Molecular phylogenetics and biogeography of galaxiid fishes (Osteichthyes: Galaxiidae): dispersal, vicariance, and the position of Lepidogalaxias salamandroides.
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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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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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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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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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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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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TL;DR: It is improbable that the distribution pattern of the family Aplochitonidae is best explained by changes in position of southern temperate land masses, as several aplochitoid species as well as Geotria australis Gray and species of Galaxias have marine stages in their life histories.
Abstract: Diagnoses of the family Aplochitonidae and its contained genera, Aplochiton and Lovettia, are presented, with descriptions of two species of Aplochiton (A. zebra ]enyns and A. taeniatus Jenyns) and the single species of Lovettia (L. sealii (Johnston)). Current knowledge of life histories and habits of these fishes is reviewed and distribution patterns are discussed. The trans-Pacific range of the family (Lovettia in Tasmania, Aplochiton in South America) has little zoogeographic significance until we know more about phylogenetic relationships of Lovettia and Aplochiton. Several aplochitonid species as well as Geotria australis Gray and species of Galaxias have marine stages in their life histories. These marine stages, and the broad range of these species in the South Pacific, make it improbable that the distribution pattern of the family Aplochitonidae is best explained by changes in position of southern temperate land masses.
51 citations
"Molecular phylogenetics and biogeog..." refers background in this paper
...The tribe Aplochitonini contains a single genus, Aplochiton, of stout, moderate-sized shes that have an adipose n and a forward dorsal n (McDowall, 1971)....
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TL;DR: It is suggested that another detailed revision is required to determine whether these divergent populations of the Cape galaxias Galaxias zebratus represent a single species or a species complex.
Abstract: Mitochondrial cytochrome b gene sequences were obtained from representatives of five populations of the Cape galaxias Galaxias zebratus. Four highly distinct genotypes were revealed, with sequence divergence values ranging from 5.8 to 13.8%. Some of the pairwise divergences are the highest yet reported for cytochrome b within a fish species, and are more typical of interspecific and intergeneric comparisons. In contrast, the low genetic divergence (0.3%) between two recently recorded populations from the Krom and Gamtoos (Kouga) Rivers indicates recent gene flow. Parsimony analysis consistently produced a tree with the population from the Olifants River on the west coast as ancestral and eastern populations as progressively more derived. Estimated divergence times for the Olifants population range from 4.4 to 6.6 million years ago. The findings suggest that another detailed revision is required to determine whether these divergent populations represent a single species or a species complex.
44 citations
TL;DR: It is concluded that Wallace's observations are broadly intelligible in the light of what is known about Indonesia's geological history and there is much to gain by biogeographers and geologists working together more closely in Indonesia.
Abstract: A. R. Wallace's name will always be linked with what was known as the Malay Archipelago, and thus it seems appropriate to reassess his contribution to Indonesian biogeography. Wallace is often regarded as the founder of 'dispersalist' biogeography. However, this simplified view seriously misrepresents Wallace's position, which was that animal and plant distributions in Indonesia could be understood in terms of the region's geological history. This view is contrasted with that of dispersalist biogeography, which is that present distributions are the result of unique events, that the present is a consequence of past accidents. The results of Wallace's work are outlined and are reinterpreted in the light of modern evidence about the tectonic development of this region. It is concluded that Wallace's observations are broadly intelligible in the light of what is known about Indonesia's geological history. There is much to gain by biogeographers and geologists working together more closely in Indonesia, for there are many outstanding problems that require resolution. This then is one future direction that may be taken as we stand at the crossroads.
44 citations
TL;DR: The Australian mudfish, Galaxias cleaveri, resembles the three New Zealand mudfishes (Neochanna spp.) in general external morphology, but unique specialisations in the vomerine-ethmoid region of the cranium and in the form of the pectoral girdle support the view that these four species are a monophyletic group.
Abstract: The Australian mudfish, Galaxias cleaveri, resembles the three New Zealand mudfishes (Neochanna spp.) in general external morphology. It is the least specialised of a transformation series that includes all four mudfishes, in which the body is elongated, eyes are small, anterior nostrils long, tubular and forward directed, dorsal and anal fins low and long, flanges on the caudal peduncle well developed, pectoral fins small, paddle-shaped, and high on sides behind head, and pelvic fins reduced or lost. Unique specialisations in the vomerine-ethmoid region of the cranium and in the form of the pectoral girdle support the view that these four species are a monophyletic group. The Australian species is therefore included in Neochanna. The presence of a marine larval and juvenile life stage in the Australian species (diadromy) probably explains the distribution of the genus, with New Zealand species together derived from the Australian one or their common ancestor by dispersal across the Tasman Sea in prevailing ocean currents. The biogeography of the Australian and New Zealand species is consistent with post-Oligocene geology, and in particular with events during and since the Pleistocene. McDoWALL, RM., 1997. Affinities, generic classification and biogeography of the Australian and New Zealand mudfishes (Salmoniformes: Galaxiidae). Records of the Australian Museum 49(2): 121-137. The genus Neochanna was established by Giinther (1867) to contain a small, cigar-shaped fish found when drains were being dug in swamplands on the West Coast of the South Island of New Zealand; it was described as N. apoda (Fig. ID). While apparently a galaxiid (Galaxiidae) from its posterior dorsal fin and lack of scales, it was distinguished from Galaxias species by lacking pelvic fins, having flattened incisorlike jaw teeth, no endopterygoid teeth, long-based and low dorsal and anal fins that are nearly confluent with a distinctly rounded caudal fin, elongated, tubular anterior nostrils that point forwards, and small eyes (McDowall, 1970). Known commonly as "brown mudfish", it became well-known as a fish often found, semi-torpid and aestivating, in damp locations from which water had dried up-beneath logs and stumps, down old root holes around the bases of forest trees, and in similar, damp places where water is ephemeral
44 citations
TL;DR: A phylogenetic analysis including aregentinoids, osmeroids, and other euteleosts concludes that the Osmerae is the sister taxon of the Neoteleostei on the basis of two synapomorphies: presence of a postmaxillary process of the premaxilla and loss of laminar bone on the anterior margin of the hyomandibula.
Abstract: Evidence of monophyly and relationships of the Argentinoidei is provided, based on a phylogenetic analysis including aregentinoids, osmeroids, and other euteleosts. the Argentinoidei is monophyletic and is composed of two monophyletic clades, Argentinoidea and Alepocephaloidea. The evidence for monophyly of the Argentinoidei is largely drawn from anatomy of the branchial basket, and other potentially corroborating evidence is presented. The Argentinoidea is monophyletic. In this analysis, bathylagids are the sister taxon of opisthoproctids, argentinids the sister of these two. The Alepocephaloidea, usually composed of three to four families, is restricted here to a single family, Alepocephalidae. The highly derived Platytroctidae is more closely related to some alepocephalids than others, and is not recognized as a separate family. The monotypic Bathylaconidae, Bathyprionidae, and Leptochilichthyidae are not recognized, because doing so would both obscure the shared history of these taxa and render the Alepocephalidae paraphyletic. The sister taxon of the Argentinoidei is the Osmeroidei. Together they comprise the Osmerae. Previous hypotheses have placed either the Salmonidae or the highly derived galaxioid Lepidogalaxias as the sister taxon of the Neoteleostei. It is hypothesized here that the Osmerae is the sister taxon of the Neoteleostei on the basis of two synapomorphies: presence of a postmaxillary process of the premaxilla and loss of laminar bone on the anterior margin of the hyomandibula. The relationships of other euteleostean clades to the Osmerae and Neoteleostei are as yet unresolved.
39 citations