Aphanisia

Aphanisia

 

one of the types of organ regression during the individual development of an organism. The term was introduced by A. N. Severtsov in 1931. In the process of aphanisia, an organ slowly develops and functions for a period of time and then at a certain stage disappears quickly, without leaving any trace. Severtsov considered the development and subsequent regression of dorsal musculature in the turtle, teeth in the sterlet, and branchial vessels in fish to be examples of aphanisia.