真鶴半島から記録されたアシビキツバサゴカイ属(多毛網、ツバサゴカイ科)の2新種

A new species of chaetopterid polychaeta, Spiochaetopterus manazuruensis n. sp., is described from sandy mud shallow bottom of Manazuru, Sagami Bay, Pacific coast of Honshu, Japan. This is the fifth species of Spiochaetopterus to be described from Japan. The species is described and figured and differentiated from other species of the genus with which it might be confused. Based on SEM observations and ones in the literature, the specialized A4 (chaetiger 4 of anterior region) chaeteae are compared with those of other 14 named and unnamed species of Spiochaetopterus. In this feature, in its small size, and in having only 2 middle segments, S. manazuruensis n. sp. appeares to be most similar to northern European S. bergensis Gitay, 1969, but differs from it in the presence of a larger, irregular brown pigmentation on each side extending from the prostomium to the peristomium, and in details of the structure of the A4 modified chaetae