Vicariance biogeography and terrane tectonics in the South Pacific: analysis of the genus Abrotanella (Compositae)

The species of Abrotanella (Compositae) form mats and cushions a few centimetres high and up to a metre or more in diameter. The flowers are less complex than those of most Compositae and lack a pappus, the usual means of dispersal in the family. There are 20 species, all restricted to mountains of Australasia and southern South America. The putative affinities of Abrotanella involve several tribes of Compositae and the genus is not considered derived within the family. A comparative analysis of areas of endemism in Abrotanella shows clear patterns of vicariance and disjunction shared with many plants and animals, and longdistance dispersal is rejected as an explanation. Abrotanella and the three genera related to it are all restricted to lands bordering the Pacific. Areas previously accepted as areas of endemism, such as New Guinea, Tasmania, New Zealand and southern South America, are shown to be polyphyletic complexes, rather than simple areas. Use of such areas in area cladograms leads to the erroneous interpretation of taxa-area relations as incongruent. Distributions of the taxa in Abrotanella are correlated with tectonic features such as plate margins, transform faults and fracture zones, and processes such as continental rifting, terrane accretion, granite emplacement and orogeny. Abrotanellapatearoa sp. nov., a high-alpine cushion-plant, is described from mountains of eastern Central Otago: Rock and Pillar Range, Lammerlaw Range, Umbrella Mountains and Garvie Mountains.     

Process and pattern in the biogeography of New Zealand – a global microcosm?

Aim  To describe New Zealand's historical terrestrial biogeography and place this history in a wider Southern Hemisphere context.
Location  New Zealand.
Methods  The analysis is based primarily on literature on the distributions and relationships of New Zealand's terrestrial flora and fauna.
Results  New Zealand is shown to have a biota that has broad relationships, primarily around the cool Southern Hemisphere, as well as with New Caledonia to the north. There are hints of ancient Gondwanan taxa, although the long-argued predominance of taxa derived by vicariant processes, driven by plate tectonics and the fragmentation of Gondwana, is no longer accepted as a principal explanation of the biota's origins and relationships.
Main conclusions  Most of the terrestrial New Zealand flora and fauna has clearly arrived in New Zealand much more recently than the postulated separation of New Zealand from Gondwana, dated at c. 80 Ma. There is a view that New Zealand may have disappeared completely beneath the sea in the early Cenozoic, and acceptance of this would mean derivation of the entire biota by transoceanic dispersal. However, there are elements in the biota that seem to have broad distributions that date back to Gondwanan times, and also some that are thought unlikely to have been able to disperse to New Zealand across ocean gaps, especially freshwater organisms. Very strong connections to the biota of Australia, rather than to South America, are inconsistent with the timing of New Zealand's ancient and early separation from Gondwana and seem likely to have resulted from dispersal.     

Phylogenetic divergence of island biotas: Molecular dates,extinction, and “relict” lineages

Island formation is a key driver of biological evolution, and several studies have used geological ages of islands to calibrate rates of DNA change. However, many islands are home to “relict” lineages whose divergence apparently pre‐dates island age. The geologically dynamic New Zealand (NZ) archipelago sits upon the ancient, largely submerged continent Zealandia, and the origin and age of its distinctive biota have long been contentious. While some researchers have interpreted NZ's biota as equivalent to that of a post‐Oligocene island, a recent review of genetic studies identified a sizeable proportion of pre‐Oligocene “relict” lineages, concluding that much of the biota survived an incomplete drowning event. Here, we assemble comparable genetic divergence data sets for two recently formed South Pacific archipelagos (Lord Howe; Chatham Islands) and demonstrate similarly substantial proportions of relict lineages. Similar to the NZ biota, our island reviews provide surprisingly little evidence for major genetic divergence “pulses” associated with island emergence. The dominance of Quaternary divergence estimates in all three biotas may highlight the importance of rapid biological turnover and new arrivals in response to recent climatic and/or geological disturbance and change. We provide a schematic model to help account for discrepancies between expected versus observed divergence‐date distributions for island biotas, incorporating the effects of both molecular dating error and lineage extinction. We conclude that oceanic islands can represent both evolutionary “cradles” and “museums” and that the presence of apparently archaic island lineages does not preclude dispersal origins.     

Changing perspectives on the biogeography of the tropical South Pacific: influences of dispersal, vicariance and extinction

Aim The biogeographical patterns and drivers of diversity on oceanic islands in the tropical South Pacific (TSP) are synthesized. We use published studies to determine present patterns of diversity on TSP islands, the likely sources of the biota on these islands and how the islands were colonized. We also investigate the effect of extinctions. Location We focus on oceanic islands in the TSP. Methods We review available literature and published molecular studies. Results Examples of typical island features (e.g. gigantism, flightlessness, gender dimorphism) are common, as are adaptive radiations. Diversity decreases with increasing isolation from mainland sources and with decreasing size and age of archipelagos, corresponding well with island biogeographical expectations. Molecular studies support New Guinea/Malesia, New Caledonia and Australia as major source areas for the Pacific biota. Numerous studies support dispersal‐based scenarios, either over several 100 km (long‐distance dispersal) or over shorter distances by island‐hopping (stepping stones) and transport by human means (hitch‐hiking). Only one vicariance explanation, the eastward drift of continental fragments (shuttles) that may have contributed biota to Fiji from New Caledonia, is supported by some geological evidence, although there is no evidence for the transport of taxa on shuttle fragments. Another vicariance explanation, the existence of a major continental landmass in the Pacific within the last 100 Myr (Atlantis theory), receives little support and appears unlikely. Extinction of lineages in source areas and persistence in the TSP has probably occurred many times and has resulted in misinterpretation of biogeographical data. Main conclusions Malesia has long been considered the major source region for the biota of oceanic islands in the TSP because of shared taxa and high species diversity. However, recent molecular studies have produced compelling support for New Caledonia and Australia as alternative important source areas. They also show dispersal events, and not vicariance, to have been the major contributors to the current biota of the TSP. Past extinction events can obscure interpretations of diversity patterns.     

The lace web spiders (Araneae,Phyxelididae) of Madagascar: phylogeny,biogeography and taxonomy

We briefly review the potential history of Madagascar as either a Darwinian or a Wallacean island, summarize the phylogenetic evidence regarding the biogeography of Madagascar spiders, examine the dispersal history of the Madagascar Phyxelididae, and monograph the family in Madagascar. Molecular phylogenetic analyses for 32 Malagasy phyxelidid exemplars, nine confamilial outgroup taxa, and seven other more distant outgroups are performed for three nuclear markers and one mitochondrial genetic marker (28S, 18S, H3 and COI) utilizing Bayesian, maximum‐likelihood and parsimony methods. These analyses suggest that there are 14 species of Phyxelididae that may be recognized from Madagascar, that these may be divided into three genera, and that the Malagasy phyxelidids form a monophyletic group, probably resulting from a single invasion of the island by an ancestor from Africa. Two new genera, ten new species, and two new combinations are proposed: Manampoka atsimo gen. nov., sp. nov. ; Rahavavy gen. nov. , including R. ida sp. nov. and R. fanivelona (Griswold, 1990) comb. nov. and R. malagasyana (Griswold, 1990) comb. nov. ; and Ambohima andrefana sp. nov. , A. antsinanana sp. nov. , A. avaratra sp. nov. , A. maizina sp. nov. , A. ranohira sp. nov. , A. vato sp. nov. , A. zandry sp. nov. and A. zoky sp. nov. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 728–810.     

Radiation following long‐distance dispersal: the contributions of time,opportunity and diaspore morphology in Sicyos (Cucurbitaceae)

Aim  To infer the most plausible explanations for the presence of 14 species of the Neotropical cucurbit genus Sicyos on the Hawaiian Islands, two on the Galápagos Islands, two in Australia, and one in New Zealand. Location  Neotropics, the Hawaiian and Galápagos archipelagos, Australia and New Zealand. Methods  We tested long‐problematic generic boundaries in the tribe Sicyoeae and reconstructed the history of Sicyos using plastid and nuclear DNA sequences from 87 species (many with multiple accessions) representing the group’s generic and geographic diversity. Maximum likelihood and Bayesian approaches were used to infer relationships, divergence times, biogeographic history and ancestral traits. Results  Thirteen smaller genera, including Sechium, are embedded in Sicyos, which when re‐circumscribed as a monophyletic group comprises 75 species. The 14 Hawaiian species of Sicyos descended from a single ancestor that arrived c. 3 million years ago (Ma), Galápagos was reached twice at c. 4.5 and 1 Ma, the species in Australia descended from a Neotropical ancestor (c. 2 Ma), and New Zealand was reached from Australia. Time since arrival thus does not correlate with Sicyos species numbers on the two archipelagos. Main conclusions  A plausible mechanism for the four trans‐Pacific dispersal events is adherence to birds of the tiny hard fruit with retrorsely barbed spines found in those lineages that underwent long‐distance migrations. The Hawaiian clade has lost these spines, resulting in a lower dispersal ability compared with the Galápagos and Australian lineages, and perhaps favouring allopatric speciation.     

Historical biogeography and phenotype‐phylogeny of Chroodiscus (lichenized Ascomycota: Ostropales: Graphidaceae)

Aim To analyse the historical biogeography of the lichen genus Chroodiscus using a phenotype‐based phylogeny in the context of continental drift and evolution of tropical rain forest vegetation. Location All tropical regions (Central and South America, Africa, India, Southeast Asia, north‐east Australia). Methods We performed a phenotype‐based phylogenetic analysis and ancestral character state reconstruction of 14 species of the lichen genus Chroodiscus, using paup * and mesquite ; dispersal–vicariance analysis (DIVA) and dispersal–extinction–cladogenesis (DEC) modelling to trace the geographical origin of individual clades; and ordination and clustering by means of pc‐ord , based on a novel similarity index, to visualize the biogeographical relationships of floristic regions in which Chroodiscus occurs. Results The 14 species of Chroodiscus show distinctive distribution patterns, with one pantropical and one amphi‐Pacific taxon and 12 species each restricted to a single continent. The genus comprises four clades. DIVA and DEC modelling suggest a South American origin of Chroodiscus in the mid to late Cretaceous (120–100 Ma), with subsequent expansion through a South American–African–Indian–Southeast Asian–Australian dispersal route and late diversification of the argillaceus clade in Southeast Asia. Based on the abundance of extant taxa, the probability of speciation events in Chroodiscus is shown to be extremely low. Slow dispersal of foliicolous rain forest understorey lichens is consistent with estimated phylogenetic ages of individual species and with average lengths of biological species intervals in fungi (10–20 Myr). Main conclusions The present‐day distribution of Chroodiscus can be explained by vicariance and mid‐distance dispersal through the interconnection or proximity of continental shelves, without the need for recent, trans‐oceanic long‐distance dispersal. Phylogenetic reconstruction and age estimation for Chroodiscus are consistent with the ‘biotic ferry’ hypothesis: a South American origin and subsequent eastward expansion through Africa towards Southeast Asia and north‐eastern Australia via the Indian subcontinent. The present‐day pantropical distributions of many clades and species of foliicolous lichens might thus be explained by eastward expansion through continental drift, along with the evolution of modern rain forests starting 120 Ma, rather than by the existence of a hypothetical continuous area of pre‐modern rain forest spanning South America, Africa and Southeast Asia during the mid and late Cretaceous.     

Minute moss beetles in the Southern Hemisphere: Molecular phylogeny,historical biogeography and habitat shifts (Coleoptera: Hydraenidae)

Minute moss beetles (Hydraenidae) are one of the most speciose and widespread families of aquatic Coleoptera, with an estimated 4000 extant species, found in the majority of aquatic habitats from coastal rock pools to mountain streams and from the Arctic Circle to the Antarctic islands. Molecular phylogenetic works have improved our understanding of the evolutionary history of the megadiverse Hydraena, Limnebius and Ochthebius in recent years, but most genera in the family have not yet been included in any phylogenetic analyses, particularly most of those which are restricted to the Southern Hemisphere. Using a multimarker molecular matrix, sampling over 40% of described species richness and 75% of currently recognized genera, we infer a comprehensive molecular phylogeny of these predominantly Gondwanan Hydraenidae. Whilst the genera we focus on are morphologically diverse, and currently classified across all four hydraenid subfamilies, our phylogenetic analyses suggest that these Gondwanan genera may instead constitute a single clade. As a result of our findings, the African genus Oomtelecopon Perkins syn.n. is shown to nest within Coelometopon Janssens, the New Zealand Homalaena Ordish syn.n. and Podaena Ordish syn.n. are synonymised with Orchymontia Broun, and the South African Pterosthetops Perkins syn.n. is synonymised with Prosthetops Waterhouse, resulting in Pterosthetopini Perkins syn.n. being synonymised with Prosthetopini Perkins. Mesoceratops Bilton & Jäch gen.n. is erected to accommodate six former members of Mesoceration Janssens, which is shown to be polyphyletic. We propose the replacement name Orchymontia ordishi Jäch & Bilton nom.n. for Homalaena dilatata Ordish, 1984 (now a junior homonym); altogether 39 new combinations are proposed. Our Bayesian divergence times infer an origin for this ‘Gondwana group’ of genera in Africa plus Madagascar in the mid-Cretaceous and suggest that both vicariant and dispersal processes, together with extinctions, have shaped the biogeographic history of these beetles in the Southern Hemisphere during the Cretaceous, resulting in geographically conserved extant lineages. Finally, we reconstruct ancestral habitat shifts across our phylogeny, revealing numerous changes in habitat occupancy in these genera, including multiple origins of fully terrestrial, humicolous taxa in different regions.     

A review of Buccipagoda Ponder, 2010 and descriptions of new species and a new genus (Gastropoda: Neogastropoda: Buccinoidea: Buccinidae)

This revision addresses two Southern Hemisphere genera in the family Buccinidae. Buccipagoda kengrahami (Ponder, 1982) and B. ponderi n. sp. are recognised from off southern Australia and B. achilles n. sp. from off New Zealand. Sagenotriton n. gen. is introduced for S. ajax n. sp. from off New Zealand, and S. bathybius (Bouchet & Warén, 1986) and S. bonaespei (Barnard, 1963) from off South Africa.     

Panbiogeography of New Caledonia,south‐west Pacific: basal angiosperms on basement terranes,ultramafic endemics inherited from volcanic island arcs and old taxa endemic to young islands

Aim To investigate areas of endemism in New Caledonia and their relationship with tectonic history. Location New Caledonia, south‐west Pacific. Methods Panbiogeographical analysis. Results Biogeographical patterns within New Caledonia are described and illustrated with reference to eight terranes and ten centres of endemism. The basement terranes make up a centre of endemism for taxa including Amborella, the basal angiosperm. Three of the terranes that accreted to the basement in the Eocene (high‐pressure metamorphic terrane, ultramafic nappe and Loyalty Ridge) have their own endemics. Main conclusions New Caledonia is not simply a fragment of Gondwana but, like New Zealand and New Guinea, is a complex mosaic of allochthonous terranes. The four New Caledonian basement terranes were all formed from island arc‐derived and arc‐associated material (including ophiolites) which accumulated in the pre‐Pacific Ocean, not in Gondwana. They amalgamated and were accreted to Gondwana (eastern Australia) in the Late Jurassic/Early Cretaceous, but in the Late Cretaceous they separated from Australia with the opening of the Tasman Sea and break‐up of Gondwana. An Eocene collision of the basement terranes with an island arc to the north‐east – possibly the Loyalty Ridge – is of special biogeographical interest in connection with New Caledonia–central Pacific affinities. The Loyalty–Three Kings Ridge has had a separate history from that of the Norfolk Ridge/New Caledonia, although both now run in parallel between Vanuatu and New Zealand. The South Loyalty Basin opened between Grande Terre and the Loyalty Ridge in the Cretaceous and attained a width of 750 km. However, it was almost completely destroyed by subduction in the Eocene which brought the Loyalty Ridge and Grande Terre together again, after 30 Myr of separation. The tectonic history is reflected in the strong biogeographical differences between Grande Terre and the Loyalty Islands. Many Loyalty Islands taxa are widespread in the Pacific but do not occur on Grande Terre, and many Grande Terre/Australian groups are not on the Loyalty Islands. The Loyalty Islands are young (2 Myr old) but they are merely the currently emergent parts of the Loyalty Ridge whose ancestor arcs have a history of volcanism dating back to the Cretaceous. Old taxa endemic to the young Loyalty Ridge islands persist over geological time as a dynamic metapopulation surviving in situ on the individually ephemeral islands and atolls found around subduction zones. The current Loyalty Islands, like the Grande Terre terranes, have inherited their biota from previous islands. On Grande Terre, the ultramafic terrane was emplaced on Grande Terre in the Eocene (about the same time as the collision with the island arc). The very diverse endemic flora on the ultramafics may have been inherited by the obducting nappe from prior base‐rich habitat in the region, including the mafic Poya terrane and the limestones typical of arc and intraplate volcanic islands.     

Welcome back New Zealand: regional biogeography and Gondwanan origin of three endemic genera of mite harvestmen (Arachnida, Opiliones, Cyphophthalmi)

Aim Biogeographers have long been intrigued by New Zealand’s biota due to its unique combination of typical ‘continental’ and ‘island’ characteristics. The New Zealand plateau rifted from the former supercontinent Gondwana c. 80 Ma, and has been isolated from other land masses ever since. Therefore, the flora and fauna of New Zealand include lineages that are Gondwanan in origin, but also include a very large number of endemics. In this study, we analyse the evolutionary relationships of three genera of mite harvestmen (Arachnida, Opiliones, Cyphophthalmi) endemic to New Zealand, both to each other and to their temperate Gondwanan relatives found in Australia, Chile, Sri Lanka and South Africa. Location New Zealand (North Island, South Island and Stewart Island). Methods A total of 94 specimens of the family Pettalidae in the suborder Cyphophthalmi were studied, representing 31 species and subspecies belonging to three endemic genera from New Zealand (Aoraki, Neopurcellia and Rakaia) plus six other members of the family from Chile, South Africa, Sri Lanka and Australia. The phylogeny of these taxa was constructed using morphological and molecular data from five nuclear and mitochondrial genes (18S rRNA, 28S rRNA, 16S rRNA, cytochrome c oxidase subunit I and histone H3, totalling c. 5 kb), which were analysed using dynamic as well as static homology under a variety of optimality criteria. Results The results showed that each of the three New Zealand cyphophthalmid genera is monophyletic, and occupies a distinct geographical region within the archipelago, grossly corresponding to palaeogeographical regions. All three genera of New Zealand mite harvestmen fall within the family Pettalidae with a classic temperate Gondwanan distribution, but they do not render any other genera paraphyletic. Main conclusions Our study shows that New Zealand’s three genera of mite harvestmen are unequivocally related to other members of the temperate Gondwanan family Pettalidae. Monophyly of each genus contradicts the idea of recent dispersal to New Zealand. Within New Zealand, striking biogeographical patterns are apparent in this group of short‐range endemics, particularly in the South Island. These patterns are interpreted in the light of New Zealand’s turbulent geological history and present‐day patterns of forest cover.     

Resolution of taxonomic problems in Australian Harpalini,Abacetini, Pterostichini,and Oodini (Coleoptera,Carabidae)

Taxonomic changes are made for several problematic Australian Carabidae in the tribes Harpalini, Abacetini, Pterostichini, and Oodini. Examination of types resulted in the synonymy of Veradia Castelnau, 1867 with Leconomerus Chaudoir, 1850; Nelidus Chaudoir, 1878, Feronista Moore, 1965, and Australomasoreus Baehr, 2007 with Cerabilia Castelnau, 1867; and newly combining Fouquetius variabilis Straneo, 1960 in the genus Pediomorphus Chaudoir, 1878; Australomasoreus monteithi Baehr, 2007 in the genus Cerabilia Castelnau, 1867; and Anatrichis lilliputana W.J. Macleay, 1888 in the genus Nanodiodes Bousquet, 1996. Cuneipectus Sloane, 1907 is placed in Pterostichini Bonelli, 1810, which is a senior synonym of Cuneipectini Sloane, 1907.     

Phylogeny, biogeography and adaptive radiation of Pachycladon (Brassicaceae) in the mountains of South Island, New Zealand

Aim To report analyses and propose hypotheses of adaptive radiation that explain distributional patterns of the alpine genus Pachycladon Hook.f. – a morphologically diverse genus from New Zealand closely related to Arabidopsis thaliana. Location South Island, New Zealand. Methods Morphological and nrDNA ITS sequence phylogenies were generated for Pachycladon. An analysis is presented of species distributional patterns and attributes. Results Phylogenetic analyses of morphological characters and nrDNA ITS sequence data were found to be congruent in supporting three New Zealand clades for Pachycladon. Monophyletic groups identified within the genus are geographically distinct and are associated with different geological parent materials. Distribution maps, latitude and altitude range, and data on geological parent material are presented for the nine named and one unnamed species of Pachycladon from New Zealand. Main conclusions (a) Panbiogeographic hypotheses accounting for the origin and present‐day distribution of Pachycladon in New Zealand are not supported.
(b) Species diversity and distributions of Pachycladon are explained by a Late Tertiary–Quaternary adaptive radiation associated with increasing specialization to geological substrates. Pachycladon cheesemanii Heenan & A.D.Mitch. is morphologically similar to the closest overseas relatives. It is a geological generalist and has wide latitudinal and altitudinal ranges, and we suggest it resembles the ancestral form of the genus in New Zealand. Pachycladon novae‐zelandiae (Hook.f.) Hook.f. and P. wallii (Carse) Heenan & A.D.Mitch. are a southern South Island group that predominantly occurs on Haast Schist, are polycarpic, have lobed leaves, and lateral inflorescences. Pachycladon enysii (Cheeseman) Heenan & A.D.Mitch., P. fastigiata (Hook.f.) Heenan & A.D.Mitch., and P. stellata (Allan) Heenan & A.D.Mitch. are restricted to greywacke in the eastern South Island, and are facultatively monocarpic, have serrate leaves, and stout terminal inflorescenes.
(c) Present distributions of Pachycladon species may relate to Pleistocene climate change. Pachycladon enysii reaches the highest altitude of New Zealand species of Pachycladon and is most common in the Southern Alps in Canterbury. We propose that this species survived on nunataks at the height of the last glaciation. In contrast, P. fastigiata grows at a lower altitude and is absent from the high mountains of the Southern Alps. We suggest it was extirpated from this area during the last glaciation.     

Incipient speciation of Catostylus mosaicus (Scyphozoa, Rhizostomeae, Catostylidae), comparative phylogeography and biogeography in south-east Australia

Aim Phylogeography provides a framework to explain and integrate patterns of marine biodiversity at infra‐ and supra‐specific levels. As originally expounded, the phylogeographic hypotheses are generalities that have limited discriminatory power; the goal of this study is to generate and test specific instances of the hypotheses, thereby better elucidating both local patterns of evolution and the conditions under which the generalities do or do not apply. Location Coastal south‐east Australia (New South Wales, Tasmania and Victoria), and south‐west North America (California and Baja California). Methods Phylogeographic hypotheses specific to coastal south‐east Australia were generated a priori, principally from existing detailed distributional analyses of echinoderms and decapods. The hypotheses are tested using mitochondrial cytochrome c oxidase subunit I (COI) and nuclear internal transcribed spacer 1 (ITS1) DNA sequence data describing population variation in the jellyfish Catostylus mosaicus, integrated with comparable data from the literature. Results Mitochondrial COI distinguished two reciprocally monophyletic clades of C. mosaicus (mean ± SD: 3.61 ± 0.40% pairwise sequence divergence) that were also differentiated by ITS1 haplotype frequency differences; the boundary between the clades was geographically proximate to a provincial zoogeographic boundary in the vicinity of Bass Strait. There was also limited evidence of another genetic inhomogeneity, of considerably smaller magnitude, in close proximity to a second hypothesized zoogeographic discontinuity near Sydney. Other coastal marine species also show genetic divergences in the vicinity of Bass Strait, although they are not closely concordant with each other or with reported biogeographic discontinuities in the region, being up to several hundreds of kilometres apart. None of the species studied to date show a strong phylogeographic discontinuity across the biogeographic transition zone near Sydney. Main conclusions Patterns of evolution in the Bass Strait and coastal New South Wales regions differ fundamentally because of long‐term differences in extrinsic factors. Since the late Pliocene, periods of cold climate and low sea‐level segregated warm temperate organisms east or west of an emergent Bassian Isthmus resulting in population divergence and speciation; during subsequent periods of warmer and higher seas, sister taxa expanded into the Bass Strait region leading to weakly correlated phylogeographic and biogeographic patterns. The Sydney region, by contrast, has been more consistently favourable to shifts in species’ ranges and long‐distance movement, resulting in a lack of intra‐specific and species‐level diversification. Comparisons between the Sydney and Bass Strait regions and prior studies in North America suggest that vicariance plays a key role in generating coastal biodiversity and that dispersal explains many of the deviations from the phylogeographic hypotheses.     

Evolution and biogeography of New Zealand's longjaw galaxiids (Osmeriformes: Galaxiidae): the genetic effects of glaciation and mountain building

1. The biological impact of glaciation in Southern Hemisphere freshwaters is poorly understood. Several large rivers of eastern South Island, New Zealand, represent a mosaic of glaciated and non-glaciated regions, and are thus well-suited for studies of post-glacial recolonization.
2. We conducted mtDNA analyses of South Island's endemic non-migratory longjaw galaxiids Galaxias prognathus and G. cobitinis (Osmeriformes: Galaxiidae) to test hypotheses of post-glacial recolonization, and to assess the vicariant effects of Pleistocene mountain building.
3. We analysed the phylogeography of longjaw cytochrome b sequences from 38 sites in central South Island ( n  = 83). On the basis of our sampling it seems that G. prognathus and G. cobitinis have a parapatric distribution in the Waitaki River system, their disjunction broadly coinciding with three large post-glacial lakes. Waitaki clades of both species are deeply divergent relative to conspecific taxa in drainages to the north and south.
4. Tests for recent population growth – predicted under post-glacial expansion of G. prognathus – do not refute recent recolonization of streams above glaciated lakes in the Waitaki River drainage. The apparent absence of potential 'source' populations from non-glaciated regions suggests a post-glacial population decline for G. prognathus below the Waitaki lakes.
5. Molecular clock calibrations based on several freshwater vicariant events elsewhere in New Zealand supported the geologically-derived hypothesis of Waitaki–Canterbury drainage isolation approximately 300 ka.     

Vicariance or long‐distance dispersal: historical biogeography of the pantropical subfamily Chrysophylloideae (Sapotaceae)

Aim Continental disjunctions in pantropical taxa have been explained by vicariance or long‐distance dispersal. The relative importance of these explanations in shaping current distributions may vary, depending on historical backgrounds or biological characteristics of particular taxa. We aimed to determine the geographical origin of the pantropical subfamily Chrysophylloideae (Sapotaceae) and the roles vicariance and dispersal have played in shaping its modern distribution. Location Tropical areas of Africa, Australasia and South America. Methods We utilized a recently published, comprehensive data set including 66 species and nine molecular markers. Bayesian phylogenetic trees were generated and dated using five fossils and the penalized likelihood approach. Distributional ranges of nodes were estimated using maximum likelihood and parsimony analyses. In both biogeographical and molecular dating analyses, phylogenetic and branch length uncertainty was taken into account by averaging the results over 2000 trees extracted from the Bayesian stationary sample. Results Our results indicate that the earliest diversification of Chrysophylloideae was in the Campanian of Africa c. 73–83 Ma. A narrow time interval for colonization from Africa to the Neotropics (one to three dispersals) and Australasia (a single migration) indicates a relatively rapid radiation of this subfamily in the latest Cretaceous to the earliest Palaeocene (c. 62–72 Ma). A single dispersal event from the Neotropics back to Africa during the Neogene was inferred. Long‐distance dispersal between Australia and New Caledonia occurred at least four times, and between Africa and Madagascar on multiple occasions. Main conclusions Long‐distance dispersal has been the dominant mechanism for range expansion in the subfamily Chrysophylloideae. Vicariance could explain South American–Australian disjunction via Antarctica, but not the exchanges between Africa and South America and between New Caledonia and Australia, or the presence of the subfamily in Madagascar. We find low support for the hypothesis that the North Atlantic land bridge facilitated range expansions at the Palaeocene/Eocene boundary.