Character phylogenies in Candacia and Paracandacia (Copepoda, Calanoida) and the inevitably paraphyletic nature of many nominal taxa above subspecies level

Abstract

Examination of the phylogenetic structure of the family Candaciidae shows the genus Paracandacia to comprise a strongly modified branch emerging from the clade commonly denoted as Candacia. This has been confirmed by studying selected character phylogenies. It is argued that the resulting paraphyletic nature of Candacia auct., though in a cladistic context undesirable on theoretical grounds, has to be accepted as inevitable. Recent studies on molluscs and arthropods, viz., have demonstrated that the continuous origin of paraphyletic taxa from previously monophyletic ones is nothing but a naturally occurring process, intrinsically embodied in the course of evolution.