Code OJ999999

See

A subclass of the order Crustacea (invertebrates with segmented, chitin-encased body and articulated appendages). Copepods have a well-defined head with a central eye. The head is fused with anterior thoracic segments to give a cephalothorax. Head appendages comprise elongate antennules, small antennae, mandibles, maxillules and maxillae. Abdominal segments usually are without appendages, except the causal (terminal) segment that bears two caudal rami ('tails').

They are widespread typical planktonic organisms. Eggs hatch to give larvae (nauplii) which attain mature forms through a fixed series of moults. Some species have desiccation-resistant eggs. Copepods are important items in the diet of many freshwater fish.

The orders (or superfamilies) Cyclopoida, Calanoida, Harpacicoida which occur in Australia are:

CYCLOPOIDA: CYCLOPIDAE (Code OJ319999) , recognised by the body shape - which is widest behind the head, tapering to the urosome - and the first antenna which comprises up to 18 segments. The taxonomy is confused by inappropriate and uncritical use of northern hemisphere names for endemic taxa (Bayley, 1992 in Shiel, 1995).

CALANOIDA comprising the families: CENTROPAGIDAE (Code OJ119999) and DIAPTOMIDAE (Code OJ129999) recognised by the body shape - which is torpedo-like - and the first antenna which comprises over 20 segments. The DIAPTOMIDAE (Code OJ129999) comprises two species of Diaptomus which are confined to northern Australia. In contrast, the Centropagidae are common in south-eastern Australia (Bayley, 1992 in Shiel, 1995).

HARPACICOIDA including families CANTHOCAMPTIDAE (Code OJ699999) and PARASTENOCARIDIDAE uncoded - the harpacticoid copepods - crustaceans lacking a carapace and in which the antennules do not reach beyond the metasome: the urosome subequal to the metasome, the major body articulation between thoracic segments 5 and 6, with the 1st and 2nd thoracic segments incorporated into the cephalothorax. Poorly known taxonomically. Found predominantly in saline inland waters, with some taxa subterranean.

References:

Bayley, I.A.E. (1992) The non-marine Centropagidae (Copepoda: Calanoida) of the world. Guides to the Identification of the Microinvertebrates of the Continental Waters of the World . 1 : 1-43. SPB Academic Publishers, The Hague.

Shiel, R.J. (1995) A Guide to Identification of Rotifers, Cladocerans and Copepods from Australian Inland Waters . Co-operative Research Centre for Freshwater Ecology Identification Guide No. 3., Albury, NSW.

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