Clam shrimps

Code OF029999

A family of the Conchostraca (clam shrimps). Conchostraca are placed along with the orders Notostraca, Anostraca and Cladocera in the class Branchiopoda, a name which refers to the foliose trunk appendages which function as gills. In Conchostraca the body is completely encased in a hinged, bivalved carapace. The antennules are one-branched (uniramous), often only one-segmented, and do not protrude from the carapace. The antennae are two-branched (biramous), project, and functioning in movement, grasping, and/or adhering to a surface. There are 10-many trunk appendages, most or all of which are flattened and function as gills. In males the first one-two pairs of trunk appendages carry claspers which are used in mating.

Conchostracans are important members of the temporary pool community but some occur in the littoral zone of larger bodies of water. Most species have drought resistant eggs. The Australian fauna comprises the families Cyzicidae, Limnadiidae, Cyclestheriidae and Lynceidae.

LIMNADIIDAE: The antennules are 2-segmented and the head carries an unpaired, often pedunculate frontal organ of uncertain function. The carapace displays a moderate number of growth lines (approximately 10) and where these lines meet the dorsal hinge they produce a serrated edge (sometimes very minor) and a pointed posterior corner. A furca is present.

Species of three genera Limnadia, Eulimnadia and Limnadopsis,are distributed widely in Australia. The endemic genus Limnadopsisis widespread, Limnadiaoccurs in the southern half of the continent; Eulimnadiain the Northern Territory, central and Western Australia.

Reference:

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