The historical biogeography of the freshwater knifefishes using mitogenomic approaches: A Mesozoic origin of the Asian notopterids (Actinopterygii: Osteoglossomorpha)

The continental distributions of freshwater fishes in the family Notopteridae (Osteoglossomorpha) across Africa, India, and Southeast Asia constitute a long standing and enigmatic problem of freshwater biogeography. The migrational pathway of the Asian notopterids has been discussed in light of two competing schemes: the first posits recent transcontinental dispersal while the second relies on distributions being shaped by ancient vicariance associated with plate-tectonic events. In this study, we determined complete mitochondrial DNA sequences from 10 osteoglossomorph fishes to estimate phylogenetic relationships using partitioned Bayesian and maximum likelihood methods and divergence dates of the family Notopteridae with a partitioned Bayesian approach. We used six species representing the major lineages of the Notopteridae and seven species from the remaining osteoglossomorph families. Fourteen more-derived teleosts, nine basal actinopterygians, two coelacanths, and one shark were used as outgroups. Phylogenetic analyses indicated that the African and Asian notopterids formed a sister group to each other and that these notopterids were a sister to a clade comprising two African families (Mormyridae and Gymnarchidae). Estimated divergence time between the African and Asian notopterids dated back to the early Cretaceous when India–Madagascar separated from the African part of Gondwanaland. Thus, estimated time of divergence based on the molecular evidence is at odds with the recent dispersal model. It can be reconciled with the geological and paleontological evidence to support the vicariance model in which the Asian notopterids diverged from the African notopterids in Gondwanaland and migrated into Eurasia on the Indian subcontinent from the Cretaceous to the Tertiary. However, we could not exclude an alternative explanation that the African and Asian notopterids diverged in Pangea before its complete separation into Laurasia and Gondwanaland, to which these two lineages were later confined, respectively.     

The collision of the Indian plate with Asia: molecular evidence for its impact on the phylogeny of freshwater crabs (Brachyura: Potamidae)

Aim We used molecular data to answer the following questions: (1) Is morphology‐based (and to some extent, geography‐based) classification of the freshwater crab family Potamidae congruent with a molecular phylogeny? (2) What historical biogeographical event could have shaped this phylogeny? Location Material from the entire geographical range of the family Potamidae was analysed, including specimens from East Asia (China, Taiwan, the Ryukyus), Southeast Asia, South Asia (northern India, the Middle East and Near East), North Africa, and southern Europe. Methods Mitochondrial DNA sequences encoding 503 base pairs (excluding the variable regions) of the large subunit rRNA (16S rRNA) gene were obtained from 72 species belonging to 49 potamid genera, representing 51% of all known genera in this species‐rich family. Sequences were compared by means of phylogenetic analyses (minimum evolution, Bayesian inference, maximum likelihood and maximum parsimony) and Bayesian relaxed molecular clock estimates. Results The family Potamidae was found to be monophyletic with two major lineages, and there was support for the recognition of two mostly allopatric subfamilies, Potaminae and Potamiscinae. This is largely consistent with the current classification proposed. The ‘Potamiscinae’ clade comprised three subclades: (1) a well‐supported ‘eastern Asia’ subclade that included species from the eastern part of the range (China, Taiwan, the Ryukyus, the Philippines, Indochina, Malay Peninsula, northern India and Myanmar/Burma); (2) a weakly supported ‘Sunda Shelf islands’ subclade that included species from the larger Southeast Asian islands on the Sunda Shelf (Borneo, Sumatra and Java); and (3) a ‘Socotra’ subclade that comprised only Socotrapotamon from Socotra Island, off the north‐east coast of Africa. Main conclusions The discrete distribution of the two subfamilies in Europe/Asia is hypothesized to be the result of vicariance due to the collision of the Indian tectonic plate with the Asian continent, and the orogeny that caused the separation of the two freshwater crab lineages around 22.8 Ma. Within the Potamiscinae, the ‘Sunda Shelf islands’ subclade separated from other potamiscines around 21.1 Ma; and the endemic fauna of the East Asian islands (Taiwan, the Ryukyus and mainland Japan) was isolated from the Asian continent c. 8.4 Ma, following the opening of the Okinawa Trough. The ‘Socotra’ subclade diverged from the ‘eastern Asia’ subclade at 19.1 Ma during the Miocene. Its taxonomic position, however, remains unclear as the members of this clade possess the key potamine character of a transverse ridge on thoracic sternite 8, suggesting that this may in fact be a relict potamid group.     

Evolutionary bottlenecks in brackish water habitats drive the colonization of fresh water by stingrays

Species richness in freshwater bony fishes depends on two main processes: the transition into and the diversification within freshwater habitats. In contrast to bony fishes, only few cartilaginous fishes, mostly stingrays (Myliobatoidei), were able to colonize fresh water. Respective transition processes have been mainly assessed from a physiological and morphological perspective, indicating that the freshwater lifestyle is strongly limited by the ability to perform osmoregulatory adaptations. However, the transition history and the effect of physiological constraints on the diversification in stingrays remain poorly understood. Herein, we estimated the geographic pathways of freshwater colonization and inferred the mode of habitat transitions. Further, we assessed habitat‐related speciation rates in a time‐calibrated phylogenetic framework to understand factors driving the transition of stingrays into and the diversification within fresh water. Using South American and Southeast Asian freshwater taxa as model organisms, we found one independent freshwater colonization event by stingrays in South America and at least three in Southeast Asia. We revealed that vicariant processes most likely caused freshwater transition during the time of major marine incursions. The habitat transition rates indicate that brackish water species switch preferably back into marine than forth into freshwater habitats. Moreover, our results showed significantly lower diversification rates in brackish water lineages, whereas freshwater and marine lineages exhibit similar rates. Thus, brackish water habitats may have functioned as evolutionary bottlenecks for the colonization of fresh water by stingrays, probably because of the higher variability of environmental conditions in brackish water.     

Molecular systematics and diversification of the Asian scimitar babblers (Timaliidae, Aves) based on mitochondrial and nuclear DNA sequences

The Asian scimitar babblers, including the genus Pomatorhinus and Xiphirhynchus, are a small group of babblers characterized by long down-curved bills and a distribution throughout East and Southeast Asia. To infer the molecular phylogeny of this group and their divergence time, we examined sequences of multiple fragments including two entire mitochondrial genes and four nuclear introns (4352 bp in total) from multiple samples of eight of the nine recognized species of Asian scimitar babblers. The phylogeny resulting from the concatenated multi-locus dataset suggests that Pomatorhinus is paraphyletic. Due to its paraphyly, we propose dividing the traditional genus Pomatorhinus into two morphologically and genetically diagnosable genera: Pomatorhinus and Erythrogenys. Results of the molecular dating based on the conventional mitochondrial DNA divergence rate indicates that the diversification of these babblers is likely congruent with the historical climatic events. Our findings shed light on the diversification of avian species in southern Asia, a poorly studied biodiversity hotspot.     

Novel polymorphic microsatellites for studying genetic diversity of red Asian arowanas

Asian arowana (Scleropages formosus) is a highly endangered fish species listed in Appendix 1 of CITES since 1980. Fourteen novel polymorphic microsatellites were isolated from a CA-enriched partial genomic DNA library, and were used for studying genetic diversity of 41 red arowanas from the wild population. Surprisingly the average allele number of the 14 polymorphic microsatellites was as high as 12.4/locus. The average observed heterozygosity was 0.78 ranging from 0.51 to 0.95, and the gene diversity was quite high (0.78). All these data suggest that high level of genetic diversity existed in the red Asian arowana population.     

Molecular phylogeny and historical biogeography of the Holarctic wetland leaf beetle of the genus Plateumaris

Leaf beetles of the genus Plateumaris inhabit wetlands across the temperate zone of the Holarctic region. To explore the phylogeographic relationships among North American, East Asian, and European members of this genus and the origin of the species endemic to Japan, we studied the molecular phylogeny of 20 of the 27 species in this genus using partial sequences of mitochondrial cytochrome oxidase subunit I (COI) and the 16S and nuclear 28S rRNA genes. The molecular phylogeny revealed that three species endemic to Europe are monophyletic and sister to the remaining 11 North American and six Asian species. Within the latter clade, North American and Asian species did not show reciprocal monophyly. Dispersal-vicariance analysis and divergence time estimation revealed that the European and North America-Asian lineages diverged during the Eocene. Moreover, subsequent differentiation occurred repeatedly between North American and Asian species, which was facilitated by three dispersal events from North America to Asia and one in the opposite direction during the late Eocene through the late Miocene. Two Japanese endemics originated from different divergence events; one differentiated from the mainland lineage after differentiation from the North American lineage, whereas the other showed a deep coalescence from the North American lineage with no present-day sister species on the East Asian mainland. This study of extant insects provides molecular phylogenetic evidence for ancient vicariance between Europe and East Asia-North America, and for more recent (but pre-Pleistocene) faunal exchanges between East Asia and North America.     

Comparative Phyloclimatic Analysis and Evolution of Ecological Niches in the Scimitar Babblers (Aves: Timaliidae: Pomatorhinus)

We present the first extensive and integrative analysis of niche evolution based on climatic variables and a dated molecular phylogeny of a heterogeneous avian group of Southeast Asian scimitar babblers of the genus Pomatorhinus. The four main clades of scimitar babblers have species that co-occur in similar areas across southern Asia but some have diverged at different timeframes, with the most recently evolved clade harboring the highest number of species. Ecological niche models and analysis of contributing variables within a phylogenetic framework indicate instances of convergent evolution of members of different clades onto similar ecological parameter space, as well as divergent evolution of members from within clades. Pomatorhinus species from different clades occupying Himalayan foothills show convergence towards similar climatic tolerances, whereas within a clade, allopatric sister-species occurring in the Himalayas have diverged to occupy different climatic parameter spaces. Comparisons of climatic tolerances of Himalayan foothills taxa with species distributed further south in Assam/Burma and Burma/Thailand indicate convergence towards similar parameter spaces in several climatic variables. Niche overlap was observed to be lower among species of the youngest clade (ruficollis) and higher among species of older clades (ferruginosus). Analysis of accumulation of ecological disparity through time indicates rapid divergence within recent time frames. As a result, Himalayan taxa originating at different temporal scales within the four main scimitar babbler clades have differentiated ecologically only in recently diverged taxa. Our study suggests that the repeated orogenic and climatic fluctuations of the Pliocene and Pleistocene within mainland Southeast Asia served as an important ecological speciation driver within scimitar babblers, by providing opportunities for rapid geographic expansion and filling of novel environmental niches.     

Phylogeography of Wild Musk Shrew (Suncus Murinus) Populations in Asia Based on Blood Protein/Enzyme Variation

The musk shrew (Suncus murinus) is an insectivore species that inhabits tropical and subtropical Asia widely. To clarify the genetic relationship among wild musk shrew populations, we examined the electrophoretic variants of biparentally inherited genetic markers at 10 loci coding for eight blood proteins/enzymes in a total of 639 animals and compared the results obtained from the mitochondrial DNA data. The principal-component analysis performed using the allele frequency data revealed that the 17 populations could be divided into two major groups, a South Asian group and a Southeast Asian group that includes several island populations bound by Myanmar. The degrees of genetic divergence among populations were higher within the Southeast Asian group than within the South Asian group. This finding was incongruent with the mtDNA diversity. Analysis conducted at the individual level showed that a shrew from the central region in Myanmar that carries a South Asian type of mtDNA showed the electrophoretic variants specific to the Southeast Asian group, suggesting that this region is a contact zone between the two major groups.     

Molecular evidence for the monophyly of East Asian groups of Cyprinidae (Teleostei: Cypriniformes) derived from the nuclear recombination activating gene 2 sequences

The family Cyprinidae is one of the largest families of fishes in the world and a well-known component of the East Asian freshwater fish fauna. However, the phylogenetic relationships among cyprinids are still poorly understood despite much effort paid on the cyprinid molecular phylogenetics. Original nucleotide sequence data of the nuclear recombination activating gene 2 were collected from 109 cyprinid species and four non-cyprinid cypriniform outgroup taxa and used to infer the cyprinid phylogenetic relationships and to estimate node divergence times. Phylogenetic reconstructions using maximum parsimony, maximum likelihood, and Bayesian analysis retrieved the same clades, only branching order within these clades varied slightly between trees. Although the morphological diversity is remarkable, the endemic cyprinid taxa in East Asia emerged as a monophyletic clade referred to as Xenocypridini. The monophyly for the subfamilies including Cyprininae and Leuciscinae, as well as the tribes including Labeonini, Gobionini, Acheilognathini, and Leuciscini, was also well resolved with high nodal support. Analysis of the RAG2 gene supported the following cyprinid molecular phylogeny: the Danioninae is the most basal subfamily within the family Cyprinidae and the Cyprininae is the sister group of the Leuciscinae. The divergence times were estimated for the nodes corresponding to the principal clades within the Cyprinidae. The family Cyprinidae appears to have originated in the mid-Eocene in Asia, with the cladogenic event of the key basal group Danioninae occurring in the early Oligocene (about 31-30 MYA), and the origins of the two subfamilies, Cyprininae and Leuciscinae, occurring in the mid-Oligocene (around 26 MYA).     

When Indian crabs were not yet Asian - biogeographic evidence for Eocene proximity of India and Southeast Asia

Background  

The faunal and floral relationship of northward-drifting India with its neighboring continents is of general biogeographic interest as an important driver of regional biodiversity. However, direct biogeographic connectivity of India and Southeast Asia during the Cenozoic remains largely unexplored. We investigate timing, direction and mechanisms of faunal exchange between India and Southeast Asia, based on a molecular phylogeny, molecular clock-derived time estimates and biogeographic reconstructions of the Asian freshwater crab family Gecarcinucidae.     

Zoogeography and biodiversity of the freshwater fishes of Southeast Asia

The ichthyofauna of the freshwater system of Southeast Asia is extremely diverse. A recent estimate of about 1000 species is probably an understatement. More than 10 new species are being added to the list annually. The distribution pattern of the Southeast Asian freshwater fishes can be divided into five zoogeographic regions. The first one is the Salween basin in Burma, with fishes mainly of the Indian subcontinent origin such as Amblypharyngodon atkinsoni, Bangana almorae and Brachydanio jayarami. The second zoogeographic area is the Mekong, Chao Phraya and Mae Khlong drainages which harbour fishes typical of the mainland of Southeast Asia such as Acanthorhodeus deignani, Barbichthys nitidus and Cirrhinus siamensis. The Malay Peninsula is the third region whose species composition is heavily influenced by the Siamese (such as Homaloptera smithi, Tuberoschistura baenzigeri and Botia beauforti) and Indonesian (such as Botia hymenophysa, Luciocephalus pulcher and Parosphromenus deissneri) elements. The islands of Sumatra, Borneo and Java are the fourth zoogeographic area of fish distribution. These islands show a high degree of endemism, especially in fishes of the family Belontiidae. Finally, the freshwater system of the Philippines is the last zoogeographic region of Southeast Asia. The area is characterized by the presence of closely related species of the cyprinids especially in Lake Lanao. Currently, high diversity of these freshwater fishes is being threatened by land development, such as deforestation, road construction and land expansion for plantation. Recent studies in the Gombak River basin show the extermination of 41 per cent of native fish species from 1969 to 1990. This is probably due to the construction of highways, logging, as well as land clearing for agriculture.     

Timing of a mtDNA gene rearrangement and intercontinental dispersal of varanid lizards

The mitochondrial genomes of the Komodo monitor (Varanus komodoensis) and the Nile monitor (V. niloticus) were previously shown to have an extensive gene rearrangement. Here, we show that this gene arrangement widely occurs in varanid taxa originated from Africa, Asia and Australasia. Based on phylogenetic relationships of the varanids constructed using mitochondrial DNA sequences encoding the NADH dehydrogenase subunit 2 gene and seven flanking tRNA genes, we estimated their divergence times by the Bayesian method without assuming the molecular clock. The results suggested that the mitochondrial DNA gene rearrangement took place once in an ancestral varanid lineage in the Paleocene or earlier. Our results are more consistent with Cenozoic over-water dispersal of Southeast Asian varanids across the Indonesian Archipelago rather than the Cretaceous Gondwanan vicariance for the origin of Australasian varanids.     

Evolution of the Eastern Asian and Eastern North American disjunct genus Symplocarpus (Araceae): insights from chloroplast DNA restriction site data

Chloroplast DNA (cpDNA) variation was surveyed with 20 restriction endonucleases for the eastern Asian and eastern North American disjunct genus Symplocarpus (Araceae). The cpDNA phylogeny reveals a sister group relationship between S. foetidus from eastern North America and S. renifolius from eastern Asia. The cpDNA divergence between the two intercontinental sister species is 0.61%, which suggests an estimated divergence time of 6.1 million years ago during the late Miocene. The Bering land bridge hypothesis is compatible with the estimated time of divergence for the migration of Symplocarpus between eastern Asia and North America. Furthermore, a single origin of the exothermic spadices in Symplocarpus is suggested by the phylogeny. The cpDNA data also provide independent support for the recognition of three species within the genus.     

On the distributional patterns of Southeast-East Asian freshwater fish and their history

Abstract Aim The extensively published data on Southeast‐East Asian freshwater fish communities and distributions were compiled and expressed into phenograms. Location River basins of Southeast China, the Indochinese Peninsula and Sundaland were studied and compared for possible lineages. Methods The Hennig86 program was employed to cluster the basins of the various subregions on the basis of their similarity in fish assemblages. In this cluster analysis, the outgroup comparison method was used, in which a reference was based on which to make corrections for unequal rates of evolution among the lineages. Results South‐eastern China, the Indochinese Peninsula and Sundaland are groups of landmass that share a common ancestor and that evolved at distinct epochs and through different geological processes, as shown from the association between the distribution of freshwater fish of Southeast‐East Asia and the twenty‐one river basins they inhabit. Main conclusions Southeast‐East Asia comprises an estimated 3500 cyprinid species. The phenograms obtained, based on their compositional and distributional patterns, suggest that the riverine fish communities of the area studied fall into nineteen biogeographical zones defined by the main river systems and their underlying geology.     

Biogeography and speciation patterns of the golden orb spider genus Nephila (Araneae: Nephilidae) in Asia

The molecular phylogeny of the globally distributed golden orb spider genus Nephila (Nephilidae) was reconstructed to infer its speciation history, with a focus on SE Asian/W Pacific species. Five Asian, two Australian, four African, and one American species were included in the phylogenetic analyses. Other species in Nephilidae, Araneidae, and Tetragnathidae were included to assess their relationships with the genus Nephila, and one species from Uloboridae was used as the outgroup. Phylogenetic trees were reconstructed from one nuclear (18S) and two mitochondrial (COI and 16S) markers. Our molecular phylogeny shows that the widely distributed Asian/Australian species, N. pilipes, and an African species, N. constricta, form a clade that is sister to all other Nephila species. Nested in this Nephila clade are one clade with tropical and subtropical/temperate Asian/Australian species, and the other containing African and American species. The estimated divergence times suggest that diversification events within Nephila occurred during mid-Miocene to Pliocene (16 Mya-2 Mya), and these time periods were characterized by cyclic global warming/cooling events. According to Dispersal and Vicariance Analysis (DIVA), the ancestral range of the Asian/Australian clade was tropical Asia, and the ancestral range of the genus Nephila was either tropical Asia or Africa. We conclude that the speciation of the Asian/Australian Nephila species was driven by Neogene global cyclic climate changes. However, further population level studies comparing diversification patterns of sister species are needed to determine the mode of speciation of these species.     

The origin and divergence of Gobioninae fishes (Teleostei: Cyprinidae) based on complete mitochondrial genome sequences

The gudgeons (subfamily Gobioninae) are a group of cyprinid fishes primarily distributed in East Asia. However, studies on their origins and divergence are scarce. Here the whole mitochondrial genome sequences of 27 gudgeon species (including one newly determined), 22 other cyprinid species, and two non‐cyprinids as outgroups are applied to infer the evolution of the gudgeons. Based on Bayesian and maximum likelihood phylogenetic analyses, the gudgeons were determined to be a monophyletic group which can be further subdivided into four monophyletic clades with strong supports. The divergence times of the gudgeons were estimated using a relaxed molecular clock method; the results indicate that these fishes originated in the early Paleocene (approx. 63.5 Mya) and that the basal Hemibarbus group diverged from the other gudgeon fishes (approx. 58.3 Mya). As an independent group the Coreius began to diverge from the remaining two groups (approx. 54.6 Mya); the most derived two groups diverged from each other (approx. 53.6 Mya). The divergences of the four gudgeon groups were within a relatively short time frame (approx. 58–53 Mya). Based on the reconstruction of evolutionary trends of gudgeon habitat, evidence is provided that supports the origin and differentiation of this fauna as being associated with some special paleo‐environmental events occurring from the early Paleocene to the Pliocene. The study represents comprehensive molecular dating and character evolution analyses of the gudgeons, and providing a valuable framework for future research in the evolution of the Gobioninae fishes.     

Genetic divergence and evolutionary relationships in six species of genera Hoplobatrachus and Euphlyctis (Amphibia: Anura) from Bangladesh and other Asian countries revealed by mitochondrial gene sequences

To elucidate the species composition, genetic divergence, evolutionary relationships, and divergence time of Hoplobatrachus and Euphlyctis frogs (subfamily Dicroglossinae, family Ranidae) in Bangladesh and other Asian countries, we analyzed the mitochondrial Cyt b, 12S, and 16S rRNA genes of 252 specimens. Our phylogenetic analyses showed 13 major clades corresponding to several cryptic species as well as to nominal species in the two genera. The results suggested monophyly of Asian Hoplobatrachus species, but the position of African Hoplobatrachus occipitalis was not clarified. Nucleotide divergence and phylogenetic data suggested the presence of allopatric cryptic species allied to Euphlyctis hexadactylus in Sundarban, Bangladesh and several parapatric cryptic species in the Western Ghats, India. The presence of at least two allopatric cryptic species among diverged Euphlyctis cyanophlyctis in Bangladesh, India, and Sri Lanka was also suggested. In some cases, our estimated divergence times matched the paleogeological events of South and Southeast Asian regions that may have led to the divergence of Hoplobatrachus and Euphlyctis taxa. Especially, land formation at Bangladesh (15–10 Ma) may have allowed the spread of these frog taxa to Southeast Asian areas, and the aridification of central India (5.1–1.6 Ma) might have affected the gene flow of widely distributed species. The present study revealed prior underestimation of the richness of the amphibian fauna in this region, indicating the possible occurrence of many cryptic species among these groups.     

Phylogeny and biogeography of Chinese and Australasian Polystichum ferns as inferred from chloroplast trnL-F and rps4-trnS sequence data

Polystichum, one of the largest genera of ferns, occurs worldwide with the greatest diversity in southwest China and adjacent regions. Although there have been studies of Chinese Polystichum on its traditional classification, geographic distributions, and even a few on its molecular systematics, its relationships to other species outside China remain little known. Here, we investigated the phylogeny and biogeography of the Polystichum species from China and Australasia. The evolutionary relationships among 42 Polystichum species found in China (29 taxa) and Australasia (13 taxa) were inferred from phylogenetic analyses of two chloroplast DNA sequence data sets: rps4-trnS and trnL-F intergenic spacers. The divergence time between Chinese and Australasian Polystichum was estimated. The results indicated that the Australasian species comprise a monophyletic group that is nested within the Chinese diversity, and that the New Zealand species are likewise a monophyletic group nested within the Australasian species. The divergence time estimates suggested that Chinese Polystichum migrated into Australasia from around 40 Ma ago, and from there to New Zealand from about 14 Ma. The diversification of the New Zealand Polystichum species began about 10 Ma. These results indicated that Polystichum probably originated in eastern Asia and migrated into Australasia: first into Australia and then into New Zealand.     

Historical biogeography of the Southeast Asian and Malesian tribe Dissochaeteae (Melastomataceae)

The region of Tropical Southeast Asia and the Malay Archipelago is a very appealing area for research due to its outstanding biodiversity, being one of the most species-rich areas in the world with high levels of endemism, and due to its complex geological history. The high number of species in tribe Dissochaeteae (Melastomataceae) and their tendency to narrow endemism makethe tribe an ideal group for examining biogeographic patterns. We sampled 58 accessions spread over 42 accepted and two undescribed species of the Dissochaeteae. Two nuclear (ETS, ITS) and four chloroplast regions (ndhF, psbK-psbL, rbcL, rpl16) were used for divergence time estimation and ancestral area reconstruction. Results from the molecular dating analysis suggest that the diversity of Dissochaeteae in the Southeast Asian region resulted from a South American ancestor in the late Eocene. The ancestor of the Dissochaeteae might have migrated from South America to Southeast Asia via North America and then entered Eurasia over the North Atlantic land bridge during the Eocene. The origin and early diversification of the Dissochaeteae in Southeast Asia dates back to the middle Oligocene, and most of the genera originated during the Miocene. Indochina and Borneo are most likely the area of origin for the most recent common ancestor of the Dissochaeteae and for many of the early diverging clades of some genera within Southeast Asia.     

Molecular phylogeny and biogeography of caecilians from Southeast Asia (Amphibia, Gymnophiona, Ichthyophiidae), with special reference to high cryptic species diversity in Sundaland

We investigated the phylogenetic relationships and estimated the history of species diversification and character evolution in two ichthyophiid genera: Caudacaecilia and Ichthyophis. We estimated the phylogenetic relationships of 67 samples from 33 localities in Southeast Asia from 3840-bp sequences of the mitochondrial 12S rRNA, 16S rRNA, and cyt b genes using Bayesian inference, maximum likelihood, and maximum parsimony methods. The Southeast Asian samples formed a well-supported clade differentiated from a South Asian sample. The Southeast Asian clade was divided into two subclades, one containing samples from South China, Indochina, Malay Peninsula, and Java. The other consisted of samples from Borneo and the Philippines. Neither Caudacaecilia nor Ichthyophis was monophyletic, nor did samples with or without light stripes lateral to the body form clades. We found several distinct sympatric lineages and undescribed species, especially from Sundaland.