The taxonomy, ecology and conservation status of the Golden-rayed Blue: a threatened butterfly endemic to western Victoria, Australia

The Golden‐rayed Blue, Candalides noelkeri sp. nov. (Lepidoptera: Lycaenidae), from the Wimmera of western Victoria, Australia, is described and illustrated. The male and female genitalia and immature stages are figured, described and compared with those of Candalides heathi and C. xanthospilos. Candalides noelkeri sp. nov. is placed in the C. xanthospilos species‐group, being most closely allied to and allopatric with C. heathi. It is predominantly univoltine, with adults usually present from late November to early February. However, it has a facultative pupal diapause that gives rise to a partial overlapping second generation in mid‐summer. The species is ecologically specialized, monophagous and has a narrow geographical range, currently known only from two localities in a restricted area near Natimuk. Within this limited area it is restricted to flood plains bordering natural salt‐lakes where the larval food plant, a prostrate form of Myoporum parvifolium (Myoporaceae), grows as a low spreading ground cover plant. Morphological and geological evidence suggest a recent (late Pleistocene) allopatric speciation event between C. noelkeri sp. nov. and C. heathi. The small, peripheral spatial distribution of C. noelkeri sp. nov. implies that differentiation has been achieved by the founder effect, either through peripheral isolates speciation (peripatric speciation) or postspeciation dispersal, possibly as a result of a barrier created by the volcanic plains in western Victoria. Available information indicates that C. noelkeri sp. nov., Victoria's only endemic species of butterfly, is facing a high risk of extinction and accordingly its conservation status should be considered as Endangered. The most serious threat at the type locality is habitat change or succession caused by invasion of Melaleuca halmaturorum, which is creating a dense shaded paperbark forest that is reducing both the preferred open sunny microhabitat and the extent of the larval food plant. Recognition of C. noelkeri sp. nov. as a flagship taxon is likely to enhance the conservation of biodiversity in remnant flood plain/salt‐lake ecosystems of temperate south‐eastern Australia. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81 , 275–299.     

DISPERSAL,VICARIANCE, AND CLOCKS: HISTORICAL BIOGEOGRAPHY AND SPECIATION IN A COSMOPOLITAN PASSERINE GENUS (ANTHUS: MOTACILLIDAE)

Dispersal and vicariant hypotheses have for decades been at odds with each other, notwithstanding the fact that both are well-established natural processes with important histories in biogeographic analyses. Despite their importance, neither dispersal nor vicariant methodologies are problem-free. The now widely used molecular techniques for generating phylogenies have provided a mechanism by which both dispersal- and vicariance-driven speciation can be better tested via the application of molecular clocks; unfortunately, substantial problems can also exist in the employment of those clocks. To begin to assess the relative roles of dispersal and vicariance in the establishment of avifaunas, especially intercontinental avifaunas, I applied a test for clocklike behavior in molecular data, as well as a program that infers ancestral areas and dispersal events, to a phylogeny of a speciose, cosmopolitan avian genus (Anthus; Motacillidae). Daughter-lineages above just 25 of 40 nodes in the Anthus phylogeny are evolving in a clocklike manner and are thus dateable by a molecular clock. Dating the applicable nodes suggests that Anthus arose nearly 7 million yr ago, probably in eastern Asia, and that between 6 and 5 million yr ago, Anthus species were present in Africa, the Palearctic, and North and South America. Speciation rates have been high throughout the Pliocene and quite low during the Pleistocene; further evidence that the Pleistocene may have had little effect in generating modern species. Intercontinental movements since 5 million yr ago have been few and largely restricted to interchange between Eurasia and Africa. Species swarms on North America, Africa, and Eurasia (but not South America or Australia) are the product of multiple invasions, rather than being solely the result of within-continent speciation. Dispersal has clearly played an important role in the distribution of this group.     

Forest giants on different evolutionary branches: Ecomorphological convergence in helicopter damselflies*

The convergent evolution of analogous features is an evolutionary process occurring independently across the tree of life. From the evolution of echolocation, prehensile tail, viviparity, or winged flight, environmental factors often drive this astonishing phenomenon. However, convergent evolution is not always conspicuous or easily identified. Giant damselflies count among the largest flying insects on Earth, and have astonishing ecologies including orb‐web spider plucking and oviposition in phytotelmata. One species occurs in the Afrotropics and 18 species are found in the Neotropics. Convergent evolution was historically hypothesized based on the ecological and morphological affinities of these two geographically distant lineages but was not supported by earlier phylogenetic inferences supporting their monophyly. Using a molecular supermatrix approach and a large selection of outgroups, we revisit and reject the monophyly of Afrotropical and Neotropical giant damselflies that is otherwise supported by a morphological phylogeny. Molecular divergence time estimation suggests an origin of Afrotropical giant damselflies in the late Paleogene, and of Neotropical ones at the Cretaceous/Paleogene boundary, thereby rejecting a long‐standing West Gondwana vicariance hypothesis. The strong ecological and morphological resemblances between these two independent lineages represents an astonishing case of Amphi‐Atlantic tropical convergent evolution.     

Repeated landmass reformation limits diversification in the widespread littoral zone mosquito Anopheles sundaicus sensu lato in the Indo‐Oriental Region

Southeast Asia harbours abundant biodiversity, hypothesized to have been generated by Pliocene and Pleistocene climatic and environmental change. Vicariance between the island of Borneo, the remaining Indonesian archipelago and mainland Southeast Asia caused by elevated sea levels during interglacial periods has been proposed to lead to diversification in the littoral zone mosquito Anopheles (Cellia) sundaicus (Rodenwaldt) sensu lato. To test this biogeographical hypothesis, we inferred the population history and assessed gene flow of A. sundaicus s.l. sampled from 18 populations across its pan‐Asian species range, using sequences from mitochondrial cytochrome c oxidase subunit 1 (CO1), the internal transcribed spacer 2 (ITS2) and the mannose phosphate isomerase (Mpi) gene. A hypothesis of ecological speciation for A. sundaicus involving divergent adaptation to brackish and freshwater larval habitats was also previously proposed, based on a deficiency of heterozygotes for Mpi allozyme alleles in sympatry. This hypothesis was not supported by Mpi sequence data, which exhibited no fixed differences between brackish and freshwater larval habitats. Mpi and CO1 supported the presence of up to eight genetically distinct population groupings. Counter to the hypothesis of three allopatric species, divergence was often no greater between Borneo, Sumatra/Java and the Southeast Asian mainland than it was between genetic groupings within these landmasses. An isolation‐with‐migration (IM) model indicates recurrent gene flow between the current major landmasses. Such gene flow would have been possible during glacial periods when the current landmasses merged, presenting opportunities for dispersal along expanding and contracting coastlines. Consequently, Pleistocene climatic variation has proved a homogenizing, rather than diversifying, force for A. sundaicus diversity.     

Molecular phylogeny and historical biogeography of the genus Tuber, the 'true truffles'

Aim Various data sets and methods of analysis were combined to produce the first comprehensive molecular phylogeny of the genus Tuber and to analyse its biogeography. Location Europe, North Africa, China, Asia, North America. Methods Phylogenetic relationships among Tuber species were reconstructed based on a data set of internal‐transcribed spacer (ITS) sequences and various phylogenetic inference methods, specifically maximum parsimony, Bayesian analysis and neighbour joining. Tajima’s relative rate test showed that Tuber 18S rRNA, 5.8S rRNA, 5.8S‐ITS2 rRNA and β‐tubulin sequences evolved in a clock‐like manner. These genes, combined or not, were employed for molecular clock estimates after construction of linearized trees using mega 3.1. We reconstructed ancestral areas in the Northern Hemisphere by means of a dispersal–vicariance analysis (diva 1.1) based on current distribution patterns of the genus Tuber determined from the literature. Results The resulting molecular phylogeny divided the genus Tuber into five distinct clades, in agreement with our previously published studies. The Puberulum, Melanosporum and Rufum groups were diversified in terms of species and geographical distribution. In contrast, the Aestivum and Excavatum groups were less diversified and were located only in Europe or North Africa. Using a global molecular clock analysis, we estimated the divergence times for the origin of the genus and for the origin of several groups. diva inferred nine dispersal events and suggested that the ancestor of Tuber was originally present in Europe or was widespread in Eurasia. Equally optimal distributions were obtained for several nodes, suggesting different possible biogeographical patterns. Main conclusions Our analyses identified several discrepancies with the classical taxonomy of the genus, and we propose a new phylogenetic classification. According to molecular clocks, the radiation of the genus Tuber could have started between 271 and 140 Ma. Used in combination with the results obtained from time divergence estimates, this allows us to propose two equally probable scenarios of intra‐ and inter‐continental diversification of the genus according to the geographic distribution of the most recent common ancestor in Europe or Eurasia. The biogeographical patterns imply intra‐continental dispersal events between Europe and Asia and inter‐continental dispersal events between North America and Europe or Asia, which are compatible with land connections during the Tertiary.     

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.     

Out of Africa: Biogeography and diversification of the pantropical pond skater genus Limnogonus Stål, 1868 (Hemiptera: Gerridae)

Gondwanan vicariance, long‐distance dispersal (LDD), and boreotropical migration have been proposed as alternative hypotheses explaining the pantropical distribution pattern of organisms. In this study, the historical biogeography of the pond skater genus Limnogonus was reconstructed to evaluate the impact of biogeographical scenarios in shaping their modern transoceanic disjunction. We sampled almost 65% of recognized Limnogonus species. Four DNA fragments including 69 sequences were used to reconstruct a phylogram. Divergence time was estimated using a Bayesian relaxed clock method and three fossil calibrations. Diversification dynamics and ancestral area reconstruction were investigated by using maximum likelihood and Bayesian approaches. Our results showed the crown group of Limnogonus originated and diversified in Africa in the early Eocene (49 Ma, HPD: 38–60 Ma), subsequently expanding into other regions via dispersal. The colonization of the New World originated from the Oriental Region probably via the Bering Land Bridge in the late Eocene. Two split events between the Old World and New World were identified: one between Neotropics and Oriental region around the middle Oligocene (30 Ma, HPD: 22–38 Ma), and the other between Neotropics and Africa during the middle Miocene (14 Ma, HPD: 8–21 Ma). The evolutionary history of Limnogonus involved two biogeographical processes. Gondwanan vicariance was not supported in our analyses. The diversification of Limnogonus among Africa, Oriental, and Neotropical regions corresponded with the age of land bridge connection and dispersed as a member associated with the broad boreotropical belt before local cooling (34 Ma). The current transoceanic disjunctions in Limnogonus could be better explained by the disruption of “mixed‐mesophytic” forest belt; however, the direct transoceanic LDD between the Neotropics and Africa could not be ruled out. In addition, the “LDD” model coupled with island hopping could be a reasonable explanation for the diversification of the Oriental and Australian regions during the Oligocene.     

Dispersal,isolation and diversification with continued gene flow in an Andean tropical dry forest

The Andes are the world's longest mountain chain, and the tropical Andes are the world's richest biodiversity hot spot. The origin of the tropical Andean cordillera is relatively recent because the elevation of the mountains was relatively low (400–2500 m palaeoelevations) only 10 MYA with final uplift being rapid. These final phases of the Andean orogeny are thought to have had a fundamental role in shaping processes of biotic diversification and biogeography, with these effects reaching far from the mountains themselves by changing the course of rivers and deposition of mineral‐rich Andean sediments across the massive Amazon basin. In a recent issue of Molecular Ecology, Oswald, Overcast, Mauck, Andersen, and Smith (2017) investigate the biogeography and diversification of bird species in the Andes of Peru and Ecuador. Their study is novel in its focus on tropical dry forests (Figure 1) rather than more mesic biomes such as rain forests, cloud forests and paramos, which tend to be the focus of science and conservation in the Andean hot spot. It is also able to draw powerful conclusions via the first deployment of genomic approaches to a biogeographic question in the threatened dry forests of the New World.