New record of Thalia cicar van Soest 1973 (Urochordata: Thaliacea) in the Equatorial Atlantic

Abstract

Thalia clear van Soest 1973 (Urochordata, Thaliacea) is considered a tropical-subtropical species, registered in the Atlantic Ocean at latitudes between 7-34° S and 6-32° N. This work enlarges the occurrence of this species for Equatorial Atlantic waters. The specimens were found in a shelf break area of the Brazilian northeastern (07° 50'-07° 70' S and 34° 23' W) during the expedition JOPS-II (Joint Oceanographic Projects II) in March 1995; and, in São Pedro e São Paulo arquipelago (0° 55' N and 29° 20' W) in May and June, 2005. These two areas are characterized by the presence of local upwelling that induces the ascent of bottom waters rich in nutrients, generating areas of larger productivity than the typically oligotrophic Equatorial Atlantic waters. The new occurrence of Thalia clear reported in this work can be related to these more productive waters of Equatorial Atlantic. The species that is most commonly found in the Atlantic Ocean is T. democratica, and the lack of past records of T. clear might have been caused by the taxonomic difficulties determining of the solitary and aggregate zooids of these two species. This work suggests the potential use of the ratios among tunic lengths as an additional character to differentiate T. clear and T. democratica oozooids.