Article: Pterygometopine trilobites from the Ordovician of Baltoscandia
A revision of the Pterygometopinae from Baltoscandia has revealed that the subfamily is more diverse at the generic level than previously known. New genera are Ingriops, Oelandiops, Upplandiops, and Keilapyge. The earliest species of Achatella are included in the new subgenus A. (Vironiaspis). The new species Oelandiops mirificus, Upplandiops calvus, Estoniops maennili, and E. fjaeckensis are described. Upplandiops calvus differs from most other dalmanitaceans in having only ten thoracic segments.