Article: The origin of the Silurian Clarkeia shelly fauna of South America, and its extension to West Africa
L. R. M. Cocks
The brachiopod Aratanea monodi Schmidt 1967 from Mauretania (West Africa) is put into the synonomy of Clarkeia antisiensis, chief constituent of the Malvinokaffric Clarkeia fauna of Central South America of Silurian age. The recently described fauna of latest Ordovician age from South Africa is considered to have been the ancestor of the Clarkeia fauna. In particular Marklandella africana is reassigned to Heteror-thella, and considered the ancestor of Heterorthella freitana; Plectothyrella haughtoni is considered the ancestor of Clarkeia itself. Eostropheodonta, Orbiculoidea and homalonotid trilobites are common to both faunas. The ecology of both the South African and Clarkeia faunas is discussed. They are considered to represent the shallower end of the benthic depth spectrum, and may have been parallel communities to the contemporaneous Hirnantia, Cryptothyrella and Eocoelia Communities of Eurasia and North America. They may also have lived in colder water than the northern communities.