Diversity of loricate ciliates (suborder Tintinnina, Protozoa): The Southern Ocean as compared to the World Ocean.

ALDER V.A.

Curitiba, Brasil

Simposio; IX SCAR International Biology Symposium; 2005

SCIENTIFIC COMMITEE ON ANTARCTIC RESEARCH

The systematics of Tintinnina is based almost exclusively on the features of their loricae. The literature on tintinnids reports over 1,000 species for the World Ocean, 7% of which inhabit the Southern Ocean. Because of the morphological variability observed in many of these species, a revision of the suborder was performed by (1) reviewing all available descriptions and converting more than 5,000 illustrations to a common scale, and (2) analyzing both qualitatively and quantitatively (Uthermol technique) materials from tropical, temperate and cold Atlantic waters. The present results indicate that most of the species previously reported are invalid systematic entities, as they are based on minor, intraspecifically variable morphological features. While the Atlantic and Pacific oceans share practically the same 178 taxa comprised in 41 genera, most of the species of the Southern Ocean were found to be endemic. The most diversified neritic genus within the World Ocean is absent in Antarctic waters. South of the Polar Front, tintinnids are represented only by 5 genera (one endemic), probably 9 species (six of them dubious as independent entities), and 16 formae. Shannon´s biodiversitiy index and biogeography of the Antarctic Ocean as based on tintinnids are discussed in comparison with Atlantic ecosystems.