Fairy shrimps, brine shrimps

Code OD999999

See Key to Families of Australian Aquatic Crustacea

An order of Crustacea (with segmented, chitin-encased body and articulated appendages). The Anostraca are placed with the orders Conchostraca, Notostraca and Cladocera in the Branchiopoda. In the Anostraca the carapace is absent and the elongate body is visibly segmented. The head is distinct from the trunk, and bears prominent stalked compound eyes and unsegmented and single-branched (uniramous) first antennae which project forward from the body, and in some species are fused at their bases. The second antennae of females are also unsegmented and single-branched, those of the male are double-jointed for grasping the female in mating. The thorax consists of 11 leg-bearing segments: the legs are two-branched (biramous), and setose. The abdomen has eight segments and a terminal telson, bearing a furca (pair of cercopods).

Fairy shrimps are active, almost always swimming with the ventral surface uppermost, paddling with the thoracic appendages. Suspension feeding anostracans filter fine food items from the water using the setae on the legs. Others scrape food from surfaces with the leg setae, and one species predates on other anostracans.

The Australian fauna comprises three families:

ARTEMIIDAE (Code OD019999) is represented in Australia by one species, Artemia salina , which is cosmopolitan in inland saline waters especially salt pans, and may be introduced. The family Artemiidae is distinguished by the telson being reduced and indistinct from the final abdominal segment, and the male lacking a frontal appendage, having a penes with a rigid base and lacking apical spines. The female has no spines on the labrum.

BRANCHIPODIDAE (Code OD029999) is represented by the single genus Brachinella comprising some twenty species occuring in fresh to slightly saline waters. The family Branchipodidae is distinguished from other Anostracans by the telson being well developed and distinct from the final abdominal segment, and the male having a frontal appendage and a flaccid penes.

THAMNOCEPHALIDAE (Code OD039999) comprises the endemic Australian genus Parartemia , with some eight species occurring in saline inland waters. The family Thamnocephalidae is distinguished from other Anostracans by the telson being reduced and indistinct from the final abdominal segment, and the male lacking a frontal appendage, having a penes with a rigid base and apical spines. The female has spines on the labrum.

Reference:

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