ACTINOPTERYGII WOODWARD, 1891

Xu, Guang-Hui & Gao, Ke-Qin, 2011, A new scanilepiform from the Lower Triassic of northern Gansu Province, China, and phylogenetic relationships of non-teleostean Actinopterygii, Zoological Journal of the Linnean Society 161 (3), pp. 595-612 : 597

SUBCLASS ACTINOPTERYGII WOODWARD, 1891 INFRACLASS ACTINOPTERI COPE, 1871 SUPERDIVISION NEOPTERYGII REGAN, 1923 ORDER SCANILEPIFORMES SYTCHEVSKAYA, 1999

Emended diagnosis: A stem group of Neopterygii differing from other closely related neopterygians in having: long-based dorsal fin consisting of more than 50 fin rays; lobe-shaped posterior margin of dorsal fin; lobe-shaped posterior margin of anal fin; unforked caudal fin (unknown for Scanilepis ); and longitudinal striated ornament on short segments of median fin rays.

Constituent taxa: Scanilepis , Evenkia , Oshia , Fukangichthys , Tanaocrossus , Mizhilepis , and the new taxon described herein.

Known distribution: Upper Triassic, Sweden; Lower Triassic, Central Siberia; Middle Triassic, Kirghizstan; Middle–Upper Triassic, North America; and Lower–Middle Triassic, China.

Remarks: The diagnostic features of the Scanilepiformes given by Sytchevskaya (1999) are listed as follows: (1) body elongate; (2) dermopterotics tending to fuse with parietal bones; (3) dorsal fin long, extending over most of the back length; (4) pectoral fin with fleshy scaly lobe; (5) caudal fin hemi-heterocercal; (6) fin rays drawn together at the bases, with short segments, longitudinally striated; (7) scales large and smooth; (8) anterior scales may bear striated ornaments.

Among the above features: (1) is a plesiomorphic condition widely distributed in actinopterygians; (2) is autapomorphic for Evenkia among scanilepiforms; (3) and (6) are diagnostic states of this group; (4) is also autapomorphic for Evenkia ; (5), (7), and (8) are character states commonly seen in many stem neopterygians as plesiomorphic conditions. Thus, the diagnosis of this group is revised in this paper.