| [Abstract, p.169] The fossil remains of a hemichordate exoskeleton, recognized as fragments of the stolons and their cyst-like swellings connected with the fusellar zooidal tubes, were derived by chemical isolation from Late Permian (Kazanian) mudstones of the Svalis Dome (central Barents Sea, Norway). These fossils, referred to as Diplohydra szaniawskii sp.nov., are the first undoubted representatives of the Class Graptolithoidea found in Permian deposits. The genus Diplohydra Kozlowski, 1959, known previously only from the Ordovician and originally established as a thecate hydroid taxon, is reinterpreted as an aberrant member of the Order Rhabdopleuroidea. This strange hemichordate, characterized by fusellar tubes distinctly narrower than stolon-like tubes and their swellings, reveals a certain degree of dimorphism in the stolon system. D. szaniawskii sp.nov. also displays some peculiar morphological features common to the Ordovician rhabdopleuroid genus Rhabdopleurites Kozlowski and the stolonoid genus Stolonodendrum Kozlowski. |
