Acta Palaeontologica Polonica

Discovery of Pterobranchia (Graptolithoidea) in the Permian

Piotr Mierzejewski and Cyprian Kulicki

Acta Palaeontologica Polonica 47 (1), 2002: 169-175

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 isolations 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 Kozłowski, 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 Kozłowski and the stolonoid genus Stolonodendrum Kozłowski.

Key words: Graptolithina, Pterobranchia, Rhabdopleuroidea, Permian, Norway, Barents Shelf.

Piotr Mierzejewski [], Instytut Paleobiologii PAN, ul. Twarda 51/55, PL−00−818 Warszawa, Poland. Present address: ul. Filtrowa 83/49, PL−02−032 Warszawa, Poland; Cyprian Kulicki [], Instytut Paleobiologii PAN, ul. Twarda 51/55, PL−00−818Warszawa, Poland.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.