The ‘Orsten’ window — a three-dimensionally preserved Upper Cambrian meiofauna and its contribution to our understanding of the evolution of Arthropoda

Abstract

Abstract ‘Orsten’-type preservation, i. e., phosphatisation of cuticles without further diagenetic deformation, has yielded three-dimensional fossils at a scale of 0.1–2.0 mm. Such fossils, first described from Upper Cambrian limestone nodules found in Sweden, have been reported from several continents and from the early Cambrian (approx. 520 M. y. BP) to the early Cretaceous (approx. 100 M. y. BP). Fossils from Cambrian ‘Orsten’-type lagerstatten are mainly representatives of different euarthropod groups and also of different evolutionary levels. This allowed the reconstruction of the early phylogeny particularly of Crustacea in great detail and the recovery of major evolutionary traits within this group, i. e., in the progressive modification of the locomotory and feeding apparatus of the head region. More recently, derivatives also of the early stem lineage toward the Euarthropoda have been discovered. These include apparently parasitic larvae of stemlineage Pentastomida (tongue worms) today living in ...