Simipercis, Johnson & Randall, 2006

Johnson, Jeffrey W. & Randall, John E., 2006, Simipercis trispinosa, a new genus and species of sandperch (Perciformes: Pinguipedidae) from eastern Australia, Memoirs of Museum Victoria 63 (1), pp. 57-64 : 58

Simipercis gen. nov.

Type species. Simipercis trispinosa sp. nov.

Diagnosis. The type species of Simipercis differs from all other genera of the family Pinguipedidae in having 3 dorsal spines, a low naked fleshy nuchal crest (fig. 1d), and dorsal angle of opercular bone broad, not forming a distinct exposed, pointed spine (figs 2a–d), and a combination of the following features: vomer and palatines edentate, subopercle and preopercle entire, 10 abdominal and 20–21 caudal vertebrae, scales including those on head and pelvic region large and ctenoid, interorbital with a single row of large scales, extending to, or just beyond anterior margin of eye, suborbital scales reaching a vertical between anterior margin of pupil and anterior margin of eye, and head and body moderately compressed (body width 1.3– 1.55 in depth in adults).

Remarks The new genus is most closely related to Parapercis Bleeker, 1863 , with similar vertebral counts and dental formulae, but is unique among pinguipedid fishes in having three dorsal spines ( Kochichthys 2, Parapercis 4–6, Pinguipes 6–7, Prolatilus 4, Pseudopercis 4–7), a low naked fleshy nuchal crest (no fleshy crest known in other genera), and dorsoposterior angle of opercular bone not forming an exposed, distinctly pointed spine (figs 2a–d). The dorsoposterior angle of the opercular bone is relatively broad and narrowly truncate posteriorly, with a minute shallow notch. The posteroventral edge of the notch forms a feeble, bluntly triangular point which is hidden by the skin in undamaged specimens. A horizontal ridge on the inner surface of the opercular bone is visible externally under light, and is situated well below the dorsal margin of the opercle. The ridge terminates slightly before the posterior tip of opercular bone. In other genera there is at least one exposed, robust, distinctly pointed opercular spine, and in Parapercis , the horizontal ridge on the inner face of the opercular bone is situated very close to (rather than well below) its dorsal margin, and extends to the tip, reinforcing the opercular spine (figs 3a–f).

Simipercis also differs from other pinguipedid genera by the combination of: vomer and palatines edentate (only Prolatilus lacks vomerine teeth, only Prolatilus and some Parapercis lack palatine teeth); margin of subopercle entire (usually at least some small spines or spinules in other genera); 10 abdominal and 20–21 caudal vertebrae ( Parapercis 9–10+18–22, Kochichthys 10+19, Pinguipes 15–16+20–21, Prolatilus 15–16+20–21, Pseudopercis 16–18+20–22); large interorbital scales extending to, or just beyond, anterior margin of eye (only Kochichthys , Prolatilus and Parapercis haackei have interorbital scales); cheek and suborbital with large ctenoid scales, extending to a vertical between anterior margin of pupil and anterior margin of eye (variously squamate or naked, usually with small cycloid scales on cheek, suborbital with small scales extending to below middle of eye or more posteriorly in other genera); and head and body moderately compressed (generally cylindrical or subcylindrical anteriorly in other genera). A detailed examination of osteological and myological features was not carried out on Simipercis ; however it agrees well with the familial diagnosis and description of Rosa and Rosa, 1998 and with additional features of the family defined by Imamura and Matsuura, 2003 that were examined (eg. unique crest on the hyomandibular present, posterior margin of opercular bone moderately concave, six branchiostegal rays, lowermost ray of pectoral fin branched, 15 branched caudal-fin rays).

Etymology. From the Latin similis, meaning similar or like, in reference to the pinguipedid genus Percis Bloch and Schneider, 1801 (the latter being preoccupied by the agonid genus Percis Scopoli, 1777 ).