Radiolarios polycystina (Protozoa: Nassellaria y Spumellaria) sedimentados en la zona centro-sur de Chile (36°-43° S)

Abstract

The radiolarians are planktonic marine protozoans, which although be only one cell, are sophisticated and complex organisms. The Subclass Radiolaria is formed by two superorders: Trypilea and Polycystina, this last is the most studied, because its skeleton from opal is resistent to the sea water disolution and for this reason are preserved in the fosil record. The radiolarians have been used like a useful oceanographic, biostratigraphic and paleoambiental tool for their silica skeleton and large geologic range. In our country the knowledge of this group is poor, for this reason the present work has the objective to contribute with the indentification and description of Polycystins radiolarians not described and recorded before for this particular zone. The material used was obtained to the PUCK R/V Sonne Cruise SO-156 Valparaíso- Chiloé-Talcahuano Expedition realized in may of 2001. The 20 samples were obtained with a multicore between 125 and 3.485 m depth distributed from Concepción to Chiloé (36°-43°S). Were idientified 28 species appertaining to 20 genus and 9 families. The major amount of individuals was found in the station 3 in front of Concepción to 789 m depth, this could be associated at the seasonals upwelling periods and process to sedimentation of the shells and opal disolution relatively short. Southward decrease the abundance of the two orders studied.