A complete styginid trilobite from the Ordovician of Sweden

Abstract

Styginidae are a small group of trilobite species, which are usually rare and most of which are incompletely known. Here we describe a complete specimen of Raymondaspisgrandigena n. sp. from the Middle Ordovician (Darriwilian, upper Arenig) of Sweden. Among the group it has an unusual combination of exceptionally large genal spines, a thorax with notably short pleural spines in the anterior tergites, and a wide concave pygidial margin. The hypostome is documented for the first time in situ in a styginid, and its attachment can be best described as semi-impendent. © 2012 Springer-Verlag.