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Journal ArticleDOI

Molecular phylogenetics and biogeography of galaxiid fishes (Osteichthyes: Galaxiidae): dispersal, vicariance, and the position of Lepidogalaxias salamandroides.

01 Dec 2000-Systematic Biology (Oxford University Press)-Vol. 49, Iss: 4, pp 777-795
TL;DR: The species-rich genus Galaxias is shown to be polyphyletic and the generic taxonomy of the Galaxiinae is reassessed in the light of phylogenetic relationships, and the loss of this migratory phase may be a major cause of speciation.
Abstract: The galaxiid fishes exhibit a gondwanan distribution. We use mitochondrial DNA sequences to test conflicting vicariant and dispersal biogeographic hypotheses regarding the Southern Hemisphere range of this freshwater group. Although phylogenetic resolution of cytochrome b and 16S rRNA sequences is largely limited to more recent divergences, our data indicate that the radiation can be interpreted as several relatively recent dispersal events superimposed on an ancient gondwanan radiation. Genetic relationships contradict the findings of recent morphological analyses of galaxioid fishes. In particular, we examine several hypotheses regarding phylogenetic placement of the enigmatic Lepidogalaxias. Although most workers consider Lepidogalaxias to be an unusual scaled member of the Southern Hemisphere galaxioids, it has also been suggested that this species is related to the Northern Hemisphere esocoids. Our data strongly suggest that this species is not a galaxiid, and the alternative hypothesized esocoid relationship cannot be rejected. The species-rich genus Galaxias is shown to be polyphyletic and the generic taxonomy of the Galaxiinae is reassessed in the light of phylogenetic relationships. Juvenile saltwater-tolerance is phylogenetically distributed throughout the Galaxiinae, and the loss of this migratory phase may be a major cause of speciation.

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Citations
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Journal ArticleDOI
TL;DR: The results confirm the hybrid origin of the South American biota: there has been surprisingly little biotic exchange between the northern tropical and the southern temperate regions of South America, especially for animals.
Abstract: The Southern Hemisphere has traditionally been considered as having a fundamentally vicariant history. The common trans-Pacific disjunctions are usually explained by the sequential breakup of the supercontinent Gondwana during the last 165 million years, causing successive division of an ancestral biota. However, recent biogeographic studies, based on molecular estimates and more accurate paleogeographic reconstructions, indicate that dispersal may have been more important than traditionally assumed. We examined the relative roles played by vicariance and dispersal in shaping Southern Hemisphere biotas by analyzing a large data set of 54 animal and 19 plant phylogenies, including marsupials, ratites, and southern beeches (1,393 terminals). Parsimony-based tree fitting in conjunction with permutation tests was used to examine to what extent Southern Hemisphere biogeographic patterns fit the breakup sequence of Gondwana and to identify concordant dispersal patterns. Consistent with other studies, the animal data are congruent with the geological sequence of Gondwana breakup: (Africa(New Zealand(southern South America, Australia))). Trans-Antarctic dispersal (Australia southern South America) is also significantly more frequent than any other dispersal event in animals, which may be explained by the long period of geological contact between Australia and South America via Antarctica. In contrast, the dominant pattern in plants, (southern South America(Australia, New Zealand)), is better explained by dispersal, particularly the prevalence of trans-Tasman dispersal between New Zealand and Australia. Our results also confirm the hybrid origin of the South American biota: there has been surprisingly little biotic exchange between the northern tropical and the southern temperate regions of South America, especially for animals.

868 citations


Cites background from "Molecular phylogenetics and biogeog..."

  • ...Molecular clock estimates of divergence times show that many classic Gondwanan groups combine an ancient vicariance pattern with relatively recent dispersal events (Waters et al., 2000b; Cooper et al., 2001), whereas other groups originated after continental breakup, and their distribution can be explained only by long-distance dispersal across oceanic barriers (Baum et al....

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  • ...…estimates of divergence times show that many classic Gondwanan groups combine an ancient vicariance pattern with relatively recent dispersal events (Waters et al., 2000b; Cooper et al., 2001), whereas other groups originated after continental breakup, and their distribution can be explained only…...

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  • ...Marine dispersal in currents associated with the West Wind Drift is also invoked to explain sister-group relationships between New Zealand–Australian marine organisms (Fell, 1962; Waters et al., 2000a)....

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  • ...…Perciformes (64) ST Farias et al., 1999 ((MAD, IND)(AFR, NSA)) TGP (1.00) 48 (SG) Galaxiidae: Teleostei, Osteichthyes, Osmeriformes (28) ST Waters et al., 2000b (AFR, AUS, SSA, NZ, NC) 60 (RG), 20 (SG)e Chamaeleonidae + Agamidae: Reptilia, Squamata, Acrodonta (70) ST Macey et al., 2000…...

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  • ...…relatively recent dispersal events (Waters et al., 2000b; Cooper et al., 2001), whereas other groups originated after continental breakup, and their distribution can be explained only by long-distance dispersal across oceanic barriers (Baum et al., 1998; Waters et al., 2000a; Buckley et al., 2002)....

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Journal ArticleDOI
TL;DR: This study represents the most extensive taxonomic sampling effort to date to collect new molecular characters for phylogenetic analysis of acanthomorph fishes, with new and reliable clades emerging from this study of the acanthomorphic radiation.

350 citations


Cites background or methods from "Molecular phylogenetics and biogeog..."

  • ...These correspond to loop regions in the 28s data set (D3 domain from 342 to 356 and D12 domain from 676 to 686), and in the 16S data set (G10 region of Waters et al. (2000) or stem 40 of Miya and Nishida (1998) from positions 683–713)....

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  • ...…(base-paired regions) and loops (non-paired regions) following the secondary structure models published for sternoptychids (Miya and Nishida, 1998), Pygocentrus nattereri (Ort ı and Meyer, 1996), Fundulus heteroclitus (Parker and Kornifield, 1996), and Galaxias brevipinnis (Waters et al., 2000)....

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  • ...For instance, Waters et al. (2000) showed that the helices G8–G14 (encompassing variable regions from l to n) in the 16s model of Alves-Gomes et al. (1995) and Ort ı (1997) were improperly paired or absent in more divergent taxa, resulting in a large loop....

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  • ...For the 12S and 16S rDNA date sets, we localized stems (base-paired regions) and loops (non-paired regions) following the secondary structure models published for sternoptychids (Miya and Nishida, 1998), Pygocentrus nattereri (Ort ı and Meyer, 1996), Fundulus heteroclitus (Parker and Kornifield, 1996), and Galaxias brevipinnis (Waters et al., 2000)....

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Journal ArticleDOI
TL;DR: The galaxioid fishes are the dominant, most speciose group of freshwater fishes (with >50 species) in the lands of the cool southern hemisphere, with representatives in western and eastern Australia, Tasmania, New Caledonia, Lord Howe Island, New Zealand, the Chatham, Auckland and Campbell Islands, Patagonian South America.
Abstract: The galaxioid fishes are the dominant, most speciose group of freshwater fishes (with >50 species) in the lands of the cool southern hemisphere, with representatives in western and eastern Australia, Tasmania, New Caledonia, Lord Howe Island, New Zealand, the Chatham, Auckland and Campbell Islands, Patagonian South America (Chile, Argentina), the Falkland Islands and South Africa. The group is most diverse in Australia and New Zealand. Lepidogalaxiidae is found only in Australia, Retropinnidae in Australia and New Zealand, and Galaxiidae across the entire range of the group. Many species are in serious conservation crisis for a diversity of reasons, including habitat deterioration and possibly fisheries exploitation, but there is enduring and pervasive information that shows that the group has been seriously impacted by the acclimatisation of salmonid fishes originating in the cool-temperate northern hemisphere, particularly brown and rainbow trout. With few exceptions, where these trout have been introduced there has been major decline in the galaxioids, especially Galaxiidae, as a result of a complexly interacting series of adverse impacts from these introduced fishes. In some places, centrarchids and cichlids may also have adverse impacts. In addition, there appear to have been adverse impacts from the translocation of galaxioids into communities where they do not naturally occur. In many instances it appears that displacement of the galaxioids has led to a situation where galaxioids and salmonids no longer co-occur, owing either to displacement or predation, leading to fish communities in which there is no explicit evidence for displacement. These effects are resulting in the galaxioid fishes being amongst the most seriously threatened fishes known.

301 citations


Cites background from "Molecular phylogenetics and biogeog..."

  • ...…the scope of the galaxioid fishes, and particularly about whether the various genera that are discussed in this account form a monophyletic group, i.e. whether they share a closest common ancestry (Gosline 1960; McDowall 1969; Johnson and Patterson 1996; Williams 1996, 1997; Waters et al. 2000b)....

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Journal ArticleDOI
TL;DR: New Caledonia must be considered as a very old Darwinian island, a concept that offers many more fascinating opportunities of study, as it is contradicted by geological evidence indicating long Palaeocene and Eocene submersions and by recent biogeographic and phylogenetic studies.
Abstract: New Caledonia has generally been considered a continental island, the biota of which largely dates back to Gondwanan times owing to its geological origin and the presence of phylogenetic relicts. This view is contradicted by geological evidence indicating long Palaeocene and Eocene submersions and by recent biogeographic and phylogenetic studies, with molecular or geophysical dating placing the biota no older than the Oligocene. Phylogenetic relicts do not provide conclusive information in this respect, as their presence cannot be explained by simple hypotheses but requires assumption of many ad hoc extinction events. The implication of this new scenario is that all the New Caledonian biota colonized the island since 37 Ma Local richness can be explained by local radiation and adaptation after colonization but also by many dispersal events, often repeated within the same groups of organisms. Local microendemism is another remarkable feature of the biota. It seems to be related to recent speciation mediated by climate, orography, soil type and perhaps unbalanced biotic interactions created by colonization disharmonies. New Caledonia must be considered as a very old Darwinian island, a concept that offers many more fascinating opportunities of study.

267 citations


Cites background from "Molecular phylogenetics and biogeog..."

  • ...2005) and galaxiid fishes (Waters et al. 2000), sisters respectively to an Australian and a New Zealand group, are dated as younger than 12 and 9 Myr ago, respectively....

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  • ...The freshwater galaxiids, supposedly unable to disperse over the sea, were often considered a relict taxon, even though the occurrence of marine larvae is pervasive in this group (Waters et al. 2000)....

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  • ...…al. 2006) Sapotaceae (Bartish et al. 2005) Proteaceae (Barker et al. 2007) Paratya (Page et al. 2005) diving beetles (Balke et al. 2007a, b) galaxiid (Waters et al. 2000) Tasmantis Scincidae (Smith et al. 2007) sandalwoods (Harbaugh & Baldwin 2007) separation from Australia fine-grained black…...

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  • ...The New Caledonian freshwater shrimp genus Paratya (Page et al. 2005) and galaxiid fishes (Waters et al. 2000), sisters respectively to an Australian and a New Zealand group, are dated as younger than 12 and 9 Myr ago, respectively....

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Journal ArticleDOI
TL;DR: A series of coordinated studies in New Zealand streams that address the effect of an exotic fish on indi- vidual behavior, population, community, and ecosystem patterns are cobbled together.
Abstract: Knowledge of the population biology of invading species will often be necessary to develop effective management procedures and policies. But because invaders can have unexpected indirect effects in food webs, invasion ecologists need to integrate processes at the population level and other ecological levels. I de- scribe a series of coordinated studies in New Zealand streams that address the effect of an exotic fish on indi- vidual behavior, population, community, and ecosystem patterns. Such case studies are important as an aid to the formulation of policy about invasions that are especially likely to become problematic. At the individ- ual level, grazing invertebrates showed changes in behavior as a result of the introduction of brown trout ( Salmo trutta ), a predator that exerts a very different selection pressure than do native fish. At the population level, trout have replaced nonmigratory galaxiid fish in some streams but not others, and have affected the distributions of crayfish and other large invertebrates. At the community level, trout have suppressed grazing pressure from invertebrates and are thus responsible for enhancing algal biomass and changing algal species composition. Finally, at the ecosystem level, essentially all annual production of invertebrates is consumed by trout (but not by galaxiids), and algal primary productivity is six times higher in a trout stream. This leads, in turn, to an increased flux of nutrients from the water to the benthic community. The trout invasion has led to strong top-down control of community structure and ecosystem functioning via its effects on individual be- havior and population distribution and abundance. Particular physiological, behavioral, and demographic traits of invaders can lead to profound ecosystem consequences that managers need to take into account.

251 citations


Cites background from "Molecular phylogenetics and biogeog..."

  • ...The vulnerability of these nonmigratory galaxiids to high discharge during the recruitment period may be a ghost of diadromy past: their ancestors migrated as pelagic larvae to estuaries and oceans (Waters et al. 2000; Waters & Wallis 2001)....

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References
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Journal ArticleDOI
01 Mar 1990-Genetics
TL;DR: It is inferred that the lake populations of G. truttaceus have probably experienced at least one, severe, but transitory bottleneck possibly induced by natural selection for life-history characters essential for survival in the lacustrine habitat.
Abstract: Galaxias truttaceus is found in coastal rivers and streams in south-eastern Australia. It spawns at the head of estuaries in autumn and the larvae spend 3 months of winter at sea before returning to fresh water. In Tasmania there are landlocked populations of G. truttaceus in a cluster of geologically young lakes on the recently glaciated Central Plateau. These populations have no marine larval stage and spawn in the lakes in spring. Speciation due to land locking is thought to be a frequent occurrence within Galaxias. To investigate the nature of the speciation event which may be occurring within lake populations of G. truttaceus we studied the mitochondrial DNA (mtDNA) and allozyme diversity of both lake and stream populations. Using the presence or absence of restriction sites recognized by 13 six-base restriction endonucleases, we found 58 mtDNA haplotypes among 150 fish collected from 13 Tasmanian and one south-east Australian mainland stream populations. The most parsimonious network relating the haplotypes by site loss or gain was starlike in shape. We argue that this arrangement is best explained by selection upon slightly beneficial mutations within the mitochondrial genome. Gene diversity analysis under Wright's island model showed that the populations in each drainage were not genetically subdivided. Only two of these stream haplotypes were found among the 66 fish analyzed from four lake populations. Despite the extreme lack of mtDNA diversity in lake populations, the observed nuclear DNA heterozygosity of 40 lake fish (0.10355) was only slightly less than that of 82 stream fish (0.11635). In the short time (3000-7000 years) that the lake fish have been landlocked, random genetic drift in a finite, stable-sized population was probably not responsible for the lack of mtDNA diversity in the lake populations. We infer the lake populations have probably experienced at least one, severe, but transitory bottleneck possibly induced by natural selection for life-history characters essential for survival in the lacustrine habitat. If speciation is occurring in the landlocked populations of G. truttaceus, then it may be driven by genetic transilience.

78 citations

Journal ArticleDOI
TL;DR: P Phenetic and parsimony analyses of the sequence divergence estimates and of sequence polymorphisms suggested that the north Pacific/Arctic form and the northwestern Atlantic form shared a common ancestor more recently than either has with the north‐eastern Atlantic form, thus supporting the hypothesis that the species complex has arisen from two independent Pacific‐Atlantic divergences probably beginning during the mid‐Pliocene.
Abstract: Episodes of trans-Arctic faunal exchange and isolation between the north Pacific and Atlantic ocean basins have been implicated as important historic geological events contributing to extant patterns of genetic diversity and structure in Holarctic faunas. We made a further test of the significance of such biogeographic events by examining mitochondrial DNA (mtDNA) restriction fragment length and cytochrome b sequence polymorphism among north Pacific and Arctic, north-western Atlantic (north-eastern North American), and north-eastern Atlantic (European) regional forms of the boreal smelt, genus Osmerus. Our analyses also assessed whether the regional forms within this 'species complex': (i) represent a single widely distributed and polytypic species, or is composed of three geographically distinct species, and (ii) resulted from a single split from north Pacific ancestral Osmerus or two independent Pacific-Atlantic divergences. MtDNA sequence divergence estimates among forms ranged from 5.6-8.9% and from 6.1-8.5% based on restriction fragment and 300 base pairs of cytochrome b sequencing, respectively. Divergence within forms averaged less than 0.5% for fragment analysis and no differences were detected from sequence analysis. Provisional dating of lineage separations in Osmerus based on our sequence divergence estimates suggested a mid-Pliocene to early Pleistocene time frame for diversification among the forms. These estimated lineage separation dates support the idea that geological events in 'Beringia' and the surrounding trans-Arctic area (e.g. opening of the Bering Seaway, Pleistocene glacial advances), occurring over a similar time frame, have influenced radiation in Osmerus. Phenetic and parsimony analyses of the sequence divergence estimates and of sequence polymorphisms suggested that the north Pacific/Arctic form and the north-western Atlantic form shared a common ancestor more recently than either has with the north-eastern Atlantic form, thus supporting the hypothesis that the species complex has arisen from two independent Pacific-Atlantic divergences probably beginning during the mid-Pliocene.

77 citations

Journal ArticleDOI
TL;DR: This paleotectonic phase lacks preserved seafloor spreading so that continental palaeomagnetism, biota and geological facies are the only indicators and physical evidence provides a unique solution for continental reconstruction since 320 Ma.
Abstract: The neotectonic supercycle of earth history started 320 million years ago with the initial coalescence of the continents in Pangea. Final coalescence took place 230 Ma ago at the same time as rift valleys induced incipient breakup that became actual from 160 Ma with the start of seafloor spreading in the Atlantic and Indian Oceans. The current phase of seafloor spreading is marked by the growth lines of magnetic anomalies, from which reconstructions of the continents during the past 160 Ma are accurately determinable by eliminating the dated parts of the seafloor. Many small terranes or fragments are not so well constrained. Palaeolatitude is less precisely determined by continental indicators of magnetic inclination. All this physical evidence provides a unique solution for continental reconstruction since 320 Ma. Less definite evidence provided by biota and geological facies has to be accommodated within this physical framework. Before the coalescence of Pangea (> 320 Ma) the constraints are reversed. This paleotectonic phase lacks preserved seafloor spreading so that continental palaeomagnetism, biota and geological facies are the only indicators. The changing configuration of Australia and its neighbours in the eastern Gondwanaland province of Pangea - India, Antarctica, Lord Howe Rise-New Zealand Plateau - is detailed through seven stages from the midJurassic breakup of Pangea

77 citations

Journal ArticleDOI
TL;DR: The phylogenetic relationships of the osmeroid fishes are examined in the context of character congruence and two problematic taxa are hypothesized to be members of the Southern Hemisphere clade, in which reductive evolution has been common.
Abstract: The phylogenetic relationships of the osmeroid fishes are examined in the context of character congruence. The Osmeroidei is monophyletic, and its sister taxon is the monophyletic Argentinoidei. The division of osmeroids into Northern and Southern Hemisphere groups is largely corroborated. Two problematic taxa, the neotenic Salangidae and the monotypic Lepidogalaxias salamandroides, are hypothesized to be members of the Southern Hemisphere clade, in which reductive evolution has been common

68 citations