Mussel shrimps, seed shrimps

Code OH999999

See Key to Families of Australian Aquatic Crustacea

The Ostracoda form a subclass (or class) of the order Crustacea (invertebrates with segmented, chitin-encased body and articulated appendages). Ostracoda have a bivalved carapace, like a clam-shell, that completely encloses all the remaining body. The body lacks obvious segments and bears a reduced number (5-7 pairs) of appendages compared to other Crustacea. The first and second antennae are well developed, readily visible and protruding beyond the shell. Ostracods resemble conchostracans, but are usually much smaller.

Ostracods fill most aquatic feeding types: from detritivores through filter feeding to carnivory. Many are benthic, some are planktonic. Ostracods can be intermediate hosts for parasitic isopods, copepods and nematodes.

Three superfamilies are recognised:

CYTHERACEA comprising the families LIMNOCYTHERIDAE (Code OH019999) , ENTOCYTHERIDAE (Code OH029999) , LEPTOCYTHERIDAE (Code OH109999) , CYTHEROMATIDAE (Code OH039999) and CYTHERIDEIDAE (Code OH049999) . The superfamily Cytheracea is recognised by the similarity of the last three limbs. Cytheridaceans brood their eggs, and sometimes the young (nauplius). Enterocytheridae, with six endemic genera and 24 species, are unusual ostracods in being commensal on several genera of Australian crayfish.

DARWINULACEA comprising the family DARWINULIDAE (Code OH059999) , recognised by the posterior three limbs being similar. The antennula with six segments and bearing short bristles, and with the carapace valves completely smooth. The superfamily, and family, is represented by the single genus Darwinula , which brood their eggs, and sometimes the young (nauplius).

CYPRIDACEA comprising the families: ILYOCYPRIDIDAE (Code OH069999) , CANDONIDAE (Code OH079999) , CYPRIDIDAE (Code OH089999) , CYPRIDOPSIDAE (Code OH099999) and NOTODROMIDAE (Code OH119999) . The superfamily Cypridacea is recognised by the dissimilarity of the last three limbs. Cypridaceans may produce resistant eggs, with development is delayed after egg deposition - there is no brood care.

Reference:

Williams, W.D. (1980) Australian Freshwater Life: The Invertebrates of Australian Inland Waters. The Macmillan Company of Australia, Melbourne.