Background: Trophic shifts from one dietary niche to another have played major roles in reshaping the evolutionary trajectories of a wide range of vertebrate groups, yet their consequences for morphological disparity and species diversity differ among groups.
Methods: Here, we use phylogenetic comparative methods to examine whether the evolution of nectarivory and other trophic shifts have driven predictable evolutionary pathways in Australasian psittaculid parrots in terms of ecological traits such as body size, beak shape, and dispersal capacity.
Results: We found no evidence for an 'early-burst' scenario of lineage or morphological diversification.
Background: DNA barcoding utilises a standardised region of the cytochrome c oxidase I (COI) gene to identify specimens to the species level. It has proven to be an effective tool for identification of avian samples. The unique island avifauna of New Zealand is taxonomically and evolutionarily distinct.
View Article and Find Full Text PDFThe taxonomic status of the geographically isolated population of Short-toed Snake-eagle Circaetus gallicus on the Lesser Sundas (=Nusa Tenggara) has been controversial. In the past they have been regarded as either a migrant population or a recently arrived resident population. Here we obtained DNA sequences from the mitochondrial cytochrome-b gene and combined genetic data with assessments of published and novel morphological data to clarify the taxonomic status of the Lesser Sundas population of C.
View Article and Find Full Text PDFWhite-bellied swiftlets of the Collocalia esculenta complex constitute a radiation of colony-breeding swifts distributed throughout the tropical Indo-Pacific region. Resolution of their taxonomy is challenging due to their morphological uniformity. To analyze the evolutionary history of this complex, we combine new biometric measurements and results from plumage assessment of museum specimens with novel as well as previously published molecular data.
View Article and Find Full Text PDFKnown for their rich biodiversity and high level of endemism, the islands of Wallacea serve as natural laboratories for the study of spatio-temporal evolution and patterns of species diversification. Our study focuses on the owl genus Ninox, particularly the Southern Boobook (N. novaeseelandiae) and Moluccan Boobook (N.
View Article and Find Full Text PDFBioclimatic models are widely used to investigate the impacts of climate change on species distributions. Range shifts are expected to occur as species track their current climate niche yet the potential for exploitation of new ecological opportunities that may arise as ecosystems and communities remodel is rarely considered. Here we show that grasswrens of the Amytornis textilis-modestus complex responded to new ecological opportunities in Australia's arid biome through shifts in habitat preference following the development of chenopod shrublands during the late Plio-Pleistocene.
View Article and Find Full Text PDFMitochondrial sequence data is often used to reconstruct the demographic history of Pleistocene populations in an effort to understand how species have responded to past climate change events. However, departures from neutral equilibrium conditions can confound evolutionary inference in species with structured populations or those that have experienced periods of population expansion or decline. Selection can affect patterns of mitochondrial DNA variation and variable mutation rates among mitochondrial genes can compromise inferences drawn from single markers.
View Article and Find Full Text PDFThe Australasian robins (Petroicidae) comprise a relatively homogeneous group of small to medium-sized insectivorous birds. Their center of diversity is Australia and New Guinea (40 species) but seven species have managed to colonize geographically distant islands such as Tanimbar, New Britain, New Zealand, New Caledonia, Norfolk Island, Vanuatu, Solomon Islands, Fiji and Samoa. To resolve the evolutionary relationships within the Petroicidae, we here present the results of a phylogenetic analysis of sequence data from two mitochondrial genes (ND2, CO1) and one nuclear intron (β-Fibrinogen intron 5) for all 14 genera and 40 of the 46 currently recognized species.
View Article and Find Full Text PDFNucleotide sequences from four mitochondrial genes and three nuclear introns were used to examine phylogenetic relationships within the Australo-papuan fairy-wrens (Passeriformes: Maluridae: Malurinae). A well-resolved and well-supported phylogenetic hypothesis of all species in the subfamily was generated. The tree contained three clades corresponding to groups with similar plumages previously identified in earlier studies: the "bi-color," "blue," and "chestnut-shouldered" groups.
View Article and Find Full Text PDFThe 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).
View Article and Find Full Text PDFThe grasswrens (Maluridae: Amytornis) are elusive songbirds from the arid zones of Australia. Although some other Australian bird genera are also largely restricted to arid regions, none show the level of localized taxonomic diversity seen in Amytornis. Furthermore, their cryptic plumage patterns provide excellent camouflage but make it difficult to determine whether shared patterns reflect phylogenetic relationships or adaptations to similar terrain.
View Article and Find Full Text PDFMol Cell Proteomics
November 2010
Venom has only been recently discovered to be a basal trait of the Anguimorpha lizards. Consequently, very little is known about the timings of toxin recruitment events, venom protein molecular evolution, or even the relative physical diversifications of the venom system itself. A multidisciplinary approach was used to examine the evolution across the full taxonomical range of this ∼130 million-year-old clade.
View Article and Find Full Text PDFSpecies identification techniques commonly utilized in Australian Forensic Science laboratories are gel immunodifussion antigen antibody reactions and hair comparison analysis. Both of these techniques have significant limitations and should be considered indicative opinion based tests. The Barcode of Life Initiative aims to sequence a section of DNA (~648 base pairs) for the Cytochrome Oxidase I mitochondrial gene (COI) in all living species on Earth, with the data generated being uploaded to the Barcode of Life Database (BOLD) which can then be used for species identification.
View Article and Find Full Text PDFEast Antarctic octopods were identified by sequencing mtCOI and using four analytical approaches: Neighbor-joining by Kimura-2-Parameter-based distances, character-based, BLAST, and Bayesian Inference of Phylogeny. Although the distance-based analytical approaches identified a high proportion of the sequences (99.5% to genus and 88.
View Article and Find Full Text PDFThe Tree of Life is rife with adaptive convergences at all scales and biological levels of complexity. However, natural selection is not likely to result in the independent evolution of identical gene products. Here we report such a striking example of evolutionary convergence in the toxic skin secretions of two distantly related frog lineages.
View Article and Find Full Text PDFThe origin and evolution of venom proteins in helodermatid lizards were investigated by multidisciplinary techniques. Our analyses elucidated novel toxin types resultant from three unique domain-expression processes: 1) The first full-length sequences of lethal toxin isoforms (helofensins) revealed this toxin type to be constructed by an ancestral monodomain, monoproduct gene (beta-defensin) that underwent three tandem domain duplications to encode a tetradomain, monoproduct with a possible novel protein fold; 2) an ancestral monodomain gene (encoding a natriuretic peptide) was medially extended to become a pentadomain, pentaproduct through the additional encoding of four tandemly repeated proline-rich peptides (helokinestatins), with the five discrete peptides liberated from each other by posttranslational proteolysis; and 3) an ancestral multidomain, multiproduct gene belonging to the vasoactive intestinal peptide (VIP)/glucagon family being mutated to encode for a monodomain, monoproduct (exendins) followed by duplication and diversification into two variant classes (exendins 1 and 2 and exendins 3 and 4). Bioactivity characterization of exendin and helokinestatin elucidated variable cardioactivity between isoforms within each class.
View Article and Find Full Text PDFNeotropical forests have brought forth a large proportion of the world's terrestrial biodiversity, but the underlying evolutionary mechanisms and their timing require further elucidation. Despite insights gained from phylogenetic studies, uncertainties about molecular clock rates have hindered efforts to determine the timing of diversification processes. Moreover, most molecular research has been detached from the extensive body of data on Neotropical geology and paleogeography.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFAnnu Rev Genomics Hum Genet
October 2009
Throughout evolution, numerous proteins have been convergently recruited into the venoms of various animals, including centipedes, cephalopods, cone snails, fish, insects (several independent venom systems), platypus, scorpions, shrews, spiders, toxicoferan reptiles (lizards and snakes), and sea anemones. The protein scaffolds utilized convergently have included AVIT/colipase/prokineticin, CAP, chitinase, cystatin, defensins, hyaluronidase, Kunitz, lectin, lipocalin, natriuretic peptide, peptidase S1, phospholipase A(2), sphingomyelinase D, and SPRY. Many of these same venom protein types have also been convergently recruited for use in the hematophagous gland secretions of invertebrates (e.
View Article and Find Full Text PDFThe predatory ecology of Varanus komodoensis (Komodo Dragon) has been a subject of long-standing interest and considerable conjecture. Here, we investigate the roles and potential interplay between cranial mechanics, toxic bacteria, and venom. Our analyses point to the presence of a sophisticated combined-arsenal killing apparatus.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFBackground: Little 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.
View Article and Find Full Text PDFWe investigated mitochondrial and nuclear DNA in the small tyrant-flycatcher genus Zimmerius (Tyrannidae) and show that molecular data are in strong disagreement with morphology-based taxonomy, but in good concordance with vocal characters. Our molecular data identified two independent cases of well-supported polyphyletic species arrangements within this genus that indicate the following taxonomic changes: elevation of Z. acer and Z.
View Article and Find Full Text PDFShed feathers obtained by noninvasive genetic sampling (NGS) are a valuable source of DNA for genetic studies of birds. They can be collected across a large geographical range and facilitate research on species that would otherwise be extremely difficult to study. A limitation of this approach is uncertainty concerning the quality of the extracted DNA.
View Article and Find Full Text PDFThe systematic relationships among avian families within Crown Corvida have been poorly studied so far and as such been of limited use for biogeographic interpretations. The group has its origin in Australia and is thought to have colonized Africa and the New World via Asia beginning some 35 Mya when terranes of Australian origin approached Asian landmasses. Recent detailed tectonic mapping of the origin of land masses in the region around Wallace's line have revealed a particularly complex movement of terranes over the last 20-30 Myr.
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