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Journal articles on the topic 'Marsupials'
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1
SOUZA ROCHA, Katarine de, Gleiciane SCHUPP DE SENA MESQUITA, Maeli Fernanda SILVA FERREIRA, Flávia de Nazaré LEITE BARROS, Renata Cecília Soares de Lima MACEDO, Elane de ARAÚJO SARAIVA, Ana Cristina MENDES-OLIVEIRA, et al. "New records of Leptospira spp. in wild marsupials and a rodent in the eastern Brazilian Amazon through PCR detection." Acta Amazonica 50, no. 4 (December 2020): 305–8. http://dx.doi.org/10.1590/1809-4392201903683.
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ABSTRACT We analyzed the presence of Leptospira spp. in liver and kidney tissue of wild marsupials and rodents trapped in a periurban forest in the eastern Brazilian Amazon. We examined 25 individuals of four marsupial and seven rodent species for the presence of the 16S rRNA gene of Leptospira in the DNA extracted from 47 liver and kidney tissue samples using PCR. We detected positive samples in 12% (3/25) of the individuals, in kidney fragments of two marsupial species (Didelphis marsupialis and Marmosops pinheiroi) and in a liver fragment of one rodent species (Echimys chrysurus). These are the first records of Leptospira spp. in M. pinheiroi and E. chrysurus and it is the first molecular survey of marsupials and rodents in the Brazilian Amazon.
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Cifelli, Richard L., and Christian De Muizon. "Marsupial mammal from the Upper Cretaceous North Horn Formation, Central Utah." Journal of Paleontology 72, no. 3 (May 1998): 532–37. http://dx.doi.org/10.1017/s0022336000024306.
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Little is known of the non-dinosaurian fauna from the Cretaceous (Maastrichtian) part of the North Horn Formation, despite its biogeographic importance. Herein we describe a new marsupial mammal from the unit, founded on an exceptionally complete specimen of a juvenile individual, and present new information on the incisor region of early marsupials, based on comparison with complete specimens from the early Paleocene of Bolivia. Alphadon eatoni, new species, is the smallest Lancian species of the genus, and departs from a presumed marsupial morphotype in having the second lower incisor enlarged. The species is, however, primitive in lacking a “staggered” pattern to the incisor series and in having a labial mandibular foramen, and in these respects it differs from Paleocene and later marsupials. Poor representation of other taxa precludes meaningful comparison to most other North American Cretaceous marsupials, although Eodelphis, thought to be distantly related, also has an enlarged i2. Although Alphadon is characterized by many primitive features, the relative development of the incisors is not what would be predicted in a morphological antecedent to later Marsupialia.
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J. Foley, William. "Marsupial Nutrition." Pacific Conservation Biology 5, no. 3 (1999): 240. http://dx.doi.org/10.1071/pc99240a.
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In the early 1980s advances in marsupial biology could no longer be encapsulated in a single volume such as Hugh Tyndale-Biscoe's "Life of Marsupials" and Cambridge University Press commissioned a series of monographs covering a range of different topics in marsupial biology. As it was, only three of that series were realized and among them was the ptedecessor to this book "Digestive Physiology and Nutrition of Marsupials" published in 1982. "Marsupial Nutrition" is a considerably expanded and comprehensive review of studies of nutrition and digestive physiology of Australasian and South American marsupials. In Australia, many ecologists view the limited nutrient status of our soils and vegetation as a fundamental limit to animal populations. This book explains firstly how Australian marsupials have responded to those limitations and secondly asks whether these responses are common amongst marsupials living in New Guinea and South America.
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Kirsch, John A. W., Mark S. Springer, and François-Joseph Lapointe. "DNA-hybridisation Studies of Marsupials and their Implications for Metatherian Classification." Australian Journal of Zoology 45, no. 3 (1997): 211. http://dx.doi.org/10.1071/zo96030.
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We review past DNA-hybridisation studies of marsupials and present a reanalysis of the data, utilising results from our and additional studies to formulate and rationalise a new classification of Marsupialia. In the reanalysis, 13 individual DNA-hybridisation matrices, many lacking some pairwise comparisons, were sutured in stages to provide the basis for generating a tree of 101 marsupials plus an outgroup eutherian; a fourteenth matrix provided data for a tree including eight additional eutherians and a monotreme. Validation was achieved by jackknifing on taxa for each matrix as well as on tables combining two or more matrices generated during assembly of the 102-taxon data set. The results are consistent with most conclusions from the individual studies and dramatise the unevenness of hierarchical levels in current classifications of marsupials. In particular, the affinities of the American marsupial Dromiciops gliroides with, and the distinctness of marsupial bandicoots from, Australasian metatherians are reaffirmed, while opossums are shown to be as internally divergent as are most members of the order Diprotodontia. Calibration of the 102-taxon tree and dating of the major dichotomies suggest that no extant marsupial lineage originated before the latest Cretaceous, and that all of them together with most South American and all Australasian fossils should be recognised as a monophyletic group contrasting with a largely Laurasian (if possibly paraphyletic) taxon. These inferences, together with the details of the phylogeny, mandate that the misleading ‘Australian’ v. ‘American’ distinction be abandoned, even as a geographic convenience.
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Tyndale-Biscoe, C. H. "Australasian marsupials - to cherish and to hold." Reproduction, Fertility and Development 13, no. 8 (2001): 477. http://dx.doi.org/10.1071/rd01079.
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Considerable interchange of mammals between South America and Australasia occurred during the first half of the Tertiary, including the presence of placental mammals in Australia. This challenges the old assumption that the marsupial radiation in Australia was made possible by the absence of placental competition, and suggests that two properties of marsupial organization may have favoured their survival in the increasingly arid climates that developed after the separation of Australasia from Antarctica. The basal metabolic rates of marsupials are about 70% of equivalent placentals, so their maintenance requirements for energy, nitrogen and water are lower, whereas their field metabolic rates are about the same, which means that they have a greater metabolic scope to call on when active. This may have given marsupials an advantage in semi-arid environments. The lengthy and complex lactation of marsupials enables the female to exploit limited resources over an extended period without compromising the survival of the young. Both these properties of marsupials enabled them to survive the double constraints of low fertility soils and the uncertain climate of Australia throughout the Tertiary. The arrival of people was followed first by the extinction of the large marsupials and, much later, by the wholesale decline or extinction of the small-to-medium sized species. The common factor in both extinctions may have been the constraints of marsupial reproduction.
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Cockburn, A. "Sex-Ratio Variation in Marsupials." Australian Journal of Zoology 37, no. 3 (1989): 467. http://dx.doi.org/10.1071/zo9890467.
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Many marsupials produce sex ratios biased towards male or female young. In several cases these changes are comfortably accommodated in the existing theory of sex allocation. Local resource competition and the Trivers-Willard hypothesis have been usefully applied to several data sets, and preliminary experimental work has supported the main tenets of theory. By contrast, several data sets lack explanation, and provide challenges to theoreticians. The high frequency of bias in marsupials does not result from data-dredging, as bias is usually reported in descriptive accounts of marsupial reproduction, without recourse to any theoretical or mechanistic explanations. It is not possible to distinguish whether the marsupial mode of reproduction is well suited to manipulate sex allocation, or whether it facilitates measurement of biased sex allocation. As for most eutherians and birds, the mechanism of prenatal sex allocation is unknown for any marsupial. However, the current interest in sex-determining mechanisms in marsupials suggests a profitable avenue for collaboration between geneticists, physiologists and evolutionary ecologists.
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Renfree, Marilyn B. "Society for Reproductive Biology Founders' Lecture 2006 Life in the pouch: womb with a view." Reproduction, Fertility and Development 18, no. 7 (2006): 721. http://dx.doi.org/10.1071/rd06072.
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Marsupials give birth to an undeveloped altricial young after a relatively short gestation period, but have a long and sophisticated lactation with the young usually developing in a pouch. Their viviparous mode of reproduction trades placentation for lactation, exchanging the umbilical cord for the teat. The special adaptations that marsupials have developed provide us with unique insights into the evolution of all mammalian reproduction. Marsupials hold many mammalian reproductive ‘records’, for example they have the shortest known gestation but the longest embryonic diapause, the smallest neonate but the longest sperm. They have contributed to our knowledge of many mammalian reproductive events including embryonic diapause and development, birth behaviour, sex determination, sexual differentiation, lactation and seasonal breeding. Because marsupials have been genetically isolated from eutherian mammals for over 125 million years, sequencing of the genome of two marsupial species has made comparative genomic biology an exciting and important new area of investigation. This review will show how the study of marsupials has widened our understanding of mammalian reproduction and development, highlighting some mechanisms that are so fundamental that they are shared by all today’s marsupial and eutherian mammals.
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Deakin, Janine E. "Marsupial X chromosome inactivation: past, present and future." Australian Journal of Zoology 61, no. 1 (2013): 13. http://dx.doi.org/10.1071/zo12113.
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Marsupial and eutherian mammals inactivate one X chromosome in female somatic cells in what is thought to be a means of compensating for the unbalanced X chromosome dosage between XX females and XY males. The hypothesis of X chromosome inactivation (XCI) was first published by Mary Lyon just over 50 years ago, with the discovery of XCI in marsupials occurring a decade later. However, we are still piecing together the evolutionary origins of this fascinating epigenetic mechanism. From the very first studies on marsupial X inactivation, it was apparent that, although there were some similarities between marsupial and eutherian XCI, there were also some striking differences. For instance, the paternally derived X was found to be preferentially silenced in marsupials, although the silencing was often incomplete, which was in contrast to the random and more tightly controlled inactivation of the X chromosome in eutherians. Many of these earlier studies used isozymes to study the activity of just a few genes in marsupials. The sequencing of several marsupial genomes and the advent of molecular cytogenetic techniques have facilitated more in-depth studies into marsupial X chromosome inactivation and allowed more detailed comparisons of the features of XCI to be made. Several important findings have come from such comparisons, among which is the absence of the XIST gene in marsupials, a non-coding RNA gene with a critical role in eutherian XCI, and the discovery of the marsupial RSX gene, which appears to perform a similar role to XIST. Here I review the history of marsupial XCI studies, the latest advances that have been made and the impact they have had towards unravelling the evolution of XCI in mammals.
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Price, Gilbert J., Kyle J. Ferguson, Gregory E. Webb, Yue-xing Feng, Pennilyn Higgins, Ai Duc Nguyen, Jian-xin Zhao, Renaud Joannes-Boyau, and Julien Louys. "Seasonal migration of marsupial megafauna in Pleistocene Sahul (Australia–New Guinea)." Proceedings of the Royal Society B: Biological Sciences 284, no. 1863 (September 27, 2017): 20170785. http://dx.doi.org/10.1098/rspb.2017.0785.
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Seasonal two-way migration is an ecological phenomenon observed in a wide range of large-bodied placental mammals, but is conspicuously absent in all modern marsupials. Most extant marsupials are typically smaller in body size in comparison to their migratory placental cousins, possibly limiting their potential to undertake long-distance seasonal migrations. But what about earlier, now-extinct giant marsupial megafauna? Here we present new geochemical analyses which show that the largest of the extinct marsupial herbivores, the enormous wombat-like Diprotodon optatum , undertook seasonal, two-way latitudinal migration in eastern Sahul (Pleistocene Australia–New Guinea). Our data infer that this giant marsupial had the potential to perform round-trip journeys of as much as 200 km annually, which is reminiscent of modern East African mammal migrations. These findings provide, to our knowledge, the first evidence for repetitive seasonal migration in any metatherian (including marsupials), living or extinct, and point to an ecological phenomenon absent from the continent since the Late Pleistocene.
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McKenzie, LM, and DW Cooper. "Low MHC class II variability in a marsupial." Reproduction, Fertility and Development 6, no. 6 (1994): 721. http://dx.doi.org/10.1071/rd9940721.
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The major histocompatibility complex (MHC) loci have been shown to be highly polymorphic in most eutherian ('placental') species studied. Several hypotheses have been advanced for the maintenance of this exceptional level of genetic variation, one of which suggests that it is necessary for successful eutherian reproduction. Marsupials (metatherians) and eutherians are the only two groups of viviparous mammals, but their modes of reproduction are quite distinct. Although marsupials have placentae, they are generally shorter lived and less invasive than in eutherians. Other investigations have shown that genetic variation at marsupial MHC class I loci is probably high. Weak or non-existent mixed lymphocyte culture responses previously reported in several marsupial species have suggested a lack of class II variation. Data have therefore been collected on the level of restriction fragment length polymorphism at MHC class II beta-chain encoding loci of a marsupial, Macropus eugenii (the tammar wallaby). This level is shown to be low, between the level of MHC variation found in cheetahs and a population of lions with a restricted genetic base. Attention is drawn to the need to collect more data on the level of class II variability in both eutherians and marsupials, and to the potential of marsupials for understanding the relation, if any, between mode of reproduction and MHC variability.
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Tojima, Sayaka, Hidaka Anetai, Kaito Koike, Saori Anetai, Kounosuke Tokita, Chris Leigh, and Jaliya Kumaratilake. "Gross anatomy of the gluteal and posterior thigh muscles in koalas based on their innervations." PLOS ONE 17, no. 9 (September 14, 2022): e0261805. http://dx.doi.org/10.1371/journal.pone.0261805.
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Morphological and functional comparison of convergently-evolved traits in marsupials and eutherians is an important aspect of studying adaptive divergence in mammals. However, the anatomy of marsupials has been particularly difficult to evaluate for multiple reasons. First, previous studies on marsupial anatomy are often uniformly old and non-exhaustive. Second, muscle identification was historically based on muscle attachment sites, but attachment sites have since been declared insufficient for muscle identification due to extensive interspecific variation. For example, different names have been used for muscles that are now thought to be equivalent among several different species, which causes confusion. Therefore, descriptions of marsupial muscles have been inconsistent among previous studies, and their anatomical knowledge itself needs updating. In this study, the koala was selected as the representative marsupial, in part because koala locomotion may comprise primate (eutherian)-like and marsupial-like mechanics, making it an interesting phylogenetic group for studying adaptive divergence in mammals. Gross dissection of the lower limb muscles (the gluteal and the posterior thigh regions) was performed to permit precise muscle identification. We first resolved discrepancies among previous studies by identifying muscles according to their innervation; this recent, more reliable technique is based on the ontogenetic origin of the muscle, and it allows for comparison with other taxa (i.e., eutherians). We compared our findings with those of other marsupials and arboreal primates and identified traits common to both arboreal primates and marsupials as well as muscle morphological features unique to koalas.
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Cowan, PE. "Changes in milk composition during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia: Phalangeridae)." Reproduction, Fertility and Development 1, no. 4 (1989): 325. http://dx.doi.org/10.1071/rd9890325.
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The milk constituents of Trichosurus vulpecula, a folivorous marsupial, showed marked quantitative and qualitative changes during the course of lactation. The milk produced in the early stages of lactation was dilute, with about 9-13% (w/w) solids during the first 3 weeks, comprising mostly carbohydrate and protein (35-40%). At 20 weeks, about three-quarters of the way through lactation, the milk was much more concentrated, about 28% solids, with lipid the predominant fraction (30-35%), after a marked decline in carbohydrate content (20-25%). Concentrations of the electrolytes sodium and potassium also underwent marked changes. The changes in milk composition of T. vulpecula during the first three-quarters of lactation were similar to those described for a range of herbivorous, insectivorous and carnivorous marsupials. In the last quarter of lactation, however, brushtail possum milk maintained a relatively stable composition, with higher levels of carbohydrate and lower levels of lipid than for other marsupials. There appears to be a uniform pattern of changes in milk composition throughout the Marsupialia over most of lactation, with family differences evident only in the latter stages.
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Sherwin, WB, and ND Murray. "Population and Conservation Genetics of Marsupials." Australian Journal of Zoology 37, no. 3 (1989): 161. http://dx.doi.org/10.1071/zo9890161.
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This article summarises current knowledge of marsupial population genetics, and discusses its relevance to the conservation of marsupial species. It has been suggested that there is much lower genetic variation within marsupial populations than in eutherian mammals. This trend is not evident in the electrophoretic data summarised here. However, genetic differentiation between populations, subspecies, and species of marsupials appears to be slightly lower than comparable values for eutherians. Genetic estimates of migration between populations are scarce at present, but show values that are comparable with eutherians. Some studies of marsupial population genetics have used non-electrophoretic characteristics, or have addressed the possibility of selection on the characters analysed. Although few, these studies indicate the suitability of marsupials for such investigations. Recent debate over the theories and applications of conservation genetics has made it clear that more research is required on individual species. Given the record of extinction of marsupials in the last 200 years, it is important to test the applicability of these theories to individual marsupial species. Several examples are discussed emphasising the need for ecological studies that estimate the effective number of reproducing individuals per generation. This figure, called the effective size, is the corner- stone of conservation genetics theory, being an important determinant of both the rate of loss of variation between individuals, and the rate of inbreeding. The effective size of the mainland population of the eastern barred bandicoot, Perameles gunnii, appears to be only about one-tenth of its census number. This result is comparable with estimates made in other vertebrates, and demonstrates that many marsupial species which appear to have an adequate census size on ecological grounds may face genetic problems resulting from small effective size.
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Moore, HD. "Gamete biology of the new world marsupial, the grey short-tailed opossum, Monodelphis domestica." Reproduction, Fertility and Development 8, no. 4 (1996): 605. http://dx.doi.org/10.1071/rd9960605.
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Mammalian gametes undergo a series of functional and developmental changes that culminate in fertilization. In order to appreciate the necessity for such complex processes as sperm maturation, capacitation and the intimate sperm-egg interactions leading to gamete fusion, it is important to understand how gametes may have evolved. In this respect, marsupials are particularly relevant since they exhibit features reminiscent of both non-mammalian vertebrates and eutherian mammals. The grey short-tailed opossum, Monodelphis domestica, is a New World marsupial from Brazil. It breeds well under laboratory conditions and is an excellent animal model to investigate marsupial gamete biology. As in other American marsupials, the spermatozoa of the opossum form pairs in the epididymis. Here, a number of studies carried out in this laboratory, related to sperm maturation, capacitation and fertilization in M. domestica, are reviewed and the gamete biology in this species is compared with what is known in other marsupials and eutherian mammals.
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Archibald, J. David. "Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?" Archives of Natural History 39, no. 2 (October 2012): 217–33. http://dx.doi.org/10.3366/anh.2012.0091.
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Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.
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Fehlberg, Hllytchaikra Ferraz, Cássia Matos Ribeiro, Pedro de Alcântara Brito Junior, Bruno César Miranda Oliveira, Camila Albano dos Santos, Martín Roberto del Valle Alvarez, Tatiane Vitor Harvey, and George Rêgo Albuquerque. "Detection of Cryptosporidium spp. and Giardia duodenalis in small wild mammals in northeastern Brazil." PLOS ONE 16, no. 8 (August 16, 2021): e0256199. http://dx.doi.org/10.1371/journal.pone.0256199.
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This study investigated the occurrence of Giardia duodenalis and Cryptosporidium spp. in rodents and marsupials from the Atlantic Forest in southern Bahia, northeastern Brazil. Two hundred and four fecal samples were collected from different forest areas in the municipalities of Ilhéus, Una, Belmonte, and Mascote. Identifications were performed using PCR and nested PCR followed by sequencing of the gdh and tpi genes for G. duodenalis, and the gp60 and Hsp-70 genes for Cryptosporidium. The total frequency of positive PCR samples for both G. duodenalis and Cryptosporidium spp. was 5.4% (11/204). Giardia duodenalis occurred in 2.94% (4/136) of rodents and 2.94% (2/68) of marsupials. The prevalence of Cryptosporidium in rodents and marsupials was 1.47% (2/136) and 4.41% (3/68), respectively. In the areas sampled, the frequency of parasitism was 50% (7/14), while the Mascote region alone had no parasitized animals. The G. duodenalis subgenotype AI was identified in the rodent species Hylaeamys laticeps, Oecomys catherinae, Oligoryzomys nigripes and Akodon cursor, and in the marsupials Gracilinanus agilis and Monodelphis americana. In the rodents Rhipidomys mastacalis, H. laticeps and in the marsupial Marmosa murina the protozoa Cryptosporidium fayeri, Cryptosporidium parvum and Cryptosporidium ubiquitum with subtypes IIa and IVg by the gp60 gene were found. In conclusion, this study provides the genetic characterization of Giardia and Cryptosporidium species and genotypes in rodents and marsupials. And, these findings reinforce that the rodent and marsupial species mentioned above play a role as new hosts for Giardia and Cryptosporidium.
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Gennari, Solange Maria, Maria Halina Ogrzewalska, Herbert Sousa Soares, Danilo Gonçalves Saraiva, Adriano Pinter, Fernanda Aparecida Nieri-Bastos, Marcelo Bahia Labruna, Matias Pablo Juan Szabó, and Jitender Prakash Dubey. "Toxoplasma gondii antibodies in wild rodents and marsupials from the Atlantic Forest, state of São Paulo, Brazil." Revista Brasileira de Parasitologia Veterinária 24, no. 3 (September 2015): 379–82. http://dx.doi.org/10.1590/s1984-29612015045.
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Toxoplasma gondii is a protozoan parasite that infects a large spectrum of warm-blooded animals, including humans. Small rodents and marsupials play an important role in the epidemiology of T. gondii because they are sources of infection for domestic and feral cats. Serum samples from 151 rodents and 48 marsupials, captured in the Atlantic Forest, São Paulo State, southeastern Brazil, were analyzed for the presence of T. gondii antibodies. Antibodies detected by the modified agglutination test (MAT ≥ 25) were found in 8.6% (13/151) of the rodents and 10.4% (5/48) of the marsupials, with titers ranging from 25 to 6400 and from 25 to 3200, respectively for the rodents and marsupials. Three of the eight species of rodents (Akodon spp., Oligoryzomys nigripesand Rattus norvegicus), and one from the four marsupial species (Didelphis aurita) presented positive animals. T. gondii was described for the first time in the rodent Oligoryzomys nigripes.
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Griffiths, M., and N. G. Simms. "Observations on the anatomy of mammary glands in two species of conilurine rodent (Muridae: Hydromyinae) and in an opossum (Marsupialia: Didelphidae)." Australian Mammalogy 16, no. 1 (1993): 9. http://dx.doi.org/10.1071/am93002.
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The pups of Pseudomys nanus and P. australis are attached to their mothers' teats for extended periods of time, analogous to the situation encountered in pouchless marsupials. The structures in the mammary glands involved in facilitating prolonged attachment are different in the two rodent species and both kinds are different from those in marsupial glands including those of Monodelphis domestica, the subject of the present study. In P. nanus, the teats are anchored to postero-ventrally directed, tubular diverticula of the body wall. In P. australis there are no diverticula. However, support for the mammary glands and teats is afforded by the body wall, in the form of two well-developed fan-shaped muscles dorsal to the mammary glands in conjunction with a broad lamina of connective tissue, smooth and striated muscle situated between the skin of the belly and the mammary glands. In M. domestica, the teats are anchored to swathes of striated voluntary muscle, derived from the ilio-marsupialis muscles which pass ventrally through the secretory parenchyma to be inserted onto the bases of the teats. Since this musculature has not been observed in the mammary glands of any eutherians so far studied, nor in those of Monotremata, it is put that it is a character unique to the Marsupialia.
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Burke, Catherine, Delaney Burnard, Adam Polkinghorne, Jonathan Webb, and Wilhelmina Huston. "Cloacal and Ocular Microbiota of the Endangered Australian Northern Quoll." Microorganisms 6, no. 3 (July 12, 2018): 68. http://dx.doi.org/10.3390/microorganisms6030068.
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The Australian northern quoll is an important predatory marsupial carnivore that is currently endangered due to inappropriate fire regimes, predation, and the spread of invasive cane toads. The microbiota of Australian marsupials has not been extensively studied, but is thought to play a role in their health. This study provides an initial characterization of the cloacal microbiota of the northern quoll, as well as other marsupials including possums and kangaroos which were opportunistically sampled. The northern quoll cloaca microbiota was dominated by Enterococcus and Lactobacillus and had a relatively high proportion of members of the Proteobacteria phylum, which has been observed in other carnivorous marsupials. The diversity and structure of the microbiota was not influenced by presence of Chlamydiales which are intracellular bacteria and potential pathogens. The microbiota of the other marsupials was quite varied, which may be related to their health status. Characterization of the northern quoll microbiota will help to better understand the biology of this endangered animal.
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Renfree, M. B., S. R. Frankenberg, and C. Freyer. "054. TROPHOBLAST, PLACENTA AND EARLY EMBRYO: HOW THE MARSUPIAL DEVELOPS." Reproduction, Fertility and Development 22, no. 9 (2010): 15. http://dx.doi.org/10.1071/srb10abs054.
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In marsupials, the blastocyst forms as a single cell layer of cells. The marsupial blastocyst has no inner cell mass, so the 80–100 cell tammar embryo remains in diapause as a unilaminar blastocyst. All marsupials have a unilaminar stage, but what is unusual is that in the tammar the total cessation of cell division and cell metabolism lasts for 11 months each year. Marsupials are placental mammals. The yolk sac forms the definitive placenta up to birth. Only very few marsupials, such as the bandicoot, have a chorio-allantoic placenta, which supplements the placental functions of the yolk sac. However, the understanding how the unilaminar layer of trophoblast cells of the diapausing blastocyst become specified into placental and embryonic tissues has been an ongoing puzzle. To identify genes that do become differentially expressed in tammar development, we targeted the stage of the earliest appearance of the embryonic disc, at which the remainder of the blastocyst is then defined as trophoblast, as well as early cleavage stages. Intriguingly, we found no evidence for early differential expression of the canonical pluripotency genes POU5F1, SOX2 and NANOG, or of CDX2. By contrast, we found overt differential expression of GATA3, the closely related gene GATA2, and FGF4. This expression profile suggests that in the tammar, mechanisms regulating trophoblast- and pluriblast-specific expression of POU5F1, SOX2, NANOG and CDX2 are temporally secondary to those regulating GATA2 & -3 and FGF4 expression. Together, our results may signify the evolution of alternative mechanisms of early lineage specification in marsupials, or alternatively reveal a general hierarchy of signalling mechanisms that are masked in the relatively rapid and ‘compressed’ development of mice. The results of our ongoing study have important implications for understanding not only marsupial stem cells but the early development of all therian mammals.
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Young, Lauren J., Jessica Gurr, Katrina Morris, Sabine Flenady, and Katherine Belov. "Molecular characterisation of Interleukin-2 in two Australian marsupials (the tammar wallaby, Notamacropus eugenii, and the Tasmanian devil, Sarcophilus harrisii) facilitates the development of marsupial-specific immunological reagents." Australian Mammalogy 41, no. 1 (2019): 39. http://dx.doi.org/10.1071/am17027.
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Interleukin-2 (IL-2) is an important regulator of cellular immunity in mammals. For many years, our inability to identify the expression of this cytokine in marsupials hindered our capacity to progress studies in metatherian immunology. Here, we report the use of molecular techniques to characterise the IL-2 gene for the tammar wallaby (Notamacropus eugenii) and the Tasmanian devil (Sarcophilus harrisii), which allowed the prediction of the structure and probable functions of the IL-2 proteins of these species. Deduced marsupial IL-2 proteins show considerable sequence identity to each other and to common brushtail possum (Trichosurus vulpecula) IL-2 (≥65%) but shared only 35% (tammar wallaby) and 32% (Tasmanian devil) identity with human IL-2. This difference means that reagents used to study IL-2 in human and other eutherians are unlikely to cross-react with marsupials. As a key step in furthering our ability to study cellular immune responses in marsupials and, more specifically, the susceptibility of macropodoid marsupials to intracellular pathogens, a polyclonal antibody was designed for the detection and future investigation of tammar wallaby IL-2 protein expression. The molecular data and polyclonal antibody described herein will support our development of gene probes and immunological reagents that will aid studies of infection and disease in marsupials.
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Cruz-Salazar, Bárbara, and Lorena Ruiz-Montoya. "Population viability analysis of common marsupials, Didelphis marsupialis and Didelphis virginiana, in a scenario of constant loss of native vegetation." Mammalia 84, no. 5 (September 25, 2020): 475–82. http://dx.doi.org/10.1515/mammalia-2019-0130.
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AbstractWe studied the population viability of two common marsupials, Didelphis marsupialis and Didelphis virginiana, based on field data and published ecological and genetic information. Using the VORTEX v. 10. 2.6 program, a 100-year simulation was performed with 1000 iterations for five populations of D. marsupialis and six of D. virginiana. A low probability of extinction was observed in both species, particularly for D. virginiana (0.000–0.007). Population size is higher considering a metapopulation dynamics approach versus individual populations for the two marsupials: 498.25 individuals for D. marsupialis and 367.41 individuals for D. virginiana. The estimated mean genetic diversity was high for both D. marsupialis (He = 0.77–0.78) and D. virginiana (He = 0.79–0.82). The survival of both species over time could be expected to increase if a metapopulation dynamics is favored over the coming decades, despite a 1.3% loss rate of forest cover. The monitoring of population size and genetic diversity is highly recommended to validate the trends suggested by the model; this is especially true for D. marsupialis, a species associated with conserved areas that are becoming progressively less abundant. This research provides information on the responses of common mammalian species to environmental changes such as deforestation.
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Robinson, ES, MB Renfree, RV Short, and JL VandeBerg. "Mammary glands in male marsupials. 2. Development of teat primordia in Didelphis virginiana and Monodelphis domestica." Reproduction, Fertility and Development 3, no. 3 (1991): 295. http://dx.doi.org/10.1071/rd9910295.
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Young and adults of both sexes of two didelphid marsupials, Didelphis virginiana and Monodelphis domestica, were examined externally for evidence of mammary gland development. Female young possessed teat numbers typical of adult females (13-15 in D. virginiana; 11-13 in M. domestica). Male young showed variable teat numbers which were always low compared with females, with the majority possessing 2-4 in anterior positions. Teats were also present in adult males of both species, in similar numbers and locations to those of young males. There are no previous reports of the presence of teats in any adult male marsupials. No mammary primordia in males have been recorded at any stage of development in the most thoroughly studied Australian marsupials. Our findings strengthen the view that there is a dichotomy between the two marsupial lineages in the regulation of male mammary gland expression.
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Green, Brian, Jim Merchant, and Keith Newgrain. "Milk Composition in the Eastern Quoll, Dasyurus viverrinus (Marsupialia : Dasyuridae)." Australian Journal of Biological Sciences 40, no. 4 (1987): 379. http://dx.doi.org/10.1071/bi9870379.
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The milk constituents of Dasyurus viverrinus, a carnivorous marsupial, exhibited major quantitative and qualitative changes during the course of lactation. The milk produced in the early stages of lactation was dilute, about 13-16070 (w/w) solids before 3 weeks with carbohydrate representing the major fraction. In the latter stages of lactation the milk was concentrated, around 30% solids, and lipid was the predominant fraction. Palmitic acid was the major fatty acid present in early-stage milk but oleic acid became predominant in milk after 10 weeks post-partum. The changes in milk composition in D. viverrinus were similar to those described for the milks of herbivorous marsupials which therefore suggests that this pattern may be uniform throughout the Marsupialia.
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Sampson, Jordan M., and Robert D. Miller. "Evolution of the Structure and Organization of the Mammalian Immunoglobulin Loci." Journal of Immunology 210, no. 1_Supplement (May 1, 2023): 224.01. http://dx.doi.org/10.4049/jimmunol.210.supp.224.01.
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Abstract There are three extant lineages of mammals: placentals (e.g. humans and mice), marsupials (e.g. kangaroos and opossums), and monotremes (e.g. platypus). Of the three lineages, the marsupials are unusually and uniformly limited in their immunoglobulin heavy chain (IgH) isotype content. All marsupials studied have only one IgM, IgG, IgE, and IgA and lack IgD. Comparatively, there is a greater complexity of IgH isotypes and subclasses in both placentals and monotremes. Marsupials also have a greater complexity in their light (L) chain V genes than IgH chains. Transposable elements (TEs), like retroelements, have been hypothesized to contribute to gene copy variation and genome evolution. Recently, these TEs have been found in the IgH loci. Here we investigate the impact these TEs have on the evolution of marsupial IgH and IgL loci. We have found that some of the TEs in the opossum IgH locus are short and non-functional, potentially contributing to the restriction seen in the locus. Conversely, the TEs in the L chain loci are longer and may explain the differences in complexity in both the V and C regions between the H and L chain loci. Supported by National Science Foundation Award IOS-2103367.
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Koenigswald von, Wighart, and Francisco Goin. "Enamel differentiation in South American marsupials and a comparison of placental and marsupial enamel." Palaeontographica Abteilung A 255, no. 4-6 (January 31, 2000): 129–68. http://dx.doi.org/10.1127/pala/255/2000/129.
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Kumar, Satish, Erica M. De Leon, Jose Granados, Deanne J. Whitworth, and John L. VandeBerg. "Monodelphis domestica Induced Pluripotent Stem Cells Reveal Metatherian Pluripotency Architecture." International Journal of Molecular Sciences 23, no. 20 (October 20, 2022): 12623. http://dx.doi.org/10.3390/ijms232012623.
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Marsupials have been a powerful comparative model to understand mammalian biology. However, because of the unique characteristics of their embryology, marsupial pluripotency architecture remains to be fully understood, and nobody has succeeded in developing embryonic stem cells (ESCs) from any marsupial species. We have developed an integration-free iPSC reprogramming method and established validated iPSCs from two inbred strains of a marsupial, Monodelphis domestica. The monoiPSCs showed a significant (6181 DE-genes) and highly uniform (r2 [95% CI] = 0.973 ± 0.007) resetting of the cellular transcriptome and were similar to eutherian ESCs and iPSCs in their overall transcriptomic profiles. However, monoiPSCs showed unique regulatory architecture of the core pluripotency transcription factors and were more like marsupial epiblasts. Our results suggest that POU5F1 and the splice-variant-specific expression of POU5F3 synergistically regulate the opossum pluripotency gene network. It is plausible that POU5F1, POU5F3 splice variant XM_016427856.1, and SOX2 form a self-regulatory network. NANOG expression, however, was specific to monoiPSCs and epiblasts. Furthermore, POU5F1 was highly expressed in trophectoderm cells, whereas all other pluripotency transcription factors were significantly downregulated, suggesting that the regulatory architecture of core pluripotency genes of marsupials may be distinct from that of eutherians.
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Cooper, DW, PG Johnston, JL Vandeberg, and ES Robinson. "X-Chromosome Inactivation in Marsupials." Australian Journal of Zoology 37, no. 3 (1989): 411. http://dx.doi.org/10.1071/zo9890411.
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Marsupial (metatherian) mammals resemble their eutherian ('placental') counterparts in having inacti- vation of one of the two X chromosomes in the soma and premeiotic germ cells of their females. The marsupial X-inactivation system differs from the eutherian system in two respects: firstly, inactivation occurs for the paternally derived allele, i.e. it is not random, and secondly it is often incomplete. Data are available for four X-linked loci, all controlling enzyme structure: glucose-6- phosphate dehydrogenase (G6PD), phosphoglycerate kinase 1 (PGKl), alpha-galactosidase (GLA) and hypoxanthine phosphoribosyl transferase (HPRT). Both the G6PD and PGKl loci exhibit incomplete X-chromosome inactivation. The pattern of partial expression differs from tissue to tissue and from species to species. One of the two X chromosomes exhibits late replication, even in cells where a paternally derived gene is partly active, showing that late replication and absence of transcription are not completely correlated. Sex chromatin bodies are not as easily found as in some eutherians. In marsupials they are most clearly demonstrable in species with small Y chromosomes. Investigations into X-inactivation in early development have just begun. Absence of inactivation at the G6PD locus in yolk sac of a kangaroo has been observed. All other tissues exhibited complete paternal X-inacti- vation for G6PD. In a dasyurid, GLA showed complete paternal X-inactivation in all embryonic and extra-embryonic tissues. The role, if any, of methylation of cytosine residues in CpG pairs in the maintenance of X-inactivation in marsupials is unclear. Preliminary evidence indicates that sex-specific differences in methylation of sex linked genes do exist in marsupials.
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Pevsner, Spencer K., David M. Grossnickle, and Zhe-Xi Luo. "The functional diversity of marsupial limbs is influenced by both ecology and developmental constraint." Biological Journal of the Linnean Society 135, no. 3 (January 4, 2022): 569–85. http://dx.doi.org/10.1093/biolinnean/blab168.
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Abstract Extant marsupials are less ecologically diverse than placentals, and this is reflected by placentals exhibiting a greater diversity of locomotor modes, including powered flight and fully aquatic swimming. One proposed explanation for this discrepancy is that the development of more disparate marsupial forelimbs is prevented by the neonate’s crawl to the pouch, which requires precocious forelimb development for climbing adaptations. To test predictions of this Developmental Constraint Hypothesis (DCH), we pursue a comparative morphometric study on osteological traits of mammalian limbs, with an emphasis on functional differentiation of marsupial limbs among locomotor modes. We apply multivariate analyses to a large dataset of limb metrics and a diverse sample of mammals, with the placental sample limited to taxa whose locomotor modes are exhibited in marsupials. Overall, we do not find consistent evidence in support of the DCH. Diprotodontia serves as an exception, with comparisons of their forelimbs to hind limbs supporting the DCH. Our results suggest that developmental constraints on marsupial forelimbs may have limited marsupial diversity to some degree. Despite this, the marsupial locomotor groups show unexpectedly high levels of morphological differentiation relative to placentals of the same locomotor modes, indicating that ecological functions may overcome developmental constraints on a macroevolutionary scale.
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Deakin, Janine E., and Sally Potter. "Marsupial chromosomics: bridging the gap between genomes and chromosomes." Reproduction, Fertility and Development 31, no. 7 (2019): 1189. http://dx.doi.org/10.1071/rd18201.
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Marsupials have unique features that make them particularly interesting to study, and sequencing of marsupial genomes is helping to understand their evolution. A decade ago, it was a huge feat to sequence the first marsupial genome. Now, the advances in sequencing technology have made the sequencing of many more marsupial genomes possible. However, the DNA sequence is only one component of the structures it is packaged into: chromosomes. Knowing the arrangement of the DNA sequence on each chromosome is essential for a genome assembly to be used to its full potential. The importance of combining sequence information with cytogenetics has previously been demonstrated for rapidly evolving regions of the genome, such as the sex chromosomes, as well as for reconstructing the ancestral marsupial karyotype and understanding the chromosome rearrangements involved in the Tasmanian devil facial tumour disease. Despite the recent advances in sequencing technology assisting in genome assembly, physical anchoring of the sequence to chromosomes is required to achieve a chromosome-level assembly. Once chromosome-level assemblies are achieved for more marsupials, we will be able to investigate changes in the packaging and interactions between chromosomes to gain an understanding of the role genome architecture has played during marsupial evolution.
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Soares, Manoel do Carmo P., Gilberta Bensabath, and Amélia P. A. Travassos da Rosa. "The presence of antibodies for hepatitis a virus in amazonia Didelphis marsupialis (Vertebrata, Marsupialia)." Revista do Instituto de Medicina Tropical de São Paulo 29, no. 2 (April 1987): 110–11. http://dx.doi.org/10.1590/s0036-46651987000200008.
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Anti-HAV was detected by enzyme - immunoassay in sera collected from 6 (18,75%) of 32 Didelphis marsupialis trapped in the Amazon region. No anti-HAV were found in the sera from 136 other wild animals, including small rodents, reptiles and other marsupials.
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Rodger, JC. "Prospects for the Artificial Manipulation of Marsupial Reproduction and Its Application in Research and Conservation." Australian Journal of Zoology 37, no. 3 (1989): 249. http://dx.doi.org/10.1071/zo9890249.
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Techniques to manipulate reproduction and productivity are well established features of the husbandry of domestic animals and the treatment of human infertility. Similar approaches are feasible in marsupials, but little work has been done to apply our considerable basic knowledge of marsupial reproduction to produce practical artificial breeding. If the reproduction and productivity of marsupials could be more effectively controlled it would greatly aid research and profoundly change both current practice in the management of zoo animals, and the strategies employed for the breeding and conservation of rare or endangered species. The present paper sets out the likely agenda, reports progress to date and discusses short and long-term prospects for the artificial breeding of marsupials. Topics discussed include: induced ovulation and superovulation, oocyte and embryo collection, semen collection and the frozen storage of sperm, artificial insemination, in vitro fertilization and embryo transfer, frozen storage of embryos, and the use of surrogate mothers in supporting both pregnancy to term, and the development of young in the pouch.
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Graves, Jennifer A. Marshall. "Kangaroo gene mapping and sequencing: insights into mammalian genome evolution." Australian Journal of Zoology 61, no. 1 (2013): 4. http://dx.doi.org/10.1071/zo13002.
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The deep divergence of marsupials and eutherian mammals 160 million years ago provides genetic variation to explore the evolution of DNA sequence, gene arrangement and regulation of gene expression in mammals. Following the pioneering work of Professor Desmond W. Cooper, emerging techniques in cytogenetics and molecular biology have been adapted to characterise the genomes of kangaroos and other marsupials. In particular, genetic and genomic work over four decades has shown that marsupial sex chromosomes differ significantly from the eutherian XY chromosome pair in their size, gene content and activity. These differences can be exploited to deduce how mammalian sex chromosomes, sex determination and epigenetic silencing evolved.
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Teta, Pablo, Javier A. Pereira, Emiliano Muschetto, and Natalia Fracassi. "Mammalia, Didelphimorphia, Chiroptera, and Rodentia, Parque Nacional Chaco and Capitán Solari, Chaco province, Argentina." Check List 5, no. 1 (March 1, 2009): 144. http://dx.doi.org/10.15560/5.1.144.
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We studied the small mammal assemblage (bats, marsupials and rodents) of Parque Nacional Chaco and Capitán Solari (Chaco Province, Argentina) based on captures and analysis of owl pellets. Twenty-one species were recorded during a brief survey, including two marsupials, seven bats, and twelve rodents. In addition, we documented the first occurrence of the bat Lasiurus ega in the Chaco Province, and extended to the southwest the distribution of the didelphid marsupial Cryptonanus chacoensis and the oryzomyine rodent Oecomys sp. We also provided a second occurrence site in the ents Calomys laucha and Holochilus brasiliensis. Identified taxa belonged to species that are typical of the Humid Chaco ecoregion of Argentina.
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Colle, Ana Cláudia, Ravena Fernanda Braga de Mendonça, Maerle Oliveira Maia, Leodil da Costa Freitas, Rute Witter, Arlei Marcili, Daniel Moura de Aguiar, et al. "Molecular survey of tick-borne pathogens in small mammals from Brazilian Amazonia." Revista Brasileira de Parasitologia Veterinária 28, no. 4 (December 2019): 592–604. http://dx.doi.org/10.1590/s1984-29612019086.
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Abstract Small non-volant mammals (marsupials and small rodents) were captured at three different timepoints from 23 forest fragments across three municipalities (Alta Floresta, Sinop and Cláudia) covering the Amazonian biome of the Mato Grosso State in Midwestern Brazil. The animal tissues (liver and spleen) and blood were screened using molecular tools for the detection of Babesia, Coxiella, Cytauxzoon, Hepatozoon, Theileria, and Anaplasmataceae agents. A total of 230 specimens (78 rodents and 152 marsupials) were trapped. Hepatozoon and Piroplasmorida agents were detected in the common opossums (Didelphis marsupialis). In turn, all samples (blood, liver, or spleen) collected from the small mammals were negative for the genus Coxiella and the family Anaplasmataceae, as detected by polymerase chain reaction (PCR). Phylogenetic analyses inferred from partial sequences of the 18S rRNA gene highlighted the occurrence of new Hepatozoon and Piroplasmorida haplotypes. Future studies determining the role of common opossum (D. marsupialis) in the epidemiological cycles of Hepatozoon and Babesia under natural conditions in the Amazonian biome are necessary.
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Casartelli, C., S. R. Rogatto, and I. Ferrari. "Cytogenetic analysis of some Brazilian marsupials (Didelphidae: Marsupialia)." Canadian Journal of Genetics and Cytology 28, no. 1 (February 1, 1986): 21–29. http://dx.doi.org/10.1139/g86-005.
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Three species of marsupials from the Amazon region (Marmosa cinerea, Caluromys lanatus, and Didelphis marsupialis) and two from the region of São Paulo (Didelphis marsupialis and Didelphis albiventris) were studied. The G-banding pattern of the species with 2n = 14 (M. cinerea and C. lanatus) was very similar, as well as the pattern of G-bands in the species with 22 chromosomes (Didelphis). All of the autosomes of M. cinerea and D. albiventris have centromeric C-bands and the Y chromosome is totally C-band positive. The long arm of the M. cinerea X chromosome is completely C-band positive except for a negative band close to the centromeric region. In D. albiventris the long arm of the X chromosome is C-band positive except for a negative band close to the telomeric region. In M. cinerea the silver-stained nucleolar organizer regions (Ag-NORs) are found in the acrocentric chromosomes, being located in the telomeric region of one pair and in the centromeric region of the other pair. Caluromys lanatus has centromeric Ag-NORs in one acrocentric and in one submetacentric chromosome pairs. Didelphis marsupialis has three chromosome pairs with telomeric Ag-NORs. In D. albiventris the Ag-NORs are terminal and located in both arms of one pair and in the long arm of two pairs of chromosomes.Key words: cytogenetics, marsupials, chromosomes.
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Jolly, SE, GA Morriss, S. Scobie, and PE Cowan. "Composition of Milk of the Common Brushtail Possum, Trichosurus Vulpecula (Marsupialia: Phalangeridae): Concentrations of Elements." Australian Journal of Zoology 44, no. 5 (1996): 479. http://dx.doi.org/10.1071/zo9960479.
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The concentrations of 11 elements (calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, strontium, sulphur and zinc) were measured in milk samples collected from 193 lactating brushtail possums, Trichosurus vulpecula, at all stages of lactation. Most elements showed patterns of change during lactation similar to those of other marsupials. The most marked changes occurred at about 80-120 days, when the growth rate of the pouch young increased and developmental changes took place, such as eye opening and fur growth. Compared with eutherians, copper and iron concentrations were high in possum milk, as in other marsupials, but zinc levels were exceptionally high. Strontium and manganese levels, not measured before in marsupial milk, were considerably higher than levels reported in eutherian milk. In contrast to eutherian mammals, marsupial young must be supplied with large quantities of minerals in the milk as almost all growth and development occurs after birth, and possum young are entirely dependent on milk supplied by the mother for about the first 100 days.
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Lapointe, FJ, and JAW Kirsch. "Construction And Verification Of A Large Phylogeny Of Marsupials." Australian Mammalogy 23, no. 1 (2001): 9. http://dx.doi.org/10.1071/am01009.
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Much of the controversy over marsupial phylogeny at higher-categorical levels stems from the piecemeal nature of the contributing studies or the paucity of taxonomic representation in many of them. Yet the problems of constructing large phylogenies are manyfold, involving the initial generation of the data as well as their efficient analysis. Often unaddressed, also, is the need to validate extremely large data sets and trees. Many of these problems can be ameliorated by treating the data as distances (or generating distances directly). We show that, contrary to the assertions of many protagonists in the total-evidence versus consensus debate, the validated data and pathlength (tree) matrices usually give very similar results, although a few additional unstable nodes may be found when the results of internal and external validations are themselves combined in a global-congruence test. Here we illustrate our protocols with a 109-taxon data set, representing combination of marsupial DNA-hybridisation data with similar information on a series of outgroups. Phylogenetically, the results affirm the marsupial groupings we have previously found, and suggest but do not unambiguously support a nearer relationship of monotremes than placentals to marsupials. This paper represents the first attempt to validate the tree of 101 marsupials presented earlier.
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PARAMESWARAN, N., R. M. O'HANDLEY, M. E. GRIGG, A. WAYNE, and R. C. A. THOMPSON. "Vertical transmission of Toxoplasma gondii in Australian marsupials." Parasitology 136, no. 9 (June 24, 2009): 939–44. http://dx.doi.org/10.1017/s0031182009006453.
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SUMMARYTo date, little is known about the dynamics of vertical transmission of Toxoplasma gondii in Australian marsupials. Studies in mice demonstrate that vertical transmission of T. gondii is common and that chronically infected mice can transmit T. gondii to successive generations. In this study, PCR and immunohistochemistry were used to detect T. gondii in chronically infected marsupial dams and their offspring. T. gondii was detected in the unfurred pouch young of 2 out of 10 chronically infected western grey kangaroos (Macropus fuliginosus) and in the unfurred pouch young of a brush-tailed bettong (Bettongia penicillata). Results of the study suggest that vertical transmission of T. gondii can occur in chronically infected Australian marsupials.
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Snipes, RL, H. Snipes, and FN Carrick. "Morphometric data on the intestines of five Australian marsupials (Marsupialia)." Australian Mammalogy 25, no. 2 (2003): 193. http://dx.doi.org/10.1071/am03193.
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THE nutritional biology of marsupials has been a subject of numerous studies, culminating in valuable compilations covering a wide range of aspects (Osman Hill and Rewell 1954; Walton and Richardson 1989; Hume 1982, 1999; Kerle 2001). Despite this thorough coverage, there remains a scarcity of morphometric data on the intestines of monotremes and marsupials. In an attempt to approach this need, an effort was initiated to provide morphometric data on monotremes (Snipes et al. 2002) and marsupials (Snipes et al. 1993, 2003).
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Cope, Holly R., Clare McArthur, Rachael Gray, Thomas M. Newsome, Christopher R. Dickman, Aditi Sriram, Ron Haering, and Catherine A. Herbert. "Trends in Rescue and Rehabilitation of Marsupials Surviving the Australian 2019–2020 Bushfires." Animals 14, no. 7 (March 27, 2024): 1019. http://dx.doi.org/10.3390/ani14071019.
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The 2019–2020 Australian bushfire season had a devastating impact on native wildlife. It was estimated that 3 billion native animals were impacted by the fires, yet there are few estimates of the number of animals that were rescued and rehabilitated post-fire. Focusing on the state of New South Wales (NSW) and Kangaroo Island, South Australia, we used a case study approach to determine the number of marsupials that were reported rescued due to the 2019–2020 bushfires in these areas and analysed species-specific trends in rescue and release success. In NSW, we found 889 reports of fire-affected marsupials in 2019–2020, mostly comprising kangaroos and wallabies (macropods; n = 458), koalas (n = 204), and possums (n = 162), with a smaller number of wombats (n = 43) and other marsupial species. Most reports of fire-affected marsupials occurred 6–8 weeks after fire ignition, and there was no difference in temporal frequency of rescues between marsupial groups. For the three main groups, the probability of survival and subsequent release differed, with macropods having the lowest probability of release after rescue (0.15 ± 0.04) compared to koalas (0.47 ± 0.04) and possums (0.55 ± 0.10). The type of injury was the main predictor of survival during rehabilitation for all three marsupial groups, with those malnourished/moribund or with traumatic injuries less likely to survive rehabilitation. Death or euthanasia occurred on the day of rescue for 77% of macropods, 48% of possums and 15% of koalas. Koalas most often died during rehabilitation rather than on the day of rescue, with 73% either dying or being euthanised between day 1 and 30 post-rescue, representing a potential welfare concern. On Kangaroo Island, koalas were the most frequently rescued marsupial species; most euthanasia cases and deaths occurred in a hospital, whereas other marsupials were mostly euthanised at triage. In both jurisdictions, koalas were over-represented while possums were under-represented relative to baseline population densities and wildlife rescue trends in the years before the 2019–2020 bushfires. These species differences in presentation post-fire warrant further investigation, as do the differences in triage, survival and release outcomes. It is hypothesised that the high intensity and large scale of the 2019–2020 fires impeded marsupial fire evasion tactics, as evidenced by the small number of animals found for rescue, and the differing rates of presentation relative to underlying population densities for the main marsupial groups. Based on our findings, there is a need for detailed record keeping and data sharing, development of consistent and evidence-based triage, treatment and euthanasia guidelines and deployment of trained wildlife emergency rescue teams with advanced search techniques to minimise animal suffering where safe to do so.
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Belov, Katherine, Robert D. Miller, Julie M. Old, and Lauren J. Young. "Marsupial immunology bounding ahead." Australian Journal of Zoology 61, no. 1 (2013): 24. http://dx.doi.org/10.1071/zo12111.
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Marsupial immune responses were previously touted as ‘primitive’ but we now know that the marsupial immune system is complex and on par with that of eutherian mammals. In this manuscript we review the field of marsupial immunology, focusing on basic anatomy, developmental immunology, immunogenetics and evolution. We concentrate on advances to our understanding of marsupial immune gene architecture, made possible by the recent sequencing of the opossum, tammar wallaby and Tasmanian devil genomes. Characterisation of immune gene sequences now paves the way for the development of immunological assays that will allow us to more accurately study health and disease in marsupials.
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Rodger, JC. "Prefertilization gamete maturation events in marsupials." Reproduction, Fertility and Development 6, no. 4 (1994): 473. http://dx.doi.org/10.1071/rd9940473.
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Despite many fundamental similarities between the gametes of marsupials and placental mammals, the regulation and timing of prefertilization gamete maturation are quite different. The marsupial acrosome is remarkably stable and an acrosome reaction (AR) is not induced by reagent effective for the sperm of placental mammals. The ultrastructure of the marsupial sperm AR is essentially similar to that of placental mammals, however, whether an equatorial segment (ES) persists to serve as the site of sperm-egg membrane fusion is unclear. Diacylglycerol induction of the AR suggests that the sperm of Australian species lack an ES, yet an ES-like region appears to be involved in fertilization in the opossum Monodelphis. The marsupial oocyte, unlike those of placentals, continues to grow throughout follicular life and major cytoplasmic maturation events occur late in oocyte development. Cortical granules only become evident shortly before ovulation and mature dark granules may only appear after ovulation. Further, the zona pellucida (ZP) changes in character and function during the peri-ovulatory period. In vitro fertilization has been achieved for an opossum but not for any Australian marsupial, owing to failure of sperm-ZP binding. Requirement for a sperm maturation process is likely, but capacitation treatments used for placental sperm in vitro have been ineffective. Since it is now feasible to experimentally manipulate marsupial gametes in vitro major advances in our understanding of their function can be expected.
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Churcher, C. S. "Dental functional morphology in the marsupial sabre-tooth Thylacosmilus atrox (Thylacosmilidae) compared to that of the felid sabre-tooths." Australian Mammalogy 8, no. 4 (October 1, 1985): 201–20. http://dx.doi.org/10.1071/am85020.
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The South American Middle to Late Pliocene fauna of Argentina included the borhyaenid marsupials Thylacosmilus atrox and Notosmilus pattersoni, the latter known only from a single Late Pliocene occurrence. Thylacosmilus atrox has been interpreted as a marsupial with a carnivorous specialisation convergent on the fissipede and machairodont sabre-tooths of Eurasia, Africa and North America. Thylacosmilus atrox superficially resembles placental sabre-tooths in general conformation but also shows remarkable divergences, some of which are attributable to its marsupial ancestry.
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Jastroch, M., K. W. Withers, S. Taudien, P. B. Frappell, M. Helwig, T. Fromme, V. Hirschberg, et al. "Marsupial uncoupling protein 1 sheds light on the evolution of mammalian nonshivering thermogenesis." Physiological Genomics 32, no. 2 (January 2008): 161–69. http://dx.doi.org/10.1152/physiolgenomics.00183.2007.
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Brown adipose tissue expressing uncoupling protein 1 (UCP1) is responsible for adaptive nonshivering thermogenesis giving eutherian mammals crucial advantage to survive the cold. The emergence of this thermogenic organ during mammalian evolution remained unknown as the identification of UCP1 in marsupials failed so far. Here, we unequivocally identify the marsupial UCP1 ortholog in a genomic library of Monodelphis domestica. In South American and Australian marsupials, UCP1 is exclusively expressed in distinct adipose tissue sites and appears to be recruited by cold exposure in the smallest species under investigation ( Sminthopsis crassicaudata). Our data suggest that an archetypal brown adipose tissue was present at least 150 million yr ago allowing early mammals to produce endogenous heat in the cold, without dependence on shivering and locomotor activity.
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Low, BOBBI S. "Marsupials." Science 232, no. 4746 (April 4, 1986): 111.2–112. http://dx.doi.org/10.1126/science.232.4746.111-a.
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MARTIN, JENNY. "Marsupials." Austral Ecology 32, no. 6 (September 2007): 719–20. http://dx.doi.org/10.1111/j.1442-9993.2007.01780.x.
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Rodger, John C. "Likely targets for immunocontraception in marsupials." Reproduction, Fertility and Development 9, no. 1 (1997): 131. http://dx.doi.org/10.1071/r96073.
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There is a growing need to manage marsupial populations as a means to mitigate economic and environmental damage and resolve animal welfare problems. In Australia, the problems of population management are highly specific and localized. In contrast, in New Zealand the problem is the control of the many millions of widely-distributed brushtail possums which are the country’s major vertebrate pest. The needs of the two countries are thus very different but immunocontraception may provide an effective and humane alternative to current lethal control strategies. This paper discusses the features of marsupial reproduction and development that offer potential as targets for immunocontraceptive interference, including: (1) sperm production and maturation in the male; (2) sperm transport and maturation in the female; and (3) sperm and egg antigens and the early embryo. Some of these antigen targets are shared with eutherian mammals but others are likely to be unique to marsupials.
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Hayman, DL. "Marsupial Cytogenetics." Australian Journal of Zoology 37, no. 3 (1989): 331. http://dx.doi.org/10.1071/zo9890331.
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This review includes a list of the chromosome numbers of marsupials and a summary of the main features of chromosome evolution in this group of mammals. Special topics discussed include sex chromosome mosaicism, the size of the marsupial X chromosome, X chromosomes and nucleolar organisers, complex sex chromosome systems, repeated DNA sequences and aspects of meiosis.
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Hetz, Jennifer A., Brandon R. Menzies, Geoffrey Shaw, and Marilyn B. Renfree. "The tammar wallaby: a non-traditional animal model to study growth axis maturation." Reproduction, Fertility and Development 31, no. 7 (2019): 1276. http://dx.doi.org/10.1071/rd18271.
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Maturation of the growth hormone (GH)/insulin-like growth factor 1 (IGF1) axis is a critical developmental event that becomes functional over the peripartum period in precocial eutherian mammals such as sheep. In mice and marsupials that give birth to altricial young, the GH/IGF1 axis matures well after birth, suggesting that functional maturation is associated with developmental stage, not parturition. Recent foster-forward studies in one marsupial, the tammar wallaby (Macropus eugenii), have corroborated this hypothesis. ‘Fostering’ tammar young not only markedly accelerates their development and growth rates, but also affects the timing of maturation of the growth axis compared with normal growing young, providing a novel non-traditional animal model for nutritional manipulation. This review discusses how nutrition affects the maturation of the growth axis in marsupials compared with traditional eutherian animal models.