Development and predation in a calanoid copepod <i>Tortanus forcipatus</i> (Giesbrecht)

Abstract

Larval stages of <i>T. forcipatus</i> have been described in detail. Six naupliar stages and 5 copepodid stages precede the adult stage. Nauplii of this species can be easily differentiated from naupliar stages of other copepods by the presence of large and broad labrum with indented posterior margin, stout hooks on the gnathobase of the mandibles and by the arrangement of spines of the caudal armature. Copepodid stages follow the general pattern of calanoid development. Reddish-brown pigment is present at the base of their antennae in living specimens. Caudal rami are asymmetrical from the 4th copepodid stage onwards and are distinct in the adults. This asymmetry seems to be closely associated with sexual maturation. Copepodid stages are active, carnivorous and show predatory habits. Predation of adults of <i>T. forcipatus</i> on juveniles of chaetognath, <i>Sagita bedoti</i> has been studied.