Leslie Christidis

Mitochondrial DNA and morphology reveal three geographically distinct lineages of the large bentwing bat (Miniopterus schreibersii) in Australia

A combined molecular and morphological analysis was undertaken to resolve the systematics of the Miniopterus schreibersii complex in Australia. The study of skull morphology and sequence analysis of two mitochondrial genes, nicotinamine dehydrogenase subunit 2 and cytochrome-b, revealed three distinct Australian forms of M. schreibersii which are treated as subspecies. M. s. orianae occurs in northern Australia, M. s. oceanensis occurs in eastern Australia from Queensland through to central Victoria and M. s. bassanii, sp. nov. occurs in Western Victoria and eastern South Australia. The biogeographical history of the complex in Australia is discussed in the light of this new revision.

A multi-gene phylogeny reveals novel relationships for aberrant genera of Australo-Papuan core Corvoidea and polyphyly of the Pachycephalidae and Psophodidae (Aves: Passeriformes)

The core Corvoidea is the largest and most diverse oscine assemblage within the Australo-Papuan region. Although central to an understanding of the evolutionary history and biogeography of the group the composition and intergeneric relationships of the Australo-Papuan radiation remain poorly understood. Here we analysed DNA sequence data from two nuclear gene regions and the mitochondrial cytochrome b gene, for 40 species of core Corvoidea to test the systematic affinities of key Australo-Papuan lineages. The families Pachycephalidae (whistlers, shrike-thrushes and allies) and Psophodidae (whipbirds, quail-thrush and allies) were both recovered as polyphyletic assemblages. The core pachycephaline assemblage comprised Pachycephala, Colluricincla, parts of Pitohui, and Falcunculus with the remaining genera resolving as four divergent lineages with no clearly defined affinities. Ptilorrhoa and Cinclosoma (Cinclosomatidae) formed a clade separate from Psophodes (Psophodidae) but neither clade showed clear affinities to any other taxa. Novel relationships were also identified for three aberrant New Guinean genera; ditypic Machaerirhynchus and monotypic Rhagologus were both nested within an assemblage that included the Artamidae and African malaconotoids (bush-shrikes and allies) while the enigmatic Ifrita was found to be part of an assemblage that included the Monarchidae and Paradisaeidae.

Taxonomy anarchy hampers conservation

We contend that the sc ient i f ic community’s failure to govern taxonomy threatens the effectiveness of global efforts to halt biodiversity loss, damages the credibility of science and is expensive to society. To address the problem, we propose that the governance of the taxonomy of complex organisms be brought under the purview of the International Union of Biological Sciences (IUBS). This is the umbrella body for biology within taxonomists that a species should represent a distinct evolutionary lineage. But there is none about how a lineage should be defined. ‘Species’ are often created or dismissed arbitrarily, according to the individual taxonomist’s adherence to one of at least 30 definitions. Crucially, there is no global oversight of taxonomic decisions — researchers can ‘split or lump’ species with no consideration of the consequences. The assumption that species are fixed entities underpins every international agreement on biodiversity conservation, all national environmental legislation and the efforts of many individuals and organizations to safeguard plants and animals. Yet for a discipline aiming to impose order on the natural world, taxonomy (the classification of complex organisms) is remarkably anarchic. There is reasonable agreement among Part of the vast ornithology collection at the American Museum of Natural History. G EO R G E ST EI N M ET Z/ N G C

Unravelling a biogeographical knot: origin of the 'leapfrog' distribution pattern of Australo-Papuan sooty owls (Strigiformes) and logrunners (Passeriformes).

Molecular analysis of two Australo–Papuan rainforest birds exhibiting correlated ‘leapfrog’ patterns were used to elucidate the evolutionary origin of this unusual pattern of geographical differentiation. In both sooty owls (Tyto) and logrunners (Orthonyx), phenotypically similar populations occupy widely disjunct areas (central–eastern Australia and upland New Guinea) with a third, highly distinctive population, occurring between them in northeastern Queensland. Two mechanisms have been proposed to explain the origin of leapfrog patterns in avian distributions: recent shared ancestry of terminal populations and unequal rates or phenotypic change among populations. As the former should generate correlated patterns of phenotypic and genetic differentiation, we tested for a sister relationship between populations from New Guinea and central–eastern Australia using nuclear and mitochondrial DNA sequences. The resulting phylogenies not only refute recent ancestry as an explanation for the leapfrog pattern, but provide evidence of vastly different spatio–temporal histories for sooty owls and logrunners within the Australo–Papuan rainforests. This incongruence indicates that the evolutionary processes responsible for generating leapfrog patterns in these co–distributed taxa are complex, possibly involving a combination of selection and drift in sooty owls and convergence or retention of ancestral characteristics in logrunners.

Molecular phylogenetics of the Diprotodontia (kangaroos, wombats, koala, possums, and allies).

Mitochondrial ND2 sequences were used to investigate the phylogenetic relationships amongst 31 diprotodontid marsupials (kangaroos, wombats, koala, possums, and allies). ND2 sequences were analyzed separately and in conjunction with available 12S rDNA sequences for 22 diprotodontid taxa. Phylogenetic analyses consistently identified monophyly for the Burramyoidea, Phalangeroidea, Petauroidea, Tarsipedoidea, Macropodoidea, and the Vombatiformes. Like previous molecular and morphological studies, relationships between the super-families were less well resolved. Inconsistency between taxonomic rank and genetic distance was identified amongst the diprotodontids.

Genetic distinctness of isolated populations of an endangered marsupial, the mountain pygmy-possum, Burramys parvus

The mountain pygmy‐possum, Burramys parvus, exists in isolated and fragmented populations in the Australian alps. To examine the degree of interpopulation divergence, mitochondrial cytochrome b and NADH dehydrogenase subunit 2 (NADH2) sequences were obtained from samples representing all populations of B. parvus. Three divergent mitochondrial DNA (mtDNA) lineages were identified which exhibited strong phylogeographical structure. This indicates the presence of three maternal clades corresponding to populations in the northern, central and southern Australian alps. Molecular clock estimates suggest that the mtDNA lineages diverged from one another 420–680 thousand years ago. On this basis it is argued that B. parvus populations have probably been isolated since the mid‐Pleistocene, and that management should focus on maintaining viable B. parvus populations in each of the three regional localities.

Chromosomal evolution within the family Estrildidae (Aves) II. The Lonchurae

Eleven species of estrildid finches were examined cytogenetically with G- and C-banding. The analysis revealed a preponderance of pericentric inversions at both the inter- and intraspecific levels. In addition, considerable variation in the pattern of heterochromatin distribution, particularly in the sex-chromosomes, was recorded as polymorphisms and interspecific differences. This variation was not found to be associated directly with either speciation or morphological change. Rather, it is argued that only those rearrangements which do not lead to meiotic problems survive in avian lineages.The chromosomal data were also used to clarify systematic relationships within the Poephilae, demonstrating that the monotypic genera Aegintha and Aidemosyne are allied to the Neochmia group.

Molecular Phylogenetic Affinities of the Night Parrot (Geopsittacus occidentalis) and the Ground Parrot (Pezoporus wallicus)

ABssRAcr.-Although designating the Night Parrot (Geopsittacus occidentalis) and the Ground Parrot (Pezoporus wallicus) as each others closest taxonomic relatives is generally accepted, placing this group with respect to other Australo-Pacific parrots has proven problematical. To examine the phylogenetic relationships of these two species, a 924-bp fragment of the cytochrome-b gene was sequenced from single representatives of the following genera: Geopsittacus, Pezoporus, Neophema, Melopsittacus, Platycercus, Polytelis, Strigops, and Calyptorhynchus. Maximum-parsimony, maximum-likelihood, and distance trees all supported a close association between Geopsittacus and Pezoporus. These two genera were also found to be closely linked with Neophema and Melopsittacus. Despite superficial morphological similarities, Geopsittacus and Strigops (Kakapo) were found not to be closely related. Received 21 December 1992, accepted 6 October 1993.

Multilocus analysis of a taxonomically densely sampled dataset reveal extensive non-monophyly in the avian family Locustellidae.

The phylogeny of most of the species in the avian passerine family Locustellidae is inferred using a Bayesian species tree approach (Bayesian Estimation of Species Trees, BEST), as well as a traditional Bayesian gene tree method (MrBayes), based on a dataset comprising one mitochondrial and four nuclear loci. The trees inferred by the different methods agree fairly well in topology, although in a few cases there are marked differences. Some of these discrepancies might be due to convergence problems for BEST (despite up to 1×10(9) iterations). The phylogeny strongly disagrees with the current taxonomy at the generic level, and we propose a revised classification that recognizes four instead of seven genera. These results emphasize the well known but still often neglected problem of basing classifications on non-cladistic evaluations of morphological characters. An analysis of an extended mitochondrial dataset with multiple individuals from most species, including many subspecies, suggest that several taxa presently treated as subspecies or as monotypic species as well as a few taxa recognized as separate species are in need of further taxonomic work.

Habitat shifts in the evolutionary history of a Neotropical flycatcher lineage from forest and open landscapes.

BackgroundLittle is known about the role ecological shifts play in the evolution of Neotropical radiations that have colonized a variety of environments. We here examine habitat shifts in the evolutionary history of Elaenia flycatchers, a Neotropical bird lineage that lives in a range of forest and open habitats. We evaluate phylogenetic relationships within the genus based on mitochondrial and nuclear DNA sequence data, and then employ parsimony-based and Bayesian methods to reconstruct preferences for a number of habitat types and migratory behaviour throughout the evolutionary history of the genus. Using a molecular clock approach, we date the most important habitat shifts.ResultsOur analyses resolve phylogenetic relationships among Elaenia species and confirm several species associations predicted by morphology while furnishing support for other taxon placements that are in conflict with traditional classification, such as the elevation of various Elaenia taxa to species level. While savannah specialism is restricted to one basal clade within the genus, montane forest was invaded from open habitat only on a limited number of occasions. Riparian growth may have been favoured early on in the evolution of the main Elaenia clade and subsequently been deserted on several occasions. Austral long-distance migratory behaviour evolved on several occasions.ConclusionAncestral reconstructions of habitat preferences reveal pronounced differences not only in the timing of the emergence of certain habitat preferences, but also in the frequency of habitat shifts. The early origin of savannah specialism in Elaenia highlights the importance of this habitat in Neotropical Pliocene and late Miocene biogeography. While forest in old mountain ranges such as the Tepuis and the Brazilian Shield was colonized early on, the most important colonization event of montane forest was in conjunction with Pliocene Andean uplift. Riparian habitats may have played an important role in facilitating habitat shifts by birds expanding up the mountains along streams and adapting to newly emerging montane forest habitat.