Distributional Range Extension of the Shallow Water Scorpionfish Parascorpaena poseidon (Perciformes: Scorpaenidae), with a Revised Diagnosis of the Species

Abstract

The distributional range of Parascorpaena poseidon Chou and Liao, 2022, previously recorded only from Taiwan, is extended into the eastern Indian and western Pacific oceans (Japan, Philippines, Thailand, Indonesia, Sri Lanka, and India), on the basis of 52 specimens (35.3–123.3 mm standard length). A revised diagnosis for the species, determined from eastern Indian and western Pacific ocean specimens, is as follows: usually 16 or 17 (rarely 15) pectoral-fin rays; 43–49 scale rows in longitudinal series; 22–26 pored lateral-line scales; 6–8 (usually 7) scale rows between 6th dorsal-fin spine base and lateral line; 6–8 (usually 7) scale rows between last dorsal-fin spine base and lateral line; 4–6 + 7–9 + 1–3 = 14–17 gill rakers; penultimate dorsal-fin spine length 60.0%–83.3% of last dorsal-fin spine length; occipital pit fairly deep; suborbital bone with two ridges, origin of first posterior to origin of second, first with a single spine, second with two - all spines of equal size; supraocular tentacle absent or very short; base of dorsal-fin soft ray covered with small scales; head and body uniformly brown when fresh; all fins with randomly distributed blackish spots; membranes of spinous portion of dorsal fin without a distinct black blotch in males; body size relatively large, maximum recorded size 128.8 mm SL. Several body proportions changing with growth, including body width, head width, snout length, interorbital width at vertical midline of eye, upper-jaw length, maxilla depth, and postorbital length (all significantly increasing), and orbit diameter and separation of opercular spine tips significantly decreasing. The new Japanese standard name “Mitsumata-nettaifusakasago” is proposed for P. poseidon.