On the synonymy of Sagitta decipiens Fowler, 1905, and Sagitta neodecipiens Tokioka, 1959, and the validity of Sagitta sibogae Fowler, 1906

The inadequacies of the original descriptions of Sagitta decipiens Fowler, 1905, and S. sibogae Fowler, 1906, have led to confusion concerning these species. Sagitta neodecipiens Tokioka, 1959, is a junior synonym of S. decipiens Fowler, 1905. S. sibogae Fowler, 1906, is the valid name for the species usually incorrectly named S. decipiens (non Fowler, 1905) because of the redescription of Ritter-Zahony (1911). S. philippini Michael, 1919, is a junior synonym of S. sibogae. The two valid species are redescribed from the types, and lectotypes have been designated

Taxonomy and zoogeography of Sagitta planctonis Steinhaus, 1896 (Chaetognatha) in the Atlantic Ocean

Depth distribution, morphology, meristic, quantitative and qualitative characters of S. planctonis and S. zetesios are compared. A factor analysis and a discriminant analysis was made. S. planctonis is considered a polytypic species consisting of two formae: S. planctonis forma planctonis and S. planctonis forma zetesios

A short note on the biogeographic patterns of the Chaetognatha fauna in the North Atlantic

Three different hydrographic regimes were identified during the MAR-ECO cruise in the North Atlantic in June 2004 between 59°N and 42°N. Chaetognaths were sampled with a non-quantitative open plankton net through the entire water column. The species composition of the chaetognaths differed between the Sub-Arctic Province (SAP) and the Cold Temperate Province (CTP), and a frontal region. In the SAP with Sub-Arctic Intermediate Water six species were found, and the species composition was dominated by three species: two of the genus Eukrohnia and one of the genus Sagitta making up 83% of the total number of specimens. In the samples from the CTP with North Atlantic Central Water 16 species were present and here five to six species made up 83% of the total number of specimens. There were no differences between the chaetognath assemblages on either side of the Mid-Atlantic Ridge. Greatest abundances were found at station 18 just northwest of the Charlie-Gibbs Fracture Zone