An order of fishes containing the pricklefishes and whalefishes. This order is recognized by G. D. Johnson and C. Patterson, but interrelationships of the taxa placed within it are debated among ichthyologists. Stephanoberyciformes is recognized as the sister group of all remaining acanthomorphs. It is defined by the following characters: pelvic girdle attached to cleithrum or coracoid of pectoral girdle; skull bone usually exceptionally thin (fragile bones often characteristic of pelagic fishes); subocular shelf absent; supramaxilla absent or reduced; and body shape variable, from elongate to short and rounded. The biology of stephanoberyciformes as a group is poorly known, and many species are known from only a few specimens. These are small deep-water fishes, ranging in total length from 2.1 to 43 cm (0.8 to 17 in.), but most are less than 10 cm (4 in.), and occupying depths to 5300 m (17,400 ft or 3.3 mi). Several species are known to be oviparous (the assumed mode of reproduction of the entire order), with planktonic eggs and larvae. The order comprises nine families, 28 genera, and about 75 described species, plus many others known but yet undescribed. Included in the order are families taken from the Beryciformes, Lampriformes, and the Trachichthyiformes taxa as described by J. A. Moore.