The rhabdosome structure of aSaetograptus species (Graptoloidea, Monograptacea) from a North German glacial boulder

Saetograptus sp. cf.Saetograptus leintwardinensis from the late Ludlow is described from material isolated from a glacial boulder. The species shows several unexpected rhabdosome structures, especially a considerably widening trumpetshaped sicular aperture with a forked dorsal tongue. The high infraspecific variation of the species is documented.