Oncaea praeclara n. sp. (Copepoda: Poecilostomatoida) from deep-sea hydrothermal vents in the eastern Pacific

A new species of planktonic copepod, Oncaea praeclara, is describedfrom a depth of 2003–2635 m at the East Pacific Rise,the Galapagos Rift, and the Guaymas Basin in the Gulf of California.The species may be recognized by a combination of characters:its relatively large size; the long caudal ramus, which is abouttwo times longer than the anal segment and has a ratio of 4.96–6.7:1;the sexual dimorphism in the armature of the fourth segmentof the second antenna; and the labrum with a nearly straightposteroventral margin having four median teeth and lateral setules.