The enigmatic Ediacaran (late Precambrian) genus Rangea and related forms
The late Precambrian genus Rangea Gürich, 1929, a frond-like fossil composed of repeated foliate elements, is one of the first discovered forms belonging to the now widely known soft-bodied assemblages characterizing the Ediacaran Period. Rangea occurs together with the genera Pteridinium Gürich, 1933, and Ernietta Pflug, 1966, in the lower parts of the Nama Group, Namibia (South West Africa).Investigation of the preservation and structure of Rangea, utilizing a methodology similar to that established by Wade (1968, 1971), indicates that it was probably a colonial octocoral consisting of a large tapering primary polyp, or oozoid, and a number of leaf-shaped, conjoined fronds which bore the feeding polyps; it is suggested to belong to a group of early Ediacaran anthozoans which provide a fossil link between the still living Telestacea and Pennatulacea. Similar investigations of Pteridinium and Ernietta disclose that their structure is different from Rangea and does not support ideas that they are related to it.