Redescription of Iniistius jacksonensis (Ramsay 1881) and description of Iniistius opalus sp. nov. from northern Australia (Perciformes: Labridae)

Abstract

The razorfish Iniistius jacksonensis (Ramsay 1881) is redescribed based on 10 specimens, including adult individuals, from eastern Australia. A second Australian species, Iniistius opalus sp. nov. is described based on 16 specimens from northern waters. Both species can be distinguished from other congeners in having a broad band of small scale rows on the cheek, a single small scale below the eye, first two dorsal-fin spines short, their length similar to those of other spines of dorsal fin, central gill-raker of lower limb of first gill arch with a single branch, greater body depth [33.6–41.5% standard length (SL) in Iniistius jacksonensis, versus 33.5–39.2% SL in I. opalus sp. nov.], and several small blotches on the anal-fin base. The new species can be distinguished from I. jacksonensis by its 10 scale rows below lateral line, four branches on central gill-raker of first upper limb of gill arch (vs. 2 branches in latter), greater head length [32.9–36.0% (mean 34.3%) vs. 29.6–32.1% (31.2%) SL], pre-pectoral-fin length [29.8–32.5% (31.2%) vs. 26.5–29.9% (28.5%) SL], orbit diameter [6.1–7.3% (6.8%) vs. 5.0–6.8% (5.8%) SL] and postorbital length [14.9–18.4% (16.8%) vs. 13.6–16.2% (14.9%) SL], and small blotches on head (vs. no blotches).