Species characters of copepodith stages in Neocalanus flemingeri and N. plumchrus (Copepoda, Calanoida, Calanidae)

摘要

The variability of main diagnostic characters in Neocalanus flemingeri and N. plumchrus copepodites was described in the material from the western part of the Bering Sea. The shape of the opal crown on the ventral tooth and relative width of the tooth row of the mandibular gnathobase are more variable than it was know before. Some of the specimens have nontypical tooth crowns. They are more numerous among younger copepodites than among the fifth ones. The first copepodites lack crowns on the ventral teeth. Some difficulties in indicating the species are considered.