Patricia A. Woolley

Reconstructing the Evolutionary Radiation of Dasyurine Marsupials with Cytochrome b, 12S rRNA, and Protamine P1 Gene Trees

We report complete sequences of the cytochrome b, 12S rRNA, and protamine P1 genes from 18 of the 21 extant species of dasyurine marsupials (family Dasyuridae). Partial sequences are included for Pseudantechinus ningbing, but no data are available for Ps. mimulus or Phascolosorex doriae. Phylogenetic analyses of these sequences yield compatible gene trees with limited resolution. Simultaneous parsimony analysis of all three genes suggests the following: (a) a basal polytomy of eight lineages; (b) a sister-group relationship between “phascolosoricine” genera (Neophascogale and Phascolosorex, which are monophyletic) and Dasyums + Sarcophilus; (c) monophyly of Dasyurus viverrinus, D. albopunctatus, D. geoffroii, and D. spartacus apart from other quolls and Sarcophilus; and (d) sister-pairing of D. geoffroii and D. spartacus Previous attempts at unraveling the phylogenetic history of dasyurines have produced strikingly inconsistent results, due in part to differences in character systems examined, interpretations of character homology and independence, and analytical methods employed. We provide some evidence that the basal polytomy is the result of rapid cladogenesis and suggest that this episode of dasyurine evolution is temporally correlated with the onset of aridification following the New Guinean uplift of 15 million years ago.

Molecular Relationships of New Guinean Three-Striped Dasyures, (Myoictis, Marsupialia: Dasyuridae)

Complete nucleotide sequences of the cytochrome b and 12S rRNA genes and partial sequences of the mitochondrial 16S rRNA gene and the nuclear ɛ-globin gene were obtained from multiple exemplars of the New Guinean dasyurid, Myoictis. Allozyme data were also obtained from most of the same animals. The molecular data show that the genus comprises a number of genetically distinct lineages which correspond with groups proposed by Woolley (2005) on the basis of a number of morphological traits, including the form of the tail i.e. Myoictis leucura (sp. nov.), M. melas, M. wallacei and M. wavicus (new status). Divergence dates estimated from the weighted-average distances for the combined cytochrome b and 12S rRNA data, calibrated with a dasyurid-thylacine divergence 25 million years ago, suggest that the early cladogenic events separating Myoictis took place in the late Miocene. Subsequent separation of M. wavicus and M. leucura from a common ancestor as well as some genetic differentiation within M. melas, took place in the medial Pliocene.

Phylogenetic relationships within Dasyurus (Dasyuromorphia: Dasyuridae): quoll systematics based on molecular evidence and male characteristics

Phylogenetic relationships among the 6 species of quolls (Dasyurus) are resolved using DNA sequences from 4 mitochondrial and 5 nuclear loci (approximately 15 kb) sampled from 1 to 29 individuals per species. Our estimate of quoll phylogeny concurs with previous DNA-based estimates in placing Dasyurus hallucatus as sister to the remaining species, and D. maculatus as sister to a clade containing D. viverrinus, D. albopunctatus, D. geoffroii + D. spartacus. We also provide the first formal description of penis anatomy in the northern quoll (D. hallucatus), documenting it as the only species of Dasyurus lacking an appendage to the penis. This appendage thus appears to constitute a morphological synapomorphy for the clade of 5 species that excludes D. hallucatus. The sequence from our single specimen of bronze quoll (D. spartacus) nested within a clade of 3 western quoll (D. geoffroii) sequences, suggesting that the species boundary between these groups (if it exists) is not yet reflected in reciprocal monophyly of mitochondrial haplotypes. Any genetic differences found between eastern and western forms of D. geoffroii would have implications for translocations of western animals into other parts of the species range.

Interspecific Affinities within the Genus Sminthopsis (Dasyuromorphia: Dasyuridae) Based on Morphology of the Penis: Congruence with Other Anatomical and Molecular Data

Abstract Among the 19 currently recognized species of Sminthopsis, differences in the morphology of the free portion of the penis can be seen in the tip, which may be bifid, blunt, knoblike, or have a terminal median process, and which may have a subterminal skin fold; and the urethral opening and terminal passage (urethral grooves or urethral chamber). The urethra may open dorsally or ventrally, and the urethral grooves may lie mesially or ventrally on the bifid portion of the tip. Ten forms can be recognized and interspecific affinities based on penis morphology have been examined for congruence with species groupings based on other independent character sets including external, cranial, and dental characters and molecular data. Penis forms showed the greatest congruence with phylogenetic groups delineated by molecular data.

Molecular Evidence for a Deep Clade of Dunnarts (Marsupialia: Dasyuridae: Sminthopsis)

Sminthopsis is the most speciose genus of living dasyurid marsupials and, along with its close relatives Antechinomys and Ningaui, constitutes the clade Sminthopsini. Phylogenetic relationships among the 23 species in this clade have been the subject of much morphological and molecular investigation, including a recent integration of penis morphology (in Sminthopsis) with molecular systematics. Several phylogenetic issues remain open, however, including the monophyly of Sminthopsis and branching order among early sminthopsin lineages. In this study, we revisit sminthopsin systematics with an expanded molecular data set, including new DNA sequences from mitochondrial (valine transfer-RNA and 16S ribosomal RNA) and nuclear (interphotoreceptor retinoid binding protein and beta-fibrinogen) loci, along with previously published sequences of cytochrome b, 12S ribosomal RNA, control region, and protamine P1. Our results again fail to establish the monophyly of Sminthopsis, but do provide a clearer resolution of early sminthopsin branching. Specifically, our phylogeny suggests three major groups of Sminthopsis species: S. longicaudata (perhaps the sister of Antechinomys); the Macroura species group of previous authors (S. crassicaudata, S. macroura, S. virginiae, S. douglasi, and S. bindi); and the remaining 13 species allied with the Murina species group. Our results depart from previous molecular findings by reuniting S. ooldea with the Murina group, while resolving S. psammophila as sister to the hairy-footed dunnarts (S. hirtipes and S. youngsoni). We suggest that this conflict traces to anomalous phylogenetic signal in previously published cytochrome b sequences. Penis morphology maps reasonably well onto our phylogeny, requiring parallel origination of only one of the ten morphotypes described for Sminthopsis.

Phylogenetic analysis of cytochromeb sequences in the dasyurid marsupial subfamily phascogalinae: Systematics and the evolution of reproductive strategies

We report DNA sequence variation in 861 bp of the mitochondrial cytochromeb gene from 10 species of the dasyurid marsupial subfamily Phascogalinae (including the New Guinean genusMurexia) and an outgroup planigale (Planigale ingrami). Phylogenetic analyses of these sequences indicate that (1) the subfamily consists of three major clades corresponding to (a)Phascogale, (b) AustralianAntechinus, and (c) New Guinean “Antechinus” andMurexia; (2) “Antechinus” habbema constitutes the earliest branch of the New Guinean clade; and (3); “Antechinus” melanurus and “A.” naso are sister species within the New Guinean clade. Among Australian antechnuses,A. stuartii andA. swainsonii are more closely related to each other than either is toA. flavipes, a result that is seemingly at odds with all previous systematic studies. Although resolution is limited, it appears thatAntechnius andMurexia species form a clade to the exclusion ofPhascogale. This relationship suggests that male semelparity is not a strong synapomorphy for Australian antechinuses and phascogales, despite its apparent physiological similarity in the two groups.

Past and present distribution of Dasycercus: toward a better understanding of the identity of specimens in cave deposits and the conservation status of the currently recognised species D. blythi and D. cristicauda (Marsupialia : Dasyuridae)

Abstract. Maps of the distribution of the two currently recognised species of Dasycercus, D. blythi and D. cristicauda have been prepared following correct identification based on tail morphology of specimens in the modern collections of all Australian museums. Localities in which the remains of Dasycercus have been found in cave deposits have also been mapped and an attempt made to determine the specific identity of some of these specimens. Following examination of larger samples of each species, differences in the premolar dentition were found to no longer be diagnostic. Most cave specimens could not be assigned to species on the basis of some dental measurements. DNA sequences could provide a means for establishing the identity of the cave specimens. Correct identification of specimens, together with knowledge of the search effort underlying the known distribution and persistence of the species in localities over their ranges, is essential for assessment of their conservation status.

A plethora of planigales: genetic variability and cryptic species in a genus of dasyurid marsupials from northern Australia

Abstract. Multiple mitochondrial and nuclear gene sequences reveal substantial genetic variation within the dasyurid marsupial genus Planigale, suggesting greater taxonomic diversity than is currently recognised. To further investigate planigale relationships 116 new mitochondrial and nuclear gene sequences, including 16 new specimens, were added to our database. We confirm the presence of an unrecognised species (Planigale ‘species 1’) limited to the Pilbara region of Western Australia and suggest that the ‘Mt Tom Price’ animals may be closely related to Planigale ingrami subtilissima. We also confirm that at least four distinct genetic lineages make up what is currently recognised as P. maculata. This complex of closely related taxa represents a radiation of sibling species rather than a single, genetically diverse one. Three of these lineages (M1 + M2, M3 and M4) are distributed sympatrically across the Top End of Australia and one (M5 = P. maculata sensu stricto) is localised to the eastern coast of Australia. Within the Planigale ingrami complex, Planigale ‘Mt Tom Price’ (lineage Ing. 1) occurs in the Pilbara in sympatry with Planigale ‘species 1’ and lineage Ing. 2 is found in the Northern Territory in sympatry with species of the P. maculata complex. There is thus a plethora of northern Australian planigales, many of which are formally undescribed and whose geographic ranges require careful re-evaluation.

Anatomy and chromosomes of two intersexual dasyurid marsupials

The intersexual phenotypes of marsupials with XXY and XO chromosome constitutions imply that not all sexual dimorphisms are under the control of testicular hormones and, ultimately, the SRY gene on the Y chromosome. It has been hypothesised that there is a gene on the X chromosome that determines whether either a scrotum will form (one copy of the gene) or a pouch with teats (two copies of the gene). Here, we describe the anatomy and chromosomes of two intersexual dasyurid marsupials. One, a Dasyuroides byrnei, had a pouch, but the reproductive tract was essentially male. The other, a Sminthopsis douglasi, had a hemipouch and a hemiscrotum and the reproductive tract was essentially female. The S. douglasi was a mosaic for cells with an apparently normal 2n = 14, XX female karyotype and cells with 2n = 14 plus (usually) two dot-like supernumerary elements 2n = 14, XX + 2B. The D. byrnei cells examined also had a 2n = 14, XX + 2B karyotype. In fibroblasts from the male and female sides of the S. douglasi, it was possible to assign the 2n = 14, XX karyotype to the male side and the 2n = 14, XX + 2B to the female side.

The Julia Creek dunnart, Sminthopsis douglasi (Marsupialia : Dasyuridae): breeding of a threatened species in captivity and in wild populations

Abstract. A detailed description of the methods used to house, maintain and assess the reproductive condition of captive Julia Creek dunnarts, Sminthopsis douglasi, that led to successful breeding of the species in captivity is provided. Basic features of the reproductive biology of this species of Sminthopsis have been established from observations made on captive animals. The females are polyoestrous, with a cycle length of ∼28 days. Young are born 13–16 days after mating and are dependent on the mother for ∼70 days. The age at which captive animals commence breeding ranged from 13 to 38 weeks (females) and 23 to 40 weeks (males). Both sexes are capable of breeding when two years old. Breeding in wild populations is seasonal and occurs over a six-month period from August to March, which encompasses the hottest and wettest time of the year. Both females and males are known to be capable of breeding in more than one season and females have the potential to rear two litters in a season. Recruitment of young to the population may be affected by heavy rainfall during the breeding season that can lead to closure of the cracks and holes in which the dunnarts shelter.