Testing for ecophenotypic variation in a benthic foraminifer

A method for identifying ecophenotypic variants is tested, using two morphological variants of the benthic foraminifer Reophax dentaliniformis Brady from the Baltic Sea. Results show that the example does not correspond to the model for ecophenotypic variation. This is interpreted as showing that the two forms are genetically differentiated and that the gene flow between them is restricted by the water circulation pattern in the Baltic.     

Free-living nematodes of the genus <Emphasis Type="Italic">Alaimella</Emphasis> Cobb 1920 (Nematoda: Leptolaimidae): A description of <Emphasis Type="Italic">A. macramphis</Emphasis> sp. n. from the White Sea and a revision of the genus

Alaimella cincta Cobb 1920 and Alaimella macramphis sp. n. are described and illustrated. Both the species were first recorded for the White Sea in northern Russia. A. cincta occurs in the shells of the agglutinated foraminiferan Reophax curtus, as well as freely in bottom sediments. A. macramphis sp. n. is described from a single male sampled from bottom sediments. A. macramphis sp. n. is distinguished from two previously known species of Alaimella (A. cincta Cobb 1920 and A. truncate Cobb 1920) by having a longer body, longer cephalic setae, and a wide amphid equal to the respective body diameter. The new species also differs from A. truncate by the distinct striation of the cuticular annulations. The Alaimella species are additionally characterized by having a posterior glandular widening of the esophagus. An emended diagnosis of the genus Alaimella Cobb 1920 and a key for species identification are provided.