Lagostrophus Research Articles

Novel microsatellites and investigation of faecal DNA as a non-invasive population monitoring tool for the banded hare-wallaby (

Monitoring programs for populations of small or medium-sized animals often use live-capture or photo-monitoring trapping methods to estimate population size. The banded hare-wallaby (Lagostrophus fasciatus), a small macropodiform marsupial, does not readily enter traps or have individually unique distinguishing physical features and is consequently difficult to monitor using these methods. Isolating DNA from faecal material to obtain individual genotypes is a promising monitoring technique and may present an alternative approach for this species. We developed novel species-specific microsatellite markers and undertook trials to assess faecal DNA degradation in ambient environmental conditions at two locations where this species has been translocated. The quality of DNA yielded from faecal pellets was evaluated through amplification failure and genotyping error rates of microsatellite markers. Error rates were compared for different treatments and exposure duration across multiple individuals. DNA was successfully obtained from all samples and error rates increased with exposure duration, peaking after 14–30 days depending on the site and treatment. The level of solar exposure was the most significant factor affecting degradation rate but both this and exposure duration had significant effects on amplification failure. Analysing DNA obtained from faecal pellets may represent a practical non-invasive method of deriving population estimates for this species and warrants further development.

Genetic Consequences of Multiple Translocations of the Banded Hare-Wallaby in Western Australia

Many Australian mammal species now only occur on islands and fenced mainland havens free from invasive predators. The range of one species, the banded hare-wallaby (Lagostrophus fasciatus), had contracted to two offshore islands in Western Australia. To improve survival, four conservation translocations have been attempted with mixed success, and all occurred in the absence of genetic information. Here, we genotyped seven polymorphic microsatellite markers in two source (Bernier Island and Dorre Island), two historic captive, and two translocated L. fasciatus populations to determine the impact of multiple translocations on genetic diversity. Subsequently, we used population viability analysis (PVA) and gene retention modelling to determine scenarios that will maximise demographic resilience and genetic richness of two new populations that are currently being established. One translocated population (Wadderin) has undergone a genetic bottleneck and lost 8.1% of its source population’s allelic diversity, while the other (Faure Island) may be inbred. We show that founder number is a key parameter when establishing new L. fasciatus populations and 100 founders should lead to high survival probabilities. Our modelling predicts that during periodic droughts, the recovery of source populations will be slower post-harvest, while 75% more animals—about 60 individuals—are required to retain adequate allelic diversity in the translocated population. Our approach demonstrates how genetic data coupled with simulations of stochastic environmental events can address central questions in translocation programmes.

Reconstructing the Evolution of Giant Extinct Kangaroos: Comparing the Utility of DNA, Morphology, and Total Evidence.

Combined "total evidence" analysis of molecular and morphological data offers the opportunity to objectively merge fossils into the tree of life, and challenges the primacy of solely DNA based phylogenetic and dating inference, even among modern taxa. To investigate the relative utility of DNA, morphology, and total evidence for evolutionary inference, we sequenced the first near-complete mitochondrial genomes from extinct Australian megafauna: a 40-50 thousand year old giant short-faced kangaroo (Simosthenurus occidentalis) and giant wallaby (Protemnodon anak). We analyzed the ancient DNA and fossil data alongside comparable data from extant species to infer phylogeny, divergence times, and ancestral body mass among macropods (kangaroos and wallabies). Our results confirm a close relationship between Protemnodon and the iconic kangaroo genus complex "Macropus", and unite the giant Simothenurus with the hare-sized Lagostrophus fasciatus (banded hare-wallaby), suggesting that the latter is the closest living link to the once diverse sthenurine kangaroo radiation. We find that large body size evolved multiple times among kangaroos, coincident with expansion of open woodland habitats beginning in the Late Miocene. In addition, our results suggest that morphological data mislead macropod phylogeny reconstruction and in turn can distort total evidence estimation of divergence dates. However, a novel result with potentially broad application is that the accuracy and precision of reconstructing ancestral body mass was improved by tracing body mass on morphological branch lengths. This is likely due to positive allometric correlation between morphological and body size variation-a relationship that may be masked or even misleadingly inverted with the temporal or molecular branch lengths that typically underpin ancestral body size reconstruction. Our study supports complementary roles for DNA and morphology in evolutionary inference, and opens a new window into the evolution of Australia's unique marsupial fauna.

Direct evidence implicates feral cat predation as the primary cause of failure of a mammal reintroduction programme

SummaryAs evidence mounts that the feral Cat (Felis catus) is a significant threat to endemic Australian biodiversity and impedes reintroduction attempts, uncertainty remains about the impact a residual population of cats following control will have on a mammal reintroduction programme. Also, behavioural interactions between cats and their prey continue to be an area of interest. Within the framework of an ecosystem restoration project, we tested the hypotheses that successful reintroductions of some medium‐sized mammals are possible in locations where feral cats are controlled (but not eradicated) in the absence of European Red Fox (Vulpes vulpes), and that hare‐wallabies that dispersed from their release area are more vulnerable to cat predation compared with those that remain at the release site. We used radiotelemetry to monitor the survivorship and dispersal of 16 Rufous Hare‐wallabies (Lagorchestes hirsutus spp.) and 18 Banded Hare‐wallabies (Lagostrophus fasciatus fasciatus) reintroduced to four sites within Shark Bay, Western Australia. Nearly all foxes were removed and feral cats were subject to ongoing control that kept their indices low relative to prerelease levels. All monitored hare‐wallabies were killed by cats within eight and 10 months following release. Significant predation by feral cats was not immediate: most kills occurred in clusters, with periods of several months where no mortalities occurred. Once a hare‐wallaby was killed, however, predation continued until each population was eliminated. Animals remaining near their release site survived longer than those that dispersed. The aetiology of predation events observed offers new insights into patterns of feral cat behaviour and mammal releases. We propose a hypothesis that these intense per capita predation events may reflect a targeted hunting behaviour in individual feral cats. Even where feral cats are controlled, the outcome from consistent predation events will result in reintroduction failures. Managers considering the reintroduction of medium‐sized mammals in the presence of feral cats should, irrespective of concurrent cat control, consider the low probability of success. We advocate alternative approaches to cat‐baiting alone for the recovery of cat‐vulnerable mammals such as hare‐wallabies.

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.

New Species of Parasitic Nematodes of the Genus Cloacina (Nematoda: Strongyloidea) from the Banded Hare Wallaby, Lagostrophus Fasciatus(Marsupialia: Macropodidae)

Two new species of Cloacina von Linstow, 1898, C. ridei sp. nov. and C. biscoei sp. nov. are described from the stomach of the banded hare wallaby, Lagostrophus fasciatus (Péron & Lesueur, 1807) from Western Australia. The two species differ from all congeners in having the excretory pore at the level of the nerve ring and the externodorsal ray arising from the dorsal ray. In spite of the relatively poor state of preservation of the nematodes, the two species are distinguishable from one another by the shape of the oesophagus, which is elongate and has combs in the bulb in C. ridei and in the shape of the buccal capsule, that of C. biscoei having an undulating anterior margin and in the shape of the cephalic papillae, with C. ridei having an enlarged distal segment and C. biscoei having a tiny distal segment.

An osteology-based appraisal of the phylogeny and evolution of kangaroos and wallabies (Macropodidae: Marsupialia)

Macropodids are the most diverse group of marsupial herbivores ever to have evolved. They have been the subject of more phylogenetic studies than any other marsupial family, yet relationships of several key clades remain uncertain. Two important problem areas have been the position of the merrnine (Lagostrophus fasciatus) and the phylogenetic proximity of tree-kangaroos and rock-wallabies. Our osteological analysis revealed strong support for a plesiomorphic clade (Lagostrophinae subfam. nov.) containing Lagostrophus and Troposodon, which is likely to have originated in the early Miocene. The extinct short-faced kangaroos (Sthenurinae) emerged in the middle Miocene as the sister lineage to a clade containing all other living kangaroos and wallabies (Macropodinae). New Guinea forest wallabies (Dorcopsini trib. nov.) are the most plesiomorphic macropodines; the other two main lineages include tree-kangaroos and rock-wallabies (Dendrolagini), and 'true' kangaroos and wallabies (Macropodini). These phylogenetic outcomes are broadly consistent with the results of recent molecular studies, although conflicts remain over the relative positions of some macropodins (e.g. Setonix, Onychogalea, and Wallabia). Given the presence of derived dendrolagins and macropodins in early Pliocene localities, it is probable that most macropodine genera originated in the late Miocene. Key functional-adaptive trajectories within the craniodental and locomotory systems of the dominant macropodid lineages represent varying responses to the spread of drier, open habitats following the Miocene Climatic Optimum.

Comparative Jaw Muscle Anatomy in Kangaroos, Wallabies, and Rat‐Kangaroos (Marsupialia: Macropodoidea)

The jaw muscles were studied in seven genera of macropodoid marsupials with diets ranging from mainly fungi in Potorous to grass in Macropus. Relative size, attachments, and lamination within the jaw adductor muscles varied between macropodoid species. Among macropodine species, the jaw adductor muscle proportions vary with feeding type. The relative mass of the masseter is roughly consistent, but grazers and mixed-feeders (Macropus and Lagostrophus) had relatively larger medial pterygoids and smaller temporalis muscles than the browsers (Dendrolagus, Dorcopsulus, and Setonix). Grazing macropods show similar jaw muscle proportions to "ungulate-grinding" type placental mammals. The internal architecture of the jaw muscles also varies between grazing and browsing macropods, most significantly, the anatomy of the medial pterygoid muscle. Potoroines have distinctly different jaw muscle proportions to macropodines. The masseter muscle group, in particular, the superficial masseter is enlarged, while the temporalis group is relatively reduced. Lagostrophus fasciatus is anatomically distinct from other macropods with respect to its masticatory muscle anatomy, including enlarged superficial medial pterygoid and deep temporalis muscles, an anteriorly inflected masseteric process, and the shape of the mandibular condyle. The enlarged triangular pterygoid process of the sphenoid bone, in particular, is distinctive of Lagsotrophus.

Phylogenetic relationships of the Banded Hare wallaby (Lagostrophus fasciatus) and a map of the kangaroo mitochondrial control region

The complete mitochondrial genome of the endangered Banded Hare wallaby (Lagostrophus fasciatus) was sequenced and used for phylogenetic analysis. The data set consisted of 10 377 nucleotides (3459 amino acids) from three kangaroo species. The phylogenetic analyses strongly supported the hypothesis that the Banded Hare wallaby is the sister-group of the wallaroo (subfamily Macropodidae). In addition to the phylogenetic reconstruction, the mt control region, or (D)-loop, from Australian marsupials has been mapped for the first time. The results show that the organization of the kangaroo control region is similar to that of placental mammals. The presence of a duplicated CSB-1 block found in all three kangaroo species is an uncommon feature of mammalian mt DNA. The CSB domain was found to be the most variable region in the control region, followed by a less variable ETAS domain. (Less)

Importance of diurnal refugia to a hare-wallaby reintroduction in Western Australia

In an effort to learn more about the potential for reintroduction of hare-wallabies to sites in Australia, 34 captive-bred hare-wallabies were released onto Peron Peninsula within the Shark Bay World Heritage Property in 2001 as part of an experimental reintroduction program. One objective of this experiment was to characterise their behaviour and daytime refugia to identify suitable habitat for future releases. The mala (Lagorchestes hirsutus) and merrnine (Lagostrophus fasciatus) were fitted with radio-transmitters and tracked daily. Merrnine were more faithful to a previously occupied shelter than mala. Mala maintained a solitary daytime habit at all times. Within the study area, mala preferentially sought low-lying vegetation primarily comprising the species Lamarchea hakeifolia, which provided dense cover up to 1 m in height, under which they constructed scrapes. L. hakeifolia was preferred as shelter vegetation instead of Triodia (spinifex) hummocks, despite Triodia hummock habitat being preferred by mala in central Australia. Merrnine occupied taller vegetation with an open understorey to 1.5 m, although the extremity of the understorey remained dense at this height. Individual merrnine sometimes sheltered with conspecifics of the opposite sex. Since both species utilised floristically and structurally variable vegetation, we suggest that they have the ability to cope with vegetation that has been altered by changes in fire regimes and introduced herbivores. This is particularly important for future reintroduction exercises as the results suggest that vegetation characteristics required to support these species, particularly mala, may be variable rather than limited to perceived necessary habitat types in central Australia or on islands. These results should allow future reintroduction projects to consider a wider range of release-site options during their planning phase.

Optimising reintroduction success by delayed dispersal: Is the release protocol important for hare-wallabies?

The transfer of threatened animals from one location to another in order to benefit the species is a technique frequently used by animal conservation managers. However, very few of these relocations have experimentally assessed the relative merits and disadvantages of commonly used release techniques. The premise examined in this study was that a higher degree of site fidelity should be advantageous for an individual through a soft release protocol. Two species of hare-wallaby, mala ( Lagorchestes hirsutus) and merrnine ( Lagostrophus fasciatus), were fitted with radio-collars and reintroduced in August 2001 onto Peron Peninsula in Western Australia. These threatened species were reintroduced using two release strategies (soft versus hard release), and their movements and body condition were monitored, for a period of four weeks post-release, using radio-telemetry and trapping. Each species averaged decreases in body condition index when exposed to both experimental release protocols. A total of 11 animals (32%) emigrated from the release sites, with 10 of these animals being male. Importantly, no relationship was found between site fidelity and release method, although body condition was significantly higher in mala which dispersed, and there was observational evidence for a male-biased dispersal for merrnine. Although the number of released individuals of each species was low, this study demonstrates an interesting trend which indicates that soft release techniques do not necessarily to confer an advantage to the successful immediate establishment and survival of either hare-wallaby species in the short term. We recommend that managers involved with species reintroduction programs consider the costs and potential outcomes of designing and installing soft release enclosures.

Mammal decline in southern Western Australia – perspectives from Shortridge's collections of mammals in 1904–07

Guy Shortridge made extensive collections of mammals in southern Western Australia in the years 1904 to 1907, less than 80 years after first European settlement of the area. This paper reviews Shortridge's unpublished letters and the published papers that resulted from his collections in a reexamination of the temporal and spatial patterns of decline of these mammals. Shortridge collected a monotreme, 25 species of marsupial, 10 species of bat, 8 species of rodent, as well as rabbits and dingoes (a total of 46 species). He collected in five broad regions: mesic woodland sites in what is now the western wheatbelt; mesic coastal scrub sites around Albany; mesic forest habitat in the far south-west corner at Margaret River, Busselton, and Bunbury; semi-arid pastoral sites at Carnarvon and Gascoyne Junction; and semi-arid mining sites at Southern Cross, Kalgoorlie and Laverton. Shortridge was struck particularly by the rich fauna of the mesic woodland and the lack of species in the semi-arid interior (he obtained 20 terrestrial native species at the former and only 3-5 species at the latter). However, since that time, several of the species Shortridge collected at the mesic woodland sites have become extinct on mainland Australia (Bettongia lesueur, Lagostrophus fasciatus, and Perameles bougainville) or are now extinct (Onchogalea lunata) and the region shows one of the highest losses of mammals within Australia. Shortridge's collections emphasise that the loss of mammals in Western Australia has been a two-step process, with an initial loss of mammals in the semi-arid interior, followed by a subsequent loss from mesic woodland and coastal sites. His collections preceded the arrival of foxes Vulpes vulpes to the State and largely preceded the spread of rabbits Oryctolagus cuniculus. Shortridge speculated that disease, predation by feral cats Felis catus, competition from house mice Mus musculus, and bushfires were major factors in overall decline, and the impact of closer settlement was important in localised declines. These, and other factors commonly cited as reasons for mammal decline (grazing and land clearing), are evaluated. The factors suggested by Shortridge for overall decline are potentially interlinked: feral cats or house mice may spread disease, feral cats may be more effective as predators in the presence of abundant house mice populations and at sites where vegetation refuges are reduced by fire, and both may reach highest densities around farms and settlements. The pattern of loss to 1907 can be explained by the spread of feral cats only if their impact on native mammals is high in semi-arid pastoral and mining areas, low in mesic areas, and low in arid areas where European impact was minimal. Possible mechanisms for such a variable impact of feral cats include: i) greater density of vegetation at mesic sites providing refuge for prey species; ii) protection conferred to prey species by poison plants Gastrolobium in the understorey of mesic woodland leading to secondary poisoning of predators; and iii) Aboriginal hunting of feral cats being effective in limiting the density and impact of cats in remote areas beyond the frontier of European colonisation.

Taxonomy and historical distribution of the wallaby genus Lagostrophus

The banded hare-wallaby (Lagostrophus fasciatus) is an endangered macropodid currently restricted to Bernier and Dorre Islands in Shark Bay, Western Australia. Historically, L. fasciatus was also recorded on the Australian mainland from far western Australia, where it became locally extinct early in the twentieth century. Here we discuss an overlooked museum specimen of L. fasciatus collected in the mid-nineteenth century near Adelaide, South Australia. This specimen considerably extends the known historical distribution of L. fasciatus, validates anecdotal reports of the species from South Australia made by early Australian naturalists, and forms the basis for our description of a new subspecies.

Molecular evidence for the last survivor of an ancient kangaroo lineage

The Australasian marsupial family Macropodidae includes potoroos and bettongs (Potoroinae) as well as larger kangaroos, wallabies, and pademelons (Macropodinae). Perhaps the most enigmatic macropodid is the banded hare wallaby, Lagostrophus fasciatus, a taxon listed as vulnerable by the IUCN. Lagostrophus had traditionally been grouped as a sister-taxon to hare wallabies (Lagorchestes), in a clade with hypsodont macropodines, or intercalated in some other fashion within Macropodinae. Flannery (1983, 1989) proposed a radically different hypothesis wherein Lagostrophus is outside of Macropodinae and is more closely related to extinct sthenurine (short-faced) kangaroos. Given this controversy, we addressed the phylogenetic placement of the banded hare wallaby using molecular sequences for three mitochondrial genes (12S rRNA, valine tRNA, 16S rRNA) and one nuclear gene (protamine P1). Diverse phylogenetic methods all provided robust support for a macropodine clade that excludes the banded hare wallaby. The split between macropodines and the banded hare wallaby was estimated at approximately 20 million years ago (mya) using the Thorne/Kishino relaxed molecular clock method. Whereas our molecular results neither corroborate nor refute the sthenurine hypothesis, since all short-faced kangaroos and their immediate ancestors are extinct, the overriding implication of molecular phylogenetic analyses is manifest: the banded hare wallaby is the only living relict of an ancient kangaroo lineage. Regardless of its precise relationships, special efforts should be directed at conserving this unique and endangered taxon, which has not been recorded from mainland Australia since 1906 and is now restricted to two tiny islands off the coast of Western Australia.

The biology of banded (Lagostrophus fasciatus) and rufous (Lagorchestes hirsutus) hare-wallabies (Diprotodontia : Macropodidae) on Dorre and Bernier Islands, Western Australia

Sex ratio, reproduction, body condition and morphology of banded (Lagostrophus fasciatus) and rufous (Lagorchestes hirsutus) hare-wallabies were assessed on Dorre and Bernier Islands. Data are derived from 236 banded hare-wallabies and 161 rufous hare-wallabies captured between 1959 and 1999. The sex ratio of captured banded hare-wallabies tended to be female-biased (0.79: 1 male: female) but was not a significant departure from parity. In contrast, pouch young tended towards a male bias at 1.35: 1. Females produced 1–2 young per year. They were capable of producing young at 1000 g, but the incidence of females carrying pouch young or lactating increased from 39% for females of 1000–1400 g to 80% for females of 1401–1800 g, then decreased slightly to 76% for females >1800 g. Births occurred throughout the year but there was some indication of a decline in the latter half of the year. Captured banded hare-wallabies ranged in weight from 850 to 2300 g. Animals on Dorre Island were in significantly better body condition than those on Bernier Island, although this could be an artefact of their shorter pes length. There was no evidence of sexual dimorphism and no differences in morphological measurements taken, other than pes length, between the two island populations. The sex ratio of captured rufous hare-wallabies was close to parity at 0.99: 1 and for pouch young tended to be male-biased at 2: 1. The smallest female with young weighed 1215 g, but the incidence of females carrying pouch young or lactating increased from 43% for females of 1215–1660 g to 61% for females of 1661–2015 g and 100% for females >2015 g. Females carried pouch young in all months sampled (March–September) and one incidence of twinning was noted. Captured rufous hare-wallabies weighed 600–2550 g. Body condition was similar for males and females and between islands, but smaller females of reproductive age were in poorer body condition than larger females. There was no evidence of sexual dimorphism but pes lengths of animals on Dorre Island were significantly shorter, head lengths longer and tail lengths shorter, than those on Bernier Island. Rufous hare-wallabies appear to show regional variation in body size, being smaller in the wetter and warmer Tanami/Alice Springs region and larger on the drier and cooler Shark Bay islands.

The distribution and abundance of the banded and rufous hare-wallabies, Lagostrophus fasciatus and Lagorchestes hirsutus

The only substantial wild populations of banded Lagostrophus fasciatus and rufous Lagorchestes hirsutus hare-wallabies occur on Bernier and Dorre Islands, off the coast of Western Australia. Banded hare-wallabies were widespread in southwestern Australia but have not been recorded there since 1906; rufous hare-wallabies had a broad distribution across arid Australia but now have a single mainland population in the Tanami Desert. We assessed distribution and abundance of hare-wallabies on Bernier and Dorre Islands from spotlight sightings of animals on a series of east-west transects across each island. Abundance was estimated using line transects. The banded hare-wallaby is the more abundant species on both islands with a population of about 3,900 on Bernier and 3,800 on Dorre Island. This species depends on the shelter afforded by low-spreading shrubs of Heterodendrum oleifolium, Acacia coriacea, A. ligulata, Diplolaena dampiera, and Ficus platypoda. Wallabies occur mainly on the dunes that form the spine of Dorre Island and the travertine of its west coast. On Bernier Island they occur in the north, where dense thickets of Acacia coriacea, A ligulata, H. oleifolium and D. dampiera, and a tall heath of Abutilon exoneum and Scaevola crassifolia are best developed. The rufous hare-wallaby has a population of about 2,600 on Bernier and 1,700 on Dorre Island. It occurs throughout both islands in most habitats, but is most abundant in the south of each. It burrows extensively on the inland sandplain and in the dunes.

Revision in the macropodid subfamily Sthenurinae (Marsupialia: Macropodoidea) and the relationships of the species of Troposodon and Lagostrophus.

As part of a cladistic analysis of the Macropodoidea, the subfamily Sthenurinae (Macropodidae) has been redefined to include species of Lagostrophus, Troposodon, Sthenurus, Simosthenurus and Procoptodon. Lagostrophus fasciatus is structurally the most primitive species of the subfamily. Retention of some primitive dental, pedal and reproductive character states indicate that sthenurines represent an early division within the Macropodidae. Synapomorphic character states for sthenurines include the possession of a sinuous-shaped occlusal edge on I1 , a well-developed postlink on upper molars, a degree of overlap between the postmetacrista and the posthypocrista, the possession of a well-developed premetacristid that usually contacts the paracristid, and a tendency towards fusion of the mandibular symphysis.

On the age composition of a small sample of individuals from a population of the banded hare wallaby, Lagostrophus fasciatus (Peron & Lesuer).

A method of estimating the relative and absolute ages of living hare wallabies is described and applied to a temporarily captured sample from a field population. The age composition pattern is analysed to estimate the potential rate of increase of the population and this is then compared with an independantly derived survivorship curve. The actual rate of increase of the hare wallabies is close to unity, a result suggesting numerical stabilization of the population. This result is discussed in relation to the small amount of information available on the biology of this animal.

The female urogential system and reproduction of the marsupial Lagostrophus fasciatus.

The female urogenital system is described. It is similar to that in Potorinae (rat kangaroos) and differs from that of Macropodinae in possessing a large anterior vaginal expansion, in having the bladder attached anteriorly, and in lacking a permanently open pseudovaginal canal. The significance of this is discussed in relation to its taxonomic position in the Macropodinae and to the validity of urogenital criteria for the classification of macropod marsupials. Lagostrophus is polyoestrous and usually monovular. Post-partum oestrus occurs but is not invariable; it may result in a fertilized egg whose development is delayed during lactation. The sequence of events in the ovary, uterus, and vagina during reproduction are similar to those in other macropod marsupials previously described. There is some evidence for a peak of breeding in the first half of the year.

The mitotic chromosomes of Marsupials and their bearing on taxonomy and phylogeny.

Chromosome numbers of marsupials vary between 2n = 11 B 10 @ and 2n =24. Most species have 14 or 22 chromosomes. There is no evidence that polyploidy has occurred in marsupial evolution. The Dasyuridae have 12 metacentric autosomes, a small metacentric X-chromosome and a very small Y-chromosome (20% of living species have been studied) and the chromosomes of Myrmecobius fasciatus are typically like those of other Dasyuridae. The Peramelidae (30% of species have been studied) have chromosomes like the Dasyuridae except that X- and Y-chromosomes are much larger. The occurrence of similar chromosome numbers in Dasyuridae and Peramelidae is not necessarily evidence of affinity. The chromosomes of the Phascolomidae are similar in number and morphology to those of the Peramelidae and the resemblances are, almost certainly, due to parallel evolution. The chromosomes of Phascolarctos are unlike those of any of the Phalangeridae and this genus might be just as easily grouped with the Phascolomidae. The Phalangeridae have considerable chromosomal heterogeneity but less than 20% of species have been studied. Two species of Cercaertus have 12 metacentric autosomes and small sex chromosomes like all members of the Dasyuridae. This suggests that the primitive phalangers may have retained the chromosome number and morphology of possible dasyurid ancestors but the resemblances may be due to parallel evolution of similar chromosome number and morphology in separate groups. The chromosomes have been studied in more than 50% of Macropodinae. Cytological evidence suggests that Thylogale (3 species studied), Petrogale (2 species studied), and probably Lagorchestes (1 species studied), all with 22 chromosomes, are a related group. Onychogalea unguifer, with 20 chromosomes, may be derived from this group. There is no justification for the placing of Thylogale billardierii in the genus Protemnodon. Lagostrophus fasciatus has 2n = 24 and its placement in a monotypic genus is justified. Macropus major and all species of Protentnodon, except P. bicolor, are a related group with 16 chromosomes. M. robustus is possibly included in this group. M. rufus has 20 chromosomes and should perhaps be placed in the separate genus Megaleia. P. bicolor, with 11 chromosomes in the male and 10 in the female, differs from all other species of Protemnodon and this genus, as at present constituted, may be diphyletic. The relationships of P. bicolor are unknown. Setonix brachyurus has 22, mostly metacentric, chromosomes and its affinities are at present unknown. Three species of Bettongia (Potoroinae) have 22 chromosomes which are mostly metacentric. Hypsiprymnodon moschatus has 22 chromosomes which are mostly acrocentric. Both genera are very different cytologically from Potorous tridactylus.