OSTEICHTHYES Huxley, 1880

Poyato-Ariza F. J. & Wenz S., 2002, A new insight into pycnodontiform fishes, Geodiversitas 24 (1), pp. 139-248 : 218

Class OSTEICHTHYES Huxley, 1880 Subclass ACTINOPTERYGII Cope, 1887 Division HALECOSTOMI Regan, 1923 sensu Patterson 1973

Order PYCNODONTIFORMES Berg, 1937 REVISED DIAGNOSIS. — Halecostome fishes with the following autapomorphic characters: laterally compressed, high to rounded body shape ; antorbital and ethmoid regions hypertrophied, with mesethmoid T-shaped in section; one or several unpaired dermal supraoccipital(s) present; parasphenoid largely developed, edentulous, inflected downwards; opercular process of hyomandibular vestigial or absent; suboperculum and interoperculum absent; operculum reduced; premaxillary process long and superficial; maxilla edentulous, loosely attached; supramaxilla absent; teeth on vomer and prearticular arranged in rows; dentary reduced; long, stout mandibular symphysis; cleithrum large, ventrally palaform; ribs alate; contour scales differentiated into dorsal ridge and ventral keel scales.