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CRUSTACEANS

Marjorie L. Reaka-Kudla The University of Maryland

I. Summary and Definition of Biodiversity in Crustacea

11. The Setting 111. Biodiversity of Fossil and Modem Crustacea

GLOSSARY

antennules, antennae (pl.) Anntennules are the first pair of sensory appendages on the head, and anten- nae are the second pair of sensory appendages on the head of crustaceans.

benthic, epibenthic Living at the bottom of the sea; epi = upon, thus epibenthic organisms live on top of sediment or hard substratum.

brackish Less salty than sea water. chelate, subchelate, chela (s.), chelae (pl.) Chelate

means having a pincher-like claw (usually due to an extension of the second from terminal segment be- side the terminal segment, forming the claw). In subchelate forms, the terminal segment merely folds back on the second from terminal segment. The chela is the clawlike appendage.

commensal, symbiotic Living in association with (e.g., on or in) another organism.

crepuscular Active in dim light conditions, such as dusk or dawn.

dorsal, ventral Dorsal part of the organism is the "back," on the opposite side of the body from the

mouth; ventral is the same side of the body as the mouth and legs for a crustacean.

extant Living. furca (s.), furcae (pl.) Forked structure, usually associ-

ated with the telson in crustaceans. gonochoristic Individual is either a male or a female

throughout life. hypersaline More salty than seawater. interstitial Living among sand or silt grains; usually

refers to an aquatic benthic environment, the inter- tidal, or in groundwater.

invertebrates Animals (usually used in reference to phyla or major taxa) that lack backbones.

macrobiota Organisms large enough to see, usually greater than 1 mm.

median, medial Along or toward the midline of the body.

phyllopod A leaflike appendage. pleopod Abdominal appendage in crustaceans. polyphyletic A group of species or lineages that have

independent origins instead of being descended from a common ancestral group.

protogynous, protandrous Different types of her- maphroditism (in contrast to gonochoristic). Indi- viduals in protogynous species develop into a repro- ductive female early in life, then change sex and become a reproductive male later in life. Individuals in protandrous species are functional males first, then females.

rami (pl.) A cuticular extension (usually relatively long and thin, can be leaflike) from the body (e.g., caudal

Encyclopedia of Biodiversity, Volume 1 Copyright D 2001 by Academic Press. All rights of reproduction in any form reserved.