Problematic triactine spicules from the Upper Ordovician of Scania, Sweden

Abstract Upper Ordovician shales of the Jerrestad Formation (Ashgill, Eodindymene pulchra Zone) from a borehole at Koangen, Scania (Skane), have yielded pyritized spicules of a previously unknown type. The spicules have two lateral rays (diverging at 125–130°) and one median ray, all in one plane and up to a millimetre in length. The rays are flattened with a central longitudinal furrow on each side, giving them a dumb-bell shaped cross section. At the central junction there is a projection approximately normal to the plane of the rays. The spicules were probably originally calcific and composed of at least five individual crystals. They are described as Vaccipraticola ypsilon n. gen., n. sp. Vaccipraticola may have been a pelagic organism somewhat similar to the pluteus larvae of some echinoderms, but the possibility that the spicules formed a ‘conventional’ spicular skeleton in a larger organism cannot be excluded. The systematic position of Vaccipraticola is unknown.