge, Mia Hillyer, Peter B. S. Spencer, Ian J. Radford, Christopher N. Johnson, and Christopher P. Burridge. "Rainfall and topography predict gene flow among populations of the declining northern quoll (Dasyurus hallucatus)." Conservation Genetics 17, no. 5 (June 25, 2016): 1213–28. http://dx.doi.org/10.1007/s10592-016-0856-z.

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Glen, A. S., O. Berry, D. R. Sutherland, S. Garretson, T. Robinson, and P. J. de Tores. "Forensic DNA confirms intraguild killing of a chuditch (Dasyurus geoffroii) by a feral cat (Felis catus)." Conservation Genetics 11, no. 3 (March 15, 2009): 1099–101. http://dx.doi.org/10.1007/s10592-009-9888-y.

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Naumova, E. I., T. Yu Chistova, A. A. Varshavskii, and G. K. Zharova. "Functional Diversity of Morphologically Similar Digestive Organs in Muroidea Species." Biology Bulletin 48, no. 3 (May 2021): 331–39. http://dx.doi.org/10.1134/s1062359021020084.

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Abstract We examine possible ways of functional adjustment of morphologically similar alimentary tracts in rodents with different dietary specializations. We study the structure of stomach and gut epithelial surface as well as the features of its colonization with microorganisms in five gerbil species: Psammomys obesus, Meriones crassus, Gerbillus henleyi, G. andersoni, and G. dasyurus. Data on the morphological diversity of mucosa-associated microbiota have been obtained and confirmed by the results of previous microbiology studies. Species differences in chymus acidity associated with dietary specialization have been determined. Variations in the activity of the endoglucanase microbial enzyme, which is crucial for rodents fed on cellulose-containing food, have also been detected. The importance of microbiota for functional adaptations to various food types in rodents with morphologically similar digestive tracts has been evaluated.

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Hernandez-Santin, Lorna, Judy A. Dunlop, Anne W. Goldizen, and Diana O. Fisher. "Demography of the northern quoll (Dasyurus hallucatus) in the most arid part of its range." Journal of Mammalogy 100, no. 4 (June 7, 2019): 1191–98. http://dx.doi.org/10.1093/jmammal/gyz092.

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Abstract The northern quoll (Dasyurus hallucatus) is a carnivorous marsupial that has suffered severe population declines over the last 50 years and is now listed as Endangered. The Pilbara region of Western Australia is a semi-arid area that represents an extreme of the northern quoll’s range. The overall objective of this study was to assess population characteristics of northern quolls at two rocky sites in the Pilbara, focusing on body condition, reproductive timing, population size, and sex-specific survival. We interpret these in the context of variation in habitat quality and the harsh climate. We found that reproduction occurred later in the year than in populations at more mesic locations where quolls have been previously studied, although their life history and demography were otherwise similar to that in other parts of their range. Contrary to our expectations, post-mating mortality of males was not complete. Population sizes differed between sites, suggesting that these rocky habitats varied in habitat quality. We suggest that local population size estimates can guide decisions on the relative importance of sites to ensure the long-term conservation of the species, given impacts of mining and the imminent invasion of introduced cane toads (Rhinella marina).

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Czarny, N. A., M. S. Harris, and J. C. Rodger. "156 ENZYMATIC DISSOCIATION AND VITRIFICATION OF PREANTRAL FOLLICLES FROM THREATENED CARNIVOROUS MARSUPIALS." Reproduction, Fertility and Development 21, no. 1 (2009): 177. http://dx.doi.org/10.1071/rdv21n1ab156.

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The mammalian ovary contains a rich resource of immature preantral follicles present regardless of cycle stage or seasonality. These follicles can be harvested enzymatically and are preserved more successfully than larger, more mature follicles. Thus, the collection and storage of preantral follicles is an applicable technique for the opportunistic harvesting of ovarian tissue from wildlife for the purpose of genebanking. This study examined the potential of such tools for the conservation of two endangered Australian carnivorous marsupials (dasyurids): the northern quoll, Dasyurus hallucatus, and the Tasmanian devil, Sarcophilus harrisii. The fat-tailed dunnart, Sminthopsis crassicaudata, is a representative model dasyurid with the typical attributes of large gametes (220 μm oocytes) and short polyovular reproductive cycles. Ovarian tissue was dissociated with 0.05–0.1% collagenase and 0.01–0.02% DNase in DMEM (all Sigma-Aldrich, St. Louis, USA) for up to 30 min before being neutralized with DMEM +10% fetal calf serum (FCS, Trace Biosciences, Castle Hill, Australia). Survival was determined using membrane permeability stains targeted to the nucleus (SYBR14 and propidium iodide, Molecular Probes, Carlsbad, CA, USA) or cytoplasm (trypan blue, Sigma) and assessed with a four-level survival score (1 = 100% live, 2 = 50–99% live, 3 = 1–49% live, 4 = 0% live) for each stage of follicular maturation: primordial (PF), early (EF), and late (LF) primary and secondary (SF) follicles (n = 100 each). Dissociated EF and LF (n = 45) from S. crassicaudata were vitrified with a three-step medium composed of up to 18% DMSO and ethylene glycol in 1 m sucrose (all Sigma; Vajta G et al. 1998 Mol. Reprod. Dev. 51, 53–58), and post-thaw viability was confirmed with trypan blue. All experiments were carried out on at least three individuals; values are presented as mean ± SEM and differences were determined with ANOVA and post hoc Tukey tests. In all species, 100% of PF were highly viable (score 1) and there was a significant decrease (P < 0.05) in the percentage of highly viable PF, EF, and LF when compared with SF, which were most commonly observed with minor damage (score 2). An incomplete layer of granulosa cells was observed in 11.92 ± 1.08% of freshly dissociated S. crassicaudata follicles. This increased to 30.34 ± 12.22% after preservation. Of the surrounded follicles, 48.40 ± 14.09% were classified as score 1 or 2 after vitrification. Nonviable staining of the oocyte was observed only in naked oocytes. Although these protocols demonstrate a reliable method for follicle collection and preliminary evidence for tools allowing the preservation of female gametes, further optimization is recommended. The demonstrated techniques are highly applicable to genebanking because they utilize material from unstimulated ovaries, as is regularly seen with tissues collected opportunistically from anestrus, ill, or old wildlife. This study was made possible by the cooperation and collection of tissues by the staff from Territory Wildlife Park, Northern Territory, and Tamara Keeley from Western Plains Zoo, New South Wales.

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SPENCER, PETER B. S., MARIA CARDOSO, RICHARD A. HOW, JASON WILLIAMS, MICHAEL BUNCE, and LINCOLN H. SCHMITT. "Cross-species amplification at microsatellite loci in Australian quolls including the description of five new markers from the Chuditch (Dasyurus geoffroii)." Molecular Ecology Notes 7, no. 6 (November 2007): 1100–1103. http://dx.doi.org/10.1111/j.1471-8286.2007.01791.x.

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White, T. D. "Gait Selection in the Brush-Tail Possum (Trichosurus vulpecula), the Northern Quoll (Dasyurus hallucatus), and the Virginia Opossum (Didelphis virginiana)." Journal of Mammalogy 71, no. 1 (February 20, 1990): 79–84. http://dx.doi.org/10.2307/1381321.

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Robinson, Natasha M., Wade Blanchard, Christopher MacGregor, Rob Brewster, Nick Dexter, and David B. Lindenmayer. "Finding food in a novel environment: The diet of a reintroduced endangered meso-predator to mainland Australia, with notes on foraging behaviour." PLOS ONE 15, no. 12 (December 17, 2020): e0243937. http://dx.doi.org/10.1371/journal.pone.0243937.

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Translocated captive-bred predators are less skilled at hunting than wild-born predators and more prone to starvation post-release. Foraging in an unfamiliar environment presents many further risks to translocated animals. Knowledge of the diet and foraging behaviour of translocated animals is therefore an important consideration of reintroductions. We investigated the diet of the endangered meso-predator, the eastern quoll Dasyurus viverrinus. We also opportunistically observed foraging behaviour, enabling us to examine risks associated with foraging. Sixty captive-bred eastern quolls were reintroduced to an unfenced reserve on mainland Australia (where introduced predators are managed) over a two year period (2018, 2019). Quolls were supplementary fed macropod meat but were also able to forage freely. Dietary analysis of scats (n = 56) revealed that quolls ate macropods, small mammals, birds, invertebrates, fish, reptiles and frogs, with some between-year differences in the frequency of different diet categories. We also observed quolls hunting live prey. Quolls utilised supplementary feeding stations, indicating that this may be an important strategy during the establishment phase. Our study demonstrated that, in a novel environment, captive-bred quolls were able to locate food and hunt live prey. However, foraging was not without risks; with the ingestion of toxic substances and foraging in dangerous environments found to be potentially harmful. Knowledge of the diet of reintroduced fauna in natural landscapes is important for understanding foraging behaviour and evaluating habitat suitability for future translocations and management.

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Jolly, Chris J., Jonathan K. Webb, Graeme R. Gillespie, and Ben L. Phillips. "Training fails to elicit behavioral change in a marsupial suffering evolutionary loss of antipredator behaviors." Journal of Mammalogy 101, no. 4 (June 16, 2020): 1108–16. http://dx.doi.org/10.1093/jmammal/gyaa060.

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Abstract Attempts to reintroduce threatened species from ex situ populations (zoos or predator-free sanctuaries) regularly fail because of predation. When removed from their natural predators, animals may lose their ability to recognize predators and thus fail to adopt appropriate antipredator behaviors. Recently, northern quolls (Dasyurus hallucatus; Dasyuromorpha: Dasyuridae) conserved on a predator-free “island ark” for 13 generations were found to have no recognition of dingoes, a natural predator with which they had coevolved on mainland Australia for about 8,000 years. A subsequent reintroduction attempt using quolls acquired from this island ark failed due to predation by dingoes. In this study, we tested whether instrumental conditioning could be used to improve predator recognition in captive quolls sourced from a predator-free “island ark.” We used a previously successful scent-recognition assay (a giving-up density experiment) to compare predator-scent recognition of captive-born island animals before and after antipredator training. Our training was delivered by pairing live predators (dingo and domestic dog) with an electrified cage floor in repeat trials such that, when the predators were present, foraging animals would receive a shock. Our training methodology did not result in any discernible change in the ability of quolls to recognize and avoid dingo scent after training. We conclude either that our particular training method was ineffective (though ethically permissible); or that because these quolls appear unable to recognize natural predators, predator recognition may be extremely difficult to impart in a captive setting given ethical constraints. Our results point to the difficulty of reinstating lost behaviors, and to the value of maintaining antipredator behaviors in conservation populations before they are lost.

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Moseby, Katherine E., Melissa A. Jensen, and Jack Tatler. "Dietary flexibility and high predator efficacy facilitate coexistence in a novel predator interaction." Journal of Mammalogy 103, no. 1 (November 26, 2021): 124–35. http://dx.doi.org/10.1093/jmammal/gyab120.

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Abstract Predator diet can be influenced by competition and intraguild predation, leading to resource partitioning and/or avoidance. For sympatric, endemic predators, these processes form as predator species coevolve, facilitating coexistence. However, when novel predator interactions occur, significant dietary overlap could create acute levels of competition leading to intraguild predation and population extinction, or accelerated changes in diet and/or spatial and temporal avoidance. We measured diet, intraguild predation, and spatial and temporal overlap in two predator species in a novel predator interaction: the western quoll (Dasyurus geoffroii), a small, native carnivore reintroduced to semi-arid Australia, and the domestic cat (Felis catus), a larger introduced carnivore already resident at the release site. Both species exhibited high dietary overlap and fed on mammals, reptiles, birds, and invertebrates. Cats included quolls in their diet. Quoll diet was broader (including carrion, bats, and plant material) and flexible, changing significantly with age, sex, and season. Introduced rabbit was the most common prey item recorded for both species (frequency of occurrence = 40–50%). However, quolls consumed rabbits in relation to their availability while rabbit consumption in cats was unrelated to availability suggesting a stronger dependence on rabbit prey. Quoll diet did not change over time since release and they did not spatially or temporally avoid cats. However, cats were significantly spatially associated with rabbits while quolls were not, suggesting higher predation efficacy in quolls possibly due to their smaller body size enabling them to catch rabbits inside warrens. Despite high dietary overlap and intraguild predation, the quoll’s broad and flexible diet and high predation efficacy appeared to assist in facilitating coexistence and reducing competition in this novel predator interaction. This dietary flexibility may be harnessed to improve conservation outcomes: reducing introduced rabbits in our study area could naturally reduce feral cat populations while having less impact on native quolls.

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Uzqueda, Adriana, Scott Burnett, Lorenzo V. Bertola, and Conrad J. Hoskin. "Quantifying range decline and remaining populations of the large marsupial carnivore of Australia’s tropical rainforest." Journal of Mammalogy 101, no. 4 (August 17, 2020): 1021–34. http://dx.doi.org/10.1093/jmammal/gyaa077.

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Abstract Large predators are particularly susceptible to population declines due to large area requirements, low population density, and conflict with humans. Their low density and secretive habits also make it difficult to know the spatial extent, size, and connectivity of populations; declines hence can go unnoticed. Here, we quantified decline in a large marsupial carnivore, the spotted-tailed quoll (Dasyurus maculatus gracilis), endemic to the Wet Tropics rainforest of northeast Australia. We compiled a large database of occurrence records and used species distributional modeling to estimate the distribution in four time periods (Pre-1956, 1956–1975, 1976–1995, 1996–2016) using climate layers and three human-use variables. The most supported variables in the distribution models were climatic, with highly suitable quoll habitat having relatively high precipitation, low temperatures, and a narrow annual range in temperature. Land-use type and road density also influenced quoll distribution in some time periods. The modeling revealed a significant decline in the distribution of D. m. gracilis over the last century, with contraction away from peripheral areas and from large areas of the Atherton Tablelands in the center of the distribution. Tests of the change in patch availability for populations of 20, 50, and 100 individuals revealed a substantial (17–32%) decline in available habitat for all population sizes, with a particular decline (31–40%) in core habitat (i.e., excluding edges). Six remaining populations were defined. Extrapolating capture–recapture density estimates derived from two populations in 2017 suggests these populations are small and range from about 10 to 160 individuals. Our total population estimate sums to 424 individuals, but we outline why this estimate is positively skewed and that the actual population size may be < 300 individuals. Continued decline and apparent absence in areas of highly suitable habitat suggests some threats are not being captured in our models. From our results, we provide management and research recommendations for this enigmatic predator.

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Bennett, JH, WG Breed, DL Hayman, and RM Hope. "Reproductive and Genetic-Studies With a Laboratory Colony of the Dasyurid Marsupial Sminthopsis-Crassicaudata." Australian Journal of Zoology 37, no. 3 (1989): 207. http://dx.doi.org/10.1071/zo9890207.

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The fat-tailed dunnart, Sminthopsis crassicaudata, is a small insectivorous dasyurid (adult weight about 16 g) widely distributed in Australia. A laboratory colony of this marsupial, which has been built up over many years, is providing material for studies of dasyurid reproductive biology and genetics. In the area of reproductive biology, we have found a marked disparity in the age of maturation between the two sexes, and we are currently studying certain aspects of spermatogenesis, sperm transport, fertilisation and early embryonic development. Genetical studies have revealed large differences between the sexes in autosomal linkage values and meiotic chromosome behaviour. In females, we have observed very limited intrachromosomal recombination and this is reflected in the distal localisation of chiasmata on the autosomes. Extreme localisation of chiasmata has not hitherto been found in a mammal, and it will be interesting to see how widely it occurs in other marsupial species. The genetical and cytological findings lead to a number of predictions that are being tested in further experimental work with the colony. Although we have been able to raise litter production to a high level, the very variable and unpredictable nature of male reproductive performance currently limits the wider use of the S. crassicaudata colony. It is clear, however, that this dasyurid has the potential to become a very useful laboratory marsupial and that it will be especially valuable for comparative biomedical studies.

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Blacket, Mark J., Mark Adams, Carey Krajewski, and Michael Westerman. "Genetic variation within the dasyurid marsupial genus Planigale." Australian Journal of Zoology 48, no. 5 (2000): 443. http://dx.doi.org/10.1071/zo00020.

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Genetic variation within the genus Planigale was examined through analyses of 12S rRNA gene sequences and allozymes. The level of genetic divergence between the five currently recognised Planigale species was compared and the magnitude of divergence among populations assessed. This examination of molecular variation within the genus revealed that Planigale contains far more taxonomic diversity than is currently recognised. Specifically, the Pilbara region of Western Australia probably contains two currently unrecognised Planigale species and there is substantial genetic heterogeneity within the widespread species P. maculata. Ambiguity over the status of several genetic and/or morphological forms within the genus indicates that further taxonomic changes are likely to be warranted in the future. This study also demonstrates that the currently accepted geographic ranges of many planigale species require careful re-evaluation and that many specimens in collections are apparently misidentified. This is especially true of P. ingrami, which appears to have a much greater range than is currently recognised, being present in South Australia.

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Renfree, MB, and AM Lewis. "Cleavage in vivo and in vitro in the Marsupial Macropus eugenii." Reproduction, Fertility and Development 8, no. 4 (1996): 725. http://dx.doi.org/10.1071/rd9960725.

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In the tammar wallaby, transport down the oviduct takes less than 24 h after fertilization and a mucoid coat is deposited within a few hours of fertilization, with excess spermatozoa trapped in the mucoid layer. The mucin coat thickens as the zygote passes down the oviduct. A proteinaceous shell is laid down outside the mucin coat in the utero-tubal region of the tract. The fertilized zygote enters the uterus in the pronuclear stage with cleavage proceeding in the uterus. In vivo, the first cleavage takes place two days post coitum (p.c.) (approximately 24 h after ovulation) but the next three cleavage stages may be completed within 24 h (between 48 h and 72 h p.c.). Thus, cell-doubling time appears to be around 8 h for 2-8-cell stages. Cleavage in vitro can occur with, or without, the shell membrane. Cleavage in early embryos of the tammar in vitro is slower than that occurring in vivo, and in vitro there may be a '4-cell block' in early development, as in dasyurids. The pattern of cleavage differs markedly from that of dasyurid marsupials in that there is no extrusion of yolk material from the cells and no separation of the blastomeres during the first cleavage stages to the 8-cell stage. The blastomeres are characterized by numerous vesicular structures and lipid droplets, but no yolk bodies. Polarity is not marked in early cleavage, but by the 8-cell stage polarity has developed with surface microvilli and numerous granular vesicles and mitochondria in the cortical regions at one pole of the cells, but sparse microvilli on the inner surfaces and at the other pole. There are complex intervillous interdigitations of microvilli between cells. However, clear identification of cells as pluriblast or trophoblast cells is not possible up to the 8-cell stage examined. These results demonstrate that this macropodid marsupial has a distinctive pattern of early development which differs from that of Didelphis and of the dasyurid marsupials so far described.

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Cardoso, Maria J., Nick Mooney, Mark D. B. Eldridge, Karen B. Firestone, and William B. Sherwin. "Genetic monitoring reveals significant population structure in eastern quolls: implications for the conservation of a threatened carnivorous marsupial." Australian Mammalogy 36, no. 2 (2014): 169. http://dx.doi.org/10.1071/am13035.

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The eastern quoll (Dasyurus viverrinus), while still relatively abundant in Tasmania, is now threatened by the recently introduced European red fox (Vulpes vulpes). Due to a lack of demographic information on eastern quolls, molecular data become a crucial surrogate to inform the management of the species. The aim of this study was to acquire baseline genetic data for use in current and future conservation strategies. Genetic variation, at seven microsatellite loci, was lower in Tasmanian eastern quolls than in quoll species from the Australian mainland. Within Tasmania, genetic variation was greater in central than peripheral populations, with the lowest levels detected on Bruny Island. Significant genetic population structure, consistent with regional differentiation, appears related to geographic distance among populations. Levels of gene flow appeared moderate, with genetic admixture greatest among central populations. Therefore, eastern quolls from genetically diverse central Tasmanian populations will become an important source for conservation initiatives if widespread declines begin to occur. Ongoing genetic monitoring of existing populations will allow conservation strategies to be adaptive. However, in order for translocations to be successful, managers must not only consider the genetic composition of founding individuals, but also habitat-specific adaptations, disease and threatening processes at translocation sites.

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Frankham, Greta J., Sean Thompson, Sandy Ingleby, Todd Soderquist, and Mark D. B. Eldridge. "Does the ‘extinct’ eastern quoll (Dasyurus viverrinus) persist in Barrington Tops, New South Wales?" Australian Mammalogy 39, no. 2 (2017): 243. http://dx.doi.org/10.1071/am16029.

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The eastern quoll (Dasyurus viverrinus) is believed to be extinct on the Australian mainland, with the last confirmed record in 1963. Recently an eastern quoll specimen was located that had been found in northern Barrington Tops National Park (200 km north of Sydney) in 1989. Partial sequences (~200 bp) of the mitochondrial DNA gene Cytochrome b were obtained from the Barrington Tops specimen and compared with sequences from known mainland and Tasmanian eastern quolls. The genetic data, while limited, are most consistent with the Barrington Tops specimen being derived from the ‘extinct’ mainland eastern quoll population. This suggests that eastern quolls survived for decades longer on the Australian mainland than previously thought and raises the possibility that they may still persist in remote areas such as Barrington Tops.

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Grealy, Alicia, Matthew McDowell, Clancy Retallick, Michael Bunce, and David Peacock. "Novel mitochondrial haplotype of spotted-tailed quoll (Dasyurus maculatus) present on Kangaroo Island (South Australia) prior to extirpation." Holocene 30, no. 1 (September 20, 2019): 136–44. http://dx.doi.org/10.1177/0959683619875805.

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Spotted-tailed quolls ( Dasyurus maculatus) – cat-sized, carnivorous marsupials – occupied Kangaroo Island (KI), South Australia, for over 50,000 years but became locally extinct following European settlement of the island in 1836. As the largest mammalian predator on KI when the Europeans colonised it, spotted-tailed quolls would have played a significant role in maintaining healthy ecosystem function. The reintroduction of spotted-tailed quolls to KI could redress some of these ecological benefits and would establish a refuge population of the species, which is considered endangered by the Australian government. However, before a reintroduction could be considered, the genetic relationship between KI’s spotted-tailed quolls and the currently recognised extant subspecies needs to be established. While subspecies are difficult to differentiate by skeletal morphology, they are genetically distinct. Here, we extracted ancient DNA from five left dentaries excavated from Kelly Hill Cave (KI) that were morphologically identified as D. maculatus. Following genetic confirmation of these identifications, we sequenced a 450-bp region of the mitochondrial D-loop to determine the subspecific genetic affiliation(s) of KI’s D. maculatus, and therefore the subspecies that may be the most appropriate candidate for reintroduction. We find that all five specimens are most closely related to the Tasmanian subspecies, but form a distinct monophyletic clade that may represent a new subspecies. Further research (including genotyping spotted-tailed quoll specimens from mainland South Australia and Western Victoria) is required before decisions are made regarding the sourcing of individuals for reintroduction to KI.

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Spencer, Peter B. S., Simon Sandover, Kimberley Nihill, Celeste H. Wale, Richard A. How, and Lincoln H. Schmitt. "Living in isolation: ecological, demographic and genetic patterns in northern Australia’s top marsupial predator on Koolan Island." Australian Mammalogy 39, no. 1 (2017): 17. http://dx.doi.org/10.1071/am16004.

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Koolan Island supports an abundant population of the threatened northern quoll (Dasyurus hallucatus). We used a mark–release–recapture program that produced 2089 captures from 2009 to 2012 to examine demographic and genetic parameters in this insular population and compare to other localities. Every captured female was either lactating or carrying up to eight young over the breeding season, July–September. Unlike several other populations, males on Koolan Island can survive long after breeding, but never into a second breeding season. Females can survive and reproduce for two successive annual breeding seasons and occasionally survive to a third. There is marked sexual dimorphism but it is less pronounced, and both sexes are smaller than their mainland counterparts. Quolls were recorded moving over 4 km and apparent abundance was far higher on Koolan Island than the mainland. Genetic analyses of nuclear and mitochondrial markers demonstrate a distinctive signature. Koolan island has only 34% of the allelic richness of the entire species, and only 38% of the alleles in Kimberley mainland and near-shore island populations. There is no evidence of recent or long-term population decline. Kimberley island faunas have distinctive demographic and genetic profiles that should be appraised before considering translocations for conservation purposes.

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Ruibal, Monica, Rod Peakall, and Andrew Claridge. "Socio-seasonal changes in scent-marking habits in the carnivorous marsupial Dasyurus maculatus at communal latrines." Australian Journal of Zoology 58, no. 5 (2010): 317. http://dx.doi.org/10.1071/zo10040.

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Scat DNA analyses and monthly monitoring were used to elucidate patterns of latrine use in a free-ranging population of a rare Australian marsupial carnivore, the spotted-tailed quoll (Dasyurus maculatus) Kerr. In all, 132 latrines were identified at large complex outcrops and on bedrock in drainage lines, creeks and rivers at a single woodland site in south-eastern mainland Australia. Annual cyclic variation in scat deposition was found over the two years that latrines were monitored. Peaks in scat deposition on latrines coincided with seasonal social behaviours and differed between sites on outcrops and sites along drainage lines. A marked increase in scat deposition on latrines in drainage lines was recorded during the mating season and at outcrop latrines when females were nursing young. Genetic analyses of scats collected over one breeding season revealed that multiple individuals of both sexes defaecated at latrines. The communal use of latrines during the mating season along with the seasonal patterns of scat deposition demonstrates that latrines are important scent-marking sites that facilitate social communication among individuals of this solitary-living species. The collective evidence indicates that latrines play a major role in aiding reproduction and interindividual spacing.

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Riley, Joanna, Jeff M. Turpin, Matt R. K. Zeale, Brynne Jayatilaka, and Gareth Jones. "Diurnal sheltering preferences and associated conservation management for the endangered sandhill dunnart, Sminthopsis psammophila." Journal of Mammalogy 102, no. 2 (April 1, 2021): 588–602. http://dx.doi.org/10.1093/jmammal/gyab024.

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Abstract Dasyurids are small mammals that can conserve energy and water by using shelters that insulate against extreme conditions, prevent predation, and facilitate torpor. To quantify the diurnal sheltering requirements of a poorly known, endangered dasyurid, the sandhill dunnart, Sminthopsis psammophila, we radiotracked 40 individuals in the Western Australian Great Victoria Desert between 2015 and 2019. We assessed the effect of habitat class (broad habitat features), plot-level (the area surrounding each shelter), and shelter characteristics (e.g., daily temperature ranges), on shelter selection and sheltering habitat preferences. Two hundred and eleven diurnal shelters (mean of 5 ± 3 shelters per individual) were located on 363 shelter days (the number of days each shelter was used), within mature vegetation (mean seral age of 32 ± 12 years postfire). Burrows were used on 77% of shelter days and were typically concealed under mature spinifex, Triodia spp., with stable temperature ranges and northern aspects facing the sun. While many burrows were reused (n = 40 across 175 shelter days), spinifex hummock shelters typically were used for one shelter day and were not insulative against extreme temperatures. However, shallow scrapes within Lepidobolus deserti hummock shelters had thermal advantages and log shelters retained heat and were selected on cooler days. Sminthopsis psammophila requires long-unburned sheltering habitat with mature vegetation. Summer fires in the Great Victoria Desert can be extensive and destroy large areas of land, rendering them a key threat to the species. We conclude that the survey and conservation of S. psammophila requires attention to long-unburned, dense lower stratum swale, sand plain, and dune slope habitats, and the tendency of S. psammophila to burrow allows the species to survive within the extreme conditions of its desert environment.

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Ruibal, Monica, Rod Peakall, Andrew Claridge, and Karen Firestone. "Field-based evaluation of scat DNA methods to estimate population abundance of the spotted-tailed quoll (Dasyurus maculatus), a rare Australian marsupial." Wildlife Research 36, no. 8 (2009): 721. http://dx.doi.org/10.1071/wr09086.

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Context. DNA extracted non-invasively from remotely collected scat samples has been used successfully to enumerate populations of a few endangered mammal species. However, scat DNA surveys relying on scent-marking behaviours need to identify if age- or sex-specific variations or seasonal changes in scat scent-marking patterns affect population estimates. Furthermore, owing to the low quantity and quality of scat DNA, a thorough assessment of the technique is needed when it is applied to different species to ensure that individual identification is reliable. Aims. In the current study, microsatellite genetic profiles derived from 208 remotely collected scats of the spotted-tailed quoll (Dasyurus maculatus), a rare Australian marsupial carnivore, were compared with DNA profiles from tissue of 22 live-trapped individuals from the same study area to critically assess the reliability of the non-invasive method to estimate population abundance. Methods. Scat samples were collected at scent-marking sites over 4 consecutive months (April–July 2005), 7 weeks of which overlapped with the trapping program to allow direct comparisons of population estimates. Key results. Combining a multiple-tubes approach with error checking analyses provided reliable genetic tags and resulted in the detection of the majority of the live-trapped population (18 of 22 individuals). Ten additional individuals not known from trapping were also observed from scat DNA. A longer-term sampling regime was required for scats than for trapping to allow direct detection of a large proportion of the population and to provide a comparable population estimate. Critically, the 4-month scat collection period highlighted the importance of performing scat surveys during the mating season when scat scent marking is more frequent, and to avoid sex and age biases in scat marking patterns. Implications. Non-invasive scat DNA sampling methods that rely on scent-marking behaviours need to consider the duration of the sampling period and temporal differences in behaviours by the sexes and age groups to ensure that meaningful population estimates are achieved.

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Woolley, P. A., N. Guedelha, and J. A. M. Graves. "Anatomy and chromosomes of two intersexual dasyurid marsupials." Reproduction, Fertility and Development 15, no. 5 (2003): 293. http://dx.doi.org/10.1071/rd03045.

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The intersexual phenotypes of marsupials with XXY and XO chromosome constitutions imply that not all sexual dimorphisms are under the control of testicular hormones and, ultimately, the SRY gene on the Y chromosome. It has been hypothesised that there is a gene on the X chromosome that determines whether either a scrotum will form (one copy of the gene) or a pouch with teats (two copies of the gene). Here, we describe the anatomy and chromosomes of two intersexual dasyurid marsupials. One, a Dasyuroides byrnei, had a pouch, but the reproductive tract was essentially male. The other, a Sminthopsis douglasi, had a hemipouch and a hemiscrotum and the reproductive tract was essentially female. The S. douglasi was a mosaic for cells with an apparently normal 2n = 14, XX female karyotype and cells with 2n = 14 plus (usually) two dot-like supernumerary elements 2n = 14, XX + 2B. The D. byrnei cells examined also had a 2n = 14, XX + 2B karyotype. In fibroblasts from the male and female sides of the S. douglasi, it was possible to assign the 2n = 14, XX karyotype to the male side and the 2n = 14, XX + 2B to the female side.

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Krajewski, Carey, Roberta Torunsky, Justin T. Sipiorski, and Michael Westerman. "Phylogenetic Relationships of the Dasyurid Marsupial Genus Murexia." Journal of Mammalogy 88, no. 3 (June 2007): 696–705. http://dx.doi.org/10.1644/06-mamm-a-310r.1.

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Foster, W. K., and D. A. Taggart. "Generation of sex ratio biases in the red-tailed phascogale (Phascogale calura)." Reproduction, Fertility and Development 20, no. 2 (2008): 275. http://dx.doi.org/10.1071/rd07031.

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Male semelparous dasyurid species are annual breeders that use a promiscuous mating system. These species have shown biases in litter sex ratios and, with females producing more young than they have available teats, this provides an opportunity for the manipulation of the sex ratio at birth. The sex ratio of embryos and pouch young, and the degree of embryonic overproduction, in red-tailed phascogales (Phascogale calura) was investigated to gain an understanding of the mechanism by which sex biases may be generated. The sex ratio of embryos did not differ from parity, but a male bias was observed in young attaching to teats. Females produced an average of 15.1 ± 1.9 corpora lutea and 10.5 ± 3.5 viable embryos, with no difference in fecundity observed with female age or weight. Because females only have eight teats, the overproduction of young, and male-biased attachment, was sufficient to explain the observed male bias in pouch young. No relationship was observed between maternal weight and sex ratio, but heavier females did tend to produce more ova. Meta-analysis of studies providing information on litter sex ratios in male semelparous dasyurid species did not show any consistent trend.

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Parrott, Marissa L., Simon J. Ward, Peter D. Temple-Smith, and Lynne Selwood. "Females Choose Mates Based on Genetic Relatedness in a Small Dasyurid Marsupial, the Agile Antechinus (Antechinus agilis)." PLOS ONE 10, no. 4 (April 29, 2015): e0122381. http://dx.doi.org/10.1371/journal.pone.0122381.

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30

Blacket, Mark J., Carey Krajewski, Agatha Labrinidis, Brian Cambron, Steven Cooper, and Michael Westerman. "Systematic Relationships within the Dasyurid Marsupial Tribe Sminthopsini—A Multigene Approach." Molecular Phylogenetics and Evolution 12, no. 2 (July 1999): 140–55. http://dx.doi.org/10.1006/mpev.1998.0604.

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31

De Leo, A. A., D. Wheeler, C. Lefevre, J. F. Cheng, R. Hope, J. Kuliwaba, K. R. Nicholas, M. Westerman, and J. A. M. Graves. "Sequencing and mapping hemoglobin gene clusters in the Australian model dasyurid marsupial Sminthopsis macroura." Cytogenetic and Genome Research 108, no. 4 (December 13, 2004): 333–41. http://dx.doi.org/10.1159/000081528.

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32

Westerman, Michael, Mark J. Blacket, Ashley Hintz, Kyle Armstrong, Patricia A. Woolley, and Carey Krajewski. "A plethora of planigales: genetic variability and cryptic species in a genus of dasyurid marsupials from northern Australia." Australian Journal of Zoology 64, no. 5 (2016): 303. http://dx.doi.org/10.1071/zo16052.

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Multiple mitochondrial and nuclear gene sequences reveal substantial genetic variation within the dasyurid marsupial genus Planigale, suggesting greater taxonomic diversity than is currently recognised. To further investigate planigale relationships 116 new mitochondrial and nuclear gene sequences, including 16 new specimens, were added to our database. We confirm the presence of an unrecognised species (Planigale ‘species 1’) limited to the Pilbara region of Western Australia and suggest that the ‘Mt Tom Price’ animals may be closely related to Planigale ingrami subtilissima. We also confirm that at least four distinct genetic lineages make up what is currently recognised as P. maculata. This complex of closely related taxa represents a radiation of sibling species rather than a single, genetically diverse one. Three of these lineages (M1 + M2, M3 and M4) are distributed sympatrically across the Top End of Australia and one (M5 = P. maculata sensu stricto) is localised to the eastern coast of Australia. Within the Planigale ingrami complex, Planigale ‘Mt Tom Price’ (lineage Ing. 1) occurs in the Pilbara in sympatry with Planigale ‘species 1’ and lineage Ing. 2 is found in the Northern Territory in sympatry with species of the P. maculata complex. There is thus a plethora of northern Australian planigales, many of which are formally undescribed and whose geographic ranges require careful re-evaluation.

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Czarny, N. A., M. S. Harris, and J. C. Rodger. "Dissociation and preservation of preantral follicles and immature oocytes from female dasyurid marsupials." Reproduction, Fertility and Development 21, no. 5 (2009): 640. http://dx.doi.org/10.1071/rd08303.

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The mammalian ovary contains numerous immature preantral follicles that are not dependent on endocrine support, unlike the more mature hormone-dependant antral follicles. Preantral follicles can be enzymatically dissociated to yield immature oocytes that survive sub-zero preservation better as they lack a temperature-sensitive meiotic spindle. These techniques are highly applicable to gamete banking, which is an urgent requirement for Australian carnivorous marsupials as several species have rapidly declining populations and risk extinction. The present study developed protocols for the transport, dissociation, preservation and culture of granulosa cell-oocyte complexes (GOC) from the ovaries of dasyurid marsupials. High viability of GOC following enzymatic dissociation is reported and it was demonstrated that GOC are of significantly better quality following refrigerated storage for 24 h compared with storage at room temperature. Oocytes from primary follicles were not damaged by cold shock or the toxicity of vitrification media and following vitrification in liquid nitrogen 69.42 ± 2.44% of oocytes were viable. However, the surrounding granulosa cells demonstrated significant damage post-thaw. These granulosa cells proliferated during a 48-h culture period resulting in significant improvements in GOC quality. The present study is a valuable step towards cryostorage of dasyurid gametes and represents fundamentally important methods by which we can contribute to the conservation of Australia’s native predators.

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Breed, W. G., and C. M. Leigh. "Morphological observations on sperm-egg interactions during in vivo fertilization in the dasyurid marsupialSminthopsis crassicaudata." Gamete Research 19, no. 2 (February 1988): 131–49. http://dx.doi.org/10.1002/mrd.1120190204.

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Mills, H. R., and P. B. S. Spencer. "Polymorphic microsatellites identified in an endangered dasyurid marsupial, the dibbler (Parantechinus apicalis)." Molecular Ecology Notes 3, no. 2 (June 2003): 218–20. http://dx.doi.org/10.1046/j.1471-8286.2003.00403.x.

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Krajewski, Carey, Mark Blacket, Larry Buckley, and Michael Westerman. "A Multigene Assessment of Phylogenetic Relationships within the Dasyurid Marsupial Subfamily Sminthopsinae." Molecular Phylogenetics and Evolution 8, no. 2 (October 1997): 236–48. http://dx.doi.org/10.1006/mpev.1997.0421.

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37

Umbrello, Linette S., Raphael K. Didham, Ric A. How, and Joel A. Huey. "Multi-Species Phylogeography of Arid-Zone Sminthopsinae (Marsupialia: Dasyuridae) Reveals Evidence of Refugia and Population Expansion in Response to Quaternary Change." Genes 11, no. 9 (August 20, 2020): 963. http://dx.doi.org/10.3390/genes11090963.

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Historical population contraction and expansion events associated with Pleistocene climate change are important drivers of intraspecific population structure in Australian arid-zone species. We compared phylogeographic patterns among arid-adapted Dasyuridae (Sminthopsis and Planigale) with close phylogenetic relationships and similar ecological roles to investigate the drivers of phylogeographic structuring and the importance of historical refugia. We generated haplotype networks for two mitochondrial (control region and cytochrome b) and one nuclear (omega-globin) gene from samples distributed across each species range. We used ΦST to test for a genetic population structure associated with the four Pilbara subregions, and we used expansion statistics and Bayesian coalescent skyline analysis to test for signals of historical population expansion and the timing of such events. Significant population structure associated with the Pilbara and subregions was detected in the mitochondrial data for most species, but not with the nuclear data. Evidence of population expansion was detected for all species, and it likely began during the mid-late Pleistocene. The timing of population expansion suggests that these species responded favorably to the increased availability of arid habitats during the mid-late Pleistocene, which is when previously patchy habitats became more widespread. We interpret our results to indicate that the Pilbara region could have acted as a refugium for small dasyurids.

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De Leo, A. A., C. Lefevre, D. Topcic, E. Pharo, J. F. Cheng, P. Frappell, M. Westerman, J. A. M. Graves, and K. R. Nicholas. "Characterization of two whey protein genes in the Australian dasyurid marsupial, the stripe-faced dunnart (Sminthopsis macroura)." Cytogenetic and Genome Research 115, no. 1 (2006): 62–69. http://dx.doi.org/10.1159/000094802.

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39

Selwood, L. "The blastocyst epithelium is not a protoderm in dasyurid marsupials: a review of the evidence." Reproduction, Fertility and Development 8, no. 4 (1996): 711. http://dx.doi.org/10.1071/rd9960711.

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Evidence from studies of cleavage and blastocysts in dasyurids in reviewed to show that the unilaminar blastocyst is not a protoderm but consists of two cell types. Cleavage and blastocyst formation in marsupials has been most comprehensively studied in dasyurids, in which the secondary oocyte and zygote are polarized with respect to the position of the nucleus, cytoskeletal elements and cytoplasmic vesicles. Polarity is reinforced by fertilization. Early cleavage divisions are associated with the polarized elimination of a yolk mass and many vesicular structures into the perivitelline space. Because secretion of the vesicular structures, of which several types are found, facilitate blastomere-zona then blastomere-blastomere associations during cleavage, a unilaminar blastocyst forms without an intervening morula stage. Polarization of the cleavage cavity is related to the appearance of two cell lineages, pluriblast and trophoblast, at the 16-cell stage. In species in which the yolk mass persists, the tier of eight cells lying nearest the yolk mass forms the pluriblast (future embryonic and extra-embryonic lineages), and the other tier forms the trophoblast (future extra-embryonic ectoderm of the yolk sac). Thus, the unilaminar blastocyst epithelium is not a protoderm. Blastocyst expansion is associated with increased cell numbers mainly in the trophoblast. Pluriblast cells begin to increase just before the appearance of the hypoblast. The two cell populations can be distinguished by ultrastructural and histological features at the end of cleavage. During blastocyst expansion they differ in appearance and behaviour in vitro and in cell-doubling time. Two populations of cells have also been found in cleavage and unilaminar blastocyst stages in other marsupials, such as opossums, brushtail possums and bandicoots.

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Start, A. N., D. Moro, M. Adams, and R. Bencini. "Dunnarts from Boullanger Island: new evidence and reassessment of a taxonomic issue with resource implications." Australian Mammalogy 28, no. 1 (2006): 51. http://dx.doi.org/10.1071/am06006.

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Crowther et al. (1999) described an island population of an Australian dasyurid marsupial, Sminthopsis griseoventer, as a new subspecies on molecular (allozyme) and morphological grounds despite a previously published, contradictory genetic study and evidence of sympatry with its mainland conspecific. The legitimacy of this taxonomic arrangement has implications for the allocation of scarce management resources because the new taxon could be considered 'Critically Endangered'. Samples of the original tissues from which the molecular data cited by Crowther et al. were obtained no longer exist. Therefore, salient components of that work were rerun with fresh tissue and the results used to reassess evidence that the island population warrants recognition as a subspecies. We conclude that neither the molecular nor the morphological data supports differentiation at taxonomic or evolutionarily significant levels. Nevertheless, there is a good case for recognising the island population as an important management unit. This case study emphasises the importance of sound taxonomy determined by macro and molecular characters as a prerequisite to allocating resources for conservation.

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Cruz, YP, A. Yousef, and L. Selwood. "Fate-map analysis of the epiblast of the dasyurid marsupial Sminthopsis macroura (Gould)." Reproduction, Fertility and Development 8, no. 4 (1996): 779. http://dx.doi.org/10.1071/rd9960779.

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Allocation of cells in the marsupial epiblast to embryonic and extra-embryonic domains has to date been studied only histologically. An unresolved issue in marsupial embryology has been the existence of a medullary plate. We re-examined the hypotheses that the medullary plate, or neurectoderm, arises before notochord formation and that the integumentary ectoderm is segregated from the ectoderm after the formation of the medullary plate. By marking epiblast cells in 65 Day-8 embryos of the dasyurid marsupial Sminthopsis macroura, with the lipophilic cell-surface marker, DiI, we demonstrated that the so-called medullary plate contains progenitors of the integumentary ectoderm of the neck, chest, limbs and flank of the embryo. Thus, cell-allocation processes in the epiblast must have segregated the entire complement of embryonic ectoderm in one event, not separate events. It is concluded that the embryonic structure called 'medullary plate' in marsupial embryos is misnamed since, in fact, it consists of both integumentary ectoderm and neurectoderm.

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42

Fletcher, TP. "Luteinizing hormone in the Kowari, Dasyuroides byrnei (Marsupialia:Dasyuridae), during the oestrous cycle and pregnancy, and the effects of gonadectomy in male and female." Reproduction, Fertility and Development 1, no. 1 (1989): 55. http://dx.doi.org/10.1071/rd9890055.

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A heterologous double antibody radioimmunoassay has been validated for measurement of LH in plasma of a dasyurid marsupial. Basal concentrations in the oestrous cycle of female kowaris were in the range of 0.5-2.0 ng NIH-oLH-S19 mL-1. Many animals showed elevated LH concentrations (3.0-12.0 ng mL-1) between 8 and 15 days before oestrous but no pre-ovulatory surge was detected. Gonadectomy resulted in greatly increased concentrations of LH, and decreases in testosterone and progesterone concentrations in male and female respectively. In the female LH values ranged from 10-50 ng mL-1 but in the male LH values were greater than 50 ng mL-1.

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BAKER, ANDREW M., THOMAS Y. MUTTON, and STEVE VAN DYCK. "A new dasyurid marsupial from eastern Queensland, Australia: the Buff-footed Antechinus, Antechinus mysticus sp. nov. (Marsupialia: Dasyuridae)." Zootaxa 3515, no. 1 (October 12, 2012): 1. http://dx.doi.org/10.11646/zootaxa.3515.1.1.

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Antechinus mysticus sp. nov. occurs in coastal Australia, ranging from just north of the Queensland (Qld)/New SouthWales (NSW) border to Mackay (mid-east Qld), and is sympatric with A. flavipes (Waterhouse) and A. subtropicus VanDyck & Crowther in south-east Qld. The new species can be distinguished in the field, having paler feet and tail base thanA. flavipes and a greyish head that merges to buff-yellow on the rump and flanks, compared with the more uniform brownhead and body of A. subtropicus and A. stuartii Macleay. Features of the dentary can also be used for identification: A.mysticus differs from A. flavipes in having smaller molar teeth, from A. subtropicus in having a larger gap between frontand rear palatal vacuities, and from A. stuartii in having a generally broader snout. Here, we present a morphologicalanalysis of the new species in comparison with every member of the genus, including a discussion of genetic structure andbroader evolutionary trends, as well as an identification key to species based on dental characters. It seems likely that theknown geographic range of A. mysticus will expand as taxonomic focus on the genus is concentrated in south-east Queensland and north-east New South Wales.

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Selwood, Lynne. "Embryonic development in culture of two dasyurid marsupials,Sminthopsis crassicaudata (gould) andSminthopsis macroura (spencer), during cleavage and blastocyst formation." Gamete Research 16, no. 4 (April 1987): 355–71. http://dx.doi.org/10.1002/mrd.1120160409.

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Fancourt, Bronwyn A. "Diagnosing species decline: a contextual review of threats,causes and future directions for management and conservation of the eastern quoll." Wildlife Research 43, no. 3 (2016): 197. http://dx.doi.org/10.1071/wr15188.

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Diagnosing the cause of a species’ decline is one of the most challenging tasks faced by conservation practitioners. For a species approaching extinction, it is not possible to go back in time to measure the agents that operated at various stages of the decline. Accordingly, managers are often restricted to measuring factors currently affecting residual populations, which may not be related to factors that operated earlier in the decline, and inferring other mechanisms from different lines of evidence. In this review, I adopt a methodical diagnostic framework to comprehensively evaluate the potential causal factors for the decline of the eastern quoll (Dasyurus viverrinus) in Tasmania, and propose a hypothesis as to the cause of decline. Potential causal agents were gleaned from two key sources: factors implicated in the eastern quoll’s historical demise on the Australian mainland, and factors that changed during the recent period of quoll decline in Tasmania. The three most likely candidate causal agents were investigated over 4 years to evaluate their likely contribution to the decline. Here, I synthesise the findings from this recent research to advance a hypothesis as to the cause of the eastern quoll decline in Tasmania. I suggest that a period of unsuitable weather reduced quoll populations to an unprecedented low abundance, and that populations are now too small to overcome established threat intensities to which they were robust when at higher densities. Residual small populations are inherently more susceptible to demographic, environmental and genetic stochasticity and are unlikely to recover without management intervention. I propose a study design to experimentally test this hypothesis, and outline priority areas for future research and actions to guide in the future management and conservation of the species. This case study illustrates an approach by which practical species conservation problems might be solved and recovery strategies may be better informed, thereby ensuring positive conservation outcomes for threatened species.

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Roberts, CT, and WG Breed. "Variation in ultrastructure of mucoid coat and shell membrane secretion of a dasyurid marsupial." Reproduction, Fertility and Development 8, no. 4 (1996): 645. http://dx.doi.org/10.1071/rd9960645.

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In the dasyurid marsupial Sminthopsis crassicaudata, the shell membrane of cleaving embryos has a compact granular structure but becomes fibrous around blastocysts. Polyclonal antibodies were raised against the extracellular coats, mucoid and shell membrane, of oocytes and early embryos. Immunogold cytochemistry resulted in labelling of secretory granules in the epithelia of both the ampulla and isthmus of the oviduct, although the secretory granules of these two regions differed in their ultrastructural appearance. Those in the ampulla were heterogeneous with areas of varying electron density, whereas those in the isthmus were electron dense and homogeneous. Shell membrane precursors were found in secretory granules in the epithelia of the uterotubal junction and endometrial glands and were electron lucent.

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47

Soon, L. L. L., and W. G. Breed. "Ultrastructure of nuclear condensation and localization of DNA and proteins in spermatozoa of a dasyurid marsupial, Sminthopsis crassicaudata." Molecular Reproduction and Development 43, no. 2 (February 1996): 217–27. http://dx.doi.org/10.1002/(sici)1098-2795(199602)43:2<217::aid-mrd11>3.0.co;2-0.

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Roberts, CT, and WG Breed. "Changes in structure of the trophectoderm of a marsupial in Mid-pregnancy up to the time of implantation." Reproduction, Fertility and Development 8, no. 4 (1996): 797. http://dx.doi.org/10.1071/rd9960797.

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Pre- and peri-implantation embryos of the dasyurid marsupial Sminthopsis crassicaudata were examined for morphological differentiation of the trophectoderm. The cells of unilaminar blastocysts were all squamous and stained intensely with toluidine blue. In bilaminar blastocysts and embryos at the early embryonic-disc stage, the trophectoderm was similar in appearance to, but stained more lightly than, the underlying endoderm. Trophoblast differentiation did not appear to occur until the mesoderm had begun to migrate between the trophoblast and endoderm beyond the embryonic disc. At this stage, trophoblasts had three distinct morphologies: (1) vacuolated, tall and columnar cells in the trilaminar region; (2) large cuboidal cells in the adjacent bilaminar region; and (3) squamous cells in the abembryonic pole of the bilaminar region. These variations in cell structure correlate with differences in subsequent functional activity in these three regions of the yolk sac placenta.

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Ruibal, Monica, Rod Peakall, Andrew Claridge, Andrew Murray, and Karen Firestone. "Advancement to hair-sampling surveys of a medium-sized mammal: DNA-based individual identification and population estimation of a rare Australian marsupial, the spotted-tailed quoll (Dasyurus maculatus)." Wildlife Research 37, no. 1 (2010): 27. http://dx.doi.org/10.1071/wr09087.

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Context. Enumeration of cryptic/rare or widely distributed mammal species is exceedingly difficult for wildlife managers using standard survey methods. Individual identification via non-invasive hair-DNA methods offers great promise in extending the information available from hairs collected to survey for presence/absence of a species. However, surprisingly few wildlife studies have attempted this because of potential limitations with the field method and genetic samples. Aim. The applicability of hair DNA to identify individuals and estimate numbers was assessed for a rare, medium-sized Australian marsupial carnivore, the spotted-tailed quoll (Dasyurus maculatus). Methods. Hair samples were obtained remotely in the field with baited hair-sampling devices (known as handi-glaze hair tubes) that permit multiple visitations by individuals and species. A hierarchical approach developed and applied to the DNA extraction and PCR protocol, based on single and four pooled hairs of each collected sample, was used to assess genotype reliability (cross-species DNA mixing, allelic dropout and false allele errors) and enumerate the local study population. These results were compared against a concurrent live-cage trapping survey that was equivalent in scale and trap density to enable a rigorous evaluation of the efficiency and reliability of the DNA-based hair-sampling technique. Key results. Of the 288 hair devices deployed, 52 (18%) captured spotted-tailed quoll hair and the majority (90%) of these samples provided adequate DNA to genetically profile individuals at 10 microsatellite loci and a sexing marker. The hierarchical approach provided a feasible way to verify whether cross-species DNA mixing had occurred in the pooled-hair DNA extracts by comparing the results against the independent single-hair DNA extract, and assess genotyping reliability of both DNA concentrations. Fewer individuals were detected using hair-sampling (n = 16) than live-trapping (n = 21), despite hair-sampling occurring over a longer period (40 cf. 26 nights). Conclusions. The population-level information gained by the DNA-based technologies adds considerable value to the remote hair-sampling method which up until the present study had been used to detect the presence of medium-sized mammals. Our study demonstrated the utility of the DNA-based hair-sampling method to identify spotted-tailed quoll individuals and for surveying local populations. However, improvements to the hair-sampling method, such as increasing the density of stations or the provision of a food reward, should be considered to enhance sampling efficiency to allow the enumeration of local populations. Implications. The use of remote hair-sampling devices that permit multiple visitations and do not require daily collection can be feasible and reliable to genetically identify individuals when coupled with appropriate strategies. By combining single- and pooled-hair DNA extracts, a good compromise between laboratory efficiency and data integrity is afforded.

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Hinds, LA, and L. Selwood. "Plasma progesterone concentrations during pregnancy in the dasyurid marsupial, Antechinus stuartii: relationship with differentiation of the embryo." Reproduction, Fertility and Development 2, no. 1 (1990): 61. http://dx.doi.org/10.1071/rd9900061.

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Antechinus stuartii females were sacrificed at various stages of pregnancy timed from the first day that epithelial cell numbers declined in the urine (day 0). Embryos were recovered and their developmental stage assessed, corpora lutea (CL) were fixed for histological sections and the plasma was taken for progesterone determination. The rate of development of the embryo appeared to parallel the formation of the CL and the plasma progesterone concentrations: cleavage (less than day 6) and the expansion of the unilaminar blastocyst (less than day 14), were periods of slow development, during which the formation of the CL was incomplete and plasma progesterone was low [less than 6 ng mL-1 (19.1 nmol L-1)] though steadily increasing. After day 14 the CL reached its maximum size and plasma progesterone was maximally elevated [greater than or equal to 15 ng mL-1 (47.7 nmol L-1)] until parturition on day 27. Rapid differentiation and growth of the embryo occurred between day 22 and day 27.

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Journal articles on the topic 'Dasyurus Genetics'

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