Biogeography and phylogeny of the free-living bryozoans in the Miocene of South America

HÅKANSSON, E.; CASADIO, SILVIO; NIELSEN, S.

Conferencia; International Bryozoology Association - 13th Conference, Concepción, 2004; 2003

The first finds of cupuladriids from Patagonia, southernmost South America, have provoked speculations as to the mode and tempo of the Neogene invasion of free-living bryozoans into South America. Two routes were utilized from a Caribbean center of evolution prior to the closure of the Isthmus of Panama, one along the east coast and one along the west coast. Migration along the east coast reached as far south as Penísula de Valdés in Patagonia whereas, on the west coast, the southernmost occurrence is around Navidad in central Chile. While the Atlantic trail apparently was utilized solely by cupuladriids ? with both Cupuladria sp. and Discoporella sp. reaching all the way to Patagonia ? the Pacific trail may also have provided a sanctuary for the last surviving members of the North American branch of the Otionellidae.