Molecular systematics and evolutionary origins of the genus Petaurus (Marsupialia: Petauridae) in Australia and New Guinea

The glider genus Petaurus comprises a group of arboreal and nocturnal marsupial species from New Guinea and Australia. Molecular data were generated in order to examine phylogenetic relationships among species within the genus and explore the time-scale of diversification and biogeographic history of the genus in Australia and New Guinea. All known species and subspecies of Petaurus (with the exception of P. biacensis) were sequenced for two mitochondrial genes (ND2 and ND4) and one nuclear marker (omega-globin gene). Phylogenetic analyses confirmed the monophyly of the genus relative to other petaurids and showed a sister relationship of P. australis to the rest of Petaurus. The analyses revealed that currently recognised species of Petaurus formed distinct mitochondrial DNA (mtDNA) clades. Considerable mtDNA diversity and seven distinct clades were identified within the species P. breviceps, with the distribution of each clade showing no correspondence with the distributional limits of known subspecies. Molecular dating analyses using BEAST suggested an early to mid-Miocene origin (18–24 mya) for the genus. Ancestral area reconstructions, using BayesTraits, did not resolve the location for the centre of origin of Petaurus, but provided evidence for at least one dispersal event from New Guinea to Australia that led to the evolution of extant Australian populations of P. breviceps, P. norfolcensis and P. gracilis. The timing of this dispersal event appears to pre-date the Pleistocene, adding to the growing number of studies that suggest faunal connections occurred between Australia and New Guinea in the Late Miocene to Pliocene period.     

A phylogeny of Diprotodontia (Marsupialia) based on sequences for five nuclear genes

Even though the marsupial order Diprotodontia is one of the most heavily studied groups of Australasian marsupials, phylogenetic relationships within this group remain contentious. The more than 125 living species of Diprotodontia can be divided into two main groups: Vombatiformes (wombats and koalas) and Phalangerida. Phalangerida is composed of the kangaroos (Macropodidae, Potoroidae, and Hypsiprymnodontidae) and possums (Phalangeridae, Burramyidae, Petauridae, Pseudocheiridae, Tarsipedidae, and Acrobatidae). Much of the debate has focused on relationships among the families of possums and whether possums are monophyletic or paraphyletic. A limitation of previous investigations is that no study to date has investigated diprotodontian relationships using all genera. Here, we examine diprotodontian interrelationships using a nuclear multigene molecular data set representing all recognized extant diprotodontian genera. Maximum parsimony, maximum likelihood, and Bayesian methods were used to analyze sequence data obtained from protein-coding portions of ApoB, BRCA1, IRBP, Rag1, and vWF. We also applied a Bayesian relaxed molecular clock method to estimate times of divergence. Diprotodontia was rooted between Vombatiformes and Phalangerida. Within Phalangerida, the model-based methods strongly support possum paraphyly with Phalangeroidea (Burramyidae + Phalangeridae) grouping with the kangaroos (Macropodiformes) to the exclusion of Petauroidea (Tarsipedidae, Acrobatidae, Pseudocheiridae, and Petauridae). Within Petauroidea, Tarsipedidae grouped with both Petauridae and Pseudocheiridae to the exclusion of Acrobatidae. Our analyses also suggest that the diprotodontian genera Pseudochirops and Strigocuscus are paraphyletic and diphyletic, respectively, as currently recognized. Dating analyses suggest Diprotodontia diverged from other australidelphians in the late Paleocene to early Eocene with all interfamilial divergences occurring prior to the early Miocene except for the split between the Potoroidae and Macropodidae, which occurred sometime in the mid-Miocene. Ancestral state reconstructions using a Bayesian method suggest that the patagium evolved independently in the Acrobatidae, Petauridae, and Pseudocheiridae. Ancestral state reconstructions of ecological venue suggest that the ancestor of Diprotodontia was arboreal. Within Diprotodontia, the common ancestor of Macropodidae was reconstructed as terrestrial, suggesting that tree kangaroos (Dendrolagus) are secondarily arboreal.     

A Phylogeny and Timescale for Marsupial Evolution Based on Sequences for Five Nuclear Genes

Even though marsupials are taxonomically less diverse than placentals, they exhibit comparable morphological and ecological diversity. However, much of their fossil record is thought to be missing, particularly for the Australasian groups. The more than 330 living species of marsupials are grouped into three American (Didelphimorphia, Microbiotheria, and Paucituberculata) and four Australasian (Dasyuromorphia, Diprotodontia, Notoryctemorphia, and Peramelemorphia) orders. Interordinal relationships have been investigated using a wide range of methods that have often yielded contradictory results. Much of the controversy has focused on the placement of Dromiciops gliroides (Microbiotheria). Studies either support a sister-taxon relationship to a monophyletic Australasian clade or a nested position within the Australasian radiation. Familial relationships within the Diprotodontia have also proved difficult to resolve. Here, we examine higher-level marsupial relationships using a nuclear multigene molecular data set representing all living orders. Protein-coding portions of ApoB, BRCA1, IRBP, Rag1, and vWF were analyzed using maximum parsimony, maximum likelihood, and Bayesian methods. Two different Bayesian relaxed molecular clock methods were employed to construct a timescale for marsupial evolution and estimate the unrepresented basal branch length (UBBL). Maximum likelihood and Bayesian results suggest that the root of the marsupial tree is between Didelphimorphia and all other marsupials. All methods provide strong support for the monophyly of Australidelphia. Within Australidelphia, Dromiciops is the sister-taxon to a monophyletic Australasian clade. Within the Australasian clade, Diprotodontia is the sister taxon to a Notoryctemorphia + Dasyuromorphia + Peramelemorphia clade. Within the Diprotodontia, Vombatiformes (wombat + koala) is the sister taxon to a paraphyletic possum group (Phalangeriformes) with kangaroos nested inside. Molecular dating analyses suggest Late Cretaceous/Paleocene dates for all interordinal divergences. All intraordinal divergences were placed in the mid to late Cenozoic except for the deepest splits within the Diprotodontia. Our UBBL estimates of the marsupial fossil record indicate that the South American record is approximately as complete as the Australasian record. The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Meteorus (Hymenoptera: Braconidae) of Australia and New Guinea

Abstract The Meteorus species of Australia and New Guinea are described, keyed and illustrated. Twenty-three species are included of which the following eighteen are new to science: achterbergi, anicus, arrogator, depressus, gloriosus, josieas, laevigatus, lindae, obscurus, ottus, palmeri, pinguicornis, sedlaceki, sritus, strabismus, tarius, townesi, varicosus . Primary type-material of five previously-described taxa has been examined: antipodalis Ashmead, bicolor Szépligeti, luteus (Cameron), trichogrammae Wilkinson, dumbletoni Muesebeck. A lecto-type is designated for luteus which is transferred to Meteorus from Protelus, bicolor is transferred to Aridelus from Meteorus and dumbletoni is placed in synonymy with ictericus (Nees).     

Relationships Among Families of Diprotodontia (Marsupialia) and the Phylogenetic Position of the Autapomorphic Honey Possum (Tarsipes rostratus)

The Australasian marsupial order Diprotodontia includes ten extant families that are grouped into the suborders Vombatiformes (koalas and wombats), Macropodiformes (kangaroos and allies), and Phalangeriformes (possums and gliders). We investigated interfamilial relationships using mitochondrial 12S rRNA, valine tRNA, and 16S rRNA gene sequences. Our results support the monophyly of both Vombatiformes and Macropodiformes, but not Phalangeriformes. Among possums and gliders, there was strong support for a petauroid clade that includes Pseudocheiridae (ringtail possums), Petauridae (sugar glider, striped possums), Acrobatidae (feathertail possums), and the monotypic family Tarsipedidae, which is represented by the highly specialized and autapomorphic honey possum (Tarsipes rostratus). Other prior hypotheses for the phylogenetic placement of the honey possum were rejected by statistical tests. The inclusion of the honey possum within Petauroidea suggests that derived ultrastructural features of Tarsipes' spermatozoa evolved independently in Tarsipes versus polyprotodont Australasian marsupials.     

Phylogeny of the Heterodoxus octoseriatus group (Phthiraptera: Boopiidae) from rock-wallabies (Marsupialia: Petrogale)

The phylogenetic position of the Heterodoxus octoseriatus group is inferred from morphological characters. Two character states support monophyly of this group. Another indicates that its sister-group is a group of 11 other Heterodoxus species (here called the H. calabyi group), that infest at least seven other genera of macropodid marsupials. Fourteen potential apomorphies, associated with the male and female genitalia, are identified. Evident rapid and divergent evolution of the genitalia, however, precludes determination of their polarity by comparison with an out-group (the sister-group). Consequently, phylogeny in the H. octoseriatus group is inferred from the close similarity of morphological characters. In light of the phylogenetic analysis and a phenogram, speciation and the evolution of morphological characters in the H. octoseriatus group is discussed.     

Phylogeny and evolution of body mass in didelphid marsupials (Marsupialia: Didelphimorphia: Didelphidae)

Most extant New World marsupials belong in the Didelphidae, which comprises ca. 110 currently recognized species of opossums. Didelphids are small mammals with their mean body mass, at species level, ranging from ca. 7 g to 2.2 kg. The largest species belong in a single clade, while substantial variation remains scattered across the remaining groups. We seek out to explore the details of this mass variation in an evolutionary framework. To this end, we first reconstructed the phylogeny of didelphids based on an extensive, although fragmentary sample of sequences from ten genes. We recovered a fully resolved, highly robust phylogeny that tested and confirmed most previously reported groupings, providing a simultaneous depiction of phylogenetic relationships for 81 % of currently recognized species and all relevant supra-specific clades. As much as 69 % of total body mass variation in didelphids was explained by this phylogenetic hypothesis. Mapped on it, mass variation evolved as much as 6.8 kg of total changes, starting from a reconstructed ancestral body mass range of 22–33 g. No single, family-wide pattern was evident; in fact, the dominant pattern for mass variation was that of increases in body mass along a few successive branches, or phyletic giantism, followed by apomorphic nanism, i.e., decreases localized in single terminal branches. Phyletic trends indicated the persistence of gradual, directional changes along considerable spans of geological time and show that substantial variation of interest resides in this and perhaps most groups of small mammals.     

Intergeneric Relationships Among Macropodoidea (Metatheria: Diprotodontia) and The Chronicle of Kangaroo Evolution

The superfamily of kangaroos (Macropodoidea) is comprised of the subfamilies Propleopinae, Hypsiprymnodontinae, Paleopotoroinae, Potoroinae, Bulungamayinae, Balbarinae, Macropodinae, and Sthenurinae. Of these, Hypsiprymnodontinae, Potoroinae, and Macropodinae are extant. Competing phylogenetic hypotheses unite potoroines with either hypsiprymnodontines or macropodines, with most recent workers following a classificatory scheme that recognizes Hypsiprymnodontidae (hypsiprymnodontines) and Macropodidae (macropodines + potoroines). To address phylogenetic relationships among living macropodoids, we analyzed sequences from three mitochondrial genes (12S rRNA, tRNA valine, 16S rRNA) and one nuclear gene (protamine P1). MtDNA and protamine P1 both support a basal split of Hypsiprymnodon from other macropodoids rather than an association of Hypsiprymnodon with potoroines. This suggests that bipedal hopping and a complex stomach evolved once among macropodids. Monophyly of the Macropodinae is supported. Among macropodines, there is support for a Dorcopsis-Dorcopsulus association. Potoroine monophyly is less clear, although among potoroines there is support for an association of Bettongia and Aepyprymnus. Divergence times were estimated using 12S rRNA, tRNA-valine, and 16S rRNA transversions and suggest that kangaroos separated from a possum-like ancestor approximately 38–44 million years ago. Hypsiprymnodon diverged from other macropodoids approximately 34 to 38 million years ago. In agreement with the fossil record, the diversification of potoroines predates the diversification of macropodines. The latter have radiated in association with the development of a more arid climate and emergent grasslands over the Australian continent.     

Phylogeography of the pademelons (Marsupialia: Macropodidae: Thylogale) in New Guinea reflects both geological and climatic events during the Plio‐Pleistocene

Aim Alternative hypotheses concerning genetic structuring of the widespread endemic New Guinean forest pademelons (Thylogale) based on current taxonomy and zoogeography (northern, southern and montane species groupings) and preliminary genetic findings (western and eastern regional groupings) are investigated using mitochondrial sequence data. We examine the relationship between the observed phylogeographical structure and known or inferred geological and historical environmental change during the late Tertiary and Quaternary. Location New Guinea and associated islands. Methods We used primarily museum specimen collections to sample representatives from Thylogale populations across New Guinea and three associated islands. Mitochondrial cytochrome b and control region sequence data were used to construct phylogenies and estimate the timing of population divergence. Results Phylogenetic analyses indicated subdivision of pademelons into ‘eastern’ and ‘western’ regional clades. This was largely due to the genetic distinctiveness of north‐eastern and eastern peninsula populations, as the ‘western’ clade included samples from the northern, southern and central regions of New Guinea. Two tested island groups were closely related to populations north of the Central Cordillera; low genetic differentiation of pademelon populations between north‐eastern New Guinea and islands of the Bismarck Archipelago is consistent with late Pleistocene human‐mediated translocations, while the Aru Islands population showed divergence consistent with cessation of gene flow in the mid Pleistocene. There was relatively limited genetic divergence between currently geographically isolated populations in subalpine and nearby mid‐montane or lowland regions. Main conclusions Phylogeographical structuring does not conform to zoogeographical expectations of a north/south division across the cordillera, nor to current species designations, for this generalist forest species complex. Instead, the observed genetic structuring of Thylogale populations has probably been influenced by geological changes and Pleistocene climatic changes, in particular the recent uplift of the north‐eastern Huon Peninsula and the lowering of tree lines during glacial periods. Low sea levels during glacial maxima also allowed gene flow between the continental Aru Island group and New Guinea. More work is needed, particularly multi‐taxon comparative studies, to further develop and test phylogeographical hypotheses in New Guinea.     

Distribution and evolution of the Anopheles punctulatus group (Diptera: Culicidae) in Australia and Papua New Guinea

The members of the Anopheles punctulatus group are major vectors of malaria and Bancroftian filariasis in the southwest Pacific region. The group is comprised of 12 cryptic species that require DNA-based tools for species identification. From 1984 to 1998 surveys were carried out in northern Australia, Papua New Guinea and on islands in the southwest Pacific to determine the distribution of the A. punctulatus group. The results of these surveys have now been completed and have generated distribution data from more than 1500 localities through this region. Within this region several climatic and geographical barriers were identified that restricted species distribution and gene flow between geographic populations. This information was further assessed in light of a molecular phylogeny derived from the ssrDNA (18S). Subsequently, hypotheses have been generated on the evolution and distribution of the group so that future field and laboratory studies may be approached more systematically. This study suggested that the ability for widespread dispersal was found to have appeared independently in species that show niche-specific habitat preference (Anopheles farauti s.s. and A. punctulatus) and conversely in species that showed diversity in their larval habitat (Anopheles farauti 2). Adaptation to the monsoonal climate of northern Australia and southwest Papua New Guinea was found to have appeared independently in A. farauti s.s., A. farauti 2 and Anopheles farauti 3. Shared or synapomorphic characters were identified as saltwater tolerance (A. farauti s.s. and Anopheles farauti 7) and elevational affinities above 1500 m (Anopheles farauti 5, Anopheles farauti 6 and A. farauti 2).