Cyclichthys Kaup, 1855

Leis, Jeffrey M., 2006, Nomenclature and distribution of the species of the porcupinefish family Diodontidae (Pisces, Teleostei), Memoirs of Museum Victoria 63 (1), pp. 77-90 : 82

Cyclichthys Kaup, 1855

Cyclichthys Kaup, 1855 (type species Diodon orbicularis Bloch )

Diagnosis. All but 1 or 2 spines fixed; all spines with 3 bases, except in C. spilostylus which has some spines on top of head with 4 bases; 9 C rays; 19–20 vertebrae; no tentacles in adults; nostril in adult a short tube with 2 openings; no spines wholly on dorsal surface of caudal peduncle; no fins spotted; no large blotches on dorsal surface.Some additional osteological characters are given by Tyler (1980, ref. 4477) for C. orbicularis .

The type species of this genus is C. orbicularis (Bloch, 1785, ref. 21381). Kaup (1855, ref. 2571) included two species in his Cyclichthys – orbicularis Bloch , and cornutus Kaup – but designated neither as type species for the genus. Subsequently, Bleeker (1865, ref. 416) was apparently the first to designate a type species for Cyclichthys and chose orbicularis Bloch ( Eschmeyer, 2005) . Fraser-Brunner (1943, ref. 1495) used Cyclichthys as a subgenus of Chilomycterus . He did not consider C. hardenbergi , but included C. orbicularis , the “Atlantic Chilomycterus ” species, and C. echinatus non- Linnaeus (= C. spilostylus ) in his concept of the subgenus Cyclichthys . Tyler (1980, ref. 4477) pointed out that C. orbicularis had osteological differences from the other diodontids he studied, and placed the species in a group on its own. However, he was not able to examine specimens of C. spilostylus or C. hardenbergi . Based on external morphology, it appears that C. orbicularis differs from other species that have been included in Cyclichthys by Fraser-Brunner (1943, ref. 1495), and there is merit in Tylerʼs placement. If this were done, then a new genus would probably have to be described for hardenbergi and spilostylus , as they do not appear to be monophyletic with the “Atlantic Chilomycterus ” species. Pending a cladistic analysis of relationships in the family, I recognize three species in Cyclichthys , which has been standard practice in recent years.