No title
The ellipsocephalid trilobite Strenuaeva spinosa occurs widely in Scandinavia in the lower part of the Ornamentaspis? linnarssoni Zone (Cambrian Series 2). Its first appearance is a readily recognisable, widespread biohorizon in Scandinavia. During ontogeny, intergenal spines are lost and the librigenae develop from a generative zone in the genal region. The palpebro-ocular ridges are distinct and
