The Evolution of the Earliest Llandovery monograptids

Abstract

AbstractThe incommodus, atavus and cyphus monograptid groups appear more or less simultaneously in the atavus Zone. The atavus and cyphus groups are related, one of these probably giving rise to the later tenuis group of monograptids, Possible roots of these groups and relationships with later monograptids are discussed. Monograptus strachani sp. nov. is proposed to replace the name M. incommodus sensu Elles & Wood.