Lamelliconcha vinacea
Similar to Lamelliconcha alternata. Lamelliconcha vinacea has more prominent umbones and a more trigonal shape than L. alternata. In addition, L. vinacea has weaker comarginal ribs of even strength and density throughout its flank; whereas, L. alternata has more rigid comarginal ribs that vary in strength (alternate weak and stronge) and density (alternate widespread and dense). L. alternata also lacks purple coloration on its beaks, which is typically found in L. vinacea.
Similar to Lamelliconcha circinata. Lamelliconcha vinacea is distinguishable by its more prominent umbones, which result in a slightly more trigonal shape. L. vinacea also has less rigid comarginal ribs and a more glossy flank than L. circinata. In addition, L. vinacea typically has purple beaks and purple coloration internally, in its umbonal cavity; this is not found in L. circinata. The two species also have different geographic distributions: L. vinacea is found in the Pacific, and L. circinata is found in the Carribean (Olsson 1961).
The overall shape is trigonal ovate. The anterior, ventral and posterior margins are rounded. The anterior dorsal margin is nearly straight, and the posterior dorsal margin is subconvex. The valves are equal in size and shape (equivalve), and there is no gape when they are closed. Sculpture consists of growth lines and erect comarginal ribs. The width of the interspace between two ribs is equal to the width of one individual rib. There are no ribs on the lunule and escutcheon. The lunule is lightly impressed, defined by a fine, shallow groove and extends 1/4 of the anterior dorsal margin. The umbo is prominent and subanterior, and the beaks also point slightly to the anterior. The escutcheon is lightly raised, defined by a fine, shallow groove and extends half the posterior dorsal margin.
The exterior is white and typically covered with bands of purple, pink, peach and/or brown coloration. The beaks and lunule are typically purple. The interior is white with purple coloration in the umbonal cavity, descending ventrally. There may also be purple coloration along the posterior dorsal margin or coinciding with external purple coloration.
The ligament is external, extends half the posterior dorsal margin and is supported by nymphal ridges. On the left valve, there are three cardinal teeth (2a, 2b, 4b), none of which are bifid. The anterior tooth (2a) is weak and the posterior tooth (2b) is robust; they are joined dorsally, forming an inverted "v" shape. 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: the anterior (3a) and central (1) teeth are not bifid, and the posterior tooth (3b) is bifid. There are also two anterior lateral teeth (A1, A3), as well as a fine weak ridge running parallel to the posterior dorsal margin, on the right valve. The posterior adductor muscle scar is slightly larger and rounder than the anterior. The pallial sinus is deep, directed slightly dorsally, and extends to the middle of the hinge plate in length.
Lamelliconcha vinacea is found in the Pacific Ocean: from Mazatlan in Mexico, to Santa Elena in Ecuador (Olsson 1961).