Provanna
Provanna is a genus of sea snails, marine gastropod mollusks in the family Provannidae. The species was named after Dall's first wife. This is a very old genus with species already existing in Cretaceous seep deposits off Japan (93 - 100 million years ago). The Caribbean and the Pacific fauna were isolated about 3 million years ago by the closure of the Central American Isthmus. Description. The apical whorls of the protoconch are lacking through decollation. The opening is then sealed with a calcareous plug. The sculpture of the ovate fusiform shell shows scattered sigmoidal axial ribs that are  crossed by spiral cords. The whorls are broad. Habitat. They are common in hydrothermal vents, hydrocarbon cold seeps and (more rarely) on deep-water food-falls, depending on the species. Most species feed on filamentous bacteria, while others feed on detritus. Species. Species within the genus "Provanna" include: Several fossil species have been described, predominantly identified from hydrocarbon seep deposits (Saether et al., 2010), including: There also are several fossil species known, but not formally described and named, from Central America, Japan, and possibly the Philippines (see Saether et al., 2010).