Haloschizopera apprisea, a New Species of Harpacticoid Copepod from Alaska, and Some Observations on Sexual Dimorphism in the Family Diosaccidae

Abstract

A new species of Haloschizopera, collected from 35-50 m depth in Auke Bay, Alaska, is described and figured. The presence of only two outer spines on the terminal exopod segment of swimming legs 2-4 make this species unique within the genus, but in other respects it appears to be most closely related to the H. exigua group of species. We show that the presence of sexually dimorphic structures on the terminal exopod segment of leg 3 is more widespread than was recognized previously within the family Diosaccidae. Specimens of the new species described in this paper were the most common representative of the family Diosaccidae in a collection of harpacticoid copepods obtained by one of us (J.W.F.) from muddy sediments in Auke Bay, Alaska (58?22'N, 138?41'W). Collections were taken during extensive ecological sampling in 1985-1986, primarily in Spring, at various depths from 30 to 50 m (Fleeger et al., 1989). Whole specimens were examined, drawn, and dissected in lactophenol; dissected parts were mounted in polyvinyl lactophenol and viewed under interference phase-contrast illumination. All figures were drawn using a drawing tube. Terminology used generally follows that of Lang (1948) except: (1) that only two major body divisions are recognized, the prosome (anterior to the major body articulation between somites bearing legs 4 and 5) and urosome (somites posterior to this articulation); and (2) that the terminology of Mielke (1984) is used for the mandible, Boxshall (1985) for the maxilliped, and Huys (1988) for the setae of the caudal ramus.