ORCID Profile
0000-0001-7531-597X
Current Organisation
University of Otago
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Life Histories | Behavioural Ecology | Evolutionary Biology | Biological Adaptation
Expanding Knowledge in the Biological Sciences | Expanding Knowledge in the Medical and Health Sciences |
Publisher: Oxford University Press (OUP)
Date: 27-06-2023
DOI: 10.1093/ZOOLINNEAN/ZLAD041
Abstract: The aptly named microcormorants (currently placed in the genus Microcarbo) form a morphologically diminutive and distinct clade sister to all other living cormorants and shags. However, the relationships within Microcarbo are largely speculative. Sequence data resolve these relationships unambiguously, with our phylogeny suggesting that the microcormorants separated from the other cormorants ~16 Mya and showing that the two African species [the reed (or long-tailed) cormorant, Microcarbo africanus, and the crowned cormorant, Microcarbo coronatus] are closely related sister taxa, forming a clade that erged from the other microcormorants ~12 Mya. The deep split between the African microcormorants and the others is considerably older than many well-recognized generic splits within the cormorants (e.g. Leucocarbo and Phalacrocorax). Thus, we suggest that the African microcormorants warrant their own genus, and we erect Afrocarbo, with type species Pelecanus africanus. Within the reduced Microcarbo, we estimate that the little pied cormorant (Microcarbo melanoleucos of Australasia) separated from the sister pair of the Javanese and pygmy cormorants (respectively, Microcarbo niger from south/southeast Asia and Microcarbo pygmaeus from Europe) ~9 Mya and that the latter two species split ~2 Mya. Given the age of these splits, the microcormorants appear to represent another ex le of morphological conservatism in the Suliformes.
Publisher: Oxford University Press (OUP)
Date: 14-05-2010
Abstract: A phylogenetic tree comprising clades with high bootstrap values or other strong measures of statistical support is usually interpreted as providing a good estimate of the true phylogeny. Convergent evolution acting on groups of characters in concert, however, can lead to highly supported but erroneous phylogenies. Identifying such groups of phylogenetically misleading characters is obviously desirable. Here we present a procedure that uses an independent data source to identify sets of characters that have undergone concerted convergent evolution. We examine the problematic case of the cormorants and shags, for which trees constructed using osteological and molecular characters both have strong statistical support and yet are fundamentally incongruent. We find that the osteological characters can be separated into those that fit the phylogenetic history implied by the molecular data set and those that do not. Moreover, these latter nonfitting osteological characters are internally consistent and form groups of mutually compatible characters or "cliques," which are significantly larger than cliques of shuffled characters. We suggest, therefore, that these cliques of characters are the result of similar selective pressures and are a signature of concerted convergence.
Publisher: Oxford University Press (OUP)
Date: 15-03-2013
Publisher: Elsevier BV
Date: 03-2021
Publisher: Springer Science and Business Media LLC
Date: 23-01-2023
DOI: 10.1186/S13059-022-02838-0
Abstract: The Australian black swan ( Cygnus atratus ) is an iconic species with contrasting plumage to that of the closely related northern hemisphere white swans. The relative geographic isolation of the black swan may have resulted in a limited immune repertoire and increased susceptibility to infectious diseases, notably infectious diseases from which Australia has been largely shielded. Unlike mallard ducks and the mute swan ( Cygnus olor ), the black swan is extremely sensitive to highly pathogenic avian influenza. Understanding this susceptibility has been impaired by the absence of any available swan genome and transcriptome information. Here, we generate the first chromosome-length black and mute swan genomes annotated with transcriptome data, all using long-read based pipelines generated for vertebrate species. We use these genomes and transcriptomes to show that unlike other wild waterfowl, black swans lack an expanded immune gene repertoire, lack a key viral pattern-recognition receptor in endothelial cells and mount a poorly controlled inflammatory response to highly pathogenic avian influenza. We also implicate genetic differences in SLC45A2 gene in the iconic plumage of the black swan. Together, these data suggest that the immune system of the black swan is such that should any avian viral infection become established in its native habitat, the black swan would be in a significant peril.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.TPB.2013.05.001
Abstract: The evolution of transgenerational epigenetic adaptation is driven by the invasion and stable inheritance of epialleles. Here, we describe a population-genetic model subject to environmentally-induced epigenetic effects in order to investigate the conditions under which an epigenetically modifiable allele (epiallele) can invade a population insensitive to such cues. Here, epigenetically modifiable in iduals have the potential to develop a phenotype that is suitable for their predicted future environment and, provided this prediction is correct, possess a biological advantage compared to their non-modifiable counterpart. However, when in iduals experience an environment that 'mismatches' their phenotype, an advantage over unmodifiable in iduals may be precluded and instead they experience a decrease in fitness. These epigenetic modifications are then inherited by the next generation which are either epigenetically reset to match their environment or, by resisting environmental cues, maintain their epigenetic status. We found that when environmental cues were common, a severe fitness cost of mismatch between environment and phenotype meant that the disadvantage was too costly and epialleles were less likely to invade. Moreover, for a wide range of parameters, a higher rate of germline epigenetic resetting decreased the likelihood of epiallele invasion. Accordingly, we found that both the frequency of environmental influences and the rate of resetting were central parameters in this system.
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.YMPEV.2009.11.008
Abstract: This study is the most extensive molecular study of the gastropod families Trochidae and Calliostomatidae published to date, in terms of both numbers of taxa and of gene sequences. As a result of Bayesian phylogenetic analyses of molecular sequence data from one nuclear gene and three mitochondrial genes, we propose dramatic changes to Trochidae family systematics, present the first molecular phylogeny for Calliostomatidae and include the first published sequence data for the enigmatic subfamily Thysanodontinae. Our phylogeny demonstrates that within the family Trochidae there is strong support for three subfamilies new to traditional classifications: Alcyninae subfam. nov., Fossarininae and Chrysostomatinae subfam. nov. As proposed, Alcyninae consists only of the nominotypical genus Alcyna, which is sister to all other trochids. The subfamily Fossarininae, as defined here, includes Fossarina, Broderipia, Synaptocochlea and "Roya"eximia and probably also Clydonochilus and Minopa. The subfamily Chrysostomatinae comprises the genera Chrysostoma and Chlorodiloma. Additional molecular support is also obtained for recently redefined Trochinae, Monodontinae, and Cantharidinae and for the traditionally recognised subfamilies Umboniinae and Stomatellinae. The subfamily Lirulariinae is not supported by the molecular data, but rather is incorporated into Umboniinae. We also demonstrate that the current concept of the subfamily Margaritinae (previously a trochid subfamily, but recently and provisionally assigned to Turbinidae) is not monophyletic. We provide preliminary evidence that whereas Margarella rosea (previously a member of Margaritinae) belongs in the trochid subfamily Cantharidinae, its presumptive congener M. antarctica is not a trochid, but instead clusters with the thysanodontine genus Carinastele. Based on the phylogenetic placement of C. kristelleae, we agree with previous proposals based on morphological data that Thysanodontinae are more closely related to Calliostomatidae than Trochidae. Both Calliostoma and Carinastele are carnivorous and if a sister relationship can be confirmed between Carinastele and Margarella antarctica it might mean that carnivory evolved twice in Trochoidea. The direction of dietary changes was not investigated in this study, but mapping diet onto the phylogeny suggests that true herbivory is predominantly a derived character. The new classification system also means that five trochid subfamilies are predominantly associated with hard substrata, one with soft substrata (Umboniinae) and two with algae and seagrass (Alcyninae and Cantharidinae). There has been a shift back to hard substrata in one umboniine clade. Two of three clades within Calliostomatidae were predominantly associated with hard substrata, but one Japanese clade is associated with sand. The finding of three new, unidentified species from very deep water means that Trochidae, like Calliostomatidae, now includes species found at bathyal depths. More deep-water species may be found as increased s ling leads to the discovery of new species.
Publisher: Proceedings of the National Academy of Sciences
Date: 03-03-2009
Abstract: The end of the Last Glacial Maximum (LGM) dramatically reshaped temperate ecosystems, with many species moving poleward as temperatures rose and ice receded. Whereas reinvading terrestrial taxa tracked melting glaciers, marine biota recolonized ocean habitats freed by retreating sea ice. The extent of sea ice in the Southern Hemisphere during the LGM has, however, yet to be fully resolved, with most palaeogeographic studies suggesting only minimal or patchy ice cover in subantarctic waters. Here, through population genetic analyses of the widespread Southern Bull Kelp ( Durvillaea antarctica ), we present evidence for persistent ice scour affecting subantarctic islands during the LGM. Using mitochondrial and chloroplast genetic markers (COI rbc L) to genetically characterize some 300 kelp s les from 45 Southern Ocean localities, we reveal a remarkable pattern of recent recolonization in the subantarctic. Specifically, in contrast to the marked phylogeographic structure observed across coastal New Zealand and Chile (10- to 100-km scales), subantarctic s les show striking genetic homogeneity over vast distances (10,000-km scales), with a single widespread haplotype observed for each marker. From these results, we suggest that sea ice expanded further and ice scour during the LGM impacted shallow-water subantarctic marine ecosystems more extensively than previously suggested.
Publisher: Wiley
Date: 06-07-2022
DOI: 10.1111/JBI.14453
Abstract: The Antarctic Circumpolar Current imparts significant structure to the Southern Ocean biota. The Antarctic Polar Front is a major barrier to dispersal, with separate species (or sometimes intraspecific clades) normally occurring either side of this feature. We examined the biogeographic structure of an apparent exception to this rule in a widespread genus of the Southern Ocean, the periwinkle snail, Laevilitorina. Southern Ocean. Littorinidae, Laevilitorininae, Laevilitorina . Using 750 specimens from 16 Southern Ocean Laevilitorina populations across km, we analysed mitochondrial COI and nuclear 28S sequences to uncover the evolutionary history of these marine near‐shore snails. We utilized multi‐locus phylogenetic reconstructions, species‐delimitation analyses, ergence‐time estimations and geometric morphometrics. Molecular data revealed that the widespread nominal species L. caliginosa comprises seven species‐level clades, all supported by morphological data, whereas the Antarctic nominal species L. antarctica , L. claviformis and L. umbilicata are conspecific. Six “ caliginosa ” clades are restricted to southern South America, but one lineage extends from Antarctica to distant sub‐Antarctic islands on both sides of the APF. Geometric morphometrics also identified significant differences among these clades, but uncoupled from genetic differentiation. The apparent trans‐APF distribution of the poorly dispersing Laevilitorina caliginosa is largely illusory: this taxon consists of at least seven discrete species, only one of which has a trans‐APF distribution. Similar to most Laevilitorina species, the remaining six “ caliginosa ” clades are narrow endemics. Biogeographical patterns in Laevilitorina reflect the role of vicariance associated with geological processes together with recent long‐distance dispersal events. Laevilitorina originated near the Eocene/Oligocene boundary and ersified during the Miocene and the Pliocene. Laevilitorina is not a cryptic‐species complex: speciation was accompanied by hitherto unrecognized morphological differentiation. This study represents the most detailed molecular work on Southern‐Ocean littorinids and reveals unforeseen ersity across this globally important region.
Publisher: Elsevier BV
Date: 11-1999
Publisher: Informa UK Limited
Date: 03-2012
DOI: 10.2216/11-47.1
Publisher: Oxford University Press (OUP)
Date: 08-2019
Abstract: Genetic data are increasingly being used to prioritize species conservation in a fiscally constrained age of seemingly boundless conservation crises. Such data can also reveal previously cryptic bio ersity requiring further revision of conservation management guidelines. Using a combination of mitochondrial (control region) and nuclear (beta fibrinogen intron 7) DNA, and morphology, we reveal that the endemic New Zealand Spotted Shag (Phalacrocorax punctatus) complex exhibits phylogenetic structure that is decoupled from previously recorded qualitative morphological variation. Crucially, the most genetically distinct populations within P. punctatus are from northern New Zealand recent surveys show that these populations, which house important genetic ersity within Spotted Shags, are in danger of being extirpated. In contrast, we find the previously phenotypically differentiated nominate (P. punctatus punctatus) and Blue (P. punctatus oliveri) Shag subspecies show no genetic and morphological separation, and are of least conservation concern.
Publisher: Oxford University Press (OUP)
Date: 12-02-2016
DOI: 10.1111/ZOJ.12376
Publisher: Wiley
Date: 28-07-2014
DOI: 10.1111/JBI.12376
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.TPB.2012.09.001
Abstract: Differences in transgenerational epigenetic stability can result in a ersity of phenotypes among genetically identical in iduals. Here we present a model that encapsulates non-genomic phenotypic variation in a population over two distinct environments that each act as a stimulus for epigenetic modification. By allowing different levels of epigenetic resetting, thereby increasing epigenetic ersity, we explore the dynamics of multiple epiallelic states subject to selection in a population-epigenetic model. We find that both epigenetic resetting and the environmental frequency are crucial parameters in this system. Our results illustrate the regions of parameter space that enable up to three equilibria to be simultaneously locally stable. Furthermore, it is clear that both continued environmental induction and epigenetic resetting prevent epigenetic fixation, maintaining phenotypic variation through different epiallelic states. However, unless both environments are reasonably common, levels of epigenetically-maintained variation are low. We argue that it is vital that non-genomic phenotypic ersity is not ignored in evolutionary theory, but instead regarded as distinct epiallelic variants. Ultimately, a critical goal of future experiments should be to determine accurate rates of epigenetic resetting, especially over several generations, in order to establish the long-term significance of epigenetic inheritance.
Publisher: Wiley
Date: 05-2009
Publisher: Wiley
Date: 27-02-2019
Abstract: While in recent years environmental DNA (eDNA) metabarcoding surveys have shown great promise as an alternative monitoring method, the integration into existing marine monitoring programs may be confounded by the dispersal of the eDNA signal. Currents and tidal influences could transport eDNA over great distances, inducing false-positive species detection, leading to inaccurate bio ersity assessments and, ultimately, mismanagement of marine environments. In this study, we determined the ability of eDNA metabarcoding surveys to distinguish localized signals obtained from four marine habitats within a small spatial scale (<5 km) subject to significant tidal and along-shore water flow. Our eDNA metabarcoding survey detected 86 genera, within 77 families and across 11 phyla using three established metabarcoding assays targeting fish (16S rRNA gene), crustacean (16S rRNA gene) and eukaryotic (cytochrome oxidase subunit 1) ersity. Ordination and cluster analyses for both taxonomic and OTU data sets show distinct eDNA signals between the s led habitats, suggesting dispersal of eDNA among habitats was limited. In idual taxa with strong habitat preferences displayed localized eDNA signals in accordance with their respective habitat, whereas taxa known to be less habitat-specific generated more ubiquitous signals. Our data add to evidence that eDNA metabarcoding surveys in marine environments detect a broad range of taxa that are spatially discrete. Our work also highlights that refinement of assay choice is essential to realize the full potential of eDNA metabarcoding surveys in marine bio ersity monitoring programs.
Publisher: The Royal Society
Date: 03-2021
DOI: 10.1098/RSOS.201831
Abstract: The Hill–Robertson effect describes how, in a finite panmictic diploid population, selection at one diallelic locus reduces the fixation probability of a selectively favoured allele at a second, linked diallelic locus. Here we investigate the influence of population structure on the Hill–Robertson effect in a population of size N . We model population structure as a network by assuming that in iduals occupy nodes on a graph connected by edges that link members who can reproduce with each other. Three regular networks (fully connected, ring and torus), two forms of scale-free network and a star are examined. We find that (i) the effect of population structure on the probability of fixation of the favourable allele is invariant for regular structures, but on some scale-free networks and a star, this probability is greatly reduced (ii) compared to a panmictic population, the mean time to fixation of the favoured allele is much greater on a ring, torus and linear scale-free network, but much less on power-2 scale-free and star networks (iii) the likelihood with which each of the four possible haplotypes eventually fix is similar across regular networks, but scale-free populations and the star are consistently less likely and much faster to fix the optimal haplotype (iv) increasing recombination increases the likelihood of fixing the favoured haplotype across all structures, whereas the time to fixation of that haplotype usually increased, and (v) star-like structures were overwhelmingly likely to fix the least fit haplotype and did so significantly more rapidly than other populations. Last, we find that small ( N 64) panmictic populations do not exhibit the scaling property expected from Hill & Robertson (1966 Genet. Res. 8 , 269–294. ( doi:10.1017/S0016672300010156 )).
Publisher: Wiley
Date: 27-12-2016
DOI: 10.1111/JBI.12908
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.TPB.2013.05.003
Abstract: Paramutation involves an interaction between homologous alleles resulting in a heritable change in gene expression without altering the DNA sequence. Initially believed to be restricted to plants, paramutation has recently been observed in animal models, and a paramutation-like event has been noted in humans. Despite the accumulating evidence suggesting that trans-acting epigenetic effects can be inherited transgenerationally and therefore generate non-genomic phenotypic variation, these effects have been largely ignored in the context of evolutionary theory. The model presented here incorporates paramutation into the standard model of viability selection at one locus and demonstrates that paramutation can create long-term biological ersity in the absence of genetic change, and even in the absence of the original paramutagenic allele. Therefore, if paramutation is present, attributing evolution to only a traditional genetic model may fail to encompass the broad scope of phenotypic differences observed in nature. Moreover, we show also that an unusual mathematical behaviour, analogous to "Ewens' gap" of the two-locus two-allele symmetric-selection model, occurs: when the rate of one parameter-for ex le, the rate of paramutation-is increased, a pair of equilibria may disappear only to reappear as this parameter increases further. In summary, by incorporating even the simplest epigenetic parameters into the standard population-genetic model of selection, we show how this type of inheritance system can profoundly alter the course of evolution.
Publisher: Wiley
Date: 15-01-2019
DOI: 10.1002/ECE3.4843
Publisher: Cold Spring Harbor Laboratory
Date: 19-08-2021
DOI: 10.1101/2021.08.18.456742
Abstract: Understanding how wild populations respond to climatic shifts is a fundamental goal of biological research in a fast-changing world. The Southern Ocean represents a fascinating system for assessing large-scale climate-driven biological change, as it contains extremely isolated island groups within a predominantly westerly, circumpolar wind and current system. The blue-eyed shags ( Leucocarbo spp.) represent a paradoxical Southern Ocean seabird radiation a circumpolar distribution implies strong dispersal capacity yet their speciose nature suggests local adaptation and isolation. Here we use genetic tools in an attempt to resolve this paradox. Southern Ocean. 17 species and subspecies of blue-eyed shags ( Leucocarbo spp.) across the geographical distribution of the genus. Here we use mitochondrial and nuclear sequence data to conduct the first global genetic analysis of this group using a temporal phylogenetic framework to test for rapid speciation. Our analysis reveals remarkably shallow evolutionary histories among island-endemic lineages, consistent with a recent high-latitude circumpolar radiation. This rapid sub-Antarctic expansion contrasts with significantly deeper lineages detected in more temperate regions such as South America and New Zealand that may have acted as glacial refugia. The dynamic history of high-latitude expansions is further supported by ancestral demographic and biogeographic reconstructions. The circumpolar distribution of blue-eyed shags, and their highly dynamic evolutionary history, potentially make Leucocarbo a strong sentinel of past and ongoing Southern Ocean ecosystem change given their sensitivity to climatic impacts.
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.TPB.2011.08.001
Abstract: There is increasing evidence that epigenetic modifications can be passed from one generation to the next. The population-level consequence of these discoveries, however, remains largely unexplored. In this paper, we introduce and analyze some simple models of constant viability selection acting on such heritable epigenetic variation. These "population-epigenetic" models are analogous to those of traditional population genetics, and are a preliminary step in quantifying the effect of non-genomic transgenerational inheritance, aiming to improve our understanding of how this sort of environmental response may affect evolution.
Publisher: Wiley
Date: 26-10-2011
Publisher: Wiley
Date: 21-06-2005
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.YMPEV.2017.07.011
Abstract: New Zealand's endemic King Shag (Leucocarbo carunculatus) has occupied only a narrow portion of the northeastern South Island for at least the past 240years. However, pre-human Holocene fossil and archaeological remains have suggested a far more widespread distribution of the three Leucocarbo species (King, Otago, Foveaux) on mainland New Zealand at the time of Polynesian settlement in the late 13th Century CE. We use modern and ancient DNA, and morphometric and osteological analyses, of modern King Shags and Holocene fossil Leucocarbo remains to assess the pre-human distribution and taxonomic status of the King Shag on mainland New Zealand, and the resultant conservation implications. Our analyses show that the King Shag was formerly widespread around southern coasts of the North Island and the northern parts of the South Island but experienced population and lineage extinctions, and range contraction, probably after Polynesian arrival. This history parallels range contractions of other New Zealand seabirds. Conservation management of the King Shag should take into account this species narrow distribution and probable reduced genetic ersity. Moreover, combined genetic, morphometric and osteological analyses of prehistoric material from mainland New Zealand suggest that the now extinct northern New Zealand Leucocarbo populations comprised a unique lineage. Although these distinctive populations were previously assigned to the King Shag (based on morphological similarities and geographic proximity to modern Leucocarbo populations), we herein describe them as a new species, the Kohatu Shag (Leucocarbo septentrionalis). The extinction of this species further highlights the dramatic impacts Polynesians and introduced predators had on New Zealand's coastal and marine bio ersity. The prehistoric presence of at least four species of Leucocarbo shag on mainland NZ further highlights its status as a bio ersity hotspot for Phalacrocoracidae.
Publisher: Oxford University Press (OUP)
Date: 08-2005
Abstract: Long-branch attraction is a well-known source of systematic error that can mislead phylogenetic methods it is frequently invoked post hoc, upon recovering a different tree from the one expected based on prior evidence. We demonstrate that methods that do not force the data onto a single tree, such as spectral analysis, Neighbor-Net, and consensus networks, can be used to detect conflicting signals within the data, including those caused by long-branch attraction. We illustrate this approach using a set of taxa from three unambiguously monophyletic families within the Pelecaniformes: the darters, the cormorants and shags, and the gannets and boobies. These three families are universally acknowledged as forming a monophyletic group, but the relationship between the families remains contentious. Using sequence data from three mitochondrial genes (12S, ATPase 6, and ATPase 8) we demonstrate that the relationship between these three families is difficult to resolve because they are separated by a short internal branch and there are conflicting signals due to long-branch attraction, which are confounded with nonhomogeneous sequence evolution across the different genes. Spectral analysis, Neighbor-Net, and consensus networks reveal conflicting signals regarding the placement of one of the darters, with support found for darter monophyly, but also support for a conflicting grouping with the outgroup, pelicans. Furthermore, parsimony and maximum-likelihood analyses produced different trees, with one of the two most parsimonious trees not supporting the monophyly of the darters. Monte Carlo simulations, however, were not sensitive enough to reveal long-branch attraction unless the branches are longer than those actually observed. These results indicate that spectral analysis, Neighbor-Net, and consensus networks offer a powerful approach to detecting and understanding the source of conflicting signals within phylogenetic data.
Publisher: Wiley
Date: 22-08-2011
DOI: 10.1002/ECE3.16
Publisher: The Royal Society
Date: 23-02-2013
Abstract: Dispersal by passive oceanic rafting is considered important for the assembly of biotic communities on islands. However, not much is known about levels of population genetic connectivity maintained by rafting over transoceanic distances. We assess the evolutionary impact of kelp-rafting by estimating population genetic differentiation in three kelp-associated invertebrate species across a system of islands isolated by oceanic gaps for over 5 million years, using mtDNA and AFLP markers. The species occur throughout New Zealand's subantarctic islands, but lack pelagic stages and any opportunity for anthropogenic transportation, and hence must rely on passive rafting for long-distance dispersal. They all have been directly observed to survive transoceanic kelp-rafting journeys in this region. Our analyses indicate that regular gene flow occurs among populations of all three species between all of the islands, especially those on either side of the subtropical front oceanographic boundary. Notwithstanding its perceived sporadic nature, long-distance kelp-rafting appears to enable significant gene flow among island populations separated by hundreds of kilometres of open ocean.
Publisher: Inter-Research Science Center
Date: 29-12-2016
DOI: 10.3354/MEPS11926
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.YMPEV.2011.09.002
Abstract: Snails in the closely related trochid genera Phorcus Risso, 1826 and Osilinus Philippi, 1847 are ecologically important algal grazers in the intertidal zone of the northeastern Atlantic Ocean and Mediterranean Sea. Here we present the first complete molecular phylogeny for these genera, based on the nuclear 28S rRNA gene and the mitochondrial 16S rRNA and COI genes, and show that the current classification is erroneous. We recognize nine species in a single genus, Phorcus: estimated by BEAST analysis, this arose 30 (± 10) Ma it consists of two subgenera, Phorcus and Osilinus, which we estimate erged 14 (± 4.5) Ma. Osilinus kotschyi, from the Arabian and Red Seas, is not closely related and is tentatively referred to Priotrochus Fischer, 1879. Our phylogeny allows us to address biogeographical questions concerning the origins of the Mediterranean and Macaronesian species of this group. The former appear to have evolved from Atlantic ancestors that invaded the Mediterranean on several occasions after the Zanclean Flood, which ended the Messinian Salinity Crisis 5.3 Ma whereas the latter arose from several colonizations of mainland Atlantic ancestors within the last 3 (± 1.5) Ma.
Publisher: Elsevier BV
Date: 12-2010
DOI: 10.1016/J.YMPEV.2010.10.011
Abstract: Durvillaea (southern bull-kelp) is an economically and ecologically important brown algal genus that dominates many exposed, rocky coasts in the cold-temperate Southern Hemisphere. Of its five currently-recognized species, four are non-buoyant and restricted to the south-western Pacific, whereas one is both buoyant and widely distributed. Durvillaea has had an unsettled taxonomic history. Although its position within the brown algae (Phaeophyceae) has now been largely resolved through the use of molecular techniques, the taxonomic status of several Durvillaea species/morphotypes remains unresolved. Previous molecular phylogenetic studies of phaeophycean taxa have included few Durvillaea s les, and have consequently paid little or no attention to variation within this genus. The current study presents phylogenetic analyses of four genetic markers (mitchondrial: COI chloroplast: rbcL and nuclear: 18S and 28S) to resolve phylogenetic relationships within Durvillaea. Results support the monophyly of solid-bladed taxa D. willana, D. potatorum, and D. sp. A (an undescribed species from the Antipodes Islands), whereas the widespread, buoyant D. antarctica is paraphyletic, with solid-bladed D.chathamensis placed sister to a D. antarctica clade from northern NZ but within D. antarctica sensu lato. The phylogenetic and ecological ersity detected within D. antarctica indicate that it is a species complex of five deeply ergent clades. Under a phylogenetic species concept, Durvillaea can be interpreted as a complex of nine distinct evolutionary lineages, only one of which has an intercontinental distribution ('subantarctic'D. antarctica).
Publisher: Wiley
Date: 04-2009
DOI: 10.1111/J.1529-8817.2009.00658.X
Abstract: Many macroalgae exhibit considerable intraspecific morphological variation, but whether such variation reflects phenotypic plasticity or underlying genetic differences is often poorly understood. We quantified both morphological and genetic variation of 96 plants from seven field sites across eastern South Island, New Zealand, to assess genetic differences between morphotypes of the southern bull kelp Durvillaea antarctica (Cham.) Har. Consistent DNA sequence differentiation across mitochondrial, plastid, and nuclear loci was correlated with two broadly sympatric morphotypes: "cape" and "thonged." These ecologically, morphologically, and genetically distinct bull-kelp lineages were previously considered to be environmentally determined phenotypes with no underlying genetic basis. Interestingly, the sheltered "cape" lineage appears essentially genetically uniform across its South Island range, whereas the exposed "thonged" lineage exhibits marked phylogeographic structure across its range. Results suggest that D. antarctica in New Zealand comprises two reproductively isolated species.
Publisher: Public Library of Science (PLoS)
Date: 10-03-2014
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/IS08030
Abstract: The seven currently recognised New Zealand species in the gastropod genus Diloma Philippi, 1845 are an important component of New Zealand’s littoral bio ersity across a range of intertidal habitats. A new cryptic species in this genus (Diloma durvillaea, sp. nov.) is described largely on molecular grounds from exposed coasts of the South Island of New Zealand from Lyttelton south, as well as the Auckland Islands. The shell is very similar to D. arida (Finlay, 1926), differing subtly in having stronger spiral ribs and less extensive or no yellow spotting. Phylogenetic analysis of the mitochondrial cytochrome c oxidase I (COI) gene shows these two species are sister-taxa and are more distinct from each other (genetic distance 11.5%) than are the morphologically ergent sister-species D. subrostrata (Gray, 1835) and D. aethiops (Gmelin, 1791) (8.2%), also from New Zealand. The new species is found in a novel habitat for the genus, in the holdfasts and on the blades of the bull kelp, Durvillaea antarctica (Cham.) Har. (Phaeophyta), at the low-tide mark on exposed coasts, whereas D. arida occurs higher up on the shore, as well as in more sheltered situations.
Publisher: Wiley
Date: 22-02-2012
DOI: 10.1111/J.1474-9726.2012.00798.X
Abstract: Dietary restriction (DR) extends the lifespan of a wide range of species, although the universality of this effect has never been quantitatively examined. Here, we report the first comprehensive comparative meta-analysis of DR across studies and species. Overall, DR significantly increased lifespan, but this effect is modulated by several factors. In general, DR has less effect in extending lifespan in males and also in non-model organisms. Surprisingly, the proportion of protein intake was more important for life extension via DR than the degree of caloric restriction. Furthermore, we show that reduction in both age-dependent and age-independent mortality rates drives life extension by DR among the well-studied laboratory model species (yeast, nematode worms, fruit flies and rodents). Our results suggest that convergent adaptation to laboratory conditions better explains the observed DR-longevity relationship than evolutionary conservation although alternative explanations are possible.
Publisher: Inter-Research Science Center
Date: 29-04-2010
DOI: 10.3354/MEPS08523
Publisher: Wiley
Date: 06-2009
Publisher: Public Library of Science (PLoS)
Date: 22-07-2013
Publisher: Springer Science and Business Media LLC
Date: 2010
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/IS06038
Abstract: Members of the genus Nerita are abundant components of the intertidal fauna in many parts of the world and yet Nerita taxonomy remains unsettled. Here, the relationships among black-shelled Nerita populations from Australia, New Zealand, Norfolk Island, Lord Howe Island, the Kermadec Islands and Easter Island are discussed. Four species are recognised: N. atramentosa Reeve, 1855 from the southern half of Australia N. melanotragus E.A. Smith, 1884 from eastern Australia, northern New Zealand, Lord Howe Island, Norfolk Island and the Kermadec Islands N. morio (G. B. Sowerby I, 1833) from Easter Island and the Austral Islands and N. lirellata Rehder, 1980 from Easter Island alone. These species are of great importance in studies of intertidal community structure and yet two of them have been consistently confused in the ecological and taxonomic literature. Moreover, the relationships among the species are not at all as implied by recent subgeneric classifications it is argued that all four species should be placed in the subgenus Lisanerita Krijnen, 2002. The superficially similar N. picea Récluz, 1841 is not closely related. An accurate taxonomy of the genus will almost certainly require considerable genetic analysis. The nomenclature for each species is herein established by complete synonymies, and lectotypes for both N. atramentosa and N. melanotragus are selected.
Location: New Zealand
Start Date: 03-2018
End Date: 05-2021
Amount: $298,409.00
Funder: Australian Research Council
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