Tintinnoinea
Identification of the taxa

The present chapter covers all tintinnid taxa recorded so far from the South Atlantic; 41 genera, 129 species, 8 varieties, and 37 formae. These numbers are the result of combining and/or invalidating many previously described species and genera. The revision is based on published data and on published and unpublished personal results from the Southwestern Atlantic and the Southern Ocean. By necessity they rely to a large extent on descriptions and illustrations from the literature (some of these taxa were not observed by the author). Illustrations are considered of special importance because they summarize practically all the traits used in tintinnid classification. For ease of comparison, a uniform magnification is used for all figures within a genus. Ample use has been made of figures in Brandt (1906), Laackmann (1910), Faría and Da Cunha (1917), Balech (1944, 1945, 1948, 1951, 1971a, b, 1975), Souto (1979), Laval-Peuto (1981) and Barría de Cao (1981, 1986), because most of them accompany original descriptions.

Most of the genera were erected by Jörgensen (1924) and by Kofoid and Campbell (1929, 1939). Because, as discussed above, polymorphism is common in most tintinnid species, several morphotypes of the same species are often included. Short diagnoses for the genera and many of the species are provided; however, where illustrations clearly depict all taxonomically important traits, diagnoses are omitted. Combined names (e.g., "Tintinnopsis" amphora/nucula) denote cases where analysis of the whole spectrum of formae did not reveal limits between the "species" involved. Dubious genera and species are denoted with a question mark and an asterisk, respectively. The designation "group" denotes categories of unclear taxonomic affinities, where probably several related taxa are lumped. For each of species one or more references ("Ref.") providing relevant descriptions and/or illustrations are included. Notice, however, that the names in the literature are not necessarily those utilized herein. For this reason, and because the system used herein involves major changes from previous literature, a listing with the corresponding equivalences for the morphotypes treated is provided.

Two alternatives are offered as a first approach to the identification of the tintinnids of the South Atlantic: a traditional key to generic level, and diagnoses of groups and subgroups of morphologically similar forms. It should be born in mind, however, that both systems are artificial, insofar as they do not reflect phylogenetic relationships.