Taxonomic confirmation of mud crab species (genus Scylla ) in Bangladesh by nuclear and mitochondrial DNA markers

Abstract

Taxonomy of mud crabs genus Scylla has been misidentified for several years due to their high morphological plasticity. Several reports concerning mud crab have been published with misleading identification in Bangladesh. In this study, partial fragments of nuclear and mitochondrial DNA of Scylla species obtained from four locations along the Bangladesh coast were used to resolve taxonomical ambiguity of mud crab species. A single PCR product from the nuclear first internal transcribed spacer (ITS-1) marker and phylogenetic trees constructed based on 16S rDNA sequences indicated that all Scylla species obtained in this study were S. olivacea. Both molecular data and morphological characters revealed that S. olivacea is the only major species in Bangladesh coastal waters. Further, the 16S rDNA haplotypes significantly differed with known S. serrata by 33%. From this study it is clear that 'S. serrata' commonly reported from Bangladesh should be S. olivacea.

Genetic characterization of the artisanal mud crab fishery in Myanmar

“…Our results found that Scylla olivacea was the only species harvested from the mangrove creeks across the Mergui archipelago, in southern Myanmar, as identified using DNA barcoding the first study of its kind in Myanmar’s marine fisheries. This is in accordance with the catch composition of the mud crab fisheries of Malaysia [ 25 ], Bangladesh [ 12 ], and Philippines [ 29 ], where S . olivacea is the only or the dominant species harvests from mangroves fishing grounds.…”

“…serrata was previously thought to be the most common species harvested across Southeast Asia, but more studies have revealed that S . olivacea is indeed the most common species [ 12 , 15 , 29 ]. Likewise, S. olivacea is the most common species found in the markets in Southeast Asia [ 2 ] and the most important crab for commercial culture in the Indo-West Pacific region leading to high prices in both local and international markets [ 30 ].…”

“…serrata have been found in sympatry, e.g. in India [ 15 , 22 , 31 ], Thailand [ 13 ], and Bangladesh [ 12 ]. Our results indicate that S .…”

“…paramamosian (Estampador 1949) [ 5 , 9 ]. Local evaluations across Southeast Asia were also conducted following Keenan et al (1998) taxonomic review to reveal the actual species occurring locally in Vietnam [ 10 ], China [ 11 ], Bangladesh [ 12 ], Thailand [ 13 ], Japan [ 14 ], and India [ 15 ].…”

Female-specific SNP markers provide insights into a WZ/ZZ sex determination system for mud crabs Scylla paramamosain, S. tranquebarica and S. serrata with a rapid method for genetic sex identification

“…Although mud crabs have been captured and cultured for over 110 years, the taxonomy of genus Scylla was controversial until the revision by Keenan et al in 1998 [53], based on genetic variations, external morphology and morphometric characters analysis [54]. Phylogenetic study on genus Scylla based on COI sequence of mtDNA showed that S. paramamosain is genetically closest to S. tranquebarica, and then to S. serrata , while, the largest genetic distance was found with S. olivacea [55, 56].…”