Allopatry and overlap in a clade of snails from mangroves and mud flats in the Indo-West Pacific and Mediterranean (Gastropoda: Potamididae:Cerithideopsilla)

Abstract

Cerithideopsilla is a genus of potamidid snails found in high abundance on sedimentary intertidal flats and beneath mangrove trees on continental shores in the tropical and subtropical Indo-West Pacific region and Mediterranean Sea. Taxonomic revisions have recognized four species, but recent molecular studies have hinted at a higher diversity. Here, we analyse 377 individuals sampled from across the known range and use a combination of molecular phylogenetic (mitochondrial COI and 16S rRNA, and nuclear 28S rRNA genes), statistical (generalized mixed Yule-coalescent GMYC method) and morphological (shell form) criteria to delimit 16 species. These form four species groups, corresponding with the traditionally recognized species C. alata, C. 'djadjariensis' (for which the valid name is C. incisa), C. cingulata and C. conica. Distribution maps were compiled using museum specimens identified by diagnostic shell characters. In combination with the molecular phylogenetic trees, these suggest an allopatric speciation mode, with diversification centred on the East Asian coastline and northern Australia, and a pronounced gap in the 'eastern Indonesian corridor', an area of low oceanic productivity. There is, however, frequently geographical overlap between sister species and we suggest from several sources of evidence (e.g. presence of C. conica in isolated saline lakes 900 km from the sea) that post-speciation transport by migratory birds has occurred. Nine of the 16 species occur between the Gulf of Tonkin and Hong Kong, so southern China is significant for both the evolution and conservation of Cerithideopsilla species.

Phylogeography of bivalve Meretrix petechialis in the Northwestern Pacific indicated by mitochondrial and nuclear DNA data

“…petechialis groups is approximately near to Taiwan Strait. In the northwestern Pacific, the Tropic of Cancer is the boundary between the warm-temperate and tropical regions, and 20°C isotherm of annual mean temperature running through the Taiwan Strait, which is a major biogeographic boundary for many species [ 82 ]. Secondly, analogous to two lineages of Mugil cephalus [ 17 ], the distribution range of northern group is consistent with gradients of the cold waters from the Subei Coastal Current (SCC) flowing southward along the ECS coast, while the southern group appeared be restricted to the warm water of the China Coastal Current (CCC) flowing from the SCS into the ECS.…”

A DNA barcode library for mangrove gastropods and crabs of Hong Kong and the Greater Bay Area reveals an unexpected faunal diversity associated with the intertidal forests of Southern China

“…However, the species is mainly found in the Yellow Sea and it is not associated with mangroves [70]. Reid and co-workers also redefined the genus Cerithideopsilla [21], which was recently renamed and divided into 16 species of Pirenella (= Cerithideopsilla) from three clades [72,73]. In Hong Kong, several species belonging to this genus were recorded, identified, misidentified and renamed in the recent years [28,32,61,74], but our study could only confirm the presence of five species (see Table 1 and Additional file 1: Table S1).…”

Checklist of mangrove snails (Mollusca: Gastropoda) in South Coast of Pamekasan, Madura Island, East Java, Indonesia

“…Often co-occurs with Pirenella cingulate (Reid and Ozawa 2016). Development with the planktonic phase of 10 to 12 days (Ozawa et al 2015). Rhinoclavis are deposit-feeding gastropods in coral-reefflat sediments.…”