Gastropods include the snails, slugs, and limpets which inhabit marine, freshwater, and terrestrial environments. They have a variety of feeding modes including detritivores, herbivores, predators, and being parasitic. Gastropods have existed since the Cambrian Period (+500 million years ago) and those with shells preserve exceptionally well in the fossil record.
J. R. Hendricks. 2018. Gastropoda. In: The Digital Encyclopedia of Ancient Life.