Is Antarctica really isolated?
Diversity of bryozoans queilostomados from the southwest Atlantic region : Antarctica is really isolated ?
During the Cenozoic , the fragmentation of Gondwana was accompanied by a gradual separation of its components and the subsequent establishment of the Antarctic Circumpolar Current , leading to a relative thermal isolation of the Antarctic biogeographical and fauna. Still, the zoogeographic affinities of several taxa from South America and Antarctica have been discussed , questioning the extent of Antarctic isolation. Here new data bryozoan species and their spatial distribution in the Patagonia region of Argentina (PA ) , and an analysis of the similarities between briozoológicas depth ranges of Argentina and neighboring regions are presented . A total of 108 species ( 378 samples), belonging to 59 genera were found . In the PA region , five new genera and 36 new species were found , while 71 species were cited for the first time in Argentina . Bathymetric ranges of 94 species were expanded and a high proportion of the species identified (87% ) also had an Antarctic distribution. The briozoológicas affinities found in this study between the closest geographical regions are in favor of the hypothesis of the sequential separation of Gondwana during the Cenozoic . In addition , in this study a large number of shared species found mainly continental slope , between the region of the PA and Antarctica, thus supporting the idea that the Southern Ocean has been less isolated in geological time than than previously thought.