THE RHADINICHTHYIDS (PALEONISCOID ACTINOPTERYGIANS) FROM THE BEAR GULCH LIMESTONE OF MONTANA (USA, LOWER CARBONIFEROUS)

Three new fusiform Namurian paleoniscoids are described: Wendyichthys dicksoni, gen. et sp. nov., Wendyichthys lautreci, sp. nov. and Cyrano rhis bergeraci, gen. et sp. nov. Their most unique features consist of their snout anatomy (with a rostropostrostral, reverse-L shaped antor bitals, a rostral notch, and the lack of premaxillaries) and the prese nce of extralateral gulars in addition to normal median and lateral gu lars. These supplementary gulars and the rostral notch were probably m echanical adaptations for a greater widening of the mouth cavity durin g abduction of the mandible: as a result these fishes probably fed by suction, either at the bottom of the water column or by intake of floa ting nutritive particles. Prior to a phylogenetic analysis of the rela tionships of these and other Bear Gulch actinopterygians, these three new taxa are placed into the Rhadinichthyidae. A revised definition of this family, including new features recognized during this study, is given after a reappraisal of the characters selected by many of the au thors who have dealt with this group. Only a few of those characters p roved to be significant for the Rhadinichthyidae, the others are eithe r plesiomorphic for actinopterygians, or paleoniscoid characters, or a re useful only at generic or specific levels.