COPEPODA (POECILOSTOMATOIDA AND SIPHONOSTOMATOIDA) FROM DEEP-SEA HYDROTHERMAL VENT AREAS OFF BRITISH-COLUMBIA, INCLUDING AMPHICROSSUS-ALTALIS, A NEW SPECIES OF EREBONASTERIDAE, WITH NOTES ON THE TAXONOMIC POSITION OF THE GENUS TYCHIDION-HUMES

Amphicrossus altalis, n.sp., belonging to the primitive poecilostomatoid family Erebonasteridae, was found at a depth of 2420 m at the Juan de Fuca Ridge off British Columbia. The male of an Amphicrossus species is described for the first time. The new copepod differs from the two recognized species of Amphicrossus in its body surface being not highly ornamented with spinules, its smooth anterior surface of the labrum, and the dimensions of the fifth leg. New records for Benthoxynus spiculifer Humes, 1984, Aphotopontius forcipafus Humes, 1987, and Stygiopontius quadrispinosus Humes, 1987, are included. The clausidiid genus Tychidion is redescribed and its taxonomic position discussed.