Pteroidichthys

Motomura, Hiroyuki & Kanade, Yuka, 2015, Review of the scorpionfish genus Pteroidichthys (Scorpaenidae), with descriptions of two new species, Zootaxa 4057 (4), pp. 490-510 : 492

Key to the species of Pteroidichthys

1a Anal fin with 3 spines and 5 soft rays (last ray divided into two branches at base); supplemental preopercular spine present..................................................................................................... 2

1b Anal fin with 2 spines and 6 soft rays (last ray divided into two branches at base); supplemental preopercular spine absent....................................................................................................... 3

2a Snout relatively short, its length 13.5–16.9% (mean 15.3%) of SL, shorter than postorbital length; posterior margin of maxilla reaching or extending beyond vertical through middle of pupil; distance between tips of lateral lacrimal and first suborbital spines shorter than or subequal to that between tips of first and second suborbital spines.... P. noronhai (Indo-West Pacific)

2b Snout relatively long, its length 18.0–21.2% (mean 19.6%) of SL, longer than postorbital length; posterior margin of maxilla just reaching to or short of vertical through anterior margin of pupil; distance between tips of lateral lacrimal and first suborbital spines longer than that between tips of first and second suborbital spines........... P. acutus n. sp. (western Pacific)

3a Dorsal-fin spines flexible (spines bend easily under slight pressure); tentacles on supraocular and posterior lacrimal spines well developed, their lengths greater than orbit diameter; numerous tentacles on trunk and fins; lateral lacrimal and suborbital spines poorly developed, indistinct, usually tiny spines and often bony protuberances without pointed tips; no distinct black blotch on soft-rayed portion of dorsal fin; recorded from shallow waters in depths of 7– 43 m .................................................................................................. P. a m b o i n e n s i s (Indo-West Pacific)

3b Dorsal-fin spines rigid (as typical of most scorpaenids); tentacles on supraocular and posterior lacrimal spines poorly developed, their lengths less than orbit diameter; few tentacles on trunk and fins; lateral lacrimal and suborbital spines well developed, with pointed tips; membranes between last spine and fourth soft ray of dorsal fin with large black blotch; recorded from deep waters in depths of 68– 122 m ............................................... P. caussei n. sp. (South Pacific)