An appraisal of the taxonomic position of<i>Enhydrosoma buchholzi</i>(Boeck, 1872),<i>E. bifurcarostratum</i>Shen &amp; Tai, 1965,<i>E. barnishi</i>Wells, 1967 and<i>E. vervoorti</i>Fiers, 1987 with definition of two new genera (Copepoda, Harpacticoida, Cletodidae)

Abstract

Abstract Some morphological features of Enhydrosoma buchholzi (Boeck, 1872), E. barnishi Wells, 1967 and E. vervoorti Fiers, 1987 are redescribed in detail.lt is shown that, in the structure of the antenna, maxillule and the form of sexual dimorphism on the P3 endopod, these species, along with E. bifilrcarostratum Shen & Tai, 1965 and a new species from Thailand have greater affinities with the genus Cletodes Brady, 1872 than with Enhydrosoma Boeck, 1872 . However, they cannot be included in the genus Cletodes because they display a more primitive setal formula on P3 and P4 exopod and apomorphic character states on the antennary endopod and P5 of both sexes. Consequently, E. buchholzi from north-west Europe (and Canada) is assigned to the genus Strongylacron gen. nov. and becomes the type species by monotypy. The other four species from the Indian Ocean and South China Sea can be clearly distinguished from Strangylacron by the structure of the rostrum. They are assigned to the genus Schizacron gen. nov. as S. barnishi (Wells, 1967) comb. nov., designated as the type species, S. bifilrcarostratus (Shen & Tai, 1965) comb. nov., S. vervoorti (Fiers, 1987) comb. nov. and S. intermedius sp. nov. A key to species of Schizacron is provided.