Numbat Research Articles

Comparative three-dimensional jaw muscle anatomy of marsupial carnivores (Dasyurus spp.) and the termite-eating numbat (Myrmecobius fasciatus).

Among marsupials, the endangered numbat (Myrmecobius fasciatus) is the only obligate myrmecophage with a diet comprised strictly of termites. Like many other specialised myrmecophagous mammals, numbats have a gracile and highly specialised skull morphology with an elongated rostrum and small braincase. Myrmecobiidae is one of four taxonomic families within the Australasian marsupial order Dasyuromorphia, and to date, the muscular anatomy of any member of this group is relatively poorly known. We utilised microdissection and contrast-enhanced microcomputed tomography scanning to provide the first comprehensive qualitative and quantitative descriptions of jaw muscle anatomy in numbats and quolls (Dasuyrus species). The arrangement of the jaw muscles across these species was conservative, both in gross anatomy and muscle proportions, corresponding to a 'generalised' mammalian pattern. In contrast to Dasyurus, the jaw muscles of the numbat were greatly reduced. Many aspects of the muscle anatomy of the numbat were similar to patterns reported in other myrmecophagous species, particularly a greatly reduced temporalis muscle. Unusually, the digastric muscle in the numbat was comprised of a single, large anterior belly while the posterior belly was absent. We propose that the enlarged anterior belly of the digastric may be linked to jaw stabilisation and coordination of tongue movements during feeding. The lateral insertion and fascial connection of the digastric to the tongue in numbats may also aid in distributing stress evenly across the jaw and minimise muscle fatigue. The muscle descriptions and three-dimensional models provided in this study will facilitate further analysis of musculoskeletal adaptation and evolution within the Dasyuromorphia.

Implications of heat exchange for a free-living endangered marsupial determined by non-invasive thermal imaging.

We used thermal imagining and heat balance modelling to examine the thermal ecology of wild mammals, using the diurnal marsupial numbat (Myrmecobius fasciatus) as a model. Body surface temperature was measured using infra-red thermography at environmental wet and dry bulb temperatures of 11.7-29°C and 16.4-49.3°C, respectively; surface temperature varied for different body parts and with environmental temperature. Radiative and convective heat exchange varied markedly with environmental conditions and for various body surfaces reflecting their shapes, surface areas and projected areas. Both the anterior and posterior dorsolateral body areas functioned as thermal windows. Numbats in the shade had lower rates of solar radiative heat gain but non-solar avenues for radiative heat gain were substantial. Radiative gain was higher for black and lower for white stripes, but overall, the stripes had no thermal role. Total heat gain was generally positive (<4 to >20W) and often greatly exceeded metabolic heat production (3-6W). Our heat balance model indicates that high environmental heat loads limit foraging in open areas to as little as 10min and that climate change may extend periods of inactivity, with implications for future conservation and management. We conclude that non-invasive thermal imaging is informative for modelling heat balance of free-living mammals.

Parental effects on offspring sex ratio in the Numbat (Myrmecobius fasciatus): does captivity influence paternal sex allocation?

Sex allocation theories predict that under different ecological conditions the production of sons and daughters will affect parental fitness differently. Skewed offspring sex ratios often occur under captive conditions where individuals are exposed to nutritional and social conditions that differ from nature. Here, we analyzed 29 years of offspring sex ratio data from a captive population of an endangered marsupial, the Numbat (Myrmecobius fasciatus). We partitioned variation in offspring sex ratio based on parental origin (captive- vs. wild-bred), parental weight, maternal age, and maternal reproductive history. Our analyses revealed no effect of parental weight or maternal origin on offspring sex ratio-however, there was a significant effect of paternal origin. Data visualization indicated that captive-bred males tended to produce male-biased litters. We discuss the result in relation to recent studies that have shown that male mammals have the capacity to be arbiters of sex allocation and highlight candidate mechanisms, but consider it with caution due to the small sample size from which the result was derived. We performed a population viability analysis (PVA) to explore the potential impact of a sex ratio skew on the sustainability of the captive Numbat population under hypothetical scenarios. Our PVA revealed that supplementation with wild individuals is critical to the persistence of the captive Numbat population and that a biased sex ratio will lead to extinction of the captive colony under certain conditions. Overall, our study demonstrates that covert sex ratio skews can persist undetected in captive populations, which have the potential to become impactful and compromise population sustainability under changed management processes.

Use of carrion fly iDNA metabarcoding to monitor invasive and native mammals.

Severely fragmented habitats increase the risks towards native mammal populations through isolation, increased edge effects, and predation. Therefore, monitoring the movement of mammal populations through anthropogenically-altered landscapes can be a valuable tool for conservation. Here we use metabarcoding of invertebrate-derived DNA (iDNA) from carrion flies (Calliphoridae and Sarcophagidae) to track mammal populations in the Wheatbelt Region of southwestern Australia, where widespread clearing for agriculture has removed most of the native perennial vegetation and replaced it with an agricultural system. Using this technique, we investigated whether the localization of the iDNA signal reflected the predicted distribution of four native species - echidna (Tachyglossus aculeatus), numbat (Myrmecobius fasciatus), woylie (Bettongia penicillata), and chuditch (Dasyurus geoffroii) - and two non-native, invasive mammal species - fox (Vulpes vulpes) and feral cat (Felis catus). We collected bulk iDNA samples (n = 150 samples, totalling 3,428 carrion flies) at a single time point from three conservation reserves and road edges between them. We detected 14 of the 40 mammal species known from the region, including our target species. Detections of target native taxa were centered on conservation reserves, with some detections from road edges nearby. We detected foxes and feral cats throughout the study area, including all conservation reserves. There was a significant difference between the diversity (F(3, 98) = 5.91, p<0.001) and composition (F(3, 43) = 1.72, p<0.01) of taxa on road edges and conservation reserves: conservation reserves hosted more native biodiversity than did road edges. Our data suggest that the signals from iDNA reflect the known distribution of target mammals in this region. The development of iDNA methods shows promise for future non-invasive monitoring for mammals. With further development, iDNA metabarcoding could assist in decision-making surrounding the conservation of endangered taxa, invasive species management and impacts of habitat fragmentation. Article Impact Statement: Carrion fly iDNA metabarcoding can be used to monitor mammalian distribution at a fine scale. This article is protected by copyright. All rights reserved.

Modeling genetic benefits and financial costs of integrating biobanking into the conservation breeding of managed marsupials.

Managed breeding programs are an important tool in marsupial conservation efforts but may be costly and have adverse genetic effects in unavoidably small captive colonies. Biobanking and assisted reproductive technologies (ARTs) could help overcome these challenges, but further demonstration of their potential is required to improve uptake. We used genetic and economic models to examine whether supplementing hypothetical captive populations of dibblers (Parantechinus apicalis) and numbats (Myrmecobius fasciatus) with biobanked founder sperm through ARTs could reduce inbreeding, lower required colony sizes, and reduce program costs. We also asked practitioners of the black-footed ferret (Mustela nigripes) captive recovery program to complete a questionnaire to examine the resources and model species research pathways required to develop an optimized biobanking protocol in the black-footed ferret. We used data from this questionnaire to devise similar costed research pathways for Australian marsupials. With biobanking and assisted reproduction, inbreeding was reduced on average by between 80% and 98%, colony sizes were on average 99% smaller, and program costs were 69- to 83-fold lower. Integrating biobanking made long-standing captive genetic retention targets possible in marsupials (90% source population heterozygosity for a minimum of 100 years) within realistic cost frameworks. Lessons from the use of biobanking technology that contributed to the recovery of the black-footed ferret include the importance of adequate research funding (US$4.2 million), extensive partnerships that provide access to facilities and equipment, colony animals, appropriate research model species, and professional and technical staff required to address knowledge gaps to deliver an optimized biobanking protocol. Applied research investment of A$133 million across marsupial research pathways could deliver biobanking protocols for 15 of Australia's most at-risk marsupial species and 7 model species. The technical expertise and ex situ facilities exist to emulate the success of the black-footed ferret recovery program in threatened marsupials using these research pathways. All that is needed now for significant and cost-effective conservation gains is greater investment by policy makers in marsupial ARTs.

Ontogenetic allometry reveals the imprint of myrmecophagy in the skull of the numbat, Myrmecobius fasciatus Waterhouse, 1836 (Marsupialia: Myrmecobiidae)

Ontogenetic allometry, the covariation of shape with size over the course of development, represents a fundamental component of morphological diversification that can vary across species and in association with ecological factors. Ontogenetic allometry patterns for the skull have been described for species from several marsupial lineages, associated with common dietary niches, e.g., carnivory. We here conduct a novel detailed examination of cranial ontogeny in the numbat (Myrmecobius fasciatus), unique among marsupials in being myrmecophagous and adopting a strictly diurnal habit. We investigated ontogenetic allometry using multivariate analyses in a postnatal series (n = 28) of complete numbat skulls to estimate the rate of growth of its major constituent elements, described by 15 measurements. We find positive allometry for length of the nasals and palate, which relates directly to the remarkable rostral elongation in the species relative to other marsupials, in addition to several other ontogenetic changes. These comprise negative allometry of palate breadth, elongation of upper and lower toothrows that produces diastemata between weakly developed teeth, and decreasing muzzle height, all of which contribute to the development of a long, tapering, narrow rostrum, with limited mastication ability, as seen in the small temporal space and poor development of crests and processes associated with jaw musculature. Our specific allometric results and comparisons, together with qualitative observations, reveal a distinct imprint of myrmecophagy on skull ontogeny in the numbat and help explain the development and evolution of specialized feeding function of this species.Norberto P. Giannini [ngiannini@amnh.org], CONICET Fundacion Miguel Lillo, Unidad Ejecutora Lillo, UEL, Tucumán, Argentina, Facultad de Ciencias Naturales, Instituto Miguel Lillo, Universidad Nacional de Tucumán, Tucumán, Argentina, Department of Mammalogy, American Museum of Natural History, New York, NY, USA;Fernando Abdala [nestor.abdala@wits.ac.za], CONICET Fundacion Miguel Lillo, Unidad Ejecutora Lillo, UEL, Tucumán, Argentina, Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa;David A. Flores [dflores@macn.gov.ar], CONICET Fundacion Miguel Lillo, Unidad Ejecutora Lillo, UEL, Tucumán, Argentina, Instituto de Vertebrados, Fundación Miguel Lillo, Tucumán, Argentina;Laura A. B. Wilson [laura.wilson@anu.edu.au], School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia, School of Archaeology and Anthropology, The Australian National University, Canberra, ACT 2601, Australia.

Genome assembly of the numbat (Myrmecobius fasciatus), the only termitivorous marsupial.

The numbat (Myrmecobius fasciatus) is an endangered Australian marsupial, and the last surviving member of the Myrmecobiidae family. The numbat regularly undergoes torpor and is unique amongst marsupials as it is the only diurnal and termitivorous species. Here we sequenced the first draft genome of the numbat using 10× Genomics Chromium linked-read technology, resulting in a 3.42 Gbp genome with a scaffold N50 of 223 kbp. A global transcriptome from liver, lung and tongue was also generated to aid genome annotation, identifying 21,465 protein-coding genes. To investigate adaptation to the numbat's termitivorous diet and arid/semi-arid range, we interrogated the most highly expressed transcripts within the tongue and manually annotated taste, vomeronasal and aquaporin gene families. Antimicrobial proteins and proteins involved in digestion were highly expressed in the tongue, alongside umami taste receptors. However, sweet taste receptors were not expressed in this tissue, which combined with the putative contraction of the bitter taste receptor gene repertoire in the numbat genome, may indicate a potential evolutionary adaptation to their specialised termitivorous diet. Vomeronasal and aquaporin gene repertoires were similar to other marsupials. The draft numbat genome is a valuable tool for conservation and can be applied to population genetics/genomics studies and to investigate the unique biology of this interesting species.

Remote sensor camera traps provide the first density estimate for the largest natural population of the numbat (Myrmecobius fasciatus)

Context Accurate estimates of population size is fundamentally important for effective conservation management of threatened species. Remote sensor camera traps often capture cryptic species that are difficult to sight or capture. When animals are individually identifiable, camera traps can be used in conjunction with mark–recapture methods to provide a robust estimate of density. This has been effective for medium and large mammals such as felid and quoll species. Less is known about whether this may be an effective approach for smaller species. The numbat (Myrmecobius fasciatus), a small diurnal marsupial once widespread across southern Australia, is now highly restricted. Low densities and crypsis make them challenging to survey, and current population monitoring methods (driving transects and sign surveys) do not provide accurate density estimates. Aims This study aimed to: (1) assess whether numbats can be individually identified using camera trap images; and (2) use spatial and non-spatial capture–recapture methods to investigate whether camera trapping is a viable population monitoring tool for numbats in the largest extant population. Methods We conducted spatial and non-spatial population modelling using images captured incidentally during a large camera-trapping project. Key results We found numbats could be individually identified by stripe patterns from camera images that, in conjunction with capture–recapture modelling, could provide a density estimate. From 6950 trap nights there were 116 numbat detections on 57 of 250 cameras. Of these, 61 detections were used to identify 29 individuals and provide a density estimate of 0.017 ha−1 ± 0.004 (CV = 0.26). This density applied across the estimated extent of distribution suggests a substantially larger numbat population in the Upper Warren, Western Australia (~1900 adults) than previously assumed. Conclusions Camera trapping is a potential method for monitoring the population density of small uniquely marked species, such as the numbat, and for monitoring population trends in response to conservation efforts such as introduced predator control and translocations, as well as management actions such as prescribed burning and timber harvesting. Implications This study contributes to the understanding of situations where camera traps can be utilised to survey small, cryptic species. To provide a more reliable density estimate, and to develop an optimal sampling layout for numbats, further studies would be required.

Sign surveys can be more efficient and cost effective than driven transects and camera trapping: a comparison of detection methods for a small elusive mammal, the numbat (

Abstract Context Determining the most efficient detection method for a target species is key for successful wildlife monitoring and management. Driven transects and sign surveys are commonly used to monitor populations of the endangered numbat (Myrmecobius fasciatus). Camera trapping is being explored as a new method. These methods were unevaluated for efficacy and cost for numbat detection. Aims To compare efficacy and costing of driven transects, sign surveys and camera trapping for detecting numbats in the Upper Warren region, Western Australia. Methods Seven repeat sign surveys and driven transects, as well as 4 months of camera trapping, were conducted concurrently at 50 sites along three transects. Numbat detection rates and costing of the three techniques were compared, and detection probabilities were compared between sign surveys and camera trapping. Key results Numbat signs were detected during 88 surveys at 39 sites, exceeding camera trapping (26 detections at 13 sites) and driven transects (seven detections near five sites). The estimated probability for detecting a numbat or a sign thereof (at a site where numbats were present) ranged from 0.21 to 0.35 for a sign survey, and 0.02 to 0.06 for 7 days of camera trapping. Total survey costs were lowest for driven transects, followed by camera trapping and sign surveys. When expressed as cost per numbat detection, sign surveys were cheapest. Conclusions Comparative studies of survey methods are essential for optimal, cost-effective wildlife monitoring. Sign surveys were more successful and cost effective than camera trapping or driven transects for detecting numbats in the Upper Warren region. Together with occupancy modelling, sign surveys are appropriate to investigate changes in occupancy rates over time, which could serve as a metric for long-term numbat monitoring. Implications There is no ‘best’ method for wildlife surveys. Case-specific comparison of animal detection methods is recommended to ensure optimal methods. For the numbat population in the Upper Warren region, further studies are needed to improve numbat detection rates from camera trapping, and to test sign surveys in autumn (March to May), when surviving juvenile numbats have established their own territory and assumptions regarding population closure are less likely to be violated.

The external ear morphology and presence of tragi in Australian marsupials.

Multiple studies have described the anatomy and function of the external ear (pinna) of bats, and other placental mammals, however, studies of marsupial pinna are largely absent. In bats, the tragus appears to be especially important for locating and capturing insect prey. In this study, we aimed to investigate the pinnae of Australian marsupials, with a focus on the presence/absence of tragi and how they may relate to diet. We investigated 23 Australian marsupial species with varying diets. The pinnae measurements (scapha width, scapha length) and tragi (where present) were measured. The interaural distance and body length were also recorded for each individual. Results indicated that all nectarivorous, carnivorous, and insectivorous species had tragi with the exception of the insectivorous striped possum (Dactylopsila trivirgata), numbat (Myrmecobius fasciatus), and nectarivorous sugar glider (Petaurus breviceps). No herbivorous or omnivorous species had tragi. Based on the findings in this study, and those conducted on placental mammals, we suggest marsupials use tragi in a similar way to placentals to locate and target insectivorous prey. The Tasmanian devil (Sarcophilus harrisii) displayed the largest interaural distance that likely aids in better localization and origin of noise associated with prey detection. In contrast, the smallest interaural distance was exhibited by a macropod. Previous studies have suggested the hearing of macropods is especially adapted to detect warnings of predators made by conspecifics. While the data in this study demonstrate a diversity in pinnae among marsupials, including presence and absence of tragi, it suggests that there is a correlation between pinna structure and diet choice among marsupials. A future study should investigate a larger number of individuals and species and include marsupials from Papua New Guinea, and Central and South America as a comparison.

Optimising camera trap height and model increases detection and individual identification rates for a small mammal, the numbat (

Camera traps are widely used to collect data for wildlife management, but species-specific testing is crucial. We conducted three trials to optimise camera traps for detecting numbats (Myrmecobius fasciatus), a 500–700-g mammal. We compared detection rates from (1) Reconyx PC900 camera traps installed at heights ranging from 10–45 cm, and (2) Reconyx PC900, Swift 3C standard and wide-angle camera traps with differing detection zone widths. Finally, we compared elevated, downward-angled time-lapse cameras installed at heights ranging from 1–2 m to obtain dorsal images for individual numbat identification. Camera traps set at 25 cm had the highest detection rates but missed 40% of known events. During model comparison, Swift 3C wide-angle camera traps recorded 89%, Swift 3C standard 51%, and Reconyx PC900 37% of known events. The number of suitable images from elevated, downward-angled cameras, depicting dorsal fur patterns, increased with increasing camera height. The use of well regarded camera trap brands and generic recommendations for set-up techniques cannot replace rigorous, species-specific testing. For numbat detection, we recommend the Swift 3C wide-angle model installed at 25-cm height. For individual numbat identification, elevated, downward-angled time-lapse cameras were useful; however, more research is needed to optimise this technique.

Wild-born versus captive-bred: a comparison of survival and refuge selection by translocated numbats (Myrmecobius fasciatus)

Abstract ContextTo re-establish a population of the threatened numbat (Myrmecobius fasciatus) in a newly created safe haven at Mount Gibson Wildlife Sanctuary, in the semi-arid zone of Western Australia, wild-born and captive-bred individuals of both sexes were translocated. AimTo compare: (1) the use of refuges by wild-born numbats pre- and post-translocation, and (2) the survival and refuge use of captive-bred numbats compared with wild-sourced numbats post-translocation. MethodsMonitoring via radio-tracking facilitated the gathering of information on survival and behaviour of numbats pre- and post-translocation, and allowed a comparison of how different factors (e.g. captive-bred or wild-born; male or female) influenced survival and establishment in a new environment. Key resultsThere were no significant differences in survival between sexes or between wild-born and captive-bred individuals. However, there were some differences in behaviour between sexes and source populations. Captive-bred numbats, regardless of sex, made greater use of tree hollows as nocturnal refuges than did their wild-born counterparts. Among wild-born numbats, there was a comparatively greater use of tree hollows and logs on the ground by males at Mount Gibson than at Scotia. The use of diurnal escape refuges did not vary between sexes or between captive-bred and wild-born individuals. ConclusionsOn the basis of the information presented here, we conclude that, in the absence of predation by mammalian predators, and with suitable release habitat, captive-bred-to-wild translocations of numbats may be as likely to succeed as are wild-to-wild translocations, at least over the first few months post-translocation. ImplicationsOptimising the size and genetic diversity of the founding population by using animals from a variety of sources may not need to be heavily constrained by concerns about the ability of captive-bred numbats to adapt to and survive life in the wild.

Parentage assignment using microsatellite DNA typing for the endangered numbat (Myrmecobius fasciatus)

The numbat (Myrmecobius fasciatus) is an endangered and peculiar marsupial with a diet that consists almost exclusively of termites. This study developed a parentage-testing system for numbats using microsatellite markers. Nineteen loci detected 143 alleles, with 4–13 alleles/locus and average expected heterozygosity of 77% (range 0.665–0.855). The total parentage exclusion probability was &amp;gt;0.9999 (given only the genotype of the offspring), &amp;gt;0.9999 for excluding a candidate parent from the parentage of an arbitrary offspring (given the genotype of the offspring and parent) and the probability of identity for full-sibs was 4.6×10–9. Overall, these microsatellites offer a simple and highly informative marker-set for parentage identification in numbats.

Patterns of habitat use by three threatened mammals 10 years after reintroduction into a fenced reserve free of introduced predators

Introduced predators are a major driver of global biodiversity loss. Over the last 200 years, the distribution and abundance of critical-weight-range mammals in Australia has declined, with many species now locally extinct or confined to small isolated refuges. From 2004 onwards as part of a major conservation initiative, the Australian Wildlife Conservancy reintroduced three threatened mammal species, the Greater Bilby (Macrotis lagotis), Bridled Nailtail Wallaby (Onychogalea fraenata) and Numbat (Myrmecobius fasciatus), into an 8000-hectare area protected by conservation fencing at Scotia Sanctuary in semi-arid New South Wales. Our study examined habitat selection for these species following multiple generations in a fenced area free of introduced predators.We used nocturnal spotlighting and diurnal search transect data collected over a two-year period to identify habitat preferences for these species, a decade after release. We used a Distance Sampling approach to examine differences in detectability between vegetation types, and Chi-Squared tests to identify differences in habitat use relative to availability. We used a Utilization Distribution (UD) analysis to identify how the spatial distribution of habitat affected its usage at Scotia Sanctuary. Habitat use of each species was compared with the results of a study conducted shortly after initial releases.We found that patterns of habitat use for these species differed to those identified following their initial release. We found a strong preference for shrub vegetation communities for all species relative to availability, as well as some variation in habitat preferences between two fenced areas (Stage 1 and Stage 2). The UD analysis revealed patterns of habitat use for one species (Bilby) that were not apparent from Chi-squared analysis, highlighting the importance of considering the spatial heterogeneity and proximity of different vegetation types when identifying species preferences.Our results demonstrate that in the absence of introduced predators these threatened species are able to use all of the vegetation types available, and by altering their habitat use over time, to persist following reintroduction into contemporary contexts within their historic ranges.

Total evidence phylogeny and evolutionary timescale for Australian faunivorous marsupials (Dasyuromorphia)

BackgroundThe order Dasyuromorphia is a diverse radiation of faunivorous marsupials, comprising >80 modern species in Australia and New Guinea. It includes dasyurids, the numbat (the myrmecobiid Myrmecobius fasciatus) and the recently extinct thylacine (the thylacinid Thylacinus cyncocephalus). There is also a diverse fossil record of dasyuromorphians and “dasyuromorphian-like” taxa known from Australia. We present the first total evidence phylogenetic analyses of the order, based on combined morphological and molecular data (including a novel set of 115 postcranial characters), to resolve relationships and calculate divergence dates. We use this information to analyse the diversification dynamics of modern dasyuromorphians.ResultsOur morphology-only analyses are poorly resolved, but our molecular and total evidence analyses confidently resolve most relationships within the order, and are strongly congruent with recent molecular studies. Thylacinidae is the first family to diverge within the order, and there is strong support for four tribes within Dasyuridae (Dasyurini, Phascogalini, Planigalini and Sminthopsini). Among fossil taxa, Ankotarinja and Keeuna do not appear to be members of Dasyuromorphia, whilst Barinya and Mutpuracinus are of uncertain relationships within the order. Divergence dates calculated using total evidence tip-and-node dating are younger than both molecular node-dating and total evidence tip-dating, but appear more congruent with the fossil record and are relatively insensitive to calibration strategy. The tip-and-node divergence dates indicate that Dasyurini, Phascogalini and Sminthopsini began to radiate almost simultaneously during the middle-to-late Miocene (11.5–13.1 MYA; composite 95% HPD: 9.5–15.9 MYA); the median estimates for these divergences are shortly after a drop in global temperatures (the middle Miocene Climatic Transition), and coincide with a faunal turnover event in the mammalian fossil record of Australia. Planigalini radiated much later, during the latest Miocene to earliest Pliocene (6.5 MYA; composite 95% HPD: 4.4–8.9 MYA); the median estimates for these divergences coincide with an increase in grass pollen in the Australian palynological record that suggests the development of more open habitats, which are preferred by modern planigale species.ConclusionsOur results provide a phylogenetic and temporal framework for interpreting the evolution of modern and fossil dasyuromorphians, but future progress will require a much improved fossil record.

Phylogenetic relationships of dasyuromorphian marsupials revisited

We reassessed the phylogenetic relationships of dasyuromorphians using a large molecular database comprising previously published and new sequences for both nuclear (nDNA) and mitochondrial (mtDNA) genes from the numbat (Myrmecobius fasciatus), most living species of Dasyuridae, and the recently extinct marsupial wolf, Thylacinus cynocephalus. Our molecular tree suggests that Thylacinidae is sister to Myrmecobiidae + Dasyuridae. We show robust support for the dasyurid intrafamilial classification proposed by Krajewski & Westerman as well as for placement of most dasyurid genera, which suggests substantial homoplasy amongst craniodental characters presently used to generate morphology-based taxonomies. Molecular dating with relaxed molecular clocks suggests that dasyuromorphian cladogenesis began in the Eocene, and that all three dasyuromorphian families originated prior to the end of this epoch. Radiation within Thylacinidae and Dasyuridae had occurred by the middle to late Oligocene, consistent with recognition of primitive thylacinids (e.g. Badjcinus turnbulli) in the later Oligocene and of putative dasyurids (e.g. Barinya wangala) by the early Miocene. We propose that all four extant dasyurid tribes were in existence by the early Miocene and that most modern dasyurid genera/species were established before the later Miocene. This is in marked contrast to the popularly accepted advocation of their origins in the latest Miocene–early Pliocene. © 2015 The Linnean Society of London

MORE STRIPED DESIGNS IN ARNHEM LAND ROCK PAINTINGS

ARNHEM Land Aboriginal rock paintings of a striped animal were first described by Brandi in 1972. Brandi claimed that the paintings represented the thylacine (Thylacinus cynocephalus) but his evidence was not conclusive and doubts still remain as to the species depicted (Clegg, in press; Marlow, quoted in E.Z. Review no. 1, 1975). In September and October 1972, the writer located five more striped paintings and an unstriped design similar in form to one of the striped paintings, at four closely grouped rock shelters near Nabarlek, on the edge of the western Arnhem Land plateau (see map). More recently, in September 1974, the writer located another three striped designs at two other sites in western Arnhem Land. One of these designs shows a female animal with four young. Tracings, photographs and descriptions of these paintings were taken and the data are given below. In attempting to identify the animals described in this paper, various features of the paintings have been taken into account. These include the stripes, overall shape and any physical features shown which may be unique to a particular species. The animals to be considered are the dingo {Canis familiaris) and the native striped marsupials the numbat (Myrmecobius fasciatus), the banded hare-wallaby (Logostrophus fasciatus) and the thylacine (Thylacinus cynocephalus). The barred bandicoot (Fer ameles bougainville) has been omitted because it bears little resemblance to any of the designs discussed.

ERYSIPELAS IN A NUMBAT (MYRMECOBIUS FASCIATUS)

An adult, female numbat (Myrmecobius fasciatus) was submitted to the Perth Zoo Veterinary Department for postmortem examination in November 2011. This radio-collared wild numbat had been found dead in the Dryandra Woodland, 191 km southeast of Perth, Western Australia. On external examination, the body condition was good. Three ticks (Ixodes spp.) were found on the thoracic region. The external pouch was contaminated with dirt and palpably flocculent, and the nipples oozed a purulent material. Histopathology showed widespread fibrin thrombi containing bacterial microcolonies within interstitial vessels of the mammary gland with surrounding necrotic tissue. Bacterial microcolonies were present throughout the kidney, intestine, lung, and mammary tissue, and culture produced a moderate growth of Erysipelothrix rhusiopathiae. Although erysipelas has been reported as a cause of morbidity and mortality in marsupials, this is the first report of erysipelas in the order Dasyuromorphia (marsupial carnivores) and highlights the need for ongoing surveillance for causes of disease in wild numbats and species recovery programs.

Ancestry of the Australian Termitivorous Numbat

The Australian numbat, Myrmecobius fasciatus, is the only marsupial that feeds almost exclusively on termites and that has a life following the diurnally restricted and dynamic geographical distribution of termites. The millions of years of this adaptation led to unique morphological and anatomical features, especially basicranial and dental characteristics, that make it difficult to identify a clear phylogenetic affiliation to other marsupials. From DNA sequence analyses, the family Myrmecobiidae is placed within the dasyuromorph marsupials, but the exact position varies from study to study, and support values are mostly rather modest. Here, we report the recovery and analysis of approximately 110,000 quasifossilized traces of mobile element insertions into the genome of a dasyurid marsupial (Tasmanian devil), 25 of which are phylogenetically informative for early dasyuromorphial evolution. Fourteen of these ancient retroposon insertions are shared by the 16 Dasyuromorphia species analyzed, including the numbat, but are absent in the outgroups. An additional 11 other insertions are present in all Dasyuridae but are absent in the numbat. These findings place numbats as the sister group to all living Dasyuridae and show that the investigated Dasyuromorphia, including the Myrmecobiidae, constitutes a monophyletic group that is separated from Peramelemorphia, Notoryctemorphia, and other marsupials.

Non-invasive assessment of stress in captive numbats, Myrmecobius fasciatus (Mammalia: Marsupialia), using faecal cortisol measurement

Annual patterns of faecal cortisol metabolite (FCM) secretion were examined in six captive numbats (Myrmecobius fasciatus). The use of enzyme-immunoassay for the measurement of FCM in the numbat faeces was validated using an adrenocorticotropic hormone (ACTH) challenge and the resultant FCM measurements represent the first description of adrenal endocrinology in this species. Total overall, baseline and peak FCM mean concentrations varied according to individual, but not gender. For males, mean baseline and overall FCM secretion was higher in spring in summer (compared to winter and autumn) and was elevated during the breeding season. For females, mean baseline FCM secretion did not differ by season or breeding season, but mean overall FCM secretion was elevated during the breeding season. Thus, male (but not female) numbats display an annual change in FCM secretion that is strongly linked to their seasonal pattern of reproduction. Significant FCM elevations (n=178) were observed in response to 20 different stressors, with these stressors being allocated to one of six categories: ANIM, ENVIRO, HAND, HEALTH, MAN and UNK. The mean proportion of positive responses to each category varied according to category, season and breeding season, but did not vary by individual or gender. ANIM and HEALTH stressors elicited a higher response rate than all other categories and an increase in the number of ANIM, ENVIRO, and HEALTH stressors were observed during the breeding season. Although there were multiple stressors within the captive environment that the numbats reacted to, this did not translate into a welfare issue.