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Abstract

publisher<Synopsis>The mangrove red snapper, Lutjanus argentimaculatus is distributed in the Indo-Pacific Oceans. This fish shows individual variations in morphological characters and resembles the Papuan black bass, L. goldiei. In order to find key characters to distinguish these two species, external and internal morphologies of L. argentimaculatus from Iriomote Island, where they are distributed sympatrically, are examined. The differences between L. argentimaculatus and L. goldiei are as follows: transverse scales above and below lateral line 6+13—15 (vs. L. goldiei; 8＋17, ref. Senou and Suzuki 1992): gill rakers 18—20 (vs. 23): head length 41.6—44.7% (vs. 40.5): eye diameter 10.5—12.0 (vs. 9.2): interobital 8.2—10.6 (vs. 6.8): length of caudal peduncle 13.1—17.6 (vs. 18.9): depth of caudal peduncle 11.4—13.2 (vs. 13.6): anal fin length 14.1—18.9 (vs. 21.7): prevomerine tooth shape crescentic band (vs. V-shape): interorpercular knob present (vs. absent). These morphological differences can be regarded as key characters between these two species