Truncatelloidea

Truncatelloidea is a superfamily of marine gastropod mollusks in the subclass Caenogastropoda. It is characterized by its distinctive shell shape, which is typically elongated and tapering towards the apex, giving the name "truncate" or "truncated" to the superfamily. The superfamily includes several families, such as Truncatellidae, which is the type family, and others like Fissurellidae and Terebridae.

The shells of Truncatelloidea are generally smooth, with a spiral sculpture that may include axial ribs or growth lines. The aperture is typically oval or rounded, and the columella is usually simple and not folded. The radula is typically simple, with a single row of teeth.

Truncatelloidea is found in a variety of marine habitats, including rocky shores, coral reefs, and deep-sea environments. They are typically deposit feeders, using their radula to scrape food from the substrate. Some species are also known to be predators, feeding on other small invertebrates.

The taxonomy of Truncatelloidea is complex, with many species and subspecies described over the years. However, recent molecular studies have suggested that the superfamily may be polyphyletic, meaning that it does not form a single evolutionary lineage. As a result, some families may be moved to other superfamilies in the future.

Despite these taxonomic uncertainties, Truncatelloidea remains an important group of marine gastropods, with many species of ecological and economic significance. They are also of interest to paleontologists, as their fossils provide valuable information about the evolution of marine life.