Species Interrelatedness in the Genus Lophocythere Silvester-Bradley, 1948 (Ostracoda) in the Late Callovian of the Russian Plate

The genus Lophocythere in Late Callovian of the Russian Plate includes the following species: L. karpinskyi (Mandelstam in Lyubimova, 1955), L. sp. A, L. sp. B and L. acrolophos Whatley, Ballent, Armitage, 2001. Based on similarities in sculpture and hinge structure, the first two species belong to the same phyletic lineage; the third belongs to the other lineage, L. propinqua Malz, 1975 (J2bt3) → L. scabra Triebel, 1951 (J2cl1–2) →? → L. sp. B. L. karpinskyi and L. sp. B invaded the sea of the Russian Plate from Western Europe during a transgression in J2cl1 (Koenigi Phase), and L. sp. A appeared there during J2cl3 (Athleta Phase). L. acrolophos also appeared in the same phase, but it probably originated from L. interrupta Triebel, 1951 (J2cl1-2). These species are the markers of transgression and indices of Pan-European correlative levels.