Journal articles: 'Dasyurid marsupial'

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Luckett, Winter, Nancy Luckett, and Tony Harper. "Initiation and early development of the postcanine deciduous dentition in the dasyurid marsupial Dasyurus viverrinus." Memoirs of Museum Victoria 80 (2021): 93–108. http://dx.doi.org/10.24199/j.mmv.2021.80.03.

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There has been disagreement for more than 100 years concerning the presence or absence of deciduous and successional third premolars in the dentition of the Australian dasyurid marsupial Dasyurus viverrinus as well as in other species of the genus Dasyurus. Most authors during the 19th and 20th centuries have considered the missing premolar in Dasyurus to be the third premolar family in both jaws, in part because of the reduction in size of the third deciduous premolar in many other genera of dasyurids. While other authors, found “the deciduous premolar to be constantly present in the young mammary foetus as a small and precociously calcified vestigial tooth”. However, the fate of this deciduous tooth, and its possible successor in later developmental stages, was never described; and the vestigial dp3 and its possible successor were assumed to undergo absorption during foetal life. With access to later developmental stages of Dasyurus viverrinus, via the extensive collections of Professor J.P. Hill, we present new evidence for the later development of dP3 and P3 in both jaws, the probable eruption of the successional P3 in both jaws and evidence that dP2 is the missing tooth in both jaws of this dasyurid species.

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Westerman, M., and PA Woolley. "Cytogenetics of Some New Guinean Dasyurids and Genome Evolution in the Dasyuridae (Marsupialia)." Australian Journal of Zoology 37, no. 5 (1989): 521. http://dx.doi.org/10.1071/zo9890521.

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Karyotypes have been obtained for ten species of New Guinean dasyurid marsupials. All species have 2n = 14 chromosomes which, except for variation in size and shape of the X chromosome, are similar in morphology, not only between species but also to Australian species. The Y chromosome of all species is punctiform. C- and G-banding procedures have been applied to eight of the species and show (1) there are no major differences between species in amounts of C-band heterochromatin, and (2) the G-band patterns of the autosomes were virtually identical. These findings suggest that there have been no major karyotypic changes accompanying speciation of dasyurids in New Guinea. Since the G-banded karyotypes are also virtually identical to those reported for Australian dasyurids it would appear that this 2n = 14 karyotype probably represents the ancestral dasyurid form which can be derived as a result of a few inversions from an ancestral marsupial karyotype. These changes must have occurred very early in the dasyurid radiation as the) are found in all extant species and genera examined. However, virtually identical G-banded karyotypes may mask major differences in nuclear DNA values.

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Dickman, Christopher R., Aaron C. Greenville, Glenda M. Wardle, and Jenna P. Bytheway. "Class Conflict: Diffuse Competition between Mammalian and Reptilian Predators." Diversity 12, no. 9 (September 15, 2020): 355. http://dx.doi.org/10.3390/d12090355.

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(1) Diffuse competition affects per capita rates of population increase among species that exploit similar resources, and thus can be an important structuring force in ecological communities. Diffuse competition has traditionally been studied within taxonomically similar groups, although distantly related intraguild species are likely also to compete to some degree. (2) We assessed diffuse competition between mammalian and reptilian predators at sites in central Australia over 24 years. Specifically, we investigated the effect of dasyurid marsupial abundance on the diet breadth of three groups of lizards (nocturnal dietary generalists, diurnal dietary generalists and dietary specialists). (3) Nocturnal generalist lizards had progressively narrower diets as dasyurid abundance increased. The diet breadth of diurnal generalist lizards was unaffected by overall dasyurid abundance, but was restricted by that of the largest dasyurid species (Dasycercus blythi). Ant- and termite-specialist lizards were unaffected by dasyurid abundance. (4) Diffuse competition, mediated by interference, between dasyurids and nocturnal generalist lizards appears to have strong effects on these lizards, and is the first such between-class interaction to be described. Diffuse interactions may be widespread in natural communities, and merit further investigation among other disparate taxon groups that occur in the same ecological guilds.

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Hughes, R. Leon. "Structure of the female reproductive tract of an adult parous Tasmanian tiger, Thylacinus cynocephalus." Australian Journal of Zoology 48, no. 5 (2000): 487. http://dx.doi.org/10.1071/zo00022.

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The present observations on the now-extinct Thylacinus are based on the reproductive system of an adult thylacine discovered among the specimens of the Hill collection at the Hubrecht Laboratory in the Netherlands. As in other marsupials, the reproductive tract was characterised by the presence of a uterus duplex and a vaginal complex where the ureters passed dorsally over each lateral vaginal canal to enter the bladder. The lateral vaginal canals each entered a urogenital sinus that terminated in a shallow cloaca. The gross dimensions of the reproductive tract of the thylacine were greater than those of any extant dasyurid marsupial. The distance from the rostral pole of the ovaries to the most caudal extremity of the urogenital sinus measured 25 cm. The distinctive aspects of the reproductive tract included a disproportionate enlargement of the corpus uteri that is without parallel in any other marsupial species. The bodies of the right and left uteri measured 10.4 cm 1.2 cm 0.9 cm and 9.1 cm 0.8 cm 0.7 cm respectively. The rostro-caudal length of the right and left cervices measured 2.7 cm and 1.7 cm respectively. The cervical canals entered the vaginal complex by way of a thick median vaginal septum. The elongated caudal component of the vaginal culs-de-sac lacked a median vaginal septum. As in other dasyurid marsupials, the lateral vaginae and associated vaginal complex were of diminutive proportions in relation to the typical marsupial pattern. The histology of the tract was remarkably good for tissue preserved since 1902 and indicated that the tissues were free of pathological changes. A characteristic marsupial pattern of ovarian folliculogenesis was evident where all but a thin peripheral zone of the cytoplasm of the primary oocyte became vacuolated during the pre-antral stage of ovarian follicle development.

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SPRATT, DAVID M. "Description of capillariid nematodes (Trichinelloidea: Capillariidae) parasitic in Australian marsupials and rodents." Zootaxa 1348, no. 1 (October 30, 2006): 1. http://dx.doi.org/10.11646/zootaxa.1348.1.1.

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Capillariid nematodes (Trichinelloidea: Capillariidae) parasitic in Australian dasyurid, peramelid and potoroid marsupials and murid rodents are described. Diagnosis of the genus Eucoleus and a key to species are given. Two species are redescribed: E. gastricus (Baylis) and E. rickardi (Beveridge and Barker), comb. nov. Nine species are described as new: E. breviductus sp. nov., E. buckenbourensis sp. nov., E. fluvidus sp. nov., E. longiductus sp. nov., E. parvulus sp. nov., E. perplexus sp. nov., E. plumosus sp. nov., E. posterus sp. nov. and E. pseudoplumosus sp. nov. Three additional species are recognized but not named. Species of Eucoleus occur in a diverse range of epithelial tissue habitats in Australian hosts throughout eastern Australia; one species is known from peramelids in Western Australia. Members of the genus have not been found in any other families of Australian marsupials. Three species are parasites of dasyurids, eight species are parasites of peramelids, two species occur in both dasyurid and peramelid hosts and two species are parasites of murid rodents. Morphologically, species of Eucoleus appear to be reasonably host specific at the family level. Molecular evidence indicates that sibling species of Eucoleus occur in distinct but closely related host species. Baruscapillaria conspecta sp. nov. is described from murid rodents and the potoroid marsupial rufous rat kangaroo, Aepyprymnus rufescens, primarily in north Queensland. Capillaria ornamentata sp. nov. is described from the distal nasal sinus behind the orbit of the eye of species of dasyurids of the genus Antechinus in southeastern Australia. Aonchotheca praeputialis (Obendorf, 1979) comb. nov. is redescribed and appears to occur exclusively in the native Rattus fuscipes. New host and geographic records, and tissue localities of the trichurid nematode, Anatrichosoma haycocki (Trichinelloidea: Trichuridae, Trichosomoidinae) are given.

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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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7

Woolley, P. A. "Pseudantechinus mimulus: a little known dasyurid marsupial." Australian Mammalogy 33, no. 1 (2011): 57. http://dx.doi.org/10.1071/am10043.

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Information has been gathered from a small number of specimens currently recognised as Pseudantechinus mimulus, 18 of which are registered in museum collections. The distribution of these specimens has been mapped and a more defined area than Alexandria Station proposed as the locality of collection of the holotype. Dental characteristics of P. mimulus, by which it was distinguished from P. macdonnellensis, have been examined and found to be more variable than previously thought. A difference between the two species was found in the morphology of the upper fourth molar. P. mimulus appears to be a seasonal breeder. Birth of the young probably occurs in August and September. The penis of P. mimulus is superficially similar to that of P. macdonnellensis. Both species have an appendage on the penis, but in P. mimulus the appendage may be shorter than that of its congener.

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8

Woolley, P. A., and C. H. Tyndale-Biscoe. "Side-tracked: unique evidence for passage of foetuses through the lateral vaginal canals in a dasyurid marsupial, Sminthopsis douglasi." Australian Mammalogy 39, no. 1 (2017): 115. http://dx.doi.org/10.1071/am16025.

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9

Frigo, L., and PA Woolley. "Development of the Skeleton of the Stripe-Faced Dunnart, Sminthopsis Macroura (Marsupialia: Dasyuridae)." Australian Journal of Zoology 44, no. 2 (1996): 155. http://dx.doi.org/10.1071/zo9960155.

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Development of the skeleton of the stripe-faced dunnart, Sminthopsis macroura (Gould), a small carnivorous marsupial, was examined in captive-bred pouch young of known age. Skeletal tissue was differentially stained with the dyes alcian blue and alizarin red to demonstrate the presence of cartilage and bone, respectively. The skeleton of the neonate is cartilaginous and ossification centres are first apparent in the skull by Day 5 post partum. The skeleton of S. macroura is well invested with bone by Day 40 of the lactation period, when the young can relinquish the nipple. The sequence of ossification is similar to that reported for other marsupials. Comparisons are made with the eutherian pattern of ossification. This study is the first published work on the ossification of a dasyurid marsupial as shown by whole-mount staining.

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10

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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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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12

Westman, Wendy, Gerhard Körtner, and Fritz Geiser. "DEVELOPMENTAL THERMOENERGETICS OF THE DASYURID MARSUPIAL, ANTECHINUS STUARTII." Journal of Mammalogy 83, no. 1 (February 2002): 81–90. http://dx.doi.org/10.1644/1545-1542(2002)083<0081:dtotdm>2.0.co;2.

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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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Westman, W., G. Kortner, and F. Geiser. "Developmental Thermoenergetics of the Dasyurid Marsupial, Antechinus stuartii." Journal of Mammalogy 83, no. 1 (February 18, 2002): 81–90. http://dx.doi.org/10.1093/jmammal/83.1.81.

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Breed, W. G., and C. M. Leigh. "Successful embryo transfer in a small dasyurid marsupial,." Theriogenology 45, no. 5 (April 1996): 1075–80. http://dx.doi.org/10.1016/0093-691x(96)00034-9.

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Goldingay, Ross L. "Small dasyurid marsupials - are they effective pollinators?" Australian Journal of Zoology 48, no. 5 (2000): 597. http://dx.doi.org/10.1071/zo00015.

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The evidence that several species of dasyurid marsupial commonly visit flowers and therefore act as pollinators is reviewed. Three species of Antechinus have frequently been trapped visiting flowering banksias. Several studies provide compelling evidence that Antechinus stuartii is an effective pollinator. It was recorded visiting flowering banksias at eight locations, where it carried abundant pollen on its snout and in its faeces. At one site, regular flower visitation was demonstrated by automated photography and by spool-and-line tracking. Pollen load data for Sminthopsis murina and Sminthopsis griseoventer suggest that these species may also act as pollinators. Evidence for pollination by Phascogale tapoatafa is anecdotal but studies at three locations report extended bouts of nectar feeding, and heavy pollen loads were directly observed at one site. Some 38 plant species are known to be visited by 10 dasyurid species, with 4–10 plant species being visited by each of five dasyurid species. These observations suggest that several species of dasyurid are likely to be important pollinators. Further studies are needed to clarify the extent of their role. This review highlights the types of data that should be sought.

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Nagy, KA, AK Lee, RW Martin, and MR Fleming. "Field Metabolic-Rate and Food Requirement of a Small Dasyurid Marsupial, Sminthopsis-Crassicaudata." Australian Journal of Zoology 36, no. 3 (1988): 293. http://dx.doi.org/10.1071/zo9880293.

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Field metabolic rates (FMRs) and rates of water flux in free-ranging fat-tailed dunnarts, Sminthopsis crassicaudata, were measured during spring (late October) using doubly labelled water. Feeding rates were estimated on the basis of water and energy fluxes. FMRs averaged 68.7 kJ d-' in adults (mean body mass= 16.6 g), and were 29.2 kJ d-' in juveniles (6.1 g). These FMRs are 6.6 times basal metabolic rate (BMR), and are much higher than the hypothetical maxima of four to five times BMR. Other dasyurid marsupials also have high FMR/BMR ratios, but so does a small petaurid marsupial. S. crassicaudata consumed 80-90% of its body mass in arthropods each day. The diet of arthropods apparently provided enough water for the animals to maintain water balance without drinking during this study.

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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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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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Wainwright, Brandon, and Rory Hope. "Flow Cytometry and Flow Sorting of Metaphase Chromosomes from the Dasyurid Marsupial Dasyurus viverrinus." Australian Journal of Biological Sciences 38, no. 4 (1985): 377. http://dx.doi.org/10.1071/bi9850377.

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Metaphase chromosomes (2n = 14) from D. viverrinus were analysed by flow cytometry and flow sorted into six homogeneous groups. Relative chromosomal DNA contents and distribution frequencies of the groups corresponded closely with values for the karyotype obtained by conventional methods.

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Graves, JAM, AH Sinclair, and JA Spencer. "Marsupial Gene Mapping and the Evolution of Mammalian Sex-Chromosome Form and Function." Australian Journal of Zoology 37, no. 3 (1989): 365. http://dx.doi.org/10.1071/zo9890365.

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Comparisons between the gene maps of distantly related mammalian species can provide information about the evolution of genome arrangement and function in mammals. Marsupial gene mapping is now being vigorously pursued, using newly developed cell and molecular techniques to complement classic breeding studies of model species. Gene associations and localisations established by all these techniques are tabulated, and the beginnings of gene maps, based on in situ hybridisation, are presented for a macropodid and a dasyurid species. The significance of marsupial gene mapping is apparent even from these limited data, which show that large autosomal regions have been conserved between marsupials and eutherians. However, an ancient X-autosome translocation is revealed, which either removed most of the human X short-arm markers (including the putative sex determining factor) to autosomes or added this region to a smaller ancestral X. The implications of these findings to theories of mammalian sex chromosome evolution and function are discussed, and a hypothesis proposed for a gradual differentiation of the mammalian X and Y chromosome, accompanied by progressive spreading of X chromosome inactivation.

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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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Menkhorst, E. M., L. A. Hinds, and L. Selwood. "Progesterone concentration in the marsupial Sminthopsis macroura: relationship with the conceptus, uterine glandular regeneration and body weight." REPRODUCTION 137, no. 1 (January 2009): 107–17. http://dx.doi.org/10.1530/rep-08-0030.

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Close examination of hormonal profiles and uterine morphology in the marsupial reproductive cycle highlights significant differences between pregnant and non-pregnant cycles. In the polyovular dasyurid marsupial Sminthopsis macroura, we identified changes associated with gestation by comparing ovarian and plasma progesterone concentrations, uterine weights, uterine epithelial mitoses, body weights and gestation lengths between pregnant and non-pregnant luteal phases. The plasma progesterone profile of S. macroura was biphasic, peaking during unilaminar blastocyst expansion and on the day of implantation. Periods of rapid embryonic development were associated with increasing plasma progesterone concentrations and animal body weight. For the first time in a polyovular marsupial, we identified 1) a correlation between ovarian progesterone concentration and conceptus number during the luteal phase just prior to implantation (total ovarian progesterone), indicating a conceptus influence on progesterone concentration; 2) a pulse of uterine epithelial mitotic activity at the time of implantation and 3) increased mitotic activity in pregnant animals during unilaminar blastocyst formation compared with non-pregnant animals. Gestation length was reduced by up to 15%, due to the loss of, or reduction in, the four-cell arrest and more rapid definitive blastocyst expansion. This is the first time a conceptus influence on gestation length has been identified in a dasyurid. This study provides further evidence for the modification of the luteal phase by pregnancy in S. macroura.

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Nelson, John E., and Robert T. Gemmell. "Birth in the northern quoll, Dasyurus hallucatus (Marsupialia : Dasyuridae)." Australian Journal of Zoology 51, no. 2 (2003): 187. http://dx.doi.org/10.1071/zo02016.

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Birth has been observed in a number of marsupial species and, in the studies to date, the newborn have crawled up to or across to the pouch. The method of birth in the quoll, a dasyurid, differs greatly from that observed in other marsupials. Births were recorded at normal speed using hand-held digital video cameras. Birth was heralded by a release of about 1 mL of watery fluid from the urogenital sinus followed by gelatinous material contained in either one or two tubes emanating from the sinus. The newborn, still encased in their placental membranes, were in the gelatinous material within a column. To exit this column, they had to grasp a hair and wriggle about 1 cm across to the pouch. In the pouch the newborn young had to compete for a teat. Although the quolls possessed 8 teats, the number of young in the pouch immediately after birth was 17, 16, 6, 16, 13 and 11 for each of the 6 quolls filmed. While birth has been described previously in another two dasyurids, the observers did not describe birth as reported here for the quoll. Nevertheless the movement of the newborn from the sinus to the pouch is so quick that this could have previously been missed. Filming birth from beneath and from the side allowed for a greater understanding of the birth process. Further studies are required to determine whether this use of a gelatinous material is part of the birth process in all dasyurids.

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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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Czarny, N. A., and J. C. Rodger. "The spermatozoa of the dasyurid marsupial, Sminthopsis crassicaudata, are highly susceptible to cold shock." Reproduction, Fertility and Development 22, no. 3 (2010): 580. http://dx.doi.org/10.1071/rd09119.

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Since the late 1970s research has suggested that marsupial spermatozoa did not suffer cold shock. We have re-examined cold shock to investigate problems with freezing of spermatozoa from a dasyurid marsupial, the fat-tailed dunnart (Sminthopsis crassicaudata). Epididymal spermatozoa were rapidly cooled to 0.5°C in a pre-cooled tube held in an iced-water slurry. Upon re-warming all spermatozoa were immotile and the addition of 10% or 20% egg yolk to the sperm medium had no beneficial effect. Spermatozoa that were rapidly cooled to 4°C maintained only 2% motility when re-warmed but the addition of at least 10% egg yolk was beneficial and upon re-warming greater than 65% of the initial motility was maintained. In order to achieve motile spermatozoa at 0°C, controlled-rate cooling at 0.5°C min–1 was examined. In the absence of egg yolk there was a significant decline in the percentage of motile spermatozoa below 4°C. However, the inclusion of at least 10% egg yolk resulted in no loss of motility in spermatozoa cooled to 0°C. This is the first experimental study indicating that spermatozoa from a marsupial are highly susceptible to cold shock and that the impact of rapid chilling can be mitigated by the addition of 10% egg yolk. The ability to successfully cool the spermatozoa of S. crassicaudata to 0°C may have an important role in future studies examining dasyurid sperm cryopreservation.

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Riley, J., DM Spratt, and PJA Presidente. "Pentastomids (Arthropoda) Parasitic in Australian Reptiles and Mammals." Australian Journal of Zoology 33, no. 1 (1985): 39. http://dx.doi.org/10.1071/zo9850039.

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Records of pentastomid arthropods parasitic in Australian reptiles and mammals are reviewed, with particular reference to material collected recently. Specimens representative of six genera are described. Sebekia sp. from the estuarine crocodile, Crocodylusporosus, is the first record of the genus in Australia and probably represents a new species. A nymph with double hooks, from the dasyurid marsupial Satanellus hallucatus, is determined as Waddycephalus sp. This represents the first evidence of double hooks in nymphal forms of the genus and of the role of marsupials as intermediate hosts of Waddycephalus. Nymphs from the peramelid marsupial, Isoodon macrourus, and from S, hallucatus are determined as Armillifer australis Riley & Self, 1981; those from Perameles nasuta are identified as A. arborealis Riley & Self, 1981. These represent the first records of marsupials as intermediate hosts of Armillifer. Adults of the genus Elenia Heymons, 1932 are confirmed as parasites of varanid lizards. E. australis Heymons, 1932 is recognized and it is suggested that specimens described by Heymons (1939), allegedly from Varanus varius at Townsville, Qld, may represent a new species. The cosmopolitan porocephalid Linguatula serrata Frolich, 1789 is recorded from the nasopharynx of the dingo or wild dog and the validity of the indigenous species, L. dingophila Johnson, 1910 is discussed. The cephalobaenid Raillietiella amphiboluri Mahon, 1954 is reported from Amphibolurus barbatus.

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Umbrello, L. S., P. A. Woolley, and M. Westerman. "Species relationships in the dasyurid marsupial genus Pseudantechinus (Marsupialia : Dasyuridae): a re-examination of the taxonomic status of Pseudantechinus roryi." Australian Journal of Zoology 65, no. 4 (2017): 240. http://dx.doi.org/10.1071/zo17059.

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The status of Pseudantechinus roryi relative to its congeners has been determined from DNA sequences obtained from both nuclear and mitochondrial gene loci. Although all other recognised species of Pseudantechinus form reciprocally monophyletic lineages in phylogenetic analyses, individuals identified in museum collections as Ps. roryi (including type specimens) were indistinguishable from those identified as Ps. macdonnellensis. Ps. roryi is thus considered to be a synonym of Ps. macdonnellensis. Neighbour-joining network analyses failed to reveal any clear biogeographic differences between populations of Ps. macdonnellensis other than some evidence of isolation by distance.

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Pavey, Chris R., and Fritz Geiser. "Basking and diurnal foraging in the dasyurid marsupial Pseudantechinus macdonnellensis." Australian Journal of Zoology 56, no. 2 (2008): 129. http://dx.doi.org/10.1071/zo08032.

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Several mammal species bask to passively rewarm during arousal from torpor, a strategy that can decrease energetic costs. Nothing is known about basking behaviour in these species or the trade-offs between energetic benefits of basking and potential costs associated with changes in activity patterns and increased predation risk. We assessed basking during winter in Pseudantechinus macdonnellensis, an Australian arid-zone marsupial that belongs to a family (Dasyuridae) that is typically nocturnal. Animals were implanted with temperature-sensitive transmitters to assess body temperatures and to assist in visually locating animals active during the day. Tagged animals regularly exhibited diurnal foraging. Foraging bouts occurred throughout the day; however, most bouts were observed within 3 h of sunset. By comparison, basking occurred much more frequently in the morning. Basking and a shift towards diurnal foraging in winter is associated with a decrease in richness and abundance of predators. P. macdonnellensis appears to compensate for the occurrence of torpor during the active phase (i.e. night) in winter by changing activity patterns such that foraging commences during what is usually the rest phase. These activity patterns are not expected to occur during the remainder of the year.

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Breed, W. G. "Sperm-egg interaction in an Australian dasyurid marsupial with special refernce to changes in acrosomal morphology." Zygote 2, no. 3 (August 1994): 201–11. http://dx.doi.org/10.1017/s0967199400001994.

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SummaryThe morphology of the acrosome of spermatozoa an Australian daysyurid marsupial during in vivo fertilisation, as seen with the tranamission electron microscope, is described. In some spermatozoa close to the outer zona surface with largely intact acrosomes, eletron-demse struts between the inner and outer acrosomal membranes could be seen; in addition fusion between the outer acrosomal and overlying plasma membranes was sometimes evident. The zona matrix close to the acrosomal region of spermatozoa with heads party embedded within the zona pellucida was less electron-dense and more filamentous than elsewhere; perhaps indicative of local lytic activety. Nevertheless some of these spermatozoa at least had partly intact acrosomes with local regions of electron-dense bridges between the two acrosomal membranes. Spermatozoa with condensed chomatin were also observed within the egg cytoplsam some of which had membranes, vacuoles or close to the dorsal nuclear surface which could, in part, be acrosomal in orgin. These observations lend some support to the recent view, based on findings from an American species, that acrosomal changes of spermatozoa of some marsupials at the of fertillsation may be somewhat similar to those of eutherian mamals in spite of the considerable differences in gamete structure and design. How generally applicable these findings are to all marsupials remains, however, to be determined.

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Voyle, Roger B., Bryan P. Haines, Kelly A. Loffler, Rory M. Hope, Peter D. Rathjen, and William G. Breed. "Isolation and characterisation of zona pellucida A (ZPA) cDNAs from two species of marsupial: regulated oocyte-specific expression of ZPA transcripts." Zygote 7, no. 3 (August 1999): 239–48. http://dx.doi.org/10.1017/s0967199499000623.

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The zona pellucida (ZP) is an extracellular glycoprotein coat that is deposited around the oocyte during folliculogenesis and performs several functions that relate to fertilisation and preimplantion development. In eutherian mammals it consists of three major glycoproteins – ZPA, ZPB, and ZPC – but little is known about its molecular constitution in marsupials. We have isolated the cDNA encoding the ZPA homologue in two distantly related marsupial series: the possum, Trichosurus vulpecula (a phalangerid) and the dunnart Sminthopsis crassicaudata (a dasyurid). The two cDNA sequences were 86% identical and showed extensive regions of homology to eutherian ZPA proteins, particularly in the central region of the molecule. Many other features of the ZPA protein, except the positioning of the N-linked glycosylation sites, were also conserved between marsupials and eutherians. ZPA expression was shown to occur maximally in the cytoplasm of the oocyte primary follicles with a little, but significant, expression in oocytes of both primordial follicles and in the cytoplasm of the oocyte in follicles with an antral cavity. No expression was seen in surrounding follicle or granulosa cells

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Righetti, Joanne, Barry J. Fox, and David B. Croft. "Behavioural mechanisms of competition in small dasyurid marsupials." Australian Journal of Zoology 48, no. 5 (2000): 561. http://dx.doi.org/10.1071/zo00023.

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The competitive behaviour of three species of small dasyurid marsupial, Antechinus swainsonii, Antechinus stuartii and Sminthopsis murina, was assessed in specially designed enclosures and smaller encounter cages, by videotaping the activity of pairs of animals, both as conspecifics and members of different species (except for A. swainsoni versus S. murina). Spatio-temporal analyses revealed differences in activity patterns and interactions within and between the species. Interference competition occurred in all intraspecific and interspecific comparisons tested. Encounter competition was judged to be the mechanism operating as all animals entered into interactions with other individuals. Encounters were particularly prevalent within Antechinus, indicating that they were more social than the relatively solitary Sminthopsis. Avoidance behaviour occurred between the two Antechinus species and this may enable them to coexist, so that this mechanism may be considered to be avoidance competition. The smaller competitor, S. murina, showed avoidance of the larger A. stuartii. Intraspecific competition was judged to be stronger than interspecific competition, but the latter could have more severe consequences, with the death of the smaller species occurring in some situations. This highlighted the asymmetric nature of competition, with body size determining the outcome of interactions between species.

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Cassone, Vincent M. "Circadian Organization and Photoreception in an Australian Dasyurid Marsupial (Sminthopsis macroura)." Journal of Biological Rhythms 2, no. 4 (December 1987): 261–68. http://dx.doi.org/10.1177/074873048700200402.

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34

Domrow, Robert. "PETAURALGES MORDAX SP. N. (ACARI: PSOROPTIDAE) FROM AN AUSTRALIAN DASYURID MARSUPIAL." Australian Journal of Entomology 27, no. 2 (May 1988): 87–90. http://dx.doi.org/10.1111/j.1440-6055.1988.tb01152.x.

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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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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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Stannard, Hayley J., and Julie M. Old. "Description of the gastrointestinal tract and associated organs of the kultarr (Antechinomys laniger)." Australian Mammalogy 35, no. 1 (2013): 39. http://dx.doi.org/10.1071/am12003.

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This paper provides a macro- and microscopic description of the digestive tract of the kultarr (Antechinomys laniger), a small dasyurid marsupial. The digestive tract was simple, with no external differentiation between the small and large intestine, and lacked a caecum. Mean gross length of the kultarr digestive tract was 165.2 ± 32.1 mm. Microscopically, the tissues had cell types similar to those of other mammals. The new information will aid future post-mortem investigations of captive kultarrs and future studies of nutrition.

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Jones, Menna, and Chris Dickman. "Introduction: Carnivorous marsupials." Wildlife Research 28, no. 5 (2001): I. http://dx.doi.org/10.1071/wrv28n5_in.

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Population dynamics and movements were investigated in a population of Pseudantechinus macdonnellensis, a dasyurid marsupial occupying rocky habitats in the Australian arid zone. Intra-annual cycling in abundance, activity and numbers of resident and transient individuals was not regular from year to year, although the number of residents was high compared with the number of transients. Juvenile recruitment varied between years and was as low as 18%. Densities were low (0.05–0.2 ha–1 for females and 0.05–0.3 ha–1 for males), and individuals exhibited large stable long-term ranges – mean Minimum Convex Polygon (MCP) area for males was 427 m2 and for females 171 m2. The constraints of the monoestrous, synchronised reproductive strategy of P. macdonnellensis, together with the ameliorating effect of its rocky habitat, which may decrease food limitation and increase survival, seem to have produced a different pattern of population dynamics to that seen in arid-zone dasyurids that are polyoestrous plains-dwellers. The patterns of movement in P. macdonnellensis also differ from plains-dwelling species, in which individuals display high life-time mobility. The existence of large but non-drifting ranges in P. macdonnellensis may be seen as a consequence of a low but relatively predictable food supply, which precludes the necessity for individuals to shift their activity to temporary patches of high food supply, but requires them to occupy a large range to obtain enough food to meet energy requirements.

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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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Selwood, Lynne. "A Timetable of Embryonic Development of the Dasyurid Marsupial Antechinus stuartii (Macleay)." Australian Journal of Zoology 28, no. 4 (2013): 645. http://dx.doi.org/10.1071/zo9800649.

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Hallam, J. F., and T. J. Dawson. "The pattern of respiration with increasing metabolism in a small dasyurid marsupial." Respiration Physiology 93, no. 3 (September 1993): 305–14. http://dx.doi.org/10.1016/0034-5687(93)90076-m.

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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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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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Beveridge, Ian. "Dasyurotaenia talboti n. sp. (Cestoda: Cyclophyllidea) parasitic in the dasyurid marsupial Dasyurus albopunctatus Schlegel, from Papua New Guinea." Transactions of the Royal Society of South Australia 139, no. 2 (June 9, 2015): 313–18. http://dx.doi.org/10.1080/03721426.2015.1051643.

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Kirsch, JAW, C. Krajewski, MS Springer, and M. Archer. "Dna-Dna Hybridization Studies of Carnivorous Marsupials .2. Relationships Among Dasyurids (Marsupialia, Dasyuridae)." Australian Journal of Zoology 38, no. 6 (1990): 673. http://dx.doi.org/10.1071/zo9900673.

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A suite of comparisons among ten radiolabelled dasyurid species and one outgroup bandicoot was generated using the hydroxyapatite chromatography method of DNA-DNA hybridisation; comparisons were also made with four other dasyurid taxa. Square matrices of DELTA-T(m)s, DELTA-Modes, and DELTA-T50H's were complied and corrected for reciprocity, additivity, and, in the case of DELTA-T(m)'s, normalised percentages of hybridisation. These matrices were analysed using the FITCH algorithm in Felsenstein's PHYLIP (Version 3.1), and all distinct topologies were jackknifed to test for internal consistency. Additionally, uncorrected DELTA-T(m), DELTA-Mode, and DELTA-T50H datasets were bootstrapped and subjected to phylogenetic analysis to assess measurement imprecision. FITCH trees from folded matrices including unlabelled species or those for which heteroduplex comparisons were incomplete were also calculated and jack-knifed, both before and after correction. With the exception of limited measurements to Dasyuroides byrnei and Dasykaluta rosamondae, which showed affinities with Dasyurus spp., the final tree was fully resolved: Sminthopsis crassicaudata and S. murina, together with the more distant Planigale maculata, are the sister-group to all other dasyurids examined, which in turn comprise two clades. One of these includes Dasyurus, Dasyuroides, and Dasykaluta; the other, 'true' Antechinus (A. flavipes, A. stuartii, A. swainsonii) as a sister-group to Antechinus melanurus plus Murexia longicaudata, with Phascogale tapoatafa representing a probable sister-group to all Antechinus with Murexia. DNA-DNA hybridisation provides no support for the genus Satanellus: most of the trees linked Dasyurus albopunctatus with D. maculatus instead of D. hallucatus. Similarly, Antechinus flavipes and A. stuartii appear to be closer to each other than either is to A. swainsonii. The historical biogeographic significance of the adopted phylogeny is considered, and it is concluded that the putative early Miocene separation of Australia and New Guinea was probably too early to account for the independent evolution of the New Guinean clade.

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Woolley, PA. "Reproduction in the Ningbing Antechinus (Marsupialia, Dasyuridae) - Field and Laboratory Observations." Wildlife Research 15, no. 2 (1988): 149. http://dx.doi.org/10.1071/wr9880149.

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The ningbing antechinus is a species of small dasyurid marsupial found in the Kimberley region of Western Australia. Observations on reproduction have been made on newly captured and laboratory maintained specimens. The breeding season is short and mating occurs in June. The young are born after a long gestation, estimated to be between 45 and 52 days, in late July and early August. They are weaned in November when about 16 weeks old and they reach sexual maturity at 10-11 months, in the first breeding season after birth. Both males and females are potentially capable of breeding in a second season.

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Agar, N. S., and B. M. McAllan. "Red cell metabolism in a small dasyurid marsupial, the brown antechinus (Antechinus stuartii)." Comparative Haematology International 5, no. 3 (1995): 201–5. http://dx.doi.org/10.1007/bf00368045.

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Holloway, J. C., and F. Geiser. "Influence of torpor on daily energy expenditure of the dasyurid marsupial Sminthopsis crassicaudata." Comparative Biochemistry and Physiology Part A: Physiology 112, no. 1 (September 1995): 59–66. http://dx.doi.org/10.1016/0300-9629(95)00089-p.

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Roberts, Claire T., William G. Breed, and Graham Mayrhofer. "Origin of the oocyte shell membrane of a dasyurid marsupial: An immunohistochemical study." Journal of Experimental Zoology 270, no. 3 (November 1, 1994): 321–31. http://dx.doi.org/10.1002/jez.1402700311.

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Menkhorst, E., N. Ezard, and L. Selwood. "Induction of ovulation and natural oestrous cycling in the Stripe-faced Dunnart, Sminthopsis macroura." Reproduction 133, no. 2 (February 2007): 495–502. http://dx.doi.org/10.1530/rep-06-0254.

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Induced ovulation allows reproduction by otherwise infertile females, and is ideal for the captive breeding of endangered species where the population is aged or breeding is unsuccessful. A predictable time of ovulation after induction has not yet been achieved in polyovular marsupials. Ovulation was induced in Sminthopsis macroura using an initial injection of 20 IU equine serum gonadotrophin (eSG; Day 0), followed on Day 4 by either 20 IU eSG (n = 25) or 0.5 mg porcine luteinizing hormone (n = 26). I.p. hormone injection was given in the morning or early evening, and reproductive status was established prior to induction. Five non-cyclic animals began to cycle naturally following induction and one gave birth to a litter. The time of ovulation after the 1st injection (7.8 ± 0.9 days) was significantly shorter (P = 0.000) and less variable than the previous study, mimicked the timing of natural cycling, and both natural and induced animals ovulated in the early morning. In vitro oocyte movement through the oviduct, observed for the first time in a marsupial, occurred in pulses. We estimated one group of oocytes could travel the length of the oviduct in 40 min, but it was probably around 4 h. The entire ovulation time (including multiple ovulations) was estimated at 7.5 h. This study has achieved a predictable timing of ovulation after stimulation, and induced noncyclic animals to cycle naturally and give birth, providing a modified methodology for use in captive breeding programs of endangered dasyurid marsupial species with low fecundity.

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Journal articles on the topic 'Dasyurid marsupial'

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