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A Revision of the Osmerid Genus Hypomesus Gill (Teleostei: Salmoniformes), with the Description of a New Species from the Southern Kuril Islands Toshiro Saruwatari,¹ Juan Andrés López,² and Theodore W. Pietsch² ¹Division of Biology of Fisheries Resources, Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano-Ku, Tokyo, 164, Japan ²School of Fisheries, University of Washington, Box 355100, Seattle, Washington 98195-5100, USA

A systematic revision of the osmerid genus Hypomesus Gill, based on a detailed analysis of external and internal morphological characters, revealed the presence of six species, one of which is described as new. These six species fall readily into three species groups: the Hypomesus nipponensis group, containing H. nipponensis McAllister, H. chishimaensis new species, and H. transpacificus McAllister; the H. olidus group, containing only H. olidus Pallas; and the H. japonicus group, containing H. japonicus Brevoort and H. pretiosus Girard. Synonymies, diagnoses, and descriptions are given for all taxa, geographic distributions are given, and a key to the species of the genus is provided.

Key Words: Teleostei, Salmoniformes, Osmeridae, Hypomesus, new species, revisionary studies, Kuril Islands, Kunashir, Iturup, Zelionyi

Introduction

The genus Hypomesus, family Osmeridae, contains relatively small fishes that inhabit fresh, brackish, and coastal marine waters of the northern Pacific Rim. Most members of the group are commercially exploited for human consumption and recreational fishing. McAllister (1963), in the most current taxonomic revision of the genus, recognized three species and four subspecies (Table 1). Based primarily on osteological characters, Kljukanov (1970a, b) elevated these subspecies to full species rank; but while Kljukanov's work was an improvement over past interpretations, he still left the nomenclature of the genus in disarray. Our interest in Hypomesus was initiated by attempts to identify material collected in the southern Kuril Islands during the 1994 expedition of the International Kuril Island Project, a biotic survey and inventory of the Kuril Archipelago funded jointly by the U.S. National Science Foundation, the Japan Society for the Promotion of Science, and the Far East Branch of the Russian Academy of Sciences. This new material, which has proved to represent an undescribed species of Hypomesus, along with preserved specimens borrowed from various institutions, and additional newly collected specimens from Japanese localities, forms the basis for the following revision.

Saruwatari, T., J. A. López, and T. W. Pietsch. 1997. A revision of the osmerid genus Hypomesus Gill (Teleostei: Salmoniformes), with the description of a new species from the southern Kuril Islands. Species Diversity, 2(1):59-82.