According to geological history, Peninsular Malaysia and Borneo formed at different times and were once connected during Quaternary glaciations. To determine how this history has influenced phylogeography, our study examined the population genetic structure of the tropical freshwater gastropod Melanoides tuberculata across Peninsular Malaysia and Borneo using the sequences from mitochondrial DNA 16S rRNA and cytochrome oxidase subunit I genes (1168 bp). In total, 104 specimens were collected from seventeen populations. All mtDNA haplotypes were identified as belonging to two highly divergent lineages, and these lineages were almost allopatric in their distributions. Our study found that the freshwater fauna in Malaysia might be divided into four regions: northeast Peninsular Malaysia, northwest Peninsular Malaysia, south Peninsular Malaysia, and Borneo. The phylogeography of M. tuberculata in Malaysia was shaped by the landforms of Peninsular Malaysia and by the paleo-river systems in the Sunda continental shelf. In addition, our study found that these two lineages in Malaysia have invaded the globe. These results suggest that Malaysia is located in important shipping lanes throughout the world, and the populations of M. tuberculate might be widely distributed throughout the world by shipping.
Kuan-chung Li, Bao-sen Shieh, Yuh-wen Chiu, Da-ji Huang, and Shih-hsiung Liang (2016) The Chevron snakehead (Channa striata) has been invading Taiwan for over 30 years, and it is currently widely distributed across diverse aquatic habitats within the island. Due to its strong environmental adaptability and carnivorous diet, C. striata has caused great negative impacts to the biodiversity of native fishes and aquatic organisms in Taiwan. To effectively restrain its spatial distribution and population, the objective of this study was to investigate the growing conditions, diet composition, and reproductive biology of C. striata in the field. In total, 294 individuals were collected from wetlands, irrigation canals, streams, and reservoirs in southern Taiwan from September 2008 to December 2010. Among 272 sex-identified individuals, more females (164) were collected than males (108). The morphological differences between the sexes could not be distinguished by the 10 body measurements recorded. Diverse food items, including snails, odonates, fishes, amphibians, and reptiles, were identified in the stomachs of 35 individuals. The minimum body length of sexually mature C. striata females exhibited at a standard length of 24.5 cm (total length 28 cm). The appearance of mature oocytes were mainly observed from July to November in 2009 and from April to October in 2010. Greater absolute fecundity (oocyte/individual) was estimated in Taiwan for C. striata than in its original distribution range possibly due to less water level fluctuation in the sampling habitats of Taiwan. The relative fecundity (oocyte/g) for C. striata was considered lower but within the documented range in Taiwan when compared with its original habitat in Malaysia. To effectively manage C. striata in Taiwan, regionally eradiating young and adult individuals, especially during the reproductive season and educating people to stop releasing it in the wild are possible ways to restrain and control the further spread of this exotic fish in Taiwan.