Cryptic genetic diversity of Neverita didyma in the coast of China revealed by phylogeographic analysis: implications for management and conservation

Abstract

Revealing cryptic biodiversity and understanding the processes that promote lineage diversification will provide valuable insights into management and protection of exploitable species. Neverita didyma is one of the most common marine species along the coast of China and possesses highly economic and nutritional value. Despite being heavily harvested each year, the genetic diversity of this species has never been assessed in the coastal areas of China. Here, we analyzed the diversity of this species based on the barcode region of the mitochondrial gene Cytochrome Oxidase subunit I (COI) and utilized different species delineation approaches to infer evolutionarily significant units (ESUs). Three distinct ESUs, with high genetic distance among each, were identified. Divergence time estimates suggested that the high genetic distances were probably associated with historical isolation of the marginal seas during Pleistocene low sea level periods. The three ESUs did not map to distinct geographical distribution, possibly attributing to the repeated isolation in different refugia and random postglacial recolonization. Moreover, N. didyma in Haizhou Bay deserves priority protection due to its unique ESU. To improve management regulations in the marine realm, our research also stresses the need for more empirical studies on genetic diversity of commercially exploited species in coastal environments of China.