A new species of scorpionfish, Scorpaena gasta, is described on the basis of five specimens collected from the warm temperate central coast of Western Australia, eastern Indian Ocean, at depths of 3–7 m. Scorpaena gasta is most similar to a Western Australian species, S. sumptuosa. The two species are distinguished from other Indo-Pacific species of Scorpaena by the following combination of characters: lateral surface of maxilla with a distinct longitudinal ridge; relatively thick skin with numerous small sensory pores covering nearly the entire predorsal area to near the first pored lateral-line scale; anteroventral surface of lower jaw with one or two pairs of slender tentacles in ventral view. Scorpaena gasta and S. sumptuosa are separated by four meristic, several morphometric, and color features. Scorpaena gasta is a small species (smallest mature female 67.4 mm SL; largest known specimen 83.6 mm SL), whereas S. sumptuosa is a relatively large species, attaining at least 241 mm SL.

The validity of the scorpionfish, Rhinopias eschmeyeri, known only from the holotype from Mauritius, is confirmed, and the species is redescribed in detail on the basis of ten specimens from the Indo-West Pacific Ocean (Mascarene Islands to Japan and Australia). Additionally, R. frondosa and R. aphanes are redescribed. These three species are characterized by having one or two small dense black spots in the soft dorsal fin; the opercle without scales between the tips of the upper and lower opercular spines and the opercular margin; and 16 (rarely 15 or 17) pectoral-fin rays. Rhinopias eschmeyeri differs from the latter two species in aspects of form, location, and number of tentacles on the head and body; form of dorsal-fin margins and caudal-fin ray tips; shape of penultimate dorsal-fin spine; degree of development in lacrimal and suborbital ridge; and coloration.

A new species of scorpionfish, Maxillicosta meridianus, is described on the basis of 24 specimens collected from southeastern Australia at depths of 10–137 m. This species has previously been identified as M. whitleyi, but differs in having the following characters: central portion of inner ridge on ventral mandibular surface located on inner edge of dentary or closer to inner edge than to central ridge, no short ridge between posterior portions of inner and central ridges; 0–6 spinous points on anterior margin of nasal spine; 5–13 spinous points on surface of preocular spine; no spines or distinct ridges on lateral margin of occipital pit between tympanic spine and origin of parietal spine base; no ossified scale behind front edge of occipital pit between tympanic spines; dorsal surface of occipital pit smooth, without spines; two (rarely one or three) spinous points at tip of upper opercular spine; posterior margin of maxilla extending slightly beyond a vertical through posterior margin of pupi...