Mitochondrial COI and nuclear RAG1 DNA sequences and analyses of specimens of the three morphologically established species in the genus Trichopsis (Perciformes: Osphronemidae) reveal new/cryptic species.

Air-breathing fish species of the genus Trichopsis have been reported in Cambodia, Lao PDR, Indonesia, Malaysia, Singapore, Thailand and Vietnam. It is only in Thailand that all three recognized species (Trichopsis vittata, Trichopsis schalleri and Trichopsis pumila), as judged by distinct external features, are found. Cambodia and Lao PDR harbor two species each. The present work involves first-time DNA sequencing and analysis based on mitochondrial (COI) and nuclear (RAG1) DNA of numerous specimens of these species and specimens of a controversial Phetchaburi (Thailand) fish population with a mixed outward appearance. In addition to confirming the morphologically clear-cut taxonomic division of the three fish species, our DNA results show that whereas the T. pumila populations form one single species, there are cryptic species in the T. vittata and T. schalleri populations and possibly a new one in the latter. Members of the putative Phetchaburi fish population have been proven to be hybrids between T. pumila and T. vittata. In addition, a new the phylogenetic tree indicating ancestral relationships is also presented. This study should generate further research to find new/cryptic species of the genus Trichopsis in all countries harboring the fish.

Biodiversity of the Betta smaragdina (Teleostei: Perciformes) in the northeast region of Thailand as determined by mitochondrial COI and nuclear ITS1 gene sequences.

In Thailand, there are currently five recognized species members of the bubble-nesting Betta genus, namely Betta splendens, B. smaragdina, B. imbellis, B. mahachaiensis and B. siamorientalis. In 2010, we indicated the possibility, based on COI barcoding evidence, that there might be two additional species, albeit cryptic, related to the type-locality B. smaragdina in some provinces in the northeast of Thailand. In the present study, after a more extensive survey of the northeast, and phylogenetic analyses based on COI and ITS1 sequences, the B. smaragdina group may be composed of at least 3 cryptic species members. The phylogenetic positions of these B. smaragdina group members in the bubble-nesting bettas' tree together with those of their congeners have been consolidated by better DNA sequence quality and phylogenetic analyses. With a better supported tree, the species statuses of B. siamorientalis and the Cambodian B. smaragdina-like fish, B. stiktos, are also confirmed.

Southeast Asian mouth-brooding Betta fighting fish (Teleostei: Perciformes) species and their phylogenetic relationships based on mitochondrial COI and nuclear ITS1 DNA sequences and analyses.

Fighting fish species in the genus Betta are found in several Southeast Asian countries. Depending on the mode of paternal care for fertilized eggs and hatchlings, various species of the betta fish are classified as mouth brooders or nest builders whose members in turn have been grouped according to their similarities mainly in morphology. The mouth brooders as well as some nest builders involved in the present study include fishes discovered and identified subsequent to previous reports on species groupings and their positions on phylogenetic trees based on DNA sequences that differ from those used by us in this study. From the mitochondrial COI gene and nuclear ITS1 gene sequences and more accurate analyses we conclude that the following members of the mouth-brooding pairs, named differently previously, are virtually identical, viz the Betta prima-Betta pallida pair and Betta ferox-Betta apollon pair. The Betta simplex, hitherto believed to be one species, could possibly be genetically split into 2 distinct species. In addition, several other established type-locality fishes could harbor cryptic species as judged by genetic differences. Assignments of fish species to groups reported earlier may have to be altered somewhat by the present genetic findings. We propose here a new Betta fish phylogenetic tree which, albeit being similar to the previous ones, is clearly different from them. Our gene-based evidence also leads to assignments of some fishes to new species groups and alters the positions of some species on the new phylogenetic tree, thus implying different ancestral relationships.