Neritimorpha

Neritimorpha is a major clade within the class Gastropoda, comprising a diverse group of snails that inhabit marine, brackish, and freshwater environments. The name derives from Nerita, a representative genus, and the group is recognized in many modern classifications as a distinct lineage of gastropods. Members of Neritimorpha are typically characterized by a shell that is often operculate (closed by a calcareous lid) and a variety of shell shapes ranging from disk-like to more turreted forms. The soft-body anatomy and radular details vary across lineages, reflecting adaptations to different habitats and feeding strategies.

Ecology and life history in Neritimorpha are diverse. Many species are grazers or detritivores that feed on biofilms, algae, and organic matter on rocks and substrates in intertidal, freshwater, or benthic environments. Some lineages tolerate brackish water or even fluctuate between marine and freshwater conditions. Reproduction and development also show variation; some species display direct development, while others have free-swimming larval stages, contributing to a broad geographic and ecological distribution.

Geographic distribution is cosmopolitan, with representatives found in temperate, tropical, and subtropical regions. Extant neritimorphs are particularly common in intertidal zones, rivers, and lakes, and they occupy a range of ecological niches from rocky shores to submerged wood and sediment.

Taxonomy and evolutionary relationships within Neritimorpha are subject to ongoing study. The group includes extant families such as Neritidae (nerites) and Neritiliidae, along with numerous extinct families known from the fossil record. While the exact phylogenetic placement of Neritimorpha has shifted with new analyses, it is widely treated as a coherent gastropod lineage that has persisted since ancient times and continues to contribute to the diversity of molluscan habitats.