Gill openings mainly lateral; anterior edge of pectoral fin not attached to side of head; anal fin present or absent; pectoral girdle halves not joined dorsally (but scapulocoracoids fused ventrally in both sharks and rays). These features, while not representing shared derived features of the clade, do serve to distinguish sharks from rays. See above under Infraclass Euselachii for reasons why the sharks and rays, unlike in the 1994 edition, are placed in separate taxa of equal rank.
Two superorders, the Galeomorphi, with four orders, and the Squalomorphi with five orders, and a total of 34 families, 106 genera, and 403 species.
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