Meretrix meretrix
Original description, by Linnaeus (1758, p. 686):
"V. testa cordata glabra, vulva fusca gibba, nymphis hiantibus.
Argenv. conch. t. 24. f. F.
Habitat in O. Indico."
Original description, by Linnaeus (1758, p. 686):
"V. testa cordata glabra, vulva fusca gibba, nymphis hiantibus.
Argenv. conch. t. 24. f. F.
Habitat in O. Indico."
Similar to Meretrix casta. Meretrix meretrix can be distinguished by its slightly more pointed posterior margin and less inflated umbo.
Similar to Meretrix lusoria. Meretrix meretrix is distinguishable by its robust valves, hinge plates and teeth, as well as its rounder shape. M. lusoria is lighter weight and has an elongate posterior margin.
Similar to Meretrix ovum. Meretrix meretrix is distinguishable by its trigonal shape and stronger umbones.
Similar to Meretrix petechialis. Meretrix meretrix is distinguishable by its highly robust valves, hinge plates and teeth.
The overall shape is trigonal ovate. The posterior margin is slightly more pointed than the anterior. The anterior dorsal margin is nearly straight, and the posterior dorsal margin is slightly convex. The valves are equal in size and shape (equivalve), and there is no gape when they are closed. Sculpture consists of growth lines only. The lunule is lightly impressed, defined by a fine shallow groove and extends 3/4 of the anterior dorsal margin. The umbo is slightly anterior, and the beaks point either to each other or slightly anteriorly. The escutcheon is lightly impressed, but otherwise not well defined.
The exterior color is white. There may be light purple or pink pigmentation along comarginal and/or radial lines. There may also be brown blotches of pigment. Sometimes dense light and dark brown comarginal and/or radial stripes cover the flank. The escutcheon is typically a darker color than the rest of the flank. The periostracum is dirty gray. The interior is white and may have a purple ray of pigment along the posterior dorsal margin.
The ligament is external, extends 1/3 to half the posterior dorsal margin and is supported by nymphal ridges. The hinge plate is robust. On the left valve, there are three cardinal teeth. The anterior tooth (2a) is lightly bifid, the central tooth (2b) is not bifid, and the posterior tooth (4b) is fused with the nymph. There are very fine vertical crenulations in the shallow groove between the nymph and the appressed tooth. 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. The nymph has fine vertical crenulations on its ventral side. There are also two anterior lateral teeth (A1, A3), and a fine ridge that runs along the posterior dorsal margin on the right valve. The posterior adductor muscle scar is rounder than the anterior. The pallial sinus is shallow.