Phylogeography in Nassarius mud snails: Complex patterns in congeneric species

Abstract

One major goal for phylogeographical studies is to elucidate respective roles of multiple evolutionary and ecological forces that shape the current distribution patterns. In marine and coastal ecosystems, it has been generated a common realization that species with enormous population size and pelagic larval stages can disperse across broad geographical scales, leading to weak or even no phylogeographical structure across large geographical scales. However, the violation of such realization has been frequently reported, and it remains largely unexplored on mechanisms responsible for various phylogeographical patterns observed in different species at varied geographical scales. Here, we used a species-rich genus Nassarius to assess and compare phylogeographical patterns in congeneric species, and discuss causes and consequences underlying varied phylogeographical patterns. Interestingly, we observed complex phylogeographical patterns both within single species and across multiple species, and multiple analyses showed varied levels of genetic heterogeneity among sites within and across species. Available evidence suggests that related species with similar biological characteristics may not be necessary to result in consistent phylogeographical patterns. Multiple factors, including larval ecology, interactions between dispersal and natural selection, and human activity-mediated dispersal, can partially explain the complex patterns observed in this study. Deep investigations should be performed on these factors, particularly their respective roles in determining evolutionary/ecological processes to form phylogeographical patterns in species with high dispersal capacities in marine and coastal ecosystems.

Mitogenomic phylogeny of Nassarius (Gastropoda: Neogastropoda)

“…conoidalis and N . nodifer has never been revealed in previous studies (Chen & Zhang, ; Pu et al, ; Zou et al, ). All these phylogenies, each based on short gene fragments, were poorly supported, often contradicting each other.…”

“…Within Nassarius , the use of subgenus is quite common in taxonomic description. However, previous molecular analyses did not find support to maintain the current use of subgenera due to the homoplastic of shell or radula characters, which are usually used to define subgenera (Galindo et al, ; Pu et al, ). In the present study, the monophyly of subgenus Zeuxis , which was represented by three species, was not supported, corresponding with previous molecular phylogenies using short gene fragments, including COI, 16S and/or ITS (Chen & Zhang, ; Li et al, ; Pu et al, ; Zou, Li, & Kong, ).…”

Mitogenomic phylogeny of mud snails of the mostly Atlantic/Mediterranean genusTritia(Gastropoda: Nassariidae)

“…After Galindo et al (2016) around 60 species were reclassified into genera other than Nassarius but more than 300 species remained tentatively in this genus (MolluscaBase, 2020b) awaiting further phylogenetic studies. In this regard, two subsequent mitogenomic studies that focused on the genus Nassarius improved the resolution of phylogenetic relationships among species restricted to the China seas (Yang, Li, Kong, & Yu, 2019;Yang et al, 2020), compared with previous attempts based on partial gene sequences (e.g., Zhang & You, 2009;Chen & Zhang, 2012;Pu et al, 2017). As a result of these mitogenomic studies, the composition of the genus Nassarius was refined, with Nassarius jacksonianus and Nassarius sp.…”

“…In this regard, two subsequent mitogenomic studies that focussed on the genus Nassarius improved the resolution of phylogenetic relationships among species restricted to the China seas (Yang et al., 2019, 2020), compared with previous attempts based on partial gene sequences (e.g. Chen & Zhang, 2012; Pu et al., 2017; Zhang & You, 2009). As a result of these mitogenomic studies, the composition of the genus Nassarius was refined, with Nassarius jacksonianus and Nassarius sp.…”

Nassarius foveolatus (Gastropoda, Nassariidae), a new record of an exotic species in Brazil

“…Interestingly, a sequence deposited as N. hepaticus (Pulteney, 1799) (FJ660644.1) in GenBank was also assigned to this group. However, since the other sequences of this species were assigned in a distant clade with N. nodifer (Powys, 1835) (see Appendices session for the entire phylogeny), this sequence probably represents an error of identification (as both species have similar shells) or even introgression between N. hepaticus and N. foveolatus, process already proposed for other Nassarius species (for details, see Pu et al, 2017).…”