atavicas is incorrectly written, and should be written as "atavistic" being its meaning:
Plural feminine adjective of atavism, of Latin origin: atavus: fourth grandparent, ancestor. It is the genetic heritage of our ancestors. By the vagaries of genetics ( in the fertilization of the egg there are genes that are discarded and others not in meiosis ) There are genes of our ancestors who sometimes appear in their descendants. This phenomenon biologists called atavism. It can also be applied to behaviours or customs of the ancestors that are kept in the present
