A New Species of Leptochelia (Crustacea, Tanaidacea) from Japan, with a Redescription of L. savignyi (Krφyer, 1842)

Abstract

In 1981, I studied the biology of a tanaid which was commonly found in sandy bottoms of Oshoro Bay, Hokkaido, northern Japan. A close examination revealed that it was a previously undescribed species of the genus Leptochelia (family Para- tanaidae) and belonged to the "Leptochelia-Gruppe 2" that was defined by Lang (1973) to accommodate a sole valid species, Leptochelia savignyi (Krdyer, 1842). The aim of the present paper is to describe this new species. To clear distinction bet- ween this new species and L. savignyi which has been believed to be polymorphic and involves many synonyms, here a precise redescription of a North Pacific form of L. savignyi is also given based upon specimens collected from Japan and North America. In addition, some notes on the structures of the genital cone and the mouth parts, using scanning electron microscopy, are presented.