Neogastropoda

Lore & Background

The name Neogastropoda—literally 'new gastropods'—reflects Ponder & Lindberg's (1997) intent to separate the radularly distinct predatory caenogastropods from the more ancestrally structured Vetigastropoda. The split rests on serial gill homology, the number and arrangement of radular teeth, and the presence or absence of a functional osphradium. In practice, the boundary is clean: a Neogastropod radula typically carries a single, often enlarged, central tooth with one or more laterals on each side, whereas Vetigastropods show a broader, more symmetric tooth row.

Diversity within the infraorder is staggering. Muricidae alone accounts for over 1,500 described species, many with the spiny, turreted shells that gave the group its old common name 'murex.' Conidae, the cone snails, number roughly 850 species and include the only marine gastropods whose venom is lethal to humans. Buccinidae (whelks) and Turbinidae (top shells) dominate temperate and tropical shorelines respectively, while the smaller Oliviidae, Cancellariidae, and Costellariidae form a mosaic of sand-burrowing and algae-grazing specialists that blur the strict carnivorous stereotype.

Fossil neogastropods are abundant from the Eocene onward, and their shells—often thick, heavily calcified, and sculpturally complex—serve as important biostratigraphic markers in marine sedimentary sequences. The infraorder's ecological dominance as benthic predators means that shifts in neogastropod assemblages are early indicators of reef degradation, eutrophication, and ocean acidification.

Reader's Guide

Key to major Neogastropoda families in the field:

Muricidae (R. P. Lesson, 1831) – Shell strongly spined or costate; aperture with an external siphonal canal; operculum calcareous, paucispiral. Distinguish from Buccinidae by the pronounced spination and the siphonal canal's length exceeding the aperture width.

Conidae (R. P. Lesson, 1831) – Shell conical, smooth to weakly costate; aperture narrow, with a short, straight siphonal canal; radula bears a single modified harpoon-like central tooth. Distinguish from Oliviidae by the harpoon tooth and the typically more elongate, less inflated whorls.

Buccinidae (R. P. Lesson, 1831) – Shell inflated, aperture broad with a well-developed siphonal canal; operculum calcareous, multispiral. Distinguish from Turbinidae by the open, elongate aperture versus Turbinidae's round, 'top-shell' aperture and the presence of a distinct outer lip callus.

Turbinidae (R. P. Lesson, 1831) – Shell globose to turbiniform; aperture round, without a true siphonal canal; outer lip thin, often with a nacreous reflection. Distinguish from Buccinidae by the absence of a siphonal canal and the more equant, top-like shell profile.

Oliviidae (R. P. Lesson, 1831) – Shell elongate-conic, aperture narrow with a short, straight canal; radula with a single central tooth and one lateral each side. Distinguish from Conidae by the absence of the harpoon tooth and the typically more slender, less robust shell.