Article: A new genus of abrograptid graptolite from the Ordovician of southern Scotland

The new genus and species, Metabrograptus scoticus, of the family Abrograptidae is described from the Upper Ordovician (Glenkiln Shales) of southern Scotland. The new genus bears the same relationship to Abrograptus as Dicranograptus bears to Dicellograptus. The recognition of this further type in the family perhaps adds some weight to Finney's (1980) reference of Reteograptus to the Abrograptidae. Although there are problems of homologizing stipe structure, it is clear that the biserial retiolitoid condition in Ordovician forms can be derived in more than one way.