| Abstract: | The taxonomic scheme of the two families of the order Isocrinida (Isocrinidae and Pentacrinidae) is given. The first family is divided at five subfamilies: Balanocrininae, Isocrininae, Metacrininae, Diplocrininae and Isselicrininae. Six genera are included in subfamily Balanocrininae: Balanocrinus (four species found in USSR), Laevigatocrinus (USSR: 3 species), Margocrinus (USSR: 4 species), Percevalicrinus (USSR: 5 species), Singularocrinus nov. gen. (monotypic) and Terocrinus nov. gen. (USSR: 1 species). Five fossil genera are included in subfamily Isocrininae: Chariocrinus (USSR: 1 species), Chladocrinus (USSR: 4 species), Isocrinus (USSR: 6 species), Raymondicrinus nov. gen. (Oligocene of USA : 2 species) and Tyrolecrinus nov. gen. (6 triassic species). Fossil representatives of three genera, namely, Metacrinus (Miocene-Recent), Nielsenicrinus (USSR: 4 species) and Cainocrinus (USSR: 1 species) are noted in subfamily Metacrininae. Five genera are included in subfamily Isselicrininae: Austinocrinus (USSR: 5 species), Buchicrinus (USSR: 5 species), Doreckicrinus (USSR: 1 species?), Isselicrinus (USSR: 4 species) and Praeisselicrinus (USSR: 1 species). Two genera are included in family Pentacrinidae: Pentacrinus (USSR: 1 species) and Seirocrinus (USSR: 4 species). Besides, the localities of 24 isocrinid species, systematic position of which is unknown, are listed (from Triassic upon Cretaceous). Three erroneous attributions to Isocrinida in USSR are pointed out. In the conclusion an outline of the phylogeny of the Isocrinida is discussed. For a majority of the wide-spread species in USSR figures are given. |
