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 Major Groups | Bivalvia (mussels)

Bivalvia (mussels)

Descriptive Features:

  • shell consists of 2 separate valves, joined dorsally by a flexible ligament or 1 or more adductor muscles
  • shape and colour variable
  • concentric growth rings present, laid down around the beak, shell and beak sculptured with nodules, ridges or folds, lined internally with nacre
  • body mass enclosed in shell, without defined head but including
  • 2 posterior siphons, ventral inhalent and dorsal exhalent
  • 2 lateral pairs of gills, ciliated, long, flat, perforated
  • muscular foot, protrusible anteroventrally
  • mouth deep in body mass, anteriorly
  • Total length: 5 mm – 20 cm
  • Taxonomic Checklist: Orders
    (families from Cardiida and Pholadida were formerly in Veneroida)

    Distribution: Australia wide

    Sensitivity Rating: SIGNAL grade 3

    AUSRIVAS Taxacode: none

    Functional Feeding Group: filtering collectors

    Ecology: Mussels occur in shallow unpolluted fresh and estuarine, permanent and temporary waters including, streams, creeks, lakes, waterholes, ponds and stream backwaters. They are found in stable silt, sand and mud. In large numbers, Bivalvia especially Corbiculidae can become pests in reticulation systems of towns and irrigation pipes. Mussels are generally dispersed by flood or piped waters, but they can also be carried on aquatic birds and insects. Parasitic larvae are dispersed by fish hosts.
    In Hyriidae and Corbiculidae species the sexes are separate but in Sphaeriidae species the individuals are hermaphrodites and self fertilize. Hyriidae and Corbiculidae species utilise external fertilization where sperm are released into water to enter the female, by way of the inhalent siphon, to the gills where unfertilised eggs are held. Eggs develop in pouches (marsupia) in the ctenidia into glochidium larvae (less than one millimetre). Corbiculidae glochidia continue to develop within the adult to be released as fully formed individuals. Hyriidae glochidia hatch, at the larval stage, into the water to become obligatory parasites on fish or large crustaceans. Encystment by fish and crustacean tissues may last from several days to months. Juveniles leave the host almost fully developed. Final stages of development to adult form takes place burrowed within the substratum.
    Mussels use their gills for filter feeding as well as respiration. They feed on zooplankton, phytoplankton, and organic detritus. Food is trapped in mucous then passed by ciliated bands to the mouth. Bivalvia move by expansions and contractions of the foot extended between the shell valves. At maximum expansion the foot swells distally so that next lengthwise contraction pulls the whole animal forward. Mussels can withstand long periods of desiccation.




    Corbicula australis 


    Information Sources: Smith 1996, Bouchet et al. 2010, Smith & Kershaw 1979, Williams 1980 
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