1Program in Environmental Management, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, 2Department of Environmental Management, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan
Morphological differences between the holoarctic species Mallotus villosus and Japanese endemic species Spirinchus lanceolatus were investigated by their morphometric and anatomical characteristics. Mallotus villosus can be distinguished from S. lanceolatus based on a combination of the following characters: snout length 30.3-34.4% head length (HL)(vs. 19.6-20.6% in S. lanceolatus); pectoral fin length 49.9-66.0% HL (vs. 84.2-90.5%); depth of caudal peduncle 4.8-5.5%/standard length (SL)(vs. 7.0-7.7%); scale area 0.36-0.42 mm2 (vs. 2.7-4.5 mm2); and concave along the anterodorsal border of the opercle deep (vs. shallow). These characteristics enable general consumers and fishery workers to differentiate M. villosus and S. lanceolatus.