Absence of Lines of Arrested Growth in Overwintered Tadpoles of the American Bullfrog, Rana catesbeiana (Amphibia, Anura)

Abstract

In order to ascertain formation of lines of arrested growth (LAGs) in anuran larvae, cross-sections of long bones in overwintered tadpoles and juveniles of Rana catesbeiana were observed. However, no LAGs were evident in these individuals, although we could observe clear LAGs in adults treated in the same way. The result contrasts to those reported for urodelan larvae. We discuss the causes of this phenomenon on the assumption that the absence of LAGs in tadpoles is common to other anurans as well.