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Rhabdopleura - like fossil from the Silurian of Gotland

   c - creeping tube of the zooidal tube
   e - erect part of the zooidal tube
   m - basal membrane

Edited by
Piotr Mierzejewski, The Count of Calmont
To the right is an excellently preserved zooidal tube of a Silurian hemichordate closely related to the extant genus Rhabdopleura. The specimen was discovered by Dr. Ralph Männil in the residue from a limestone sample from Möllbos (Halla Beds), Gotland.  

Similar specimen was described by Kozlowski (1970) under the generic name Eorhabdopleura from the Ordovician of Poland. However, the zooidal tube of Eorhabdopleura urbaneki Koz³owski, the type species of the genus Eorhabdopleura, does not display any features which would be of  diagnostic value  for a species. Therefore, both the generic name Eorhabdopleura and the specific name Eorhabdopleura urbaneki may be treated as nomina dubia, as it was shown by Mierzejewski (1986). The fact that the holotype of E. urbaneki has been accompanied by remains of Kystodendron longicarpus (Eisenack, 1937) sensu Kozlowski, 1959 suggests that the taxa are conspecific.
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