Bullacta exarata

Bullacta exarata, common name the Korean mud snail, is a species of a sea snail or bubble snail, a marine gastropod mollusc in the family Haminoeidae, the bubble snails. Bullacta exarata is a commercially important mollusc which is used as a food item in eastern China. Bullacta exarata is the only species in the genus Bullacta. cf. Bullacta is the type genus of the family Bullactidae Thiele, 1926, as shown in the taxonomy of the Gastropoda by Bouchet & Rocroi (2005). Based on phylogenetic genetic analysis by Malaquias (2010), Bullacta exarata should be placed in the family Haminoeidae. Bullacta exarata is endemic to coastlines of the South and East China Seas from Hainan to the Bohai Sea in north-eastern China, the western coast and south coast of Korea and Japan.An ecotype of this snail introduced from further south has become invasive in Laizhou Bay, with population densities of over 160 snails per square meter. The shell is bullate, fairly thick, white, spirally striate, with a well-developed periostracum. There is no spire and no umbilicus. The columella is smooth and simple. The aperture extends for the whole length of the shell, and is narrower above than below. The apertural lip extends upwards beyond the apex of the shell. The height of the shell is 8 mm and the width of the shell is 6 mm.