Bothriolepid antiarchs (Vertebrata, Placodermi) from the Devonian of the north-western part of the East European Platform

A large collection of bothriolepid antiarch material from 26 localities in the north-western part of the East European Platform (Latvia, Lithuania, and the Leningrad, Novgorod, and Pskov regions of Russia) is described and illustrated, with a critical treatment of previously described material. The genus Grossilepis Stensiö, 1948 is represented by two species, Grossilepis tuberculata (Gross, 1941) and G. spinosa (Gross, 1942). All remaining material is referred to the genus Bothriolepis Eichwald, 1840: B. prima Gross, 1942, B. obrutschewi Gross, 1942, B. cellulosa (Pander in Keyserling, 1846), B. panderi Lahusen, 1880, B. traudscholdi Jaekel, 1927, B. maxima Gross, 1933, B. evaldi Lyarskaja, 1986 come from the Givetian(?)-Frasnian deposits, and leptocheira curonica Gross, 1942, B. ornata Eichwald, 1840, B. jani Luksevics, 1986, B. heckeri n. sp., B. ciecere Lyarskaja Lyarskaja & Savvaitova, 1974 as well as one unnamed form come from the Famennian sequence. The stratigraphic distribution of bothriolepids through the Middle/Upper Devonian of the Main Devonian Field is clarified in a proposed new version of the vertebrate zonation. A cladistic analysis of the distribution of several features within the family Bothriolepididae using the PHYLIP program package provides a new version of the interrelationships of bothriolepids.