cenogenetic

adjective

ce·​no·​ge·​net·​ic

variants or coenogenetic or chiefly British caenogenetic

ˌsē-nə-jə-ˈnet-ik, ˌsen-ə- 

: relating to or being a specialized adaptive character (as the amnion or chorion surrounding the embryo of higher vertebrates) that is not represented in primitive ancestral forms