Order

Mytilida

  Class

Bivalvia

  No. of Genera in Ref.

  No. of Species in Ref.

  Environment

Fresh : No | Brackish : No | Marine : Yes

  Aquarium

  First Fossil Record

     

  Remark

Author from Ref. 3477. Shell equivalve and very inequilateral, generally elongate-ovate, subtrigonal or cylindrical, often with a narrow byssal gape at ventral margin. Umbones prosogyrate, at or near anterior end of shell. Outside quite smooth or radially ribbed; sculpture often stronger on posterodorsal and anterior areas, reduced on ventral median area. Periostracum usually prominent, smooth, lamellate or hairy. Ligament external, often deep-set along posterior dorsal margin, supported by a calcified whitish ridge which may be compact or finely pitted. Hinge teeth absent or reduced; small marginal crenulations sometimes present behind and/or along the ligament. Adductor muscle scars unequal, the anterior one small to sometimes absent in the adult; posterior adductor scar large, often more or less confluent with pedal or byssal retractor scars. Pallial line without a sinus. Inner side of shell with an extensive nacreous layer. Internal margins smooth or crenulated. Gills of fillibranchiate type, branchial sheets smooth and often rather unequal. Foot elongated and grooved, with a well-developed byssus. Siphons short to absent. Mantle with special glands in boring forms. Sedentary animals, mainly attached to hard substrates by their well-developed byssus, sometimes nestlers, coral and rock borers, or associated with ascidians. Many species of this family are collected in the area for human consumption, food for animals, or as baits. Some mytilids represent nowadays major commercial species and aquaculture has strongly developed in many regions to keep up with increasing demand (Ref. 348).

  Etymology

  Division

  Reproductive guild

  Typical activity level

  Main Ref.

  Coordinator