THE ONTOGENY OF THE LATE PERMIAN TEREBRATULIDS (BRACHIOPODA) GRUNTELASMA SMIRNOVA, GRIGORJEVAELASMA SMIRNOVA, AND CAMPBELLELASMA SMIRNOVA AND THEIR TAXONOMIC POSITION

Abstract

A specific type of ontogenetic change combining elements of dielasmoid and angustothyridid stages of brachidium development is established for the Late Permian genera Gruntelasma Smirnova, 2004, Grigorjevaelasma Smirnova, 2004, and Campbellelasma Smirnova, 2004 from the Russian Platform. On this basis, these genera are assigned to the superfamily Compositelasmatoidea Smirnova, family Compositelasmatidae.