Lioconcha castrensis (Linnaeus, 1758)
- Biogeographic Region: Japan; Indian Ocean and Indo Pacific
- Feeding Strategy: Suspension feeder
- Life Habit: Burrower (shallow)
Similar to Lioconcha fastigiata. Lioconcha castrensis is distinguishable by its truncated posterior margin and its less elongate, more circular shape.
Similar to Lioconcha hieroglyphica. Lioconcha castrensis is taller and less elongate in shape; it also typically has larger tent marks on its exterior than L. hieroglyphica.
Similar to Lioconcha ornata. Lioconcha castrensis has a more truncated posterior margin than L. ornata.
Similar to Lioconcha trimaculata. Lioconcha castrensis is distinguishable by its more inflated valves and umbones.
The overall shape is trigonal ovate. The posterior margin is subtruncated, and the ventral and anterior margins are rounded. The valves are equal in size and shape (equivalve), and there is no gape when they are closed. The valves are thick-walled and highly inflated. Sculpture consists of growth lines and very fine wrinkled ridges at the anterior and posterior areas of the flank. The lunule is heart shaped, not impressed and defined by a fine shallow groove; it extends half the anterior dorsal margin. The commissural margin is raised at the center of the lunule, rising slightly above the shell flank. The umbo is slightly anterior and the beaks also point slightly to the anterior. The escutcheon is not well defined.
The exterior is white or light tan; other coloration and patterns highly vary. Typically, there are light or dark brown mountain-like patterns, that may be fine or thick, on the surface of the flank. The pattern may be continuous or broken. The interior is white.
The ligament is external, extends 1/3 to half of the posterior dorsal margin and is supported by nymphal ridges. The hinge plate, like the rest of the shell, is robust. On the left valve, there are three cardinal teeth (2a, 2b, 4b), none of which are bifid. The posterior tooth (4b) is fused with the nymph. There is also one anterior lateral tooth (A2) on the left valve. On the right valve, there are three cardinal teeth (3a, 1, 3b), none of which are bifid. There are also two anterior lateral teeth (A1, A3) on the right valve. A very fine ridge runs parallel to the posterior dorsal margin on both the left and right valves. The posterior adductor muscle scar is slightly larger and rounder than the anterior adductor muscle scar. The pallial sinus is absent.
- Lioconcha lorenziana (Dillwyn, 1817) (synonym (subjective = heterotypic))