Phylogenetic Diversity of Freshwater Gastropods

Freshwater gastropods constitute a remarkably diverse assemblage of molluscs inhabiting lentic and lotic environments worldwide. Their phylogenetic diversity spans multiple caenogastropod and heterobranch clades, including families such as Viviparidae, Hydrobiidae, Planorbidae and Tateidae. Over the past two decades, integration of mitochondrial and nuclear markers with genome-wide single nucleotide polymorphism (SNP) data has revealed deep lineage splits, instances of cryptic speciation and complex patterns of historical biogeography. Vicariance events driven by tectonic uplifts and palaeodrainage rearrangements, together with repeated lake expansions and contractions, have repeatedly reshaped species distributions and engendered adaptive radiations in ancient lake systems. Moreover, introgressive hybridisation has blurred species boundaries in some taxa, emphasising the need for multilocus approaches in taxonomy and conservation planning. Phylogenomic frameworks have not only refined classification schemes but also uncovered hitherto unrecognised clades, informing our understanding of freshwater ecosystem function. Given the sensitivity of gastropods to water quality and habitat fragmentation, elucidating their evolutionary relationships is paramount for biodiversity assessments and the development of targeted conservation measures across river basins and inland seas.

Research from Nature Portfolio

Recent studies have demonstrated discordance between mitochondrial and nuclear phylogenies in East Asian viviparid snails. Multi-locus phylogenomic analyses combining two mitochondrial markers with genome-wide SNP datasets resolved four major mitochondrial clades within Cipangopaludina chinensis, whereas nuclear clusters supported only two groups. Divergence time estimation placed these splits in the late Pliocene to early Pleistocene, coinciding with regional climatic shifts. Shell morphology corresponded more closely with nuclear phylogenetic clusters, while mitochondrial lineages were strongly structured by geography. Evidence of introgressive hybridisation further complicates species delimitations and highlights the necessity of integrative approaches to resolve taxonomic boundaries and reconstruct evolutionary histories of freshwater gastropods.

Phylogenetic Diversity of Freshwater Gastropods publication trend

The graph below shows the total number of articles in phylogenetic diversity of freshwater gastropods across all publications each year (not limited to Nature Index journals).

Technical terms

Phylogenomic analysis: Evaluation of evolutionary relationships using genome-scale molecular data, often combining mitochondrial and nuclear markers.

Adaptive radiation: Rapid diversification of a single ancestral lineage into multiple species exploiting different ecological niches.

Introgressive hybridisation: Transfer of genetic material between species through repeated backcrossing of hybrid individuals with parental lineages.

Divergence time estimation: Method to infer the historical timing of lineage splits using molecular clock models and calibration points.

References

1. Enigmatic incongruence between mtDNA and nDNA revealed by multi-locus phylogenomic analyses in freshwater snails. Scientific Reports (2019).
2. Recent lake expansion triggered the adaptive radiation of freshwater snails in the ancient Lake Biwa. Evolution Letters (2019).
3. Diversification in ancient Lake Biwa: integrative taxonomy reveals overlooked species diversity of the Japanese freshwater snail genus Semisulcospira (Mollusca: Semisulcospiridae). Contributions to Zoology (2023).
4. A new genus of river snails, Dalipaludina (Gastropoda, Viviparidae), endemic to the Yunnan Plateau of SW China. Zoosystematics and Evolution (2023).