Walossek, D. & Müller, K. J. 1990 10 15: Upper Cambrian stem‐lineage crustaceans and their bearing upon the monophyletic origin of Crustacea and the position of Agnostus. Lethaia, Vol. 23, pp. 409–427. Oslo. ISSN 0024–1164. Three new arthropods in uncompressed condition have been discovered in Upper Cambrian limestone nodules (Orsten) of Västergötland, Sweden. Together with Martinssonia elongafa Müller & Walossek, 1986, they are recognized as descendants of early offshoots from the stem‐lineage of Crustacea. Their morphology provides new insights into the evolutionary path and progressive development of ground plan characteristics along the stem‐lineage and gives further support for the monophyletic origin of Crustacea s. str., which embraces all taxa with extant derivatives. Structures of the ventral morphology shared between these stem‐lineage crustaceans and Agnostus lead to the consideration of alternatives for the currently assumed position of agnostids. ▭Crustacea. ontogeny, phosphatization. phylogeny, stem‐lineage, Sweden, 3 D‐preseroation, Trilobita

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Mülkr. Klaus 1. 1979 01 IS: Phosphatocopine ostracodes with preserved appendages from the Upper Cambrian of Sweden. Lethaia. Vol. 12. pp. 1–27. Oslo. ISSN 0024–1164. More than 400 specimens of phosphatocopine ostracodes. representing different moult stages of Vestrogothia. Falites and Hesslandona have been recovered, with body and appendage structures preserved in minute detail. from anthraconites in the Upper Cambrian of Sweden and drift boulders deriving from that area. The secondary phosphatization of these structures, leading to preservation. is extensively discussed. It comprises even the inner lamella, but the abdomen is not preserved. Hypostome and lower lip are well developed. The large antennula is composed of a basipodite with probably two podomeres and a long exopodite with up to 18 podomeres bearing long spines, forming a natatory organ, and a broad endopodite of two to three podomeres. The biramous organization of the antennula is a unique, most primitive feature of phylogenetic significance. The antennae and up lo four additional pairs of appendages are also biramous and similar to the antennulae, not yet differentiated for specialized functions. Only the last pair is uniramous, but a second branch may have developed in subsequent moult stages not represented in the material. The movement of food into the mouth was achieved by the endites of antennulae and antennae, a function transferred backwards to other appendages during the course of ostracode phylogeny and reflected in ontogenetic trends among Recent ostracodes. The phosphatocopines were nectobenthic, filtering plankton feeders.

Six monotypic new genera of small crustaceans with phosphatised integument are described from Upper Cambrian, mainly bituminous limestone of southern Sweden. These are Dala peilertae, Bredocaris admirabilis, Walossekia quinquespinosa, Rehbachiella kinnekullensis, Skara anulata and Oelandocaris oelandica. The well‐preserved details reveal a nauplius‐like organisation of the head region. At least in Bredocaris, Walossekia, and Rehbachiella the head tagma has only three to four specialised pairs of appendages; Skara and Oelandocaris have five pairs of headal limbs. The antennae and the mandibulae served for locomotion and for mastication. All species have a filter apparatus with a distinct filter groove and serially constructed appendages. Four of the six forms had developed a conspicuous median compound eye. Specialisation in the development of the limbs, etc., suggests that some of the forms were benthie, while others may have been epibcnthic and active swimmers, Crustacea, Dala, Bredocaris, Walossekia, Rehbachiella, Skara, Oelandocaris, soft‐part preservation, Upper Cambrian, Sweden.