Chapter 3 North Carolina Species
3.9 Snails 3.9.1 Introduction Snails and slugs are members of the phylum Mollusca and are in the taxonomic class Gastropoda (commonly gastropods). There are about 40,000 snail species identified worldwide, making this the largest group of living mollusks. According to the NatureServe Explorer database there are 225 terrestrial snail species and 58 freshwater snail species occurring in North Carolina (NatureServe 2025) . Gastropods are protected under state law in North Carolina, and the NC Natural Heritage Program collects data on rare gastropod species. Gastropods have a muscular foot used for movement, and in some species, it is modified for swimming or burrowing. Snails respire using a lung (group Pulmonata) or gills (several taxonomic groups) ( Brusca and Brusca 1990; Hickman et al. 2000) . They occupy both wetland and dry landscapes as well as fresh, brackish, and marine waters; however, only freshwater and terrestrial gastropods are addressed in this version of the SWAP. Most snails have a single spirally coiled shell, whereas slugs lack an external shell. Snails also have a mantle that covers internal organs and extends outward to attach to the shell, a well- developed head with eyes and either one or two pairs of tentacles, and a concentration of nervous tissue and cerebral ganglia that forms a primitive brain. Shells may have an operculum, a horny plate that seals the opening when the snail withdraws its body into the shell. Most snails use a radula (a horny, ribbonlike structure found in the mouth) in some aspects of their feeding behavior, which include grazing, browsing, or feeding on plankton. They may also be scavengers or detritivores. Snails found in North Carolina include carnivores that prey on other snails and slugs, such as the Gray-foot Lancetooth and the Rosy Wolfsnail, and herbivores or detritivores, such as the Flamed Tigersnail and Mountain Disc. Most land snails and slugs are hermaphrodites, producing both spermatozoa and ova so individuals have the potential to lay eggs. Some freshwater snails (e.g., Apple Snail) and marine species (e.g., Periwinkles) have separate sexes. 3.9.1.1 Freshwater Snails In the United States, freshwater gastropods are an especially diverse group of invertebrates, and their highest diversity is in the Southeast (Lydeard and Mayden 1995, Brown et al. 1998, Lysne et al. 2008) . An assessment by the American Fisheries Society (AFS) (Johnson et al. 2013) estimates there are 703 native aquatic gastropods from North America (Canada, United States) with the greatest species richness being associated with flowing (lotic) waters (Johnson 2009) . The southeastern United States is recognized as having a high diversity of freshwater gastropods (Lydeard and Mayden 1995; Brown et al. 1998; Lysne et al. 2008) . Many are endemics with very small geographic ranges, often isolated to a single location, watershed, or geographically restricted drainage (Johnson et al. 2013) .
2025 NC Wildlife Action Plan
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