Abstract
In the Southern Hemisphere the species attributed to Corella eumyota, Traustedt, 1882 are likely more varied than previously expected. This ascidian species was described from specimens collected at Valparaiso (Chile). Until now it was considered as a widely distributed species in the southern hemisphere. New collections from Chile and the Antarctic area have allowed to separate two species and re-establish Corella antarctica Sluiter, 1905 as a valid species (Alurralde 2013).A morphological re-examination of many specimens from the MNHN collections and especially recent surveys as CEAMARC and REVOLTA confirms that Antarctic specimens from the Antarctic Peninsula and Terre Adélie obviously differ from sub-Antarctic material more varied than previously estimated. On the other hand, C. eumyota invasive in Europe (Lambert 2004) has been shown to be the same as specimens from Chile, New Zealand and other sub-Antarctic regions. The present morphological study compares Corella from different regions and describes a new species Corella brewinae n. sp that is found living mixed with C. eumyota populations.