Publication Date
10-21-1976
Series Number
170
Abstract
Modified scales in the cloacal region of two osteolepid rhipidistians are described for the first time. A specimen of Megalichthys sp. (from the Pennsylvanian of Ohio), consisting of an isolated portion of the pelvic region, shows five enlarged scales along the ventral midline: two sets of paired flanking scales and one unpaired central scale. There is no direct evidence of the cloaca in this specimen. In the only known specimen of Sterropterygion brandei (from the Upper Devonian of Pennsylvania), the cloacal position is preserved, and there is one pair of enlarged scales flanking the opening. The modified scales in both genera are interpreted as being secondary sexual characteristics. The apparent absence of scales modified for reproductive functions in other fossil taxa is discussed.