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Southwest Florida Shells with Emphasis on Sanibel & Captiva

By José H. Leal

Family Nassariidae

Phrontis vibex

(Say, 1822)

Bruised Nassa

Shell size to 15 mm; size small, stubby, thick-walled, with about five-seven shouldered whorls. Spire moderately elevated. Sculpture of 7-12 axial ribs crossed by cordlets of variable size. Color white or light tan, variably mottled with darker tones. This is a very variable species, common in the back bays and mud flats of SW Florida. Individuals in this species are active scavengers, feeding on decaying bodies of invertebrates, fish, and other marine animals. The first supplementary image shows several Bruised Nassa feeding on a small, dead horseshoe crab at low tide on Bunche Beach, Fort Myers, Florida, in 2014. Bruised Nassa are voracious scavengers, capable of detecting the carcasses of dead marine animals from long distances and moving at relatively high speeds to approach and feed on them. The second supplementary image, a live Bruised Nassa gliding on the glass of one of the Museum aquariums, in February 2020. The snail’s eyes are located near the bases of each tentacle, the siphon is extended to “smell” the ambient water, and the short, orangish snout is probing the glass for morsels of food. The back of the snail’s large foot (on the right) bears a couple of small epipodial tentacles, which apparently have a sensorial function, alerting the snail of approaching predators. All photos by José H. Leal