Dasyuromorphia

(Australasian carnivorous marsupials)

Class Mammalia

Order Dasyuromorphia

Number of families 3

Number of genera, species 23 genera; 71 species

Evolution and systematics

The order Dasyuromorphia includes three families of carnivorous marsupials in the superfamily Dasyuroidea: the Dasyuridae (dasyures), the Myrmecobiidae (numbat), and the Thylacinidae (thylacines). The dasyurids and thylacinids are more closely related to each other than they are to the numbat. The Australian marsupial radiation produced a number of other species of carnivorous marsupials in the otherwise herbivorous order Diprotodontia. These include two genera (Thylacoleo and Wakaleo) and seven species of large, up to 220 lb (100 kg), predatory marsupial lions of the family Thylacoleonidae, which are most closely related to koalas and wombats (superfamily Vombatoidea), and an omnivorous (partly flesh-eating) giant rat-kangaroo, in the subfamily Propleopinae, family Hypsiprymnodontidae, superfamily Macropodoidea.

The earliest known carnivorous marsupial in Australia, Djarthia murgonensis, comes from the early Eocene (55 million years ago [mya]). The taxonomic affiliation of this and two other early carnivorous marsupials is not certain, as key anatomical features used to clearly identify them to family level or even to separate them from the South American marsupial fauna are lacking in the fossils found to date. The Australian dasyuromorphian and American marsupial taxa are quite distinct but are allied in the possession of many incisors (polyprotodonty) which distinguish them from the herbivorous Diprotodontia. Dasyuromorphians originated in the late Oligocene. The early radiation comprised the very conservative or "primitive" thylacinids. Ranging in size from small dog-sized, 70.5–176.4 oz (2–5 kg) to slightly larger than 65 lb (30 kg), thylacines dominated the Australian carnivorous marsupial fauna until the late Miocene, after which they steadily declined to two species present in the Pleistocene and only one persisting until historic times. Dasyurids first appeared in the fossil record in the early to middle Miocene but were rare until the late Miocene when they diversified and replaced the thylacine as the dominant marsupial carnivore fauna. Most of the Pleistocene fossil dasyurids are from still-living taxa, although none of the living groups occur earlier than the Pliocene. Dasyurids are considered to be highly specialized or "derived" dasyuromorphians in terms of their morphology. The numbats are represented by only one living species which appeared in the fossil record as recently as the Pleistocene. The numbat is a highly specialised dasyuromorphian, with features of the skull, teeth, and tongue adapted for termite feeding.

Physical characteristics

Dasyuromorphians are quadrupedal (move on four legs), with four toes on the front feet, four or five toes (including

a clawless toe called a hallux) on the hind feet, long tails and long, pointed snouts, and are considerably uniform in body shape despite the large size variation, from 0.14 oz (4 g) to more than 65 lb (30 kg). Extreme exceptions in body form include the kultarr, which has elongated hind legs and bounds rather than runs, and the robust form and massive skull, teeth and jaw musculature of the specialist scavenger, the Tasmanian devil. Unlike placental carnivores, the fleshy foot pad of thylacines and dasyures extends to the heel and wrist joint, which may contact the ground when stationary or moving slowly, although most species are digitigrade (run on the toes) when moving fast. Arboreal (tree-dwelling) species tend to have broader feet and a better-developed, more dexterous hallux. Some dasyurid species store fat in the tail. None are prehensile and in some such as the thylacine, the tail is semi-rigid. Tail length is generally shorter than body length, except in the numbat and in the long-tailed dunnart.

The dentition is polyprotodont, meaning many incisors (four upper, three lower), which distinguishes this group of marsupials from the Diprotodontia or herbivorous marsupials. Premolars number three in thylacines and numbats, two in dasyures. All molar teeth (four in thylacines and dasyures; five in numbats) are similar in form, in contrast with the differentiation of slicing and grinding functions into separate teeth in the placental carnivores. Thylacine and dasyure molars each retain meat-slicing (carnassial) cusps and function, and grinding surfaces. This marsupial feature may be a consequence of reproductive mode. Permanent teat-attachment during tooth development appears to suppress the eruption of the deciduous teeth, which remain vestigial, leading to early eruption of the permanent dentition. Each of these permanent molars must, in turn, function as slicing and grinding/crushing teeth when they first erupt, and then either specialized slicing or crushing teeth when they achieve their final position in the mature jaw. Tooth structure ranges from simple, cuspless molars in the termite-eating numbat, to the more complex slicing/crushing molars of the other two families. The degree of carnassiality (or meat-slicing function) grades with diet. Highly carnivorous taxa, such as thylacines and devils, have well-developed carnassial cusps, reduced crushing surfaces, and molar orientation is more antero-posterior. This is particularly the case in the two rear molars, which are biomechanically positioned in adults for maximal slicing function, in a position halfway along the jaw bone comparable to the carnassial tooth in placental carnivores. As the diet becomes more insectivorous, the crushing surfaces (the rear part of each molar tooth) become larger

at the expense of the carnassial cusps (sharp, pointy bits) and the molar teeth become wider and more triangular in shape. A feature at least of the larger dasyuromorphians is continual or over-eruption of the canine teeth throughout life. This may be a consequence, again, of early eruption of the permanent teeth at an age when the juvenile animal is less than half of its adult size. Over-eruption, while probably a response to tooth wear and occlusal patterns, has the effect that the canine teeth continue to get bigger as the individual grows.

Coat color in most species ranges from sandy to reddish to grayish brown, sometimes with a lighter colored underbelly. Black is rare (only devils and one of the two color phases of the eastern quoll) and only eight taxa have distinct markings: stripes on the back in the thylacine, numbat and three groups of New Guinean dasyurids, a facial stripe in the numbat, spots in the quolls and white chest, shoulder and rump markings in the devil. Fur length is mostly short to slightly wispy, although tail fur can vary from short, to a bushy tip, to completely fluffy or bushy.

Distribution

The order Dasyuromorphia comprises the Australian radiation of the polyprotodont marsupials and is restricted to Australia, New Guinea, Tasmania, and some smaller close-by islands. At times during evolutionary history, including most recently the Pleistocene (2 million to 10,000 years ago), land bridges connected Australia and New Guinea, and Australia and Tasmania, and there was opportunity for interchange between the faunas of these major land masses. This historical pattern of connectivity between land masses is reflected in the distributions and genetic relationships of species. Two species of dasyurids in the genus Sminthopsis—S. archeri and S. virginiae—have ranges that cross Torres Strait from northern Australia to New Guinea, and one of the New Guinean quolls, the bronze quoll (Dasyurus spartacus), is very closely related to the chuditch (D. geoffroii) from the Australian mainland. All of the Tasmanian dasyurid species are currently, historically, or prehistorically (depending on the timing of mainland extinctions) represented in mainland populations (seven species). Where genetic studies have been carried out, mainland and Tasmanian populations represent different evolutionary significant units, a consequence of over 10,000 years of evolutionary separation. It is notable, however, that these faunal interchanges were restricted largely to savanna and woodland species. The cold, dry conditions that prevailed during the Pleistocene precluded the development of significant rainforest corridors. Rainforest Antechinus of Cape York and the sister clade Murexia from New Guinea did not make it across the land bridge, although some small dasyurids of wet habitats (Antechinus minimus—closed, wet heath, grass or sedgelands; A. swainsonii—wet forest and heath) do occur on either side of Bass Strait.

Habitat

Carnivorous marsupials occupy habitats from deserts to mountain tops to rainforests and show an accordingly wide range of behavioral, morphological, and physiological adaptations.

Australia's small desert dasyurids are remarkable in their ability to move very long distances in response to local rainfall and fire events, thereby utilizing different vegetative growth stages and short-term flushes in food availability. Planigales live in deep soil cracks and have a suitably flattened body shape. Arboreal and scansorial (above-ground) species, including the antechinuses, are more likely to have a well-developed and dexterous clawless hallux on the inside of the hind foot, which assists with grasping branches or rocks. Very capable climbers such as spotted-tailed quolls (Dasyurus maculatus), also possess fleshy ridges on their foot pads and sharp claws. Spotted-tailed quolls can climb large, straight trees to kill possum prey in their daytime tree-hollow refuges, move from tree to tree through the canopy, and climb head-first down trees.

Dasyurids live at extremes of temperature, have a low basal metabolic rate like other marsupials, experience a fluctuating food supply, and most species are small and so lose and gain heat easily. Carnivorous marsupials cannot sweat but resort to licking, panting, and lying flat out on the substrate to keep cool. Strategies to conserve body heat and reduce energy expenditure are diverse. Surface-dwelling desert species such as ningaui have a spherical body shape, which maximises heat conservation. Antechinuses and Tasmanian devils increase fur thickness in winter and the fur color of some species (fat-tailed dunnart, Sminthopsis crassicaudata) becomes darker towards temperate regions. Most dasyurids use protected locations in hollow logs and trees, underground burrows, soil crevices, caves, and tussock grasses to rest during the day or between foraging bouts. Many species line their nest with insulative dead vegetation which they harvest and carry in their mouth, and some huddle in groups comprising adults, or mother and offspring. Huddling in communal nests reduces energy expenditure in dunnarts by 20%. Torpor, in which the body temperature is voluntarily reduced to between 52–82°F (11–28°C) for periods of several hours, is used by half of dasyurids and the numbat, species ranging from 0.17 oz (5 g) to 35 oz (1,000g) in body size. Torpor is employed as a daily or occasional strategy to conserve energy while resting, under the stresses of cold or food restriction. The females of some species even go into torpor when with young. The slow marsupial development rate may allow this without adverse effects on the babies. Perhaps as a consequence of their relatively low basal metabolic rate, common to all marsupials, carnivorous marsupials have a pronounced ability to increase metabolic rate when cold that exceeds that of some placental mammals.

Another interesting question to ask is what determines how species live together. As most carnivorous marsupials are generalised predators that can take a wide size range of invertebrate and vertebrate prey, structurally complex habitats that offer a variety of different places to forage are an important contributor to local species diversity.

Rather counter-intuitively, it is the arid zone habitats, as well as forest and heath, that are more structurally complex and offer the most opportunities for multiple species to partition resources. This may explain why there are so many species of desert dasyurids. Although the scansorial or above-ground foraging niche, that is important in forest, is lacking in deserts, a wealth of opportunities to segregate are provided by cracks in clay soils, sandy, sand dune and rocky substrates, and structurally complex vegetation such as hummock grasslands.

In forests, the arboreal or above-ground foraging niche contributes to species coexistence. A number of antechinuses are scansorial, meaning that they scramble around both on the ground and a number of metres up into shrubs and trees, even denning in tree hollows. Among the larger marsupial carnivores of Tasmania, spotted-tailed quolls separate from their close competitors, eastern quolls (Dasyurus viverrinus) and devils (Sarcophilus laniarus), on their greater arboreal use of habitat.

Behavior

Australian mammals are almost all nocturnal or crepuscular and the carnivorous marsupials are no exception. Most are nocturnally active, although some diurnal foraging and basking activity has been recorded in a number of species for which detailed field observations are available, including in antechinuses and thylacines. In some populations, spotted-tailed quolls exploit opportunities to prey upon nocturnal possum prey asleep in tree hollows, and are almost arhythmic in their activity. Three species are substantially or completely diurnal, the numbat, the speckled dasyure from New Guinea, and the southern dibbler (Parantechinus apicalis) from Western Australia.

Well developed auditory and olfactory communication could be expected in these primarily nocturnal mammals, although carnivorous marsupials use a variety of visual displays as well. Vocalizations range from hisses, growls, squeaks, barks to screeches in the low (0.1 kHz) to ultrasonic (most less than 12 kHz) frequency range. Contact calls between mother and young start while young are still living in the pouch and consist of squeaks and wheezes which are returned by the mother at a lower pitch. Aggressive calls range from hisses, to growls and screeches. The screech of spotted-tailed quolls has been described as a blast from a circular saw and that of the Tasmanian devil sufficient to "raise the devil," a trait which may have contributed to its name. Female planigales and quolls in estrus emit male-attracting soft clucking calls when receptive to mating. Tasmanian devil females, and to a lesser extent males, crouch mouth to open mouth and give continuous soft barks, each of which ends in a whine. Unwelcome suitors are repelled aggressively.

Scent is an important vehicle for the dissemination of social and reproductive information between individuals, such as male dominance status and the estrous state of females. In carnivores, the information-laden metabolic breakdown products of reproductive hormones are excreted mainly via the feces, although urine of male antechinus also contains sex-specific compounds. Dasyurids have well-developed paracloacal glands from which a pungent, viscous, yellowish liquid is exuded during cloacal dragging form of scent marking. Male Tasmanian devils cloacal drag frequently in the presence of oestrous females, and both sexes mark frequently during non-breeding social interactions. This behavior is well established even in advanced pouch young before the glands have begun to produce scent. Sternal skin glands and chest rubbing are widespread primarily among males of the smaller dasyurids (antechinuses, dunnarts, phascogales), an activity which increases during the breeding season under the control of male reproductive hormones (testosterone). Female quolls and devils produce prodigious quantities of reddish oil in the pouch, the quality and quantity of which is an indicator of estrous state, but which probably also serves to prepare the pouch for occupancy by the young. That this oil also has a function in communicating reproductive state is suggested by the intense interest that males show in sniffing the female's pouch compared with her cloaca.

Visual signals include extensive repertoires of postures, which the use of light-amplifying equipment enables humans to observe. Tasmanian devils use in excess of 20 different postures in social interactions. Visual displays that accentuate body size and weaponry (threat displays) or reproductive readiness usually prelude potentially dangerous aggressive or reproductive interactions. Open mouthed threat displays that show the teeth are common.

Feeding ecology and diet

Competition for food contributes to differences in foraging niche among all size ranges of carnivorous marsupials that live together, with the exception of the termite-eating numbat but including, historically, the thylacine. Competition appears to be more prevalent in mesic forests and heathlands than in arid environments, where droughts, floods, and unpredictable food supplies may often reduce populations to low levels. Competition from larger antechinus species excludes smaller species from the highest quality habitat, with the result that the smaller species eats smaller prey for which they probably have to work harder. In Tasmania, food competition among the larger carnivores has resulted in separation between species on prey size. If species consume different-sized prey, competition for the same prey items is reduced. Competition has been sufficiently intense over a long enough time scale to drive evolutionary changes in canine tooth size among the quolls. Canine tooth strength, which determines the size of prey that can be killed, have become evenly spaced. Even spacing in prey size among species minimizes competition.

Reproductive biology

Short life spans, leading in their extreme form to single breeding followed by death in the first year of life (semelparity), are a defining feature of carnivorous marsupials. Among mammals, semelparity has arisen only in dasyurids and didelphids, in which groups it has evolved at least six times, including in medium-sized species over 2.2 lb (1 kg) in body weight (northern quoll, Dasyurus hallucatus). All carnivorous marsupials, including thylacines and possibly numbats,

are short-lived, however, compared to similar-sized placental mammals. This entire taxon seems to be evolutionarily disposed towards early senescence.

Semelparity among dasyurids is obligate in most antechinuses (Antechinus spp.), in both Phascogale species and in the little red kaluta (Dasykaluta rosamondae), but faculatative in the dibbler and the northern quoll. In the larger antechinuses, complete male die-off occurs immediately after mating but females may live to breed in a second year. The adaptive explanation developed on antechinus to explain die-off postulates that as a consequence of small body size, slow growth and the consequent long period of time required to raise young to independence, and tightly seasonal environments in which food is limiting, males and females are unlikely to be able to gain sufficient energy to breed and then survive to a second year. Their best option may be to put all their energy into one big reproductive effort in the first year, even if it kills them. In antechinuses, a consequence of the need to wean young in a tightly seasonal climate at the time of year when food supplies are maximal is that mating occurs in winter when food resources are scarce. Males are unable to store sufficient fat to see them through the intense mating rut and overcome this energy deficit by using elevated levels of stress hormones to promote the use of protein in muscle tissue as an energy resource. This only becomes possible through complete destruction of the ability to produce more sperm before mating starts (sperm production would interfere with synthesis of stress hormones but also removes any possibility of breeding in a second year) and the shutdown of a negative feedback system that prevents sustained levels of damaging stress hormones in most mammals. Death results from a multitudinous cascade of events related to dramatic loss of body condition and immunosuppression from prolonged elevation of stress hormone levels. Males become anaemic and support huge numbers of ectoparasites, which exacerbates their problems. The proximal cause of death is usually gastrointestinal ulcers or an outbreak of a normally benign disease.

This model is supported by the geographic distribution of semelparous species, which are generally restricted to tightly seasonal environments where reproductive opportunities are limited to a narrow window each year. Iteroparous or multiple-breeding species, such as some dunnarts, include most species from unpredictable arid environments where putting all the eggs in one reproductive basket would be a risky strategy indeed. The lack of sustained elevated stress hormone levels, and opportunities, that come with larger body size and tail fat stores, for sufficient fat storage to tide over the mating period in the northern quoll suggests that a universal model of male die-off remains obscure.

Very small quantities of some of the largest sperm produced by any mammal are other unique features of reproduction in carnivorous marsupials. Complete failure of sperm production prior to the mating period in antechinuses and limited sperm storage leave comparatively small amounts of sperm available for a very intense, once in a lifetime rut; in the brown antechinus (Antechinus stuartii) as few as eight ejaculations. Dasyurid sperm have an unusual form of motility which may compensate for this apparent disadvantage.

Copulation in semelparous species is an intense affair with intromission lasting as long as seven to 12 hours. Given the limited sperm supplies, it must be assumed that sperm is used carefully and ejaculation is timed to maximise the chance of fertilization. Most of the time and energy devoted to mating probably serves the dual functions of stimulating the female and mate guarding, both of which increase the male's chance of siring the young. Physical stimulation provided by the thrusting male during copulation improves sperm transport up the female reproductive tract, and occupying the female in copulo for a substantial proportion of the limited time in which she is in estrus physically prevents other males from mating with her. Antechinus, which mate in communal leks, are able to turn 180° while in copulo and fight off other males. Tasmanian devils indulge in ferocious mate guarding, keeping the female a prisoner in the den for days at a time without food or water, until her estrus is finished or the female's desire to escape reaches such an intensity that she succeeds in fighting off the male. Both male and female are likely to be injured in this process.

The female is by no means a passive spectator in the mating business. Female Tasmanian devils actively assess different males and solicit copulations from the male of their choice, avoiding or fighting off the others. Long periods of behavioral estrus allow time for females to mate with a number of males, resisting mate guarding attempts and fighting each one off in turn.

Multiple paternity has been found in all of the small number of species in which mating systems have been investigated using genetic paternity markers, and suggest high levels of promiscuity among females. Four fathers per litter is not uncommon in devils (four teats) and up to seven fathers have been recorded in the agile antechinus (six to 10 teats), with 50% of litters having three or more. Prolonged copulation, larger than average testes size (correlated with greater sperm production), strong male-biased sexual size dimorphism (males larger than females), intense mate guarding, long periods of behavioral estrus, prolonged periods of sperm storage within the female reproductive tract prior to ovulation, and higher population densities are associated with the likelihood of sperm competition (between the sperm of different males within the female reproductive tract) and possibly the intensity of female choice. Semelparous species such as antechinueses exhibit all of the above traits. Iteroparous species from less predictable, arid environments, such as some dunnarts, do not.

Carnivorous marsupials, at least the dasyurids, have one more trick up their metaphorical sleeves. Together with bats, dasyurids are unique among mammals in having sperm storage facilities in the female reproductive tract. (Sperm storage is common in birds and insects.) Ovulation occurs up to 12 days after behavioral estrus and the sperm of several males are stored, possibly right next to each other, in tiny crypts in the oviducts. The sperm is reactivated and released at ovulation. This puts quite a different spin on how sperm competition might operate.

Parental care in all carnivorous marsupials for which it is known is restricted to maternal care of the young during permanent attachment to the teat and lactation. Once young have permanently vacated the pouch, they are deposited in a vegetation-lined nest in a den (underground burrow, cave, or hollow log). Apart from records of chuditch (western quolls) moving young to new dens on their back, there are no other records of females escorting young outside the den. Juvenile chuditch gradually explore further and further from the mother's den as they grow and teach themselves to forage and hunt. As weaning from lactation approaches, both mother and young start to spend nights apart in different dens. The frequency of these separations increases until the male young disperse. Once the males move away from the mother's home range they move rapidly over long distances.

Among many mammals, and it appears most carnivorous marsupials, it is usually the male offspring that disperse from their mother's home range, females staying close to home for life. Females thus exact a longer term cost to the mother, although the difference in the number of young produced by both good and poor quality females will not be great. If, however, there are major differences among individual males in reproductive success, it may be advantageous for females to invest more heavily in male offspring. Strongly male-biased sex ratios occur in some species of dasyurids, including in agile antechinuses. The mechanism of sperm storage offers possibilities for sex-based sperm selection.

Conservation

The pattern of endangerment among the carnivorous marsupials is consistent with that for Australian mammals in general.

Australia accounts for 50% of the world's recent mammalian extinctions, the causes of which are multiple and confounded. Causes include habitat destruction, fragmentation, and degradation resulting from land clearance, altered fire regimes, and grazing by introduced livestock and rabbits, and vulnerability to predation by introduced foxes. Dasyurids track the overall mammalian pattern, in which extinctions and declines have been greatest in arid areas and in medium-sized terrestrial species. An exception to this is the thylacine, which has the distinction of being the only large carnivore globally to become extinct in recent times. The loss of the thylacine represents not just a species but also an entire genus and a family extirpated.

Significance to humans

Many species of native marsupials had a place in the dream-time histories of aboriginal peoples. Aboriginal histories have indeed revealed ecological information on species that became extinct prior to European documentation. However, except for the very distinctive animals, aboriginal peoples did not necessarily distinguish between species of the smaller Australian mammals. The larger, more distinctive species were held in reverence, with dreaming stories, totemic status, and ritual treatment that sometimes precluded consumption. Aboriginal peoples probably hunted and ate all species of carnivorous marsupials depending on abundance.

Commercial exploitation of carnivorous marsupials for furs or skins has not been recorded, apart from early collecting for museums, despite the beautiful coat patterns of some of the larger species. Perhaps the lack of intensely cold climates and winter pelts contributed to this lack of economic interest. Some species may confer economic benefits in their dietary proclivity for agricultural and forest insect pests and their abilities in dispatching rodents. The diet of eastern quolls living on farmland is dominated at times of the year by pest pasture grubs (corbie grubs and wire worms).

Economic impacts of carnivorous marsupials are restricted to the larger species. The predatory abilities of carnivorous marsupials in tackling large prey (relative to their body size) means that any species larger than 4.8 oz (150 g) can take on domestic poultry. Inadequately housed poultry may be targeted by phascogales, quolls, and devils, particularly at night and especially by young animals and females feeding young. Lambs in the first 24 hours of life are vulnerable to Tasmanian devils. Lambs from multiple births and certain breeds of sheep are more vulnerable. Fencing is not difficult (strong mesh wire, no holes, footings 6 in [15 cm] below ground), but education and attitudinal change is a major hindrance. Thylacines would have killed sheep of all sizes. Persecution on individual properties can have a significant impact on local populations of devils in particular and certainly did on thylacines.

Resources

Books

Archer, M., T. Flannery, S. Hand, and J. Long. Prehistoric Mammals of Australia and New Guinea: One Hundred Million Years of Evolution. Sydney: UNSW Press, 2002.

Cockburn, A. "Living slow and dying young—senescence in marsupials." In Marsupial Biology: Recent Research, New Perspectives. Sydney: UNSW Press, 1997.

Dickman, R. R. "Distributional ecology of dasyurid marsupials." In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Dixon, J. M. "Thylacinidae." In Fauna of Australia, Canberra: Australian Government Publishing Service, 1989.

Flannery, T. Mammals of New Guinea. Sydney: Reed Books, 1995.

Friend, J. A. "Myrmecobiidae." In Fauna of Australia, pp. 583-590. Canberra: Australian Government Publishing Service, 1989.

Krajewski, C., and M. Westerman. "Molecular systematics of Dasyuromorphia." In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Maxwell, S., A. A. Burbidge, and K. Morris. "The Action Plan for Australian Marsupials and Monotremes. IUCN/SSC Australasian Marsupial and Monotreme Specialist Group, Wildlife Australia, Environment Australia, Canberra ACT Australia." In Wildlife Australia, Endangered Species Program, Project Number 500 Report. Canberra: Australian Government Publishing Service, 1996.

Morton, S. R., C. R. Dickman, and T. P. Fletcher. "Dasyuridae." In Fauna of Australia. Canberra: Australian Government Publishing Service, 1989.

Strahan, R., ed. The Mammals of Australia. Sydney: Reed Books, 1995.

Taggart, D. A., G. A. Shimmin, C. R. Dickman, and W. G. Breed. "Reproductive Biology of Carnivorous Marsupials: Clues to the Likelihood of Sperm Competition." In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Toftegaard, C. L., and A. J. Bradley. "Chemical communication in dasyurid marsupials." In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Ward, S. J. "Biased sex ratios in litters of carnivorous marsupials; Why, when & how?" In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Wilson, B. A., C. R. Dickman, and T. P. Fletcher. "Dasyurid dilemmas: Problems and solutions for conserving Australia's small carnivorous marsupials." In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Wroe, S. "Australian marsupial carnivores: an overview of recent advances in palaeontology." In Predators with Pouches: The Biology of Carnivorous Marsupials. Melbourne: CSIRO Publishing, 2003.

Periodicals

Dickman, C. R. "An experimental study of competition between two species of dasyurid marsupials." Ecological Monographs 56 (1986): 221–241.

Firestone, K. B., M. S. Elphinstone, W. B. Sherwin, and B. A. Houlden. "Phylogeographical population structure of tiger quolls Dasyurus maculatus (Dasyuridae: Marsupialia), an endangered carnivorous marsupial." Molecular Ecology 8 (1999): 1613–1625.

Fisher, D. O., and C. R. Dickman. "Body size–prey size relationships in insectivorous marsupials: tests of three hypotheses." Ecology 74 (1993): 1871–1883.

Jones, M. E. "Character displacement in Australian dasyurid carnivores: size relationships and prey size patterns." Ecology 78 (1997): 2569–2587.

Jones, M. E., and L. A. Barmuta. "Diet overlap and abundance of sympatric dasyurid carnivores: a hypothesis of competition?" Journal of Animal Ecology 67 (1998): 410–421.

Kraaijeveld-Smit, F. J. L., S. J. Ward, and P. D. Temple-Smith. "Multiple paternity in a field population of a small carnivorous marsupial, the agile antechinus, Antechinus agilis." Behavioral Ecology and Sociobiology 52 (2002): 84–91.

Righetti, J., B. J. Fox, and D. B. Croft. "Behavioural mechanisms of competition in small dasyurid marsupials." Australian Journal of Zoology 48 (2000): 561–576.

Soderquist, T. R., and M. Serena. "Juvenile behaviour and dispersal of chuditch (Dasyurus geoffroii) (Marsupialia: Dasyuridae)." Australian Journal of Zoology 48 (2000): 551–560.

Taggart, D. A., and P. D. Temple-Smith. "An unusual mode of progressive motility in spermatozoa from the dasyurid marsupial, Antechinus stuartii." Reproduction, Fertilization and Development 2 (1990): 107–114.

——. "Transport and storage of spermatozoa in the female reproductive tract of the brown marsupial mouse, Antechinus stuartii (Dasyuridae)." Journal of Reproduction and Fertility 93 (1991): 97–110.

——. "Comparative studies of epididymal morphology and sperm distribution in dasyurid marsupials during the breeding season." Journal of Zoology 232 (1994): 365–381.

Menna Jones, PhD