Gobiesociformes

Gobiesociformes: Pelvic fins modified into a thoracic sucking disc (permitting fish to adhere to substrate), with underlying pelvic bones specialized for supporting disc (pelvic skeleton highly reduced in Alabes; each pelvic fin with one small spine and four soft rays (rarely five); single dorsal fin without spines; head and body scaleless; branchiostegal rays 5-7 (three in Alabes); no circumorbital bones posterior to the lachrymal; articular process of premaxilla either fused with ascending process or absent; basibranchials one and two probably absent; supracleithrum with concave process that articulates with condyle oncleithrum (not known from other fishes); basisphenoid and orbitosphenoid absent; genital papilla behind anus; three or three and half gills; hypurals fused into a single plate; no swim bladder. The following characters apply to all species except Alabes: scapula and four pectoral radials and 16-31 pectoral fin rays; usually two postcleithra (rarely one); either common gill opening or separate opening on each side; pleural ribs attached to the epineural (?) ribs (an opposite relationship to that found in most fish); total caudal fin rays 16-27 (8-14 articulating on hypural fan); vertebrae 25-54 (11-20 + 13-33). Maximum length normally.
 * See Fishbase.

Families in this order:
 * Gobiesocidae