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Andrew M Baker – 1st expert on this subject based on the ideXlab platform
Taxonomy and redescription of the Swamp Antechinus, Antechinus minimus (E. Geoffroy) (Marsupialia: Dasyuridae)Memoirs of the Queensland museum, 2020Co-Authors: Andrew M Baker, Steve Van DyckAbstract:
We provide a taxonomic redescription of the dasyurid marsupial Swamp Antechinus, Antechinus minimus (Geoffroy, 1803). In the past, A. minimus has been classified as two subspecies: the nominate A. minimus minimus (Geoffroy, 1803), which is found throughout much of Tasmania (including southern Bass Strait islands) and A. minimus maritimus (Finlayson, 1958), which is found on mainland Australia (as well as some near-coastal islands) and is patchily distributed in mostly coastal areas between South Gippsland (Victoria) and Robe (South Australia). Based on an assessment of morphology and DNA, we conclude that A. minimus is both distinctly different from all extant congeners and that the two existing subspecies of Swamp Antechinus are appropriately taxonomically characterised. In our genetic phylogenies, the Swamp Antechinus was monophyletic with respect to all 14 known extant congeners; moreover, A. minimus was well-positioned in a large clade, together with all four species in the Dusky Antechinus complex, to the exclusion of all other Antechinus. Within A. minimus, between subspecies there were subtle morphological differences (A. m. maritimus skulls tend to be broader, with larger molar teeth, than A. m. minimus, but these differences were not significant); there was distinct, but only moderately deep genetic differences (3.9–4.5% at mtDNA) between A. minimus subspecies. Comparatively, across Bass Strait, the two subspecies of A. minimus are morphologically and genetically markedly less divergent than recently recognised species pairs within the Dusky Antechinus complex, found in Victoria (A.
mimetes) and Tasmania (A. swainsonii) (9.4–11.6% divergent at mtDNA)
vegetation structure and ground cover attributes describe the occurrence of a newly discovered carnivorous marsupial on the tweed shield volcano caldera the endangered black tailed dusky Antechinus Antechinus arktosEcology and Evolution, 2020Co-Authors: Caitlin E Riordan, Andrew M Baker, Coral Pearce, Bill J F Mcdonald, Ian GyntherAbstract:
The black-tailed dusky Antechinus (Antechinus arktos) is a recently discovered, endangered, carnivorous marsupial mammal endemic to the Tweed Shield Volcano caldera, straddling the border between Queensland and New South Wales in eastern Australia. The species’ preference for cool, high-altitude habitats makes it particularly vulnerable to a shifting climate as these habitats recede. Aside from basic breeding and dietary patterns, the species’ ecology is largely unknown. Understanding fine-scale habitat attributes preferred by this endangered mammal is critical to employ successful conservation management. Here, we assess vegetation attributes of known habitats over three sites at Springbrook and Border Ranges National Parks, including detailed structure data and broad floristic assessment. Floristic compositional assessment of the high-altitude cloud rainforest indicated broad similarities. However, only 22% of plant species were shared between all sites indicating a high level of local endemism. This suggests a diverse assemblage of vegetation across A. arktos habitats. Habitat characteristics were related to capture records of A. arktos to determine potential fine-scale structural habitat requirements. Percentage of rock cover and leaf litter were the strongest predictors of A. arktos captures across survey sites, suggesting a need for foraging substrate and cover. Habitat characteristics described here will inform predictive species distribution models of this federally endangered species and are applicable to other mammal conservation programs.
systematics biogeography and ancestral state of the australian marsupial genus Antechinus dasyuromorphia dasyuridaeZoological Journal of the Linnean Society, 2019Co-Authors: Thomas Y Mutton, Andrew M Baker, Matthew J Phillips, Susan Fuller, Litticia M BryantAbstract:
Since 2012 the number of recognized taxa in the Australian carnivorous marsupial genus Antechinus has increased from 10 to 15 species. The systematic relationships among these species and others in the genus are not well resolved. We undertook the first comprehensive, molecular systematic analysis of the genus, incorporating all known species and subspecies of Antechinus. Two mitochondrial (mtDNA) and four autosomal nuclear genes were sequenced. Four clades of Antechinus were consistently reconstructed in the concatenated and mtDNA analyses: (1) dusky Antechinuses (A. arktos, A. swainsonii, A. vandycki and A. mimetes) and A. minimus; (2) A. godmani; (3) A. agilis, A. stuartii and A. subtropicus; (4) A. argentus, A. mysticus, A. adustus, A. flavipes, A. leo and A. bellus. The inclusion of A. adustus in clade 4 is surprising, because previous morphology-based studies suggested it was a member of clade 3. However, analysis of the nuclear dataset and multi-species coalescence analysis did not separate clades 3 and 4. Within clade 3, A. stuartii is not monophyletic and may be more appropriately classified as two species. Timing of cladogenesis is estimated for all 15 species of Antechinus, permitting us to posit an evolutionary scenario for the group. BEAST analysis dated the divergence of Antechinus from extant congeners to the Late Miocene and cladogenesis among all extant Antechinus to the Plio-Pleistocene. Wet, closed habitat was reconstructed as the most probable ancestral state for the genus Antechinus and the four main Antechinus clades. Overall, increasing aridity from the Miocene to the Pleistocene and a number of well-known biogeographic barriers to mesic species, appear to have driven speciation in Antechinus.
Andrea C Taylor – 2nd expert on this subject based on the ideXlab platform
phenotype and gene flow in a marsupial Antechinus flavipes in contrasting habitatsBiological Journal of The Linnean Society, 2008Co-Authors: Hania Lada, Ralph Charles Mac Nally, Andrea C TaylorAbstract:
Ecological factors are important drivers of phenotypic divergence, which may lead to incipient speciation. A variety of habitats should be preserved to maintain evolutionary potential. We used the marsupial, the yellow-footed Antechinus (Antechinus flavipes) as a model species for investigating phenotypic differentiation between animals inhabiting two habitat types in south-eastern Australia: flood-plain river red gum and box–ironbark forests. All tested phenotypic characteristics varied between years at the same sites and therefore were not useful for investigating morphological specialization that may lead to speciation. Males generally were significantly heavier when Antechinus densities were lower, but exceptions were found, possibly related to food availability. Teat-number variation recently has been shown to be associated with habitat specialization and incipient speciation within Antechinus agilis. We investigated genetic differentiation associated with this trait in A. flavipes. Population genetic analyses of microsatellite genotypes and mitochondrial DNA haplotypes revealed that sympatric 12-, 13- and 14-teat females in Chiltern forest were part of one freely interbreeding population. Our parentage analyses found two cases where 13-teat mothers produced 12-teat daughters. This suggests either plasticity or paternal genetic influence on the offspring’s teat-number phenotype. Laboratory matings may be required to resolve the extent to which teat number is heritable in A. flavipes. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 303–314.
distinguishing past from present gene flow along and across a river the case of the carnivorous marsupial Antechinus flavipes on southern australian floodplainsConservation Genetics, 2008Co-Authors: Hania Lada, Ralph Charles Mac Nally, Andrea C TaylorAbstract:
Humans have altered many floodplain ecosystems around the world by clearing vegetation, building towns and regulating river flows. Studies discerning gene flow and population structure of floodplain-dwelling animals are rare yet are necessary for understanding the effects of human actions on native populations. In south-eastern Australia, the yellow-footed Antechinus (Antechinus flavipes) is the only carnivorous marsupial on many lowland floodplains, yet our knowledge of impacts of human activities is limited. The control region of mitochondrial DNA and 11 microsatellite DNA markers were used to explore historic and current gene flow in A. flavipes across and along the Murray River. Simulations were carried out to test different migration models. We found evidence for historic gene flow along and across the river but inferred that small towns and farmland or cleared floodplain sections restricted current gene flow along the river. Populations along the river appear to be isolated, and should be maintained at large enough sizes to avoid genetic problems such as inbreeding depression and loss of evolutionary potential. We also investigated whether 50-year-long maintenance of high water levels for irrigation in summer, at the time of juvenile dispersal, has led to restrictions in gene flow across the river. We found no evidence for restrictions to gene flow across the river and suggest that large floods and dropping tree branches may aid dispersal across the river.
responses of a carnivorous marsupial Antechinus flavipes to local habitat factors in two forest typesJournal of Mammalogy, 2008Co-Authors: Hania Lada, Ralph Charles Mac Nally, Andrea C TaylorAbstract:
Abstract Ecosystems around the world have been degraded or destroyed by human activities, including regulation of river flows, clearance of vegetation, and removal of fallen timber. In southeastern Australia much of the original vegetation was converted to farmland. Remaining forests such as hilly box–ironbark and floodplain river red gum (Eucalyptus camaldulensis) are mostly regrowth. The yellow-footed Antechinus (Antechinus flavipes) inhabits both types of forests and is the only small, native, carnivorous mammal on most floodplains in southeastern Australia. In this region, frequency of flooding has been reduced by regulation of river flows, which has led to decline in conditions favorable for flood-adapted terrestrial and aquatic organisms. Here, we compared numbers of A. flavipes in box–ironbark forests, and in river red gum forests that were deprived of floods; partially inundated with environmental flows; flooded naturally; and watered in large, artificial floods. We found that abundance of A. flav…
Peter Templesmith – 3rd expert on this subject based on the ideXlab platform
females choose mates based on genetic relatedness in a small dasyurid marsupial the agile Antechinus Antechinus agilisPLOS ONE, 2015Co-Authors: Marissa L Parrott, Simon J Ward, Peter Templesmith, Lynne SelwoodAbstract:
Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile Antechinus (Antechinus agilis), during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female Antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile Antechinus.
effects of drought on weight survival and breeding success of agile Antechinus Antechinus agilis dusky Antechinus a swainsonii and bush rats rattus fuscipesWildlife Research, 2007Co-Authors: Marissa L Parrott, Simon J Ward, Peter Templesmith, Lynne SelwoodAbstract:
Extreme weather conditions, such as drought, significantly decrease the survival and breeding success of numerous species. Despite the frequent occurrence of such conditions in Australia, little is known about the effects of changing environmental conditions on the native small mammals. This study, conducted from 2002 to 2004, focussed on sympatric wild populations of the agile Antechinus (Antechinus agilis), with more limited information on the dusky Antechinus (A. swainsonii) and the bush rat (Rattus fuscipes). Bodyweights of agile Antechinus before and during the breeding season were significantly lower in 2003 (drought) than in 2002 or 2004. Survival of female agile Antechinus and the number of young per litter also decreased significantly during drought. In contrast, the dusky Antechinus showed no difference in mean bodyweights between years, high survival rates of females and similar litter sizes in 2002 and 2003. There was also no difference in bodyweight of bush rats between years. Low rainfall was recorded during pregnancy and lactation in the agile Antechinus, but rainfall was higher during pregnancy and lactation in the dusky Antechinus. The survival and breeding success of the agile Antechinus may have been adversely affected by a combination of interspecific competition, timing of the breeding season and severity of the drought.
olfactory cues genetic relatedness and female mate choice in the agile Antechinus Antechinus agilisBehavioral Ecology and Sociobiology, 2007Co-Authors: Marissa L Parrott, Simon J Ward, Peter TemplesmithAbstract:
Females show mate preferences for males that are genetically dissimilar to themselves in a variety of taxa, but how females choose these males is not clearly understood. In this study, we examined the effects of olfactory stimuli and genetic relatedness on female mate choice in a small carnivorous marsupial, the agile Antechinus (Antechinus agilis), during two breeding seasons. Captive female Antechinus in oestrus were provided with a combination of male urine and body scent from two novel males, one more genetically similar and one more dissimilar to the females, in a Y-maze olfactometer. Genetic relatedness between females and pairs of males was determined using highly polymorphic, species-specific, microsatellite markers. Females consistently chose to visit the scents of males that were genetically dissimilar to themselves first, spent significantly more time near the source of those scents and showed more sexual and non-exploratory behaviours near those scents. These data demonstrate that chemosensory cues are important in mate choice in the agile Antechinus and that females prefer males that are genetically dissimilar to themselves.