Identification of two Bithynia species from Heng County, Guangxi Zhuang Autonomous Region, China by using morphological and DNA barcoding methods

Abstract

To distinguish two Bithynia species, Bithynia fuchsiana and Bithynia robusta collected from Heng County, Guangxi Zhuang Autonomous Region, by using morphological and DNA barcoding methods. The adult B. fuchsiana and B. robusta were collected from the biotope such as rivers, ditches and ponds in Heng County of Guangxi Zhuang Autonomous Region, China. The two species specimens were identified by measuring shell morphological parameters, comparing the characters of the male reproductive system, and using the COI gene barcoding technique and building phylogenetic tree. B. fuchsiana and B. robusta were similar morphologically in the shell appearance; they had the similar snail height, snail width, shape and male reproductive structure. The DNA sequence analysis showed that the COI gene of the two Bithynia species had low sequence divergence with 11 variation sites among 22 sequences. The length of the COI gene segment was 517 bp and no insertion sites and deletion loci after sequence edited. All individuals of the two species gathered to one clade in the phylogenetic tree based on COI gene. According to the evidence of morphology and COI gene coding sequence, B. fuchsiana and B. robusta from Heng County, Guangxi Zhuang Autonomous Region, are likely to be the same species.