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Family Lucinidae Lucinas
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The Lucinidae is a member of the subclass Heterodonta, so named because of the structure of the hinge teeth. In general, there are one or two cardinal teeth immediately below the umbo, and zero, one, or two lateral teeth either side of the cardinal teeth The exact configuration of the teeth varies from species to species; in some cases the hinge is degenerate, with no hinge teeth at all. The Lucinidae is a family of about 400 species which occur worldwide in tropical and temperate waters. In NSW there are 14 species known, some of which intrude into the north of the state from the tropics and some of which have a southern Australian distribution. Lucinids live in sandy or muddy environments, shallowly or deeply buried within the intertidal zone; some species occur commonly in seagrass beds, such as in Gunnamatta Bay in Port Hacking. Other species live in the shallow subtidal from which they may be washed up on harbour or open ocean beaches. Further species live in deeper water and are only obtained by dredging - one species, Lucanoma euclia, is known down to 860 m, and consequently is rarely seen. Lucinids have many unusual anatomical features when compared with other bivalves, one of the most unusual being their symbiosis with bacteria acquired from the environment leading to a dependency on bacteria for food (although they can extract plankton as other filter-feeding bivalves do). The bacteria provide energy to the mollusc by oxidising sulphides from the substrate. This allows these molluscs to live in low oxygen and sulphide-rich muddy environments such as mangrove mud or deeply buried in seagrass beds. Additional Species Lucina quadrata Angas, 1877 is a minute 3 mm long species from Shark Island, Sydney Harbour. It is known only from the holotype. The name is preoccupied, so it has been renamed as Epicodakia boamilliensis Pacaud, Coppini, Buisson & F. Meunier, 2024. Bathycorbis despecta (Hedley, 1904). This is a rare, deep water species of which the Australian Museum holds only four specimens. Originally placed in Lucinidae, Taylor & Glover (2021) tentatively placed it in the family Astartidae Family Reference Taylor, J.D. & Glover, E.A. 2021. Biology, evolution and generic review of the chemosymbiotic bivalve family Lucinidae. Ray Society Monograph 182, 318 pp. Coverage All NSW species are detailed here, except for the two species given in Additional Species above. Identification Notes Lucinids in NSW are roughly circular with protruding umbones and vary in size from 7 mm up to 65 mm in width. Their colour is uniformly white. There is a variety of exterior sculptural patterns, based on commarginal ridges and radial ribs or grooves. The following characters assist in the identification of species: Shape: Circular or oval. Position of umbo: Central or displaced posteriorly. Muscle scars: There are two muscle scars, the posterior being roughly circular or ovate, and the anterior more or less elongate. The pallial line is always continuous in NSW species. The length of the anterior muscle scar varies with the species - see Lucinola euclia for an example of a long anterior muscle scar and a continuous pallial line. Exterior sculpture: Commarginal sculpture and strong radial sculpture
Commarginal sculpture with radial sculpture absent, or very faint, or restricted to interspaces but not crossing the concentric sculpture.
Two directional sculpture
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