Mesozoic first appearances

thumb|Rearing white-clawed crayfish at Cynrig hatchery, Wales. Establishing a breeding population from introduced captive-bred animals. thumb|Cajun style crayfish thumb|Dried crayfish at an African market

Equisetaceae, also known as the horsetail family, is a family of ferns and the only surviving family of the order Equisetales, with one surviving genus, Equisetum, comprising about twenty species.

Serphitidae is a family of microscopic parasitic wasps known from the Cretaceous period.