Development of Leg 5 of Copepods Belonging to the Calanoid Superfamily Centropagoidea (Crustacea)

Leg 5 development is described for 10 species from 10 genera in 6 families of centropagoidean calanoid copepods. Segment homologies are inferred from the order in which arthrodial membranes, setae, and attenuations are added to ramal segments during late copepodid development. Among centropagoidean males, the grasping chela on the side opposite the male genital pore develops in three different ways. The fixed part of the chela may be a ventral attenuation of the basis, or of the proximal exopodal segment, or of the middle exopodal segment, suggesting that a male leg 5 chela is not a synapomorphy of the Centropagoidea because nonhomologous segments make up the convergent morphology. In like manner, a grasping subchela on the side opposite the male genital pore is expressed in three different ways: basis plus proximal, middle and distal exopodal segments; basis plus proximal and distal exopodal segments; or basis plus distal exopodal segment; so nonhomologous segments also result in a convergent su...