Abstract
Elements of Fimbulispina laurentica gen. et sp. nov. from the Fimbuldal Formation (middle Cambrian, Miaolingian Series, Drumian Stage) of North Greenland (Laurentia) are interpreted as the circum-oral grasping spines of a stem-group chaetognathiferan. Association of the elements into the arrays known from fossil and recent free swimming chaetognathans (arrow worms) has not been observed. The elements differ from the simple, hollow, cones characteristic of contemporaneous protoconodont elements in displaying a transversely convex posterior face, a deeply channelled anterior face, a pair of internal lath-like structures and two basal cavities. In terms of their overall cross-section they are reminiscent of elements of Dakorhachis thambus from the Weeks Formation (Miaolingian Series) of Utah. Seen collectively, the morphological variation displayed by these elements attests to the diversity of ‘graspers’ in stem-group chaetognathiferans. John S. Peel [john.peel@pal.uu.se], Department of Earth Sciences (Palaeobiology), Uppsala University, Villavägen 16, Uppsala, SE-75236, Sweden.
Published Version
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