Floridobia is a genus of very small freshwater snails (and one species found in brackish coastal marshes) that have an operculum, in the family Hydrobiidae, the mud snails.
Floridobia siltsnails are dioecious (having separate male and female individuals). Females are usually much larger and more numerous than males. They are believed to have a life-span of about one year. In the relatively warm waters of Florida springs, reproduction occurs year-round. The snails feed on microbial organisms and detritus attached to surfaces. Floridobia species tolerate low dissolved oxygen levels found near spring vents, which helps protect then from most fish predators.
A study of F. floridana reported that the increased presence of cyanobacteria in its diet slowed its growth. Cyanobacteria blooms are becoming more common in Florida springs due to excess nitrogen entering the groundwater feeding springs, thus threatening the survival of siltsnails.
Species of Floridobia were classified in the genus Cincinnatia prior to 2002, based on the structure of the penis. Thompson and Hershler erected the new genus of Floridobia in 2002, moving 15 species from Cincinnatia, based on the structure of the penis and the female genitalia. A study of mitochondrial DNA in nymphophiline snails published in 2003 found that Floridobia formed a monophyletic clade, with F. winkleyi as a sister to the Florida Floridobia species.
Species Most of the known species in the genus are endemic to a single spring, a set of springs, or a spring run, in Florida. Species within the genus Floridobia include:
SpeciesCommon nameRangeFloridobia alexander (F. G. Thompson 2000)Alexander siltsnailAlexander Springs, FloridaFloridobia floridana (Frauenfeld 1863)hyacinth siltsnailNorthern peninsular Florida, Cumberland Island, GeorgiaFloridobia fraterna (Thompson, 1968) creek siltsnailSt Johns River drainage, FloridaFloridobia helicogyra (Thompson, 1968) Crystal siltsnailHunter Spring, FloridaFloridobia leptospira (F. G. Thompson 2000)flatwood siltsnail, Glen Branch siltsnailGlen Branch, Lake County, FloridaFloridobia mica (Thompson, 1968) Ichetucknee siltsnail, Coffee Spring siltsnailCoffee Spring, Ichetucknee Springs State Park, FloridaFloridobia monroensis (Dall, 1885) Enterprise siltsnailBenson's Mineral Spring, in Enterprise, FloridaFloridobia parva (Thompson, 1968) pygmy siltsnailBlue Spring, FloridaFloridobia petrifons (Thompson, 1968)Rock Springs siltsnailRock Springs, FloridaFloridobia ponderosa (Thompson, 1968) ponderous siltsnailPalm Spring, Sanlando Springs, FloridaFloridobia porterae (F. G. Thompson, 2000) Green Cove springsnailGreen Cove Springs, FloridaFloridobia vanhyningi (Vanatta, 1934) Seminole siltsnailSeminole Springs, FloridaFloridobia wekiwae (Thompson, 1968) Wekiwa siltsnailWekiwa Springs, FloridaFloridobia winkleyi(Pilsbry, 1912)New England siltsnailCoastal (brackish) marshs of Connecticut, Maine, and Massachusetts;Hudson River, New York
Two possible new Floridobia species have been identified, but have not been published and accepted as of 2023. Floridobia species A has been reported from the Ogeechee River in Georgia. The Waccamaw Floridobia has been reported from Lake Waccamaw, North Carolina.
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