Classification and evolution of the burrowing sea anemones (Anthozoa: Actiniaria: Athenaria): a review of the past and current views

Abstract

The opinions of systematists about the classification and evolution of burrowing sea anemones have repeatedly changed over the long-term study of Actiniaria. Four stages can be distinguished over the course of the classification history. Each system was characterized by the use of mainly one particular feature. These features were: (1) characters of the external morphology, (2) arrangement of the mesenteries, (3) presence or absence of the basilar muscles and (4) molecular markers. The views on the origin and the evolution of the burrowing sea anemones were also altered more than once, that led to the emergence of several hypotheses. The burrowing sea anemones were considered as a primitive group or, on the contrary, as more advanced descendants of large hexamerous actinians.