Clam shrimps

Code OF999999

See Key to Families of Australian Aquatic Crustacea

An order of Crustacea (with segmented, chitin-encased body and articulated appendages). The Conchostraca are placed with the orders Notostraca, Anostraca and Cladocera in the Branchiopoda. Conchostracans have the complete body encased in a hinged, bivalved carapace. The first antennae are one-branched (uniramous), do not protrude from the shell, may be very small; the second antennae are two-branched (biramous) and project from the shell, functioning in movement, grasping the partner in mating, and/or in adhering to a surface.

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

CYZICIDAE (Code OF019999) has no frontal organ and the carapace (which encloses the whole animal) shows more than 10 growth lines with lobed antennules and claws on the first and second pair of trunk appendages. Cyzicus , with some eight species, is known from all mainland states.

LIMNADIIDAE (Code OF029999) has the carapace (which encloses the whole animal) showing growth lines and has a serrated edge, and there is a distinct frontal organ. Species of the three genera Limnadia , Eulimnadia and Limnadopsis are distributed widely in Australia. The endemic genus Limnadopsis is widespread, Limnadia occurs in the southern half of the continent; Eulimnadia in Northern Territory, central and Western Australia.

CYCLESTHERIIDAE (Code OF039999) has no frontal organ and the carapace (which encloses the whole animal) shows few growth lines (less than 10) with simple antennules and claws only on the first pair of trunk appendages. Cyclestheria is represented in Australia by a single non-endemic species C. hislopi , which occurs in Queensland and New South Wales.

LYNCEIDAE (Code OF049999) has no frontal organ and the carapace (which encloses the whole animal) has no growth lines. The two species in the genus Lynceus are recorded from central and eastern Australia.

Reference:

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