Phylogenetics, zoogeography, and the role of dispersal and vicariance in the evolution of the Rana catesbeiana (Anura: Ranidae) species group

The Rana catesbeiana species group consists of seven species, each variously distributed across eastern North America. We estimated the evolutionary relationships among 31 exemplars and used the phylogenetic hypothesis to examine the potential modes of speciation and relative role of dispersal in the evolution and zoogeography of this species group. Phylogenetic relationships based on 1554 combined base pairs of the cytochrome b and ND2 mitochondrial genes suggest that the species are closely related, having undergone rapid radiation from a common ancestor during the late Miocene or Pliocene. A Pleistocene origin for the rare R. okaloosae is suggested by its pattern of paraphyly with R. clamitans and by its geographically restricted distribution, although hybridization as the explanation for paraphyly cannot be ruled out. Dispersal–vicariance analysis suggested a Coastal Plain biogeographical region origin of the species group, supporting the notion that the region was an important centre of anuran diversification, with post-speciation dispersal playing a major role in explaining the distribution of the widespread species, R. catesbeiana , R. clamitans, and R. septentrionalis . High sea levels during the late Tertiary, greatly reducing and insularizing parts of the southern Coastal Plain region may have played a major role in the diversification of this group.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 601–624.     

Molecular phylogeny and historical biogeography of the large carpenter bees, genus Xylocopa (Hymenoptera: Apidae)

The biogeographical history of major groups of bees with worldwide distributions have often been explained through hypotheses based on Gondwanan vicariance or long distance dispersal events, but until recently these hypotheses have been very difficult, if not impossible, to distinguish. New fossil data, comprehensive information on Mesozoic and Cenozoic coastline positions and the availability of phylogenetically informative DNA markers now makes it feasible to test these hypotheses for some groups of bees. This paper presents historical biogeographical analyses of the genus Xylocopa Latreille, based on phylogenetic analyses of species belonging to 22 subgenera using molecular data from two nuclear genes, elongation factor‐1α (EF‐1α) and phosphoenolpyruvate carboxykinase (PEPCK), combined with previously published morphological and mitochondrial data sets. Phylogenetic analyses based on parsimony and likelihood approaches resulted in several groups of subgenera supported by high bootstrap values (>85%): an American group with the Oriental/Palaearctic subgenera Nyctomelitta and Proxylocopa as sister taxa; a geographically diverse group (Xylocopa s.l); and a group consisting of African and Oriental subgenera. The relationships among these three clades and the subgenus Perixylocopa remained unresolved. The Oriental subgenus Biluna was found to be the sister group of all other carpenter bee subgenera included in this study. Using a relaxed molecular clock calibrated using fossil carpenter bees, we show that the major splits in the carpenter bee phylogeny occurred well after the final breakup of Gondwanaland (the separation of South America and Africa, 100 Mya), but before important Miocene fusion events. Ancestral area analysis showed that the genus Xylocopa most likely had an Oriental‐Palaearctic origin and that the present world distribution of Xylocopa subgenera resulted mainly from independent dispersal events. The influence of Pleistocene glaciations on carpenter bee distributions is also discussed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 77 , 249–266.     

Phylogeny and biogeography of highly diverged freshwater fish species (Leuciscinae,Cyprinidae, Teleostei) inferred from mitochondrial genome analysis

The distribution of freshwater taxa is a good biogeographic model to study pattern and process of vicariance and dispersal. The subfamily Leuciscinae (Cyprinidae, Teleostei) consists of many species distributed widely in Eurasia and North America. Leuciscinae have been divided into two phyletic groups, leuciscin and phoxinin. The phylogenetic relationships between major clades within the subfamily are poorly understood, largely because of the overwhelming diversity of the group. The origin of the Far Eastern phoxinin is an interesting question regarding the evolutionary history of Leuciscinae. Here we present phylogenetic analysis of 31 species of Leuciscinae and outgroups based on complete mitochondrial genome sequences to clarify the phylogenetic relationships and to infer the evolutionary history of the subfamily.