Abstract
Due to the recent increasing importance of microcharacters in copepod taxonomy, it has become evident that many species lacking detailed descriptions actually constitute to a species complex. In this study, Nitocraaffinis is redescribed based on lectotype material from Lake Timsah (Egypt) which facilitated a thorough detailed comparison with specimens of N.affinis recorded from distantly related localities. The results unequivocally revealed that the specimens of N.affinis examined in this study belong to a different species. As a result, four new species, Nitocrasonmezisp. nov. and Nitocraserdarsakisp. nov. from the Turkish coast, Nitocraalperisp. nov. from the Indian Ocean, and Nitocraloweaesp. nov. from Brighton, England are herein described as new to science. On the other hand, all subspecies of N.affinis, namely N.affinisrijekana Petkovski, 1954, N.affiniscalifornica Lang, 1965, N.affinisstygia, Por. 1968, and N.affiniscolombiensis Fuentes-Reinés & Suárez-Morales, 2014 are elevated to species rank. An updated key the species of the affinis group is also provided.