72 LUNG-Heft 1/2015 - 79. Tagung Norddeutscher Geologen Xenusion auerswaldae POMPECKJ 1927, a remarkable Lower Cambrian fossil in an erratic boulder from Hiddensee island – the “Halle specimen” NORBERT HAUSCHKE 1 & SOPHIE KRETSCHMER 1 Dedicated to Dr GÜNTER KRUMBIEGEL (1926 - 2014) The noteworthy fossil Xenusion auerswaldae POMPECKJ 1927, which is embedded in an erratic boulder (Fig. 1), is one of the most valuable specimens preserved and scientifically supervised in the Geological and Palaeontological Collections of Martin Luther University Halle-Wittenberg. The sedimentary erratic boulder is a quartzitic sandstone with a characteristically red lamination, and can presumably be classified as the Lower Cambrian Kalmarsund Sandstone (File-Haidar-Formation; see RUDOLPH 2013), which crops out in southeastern Sweden. After the first discovery of the fossil from Sewekow in Brandenburg, POMPECKJ (1927; see also JAEGER & MARTINSSON 1967) assigned it as the holotype of a new genus and species and named it Xenusion auerswaldae. The specimen is housed in the Palaeontological Collections of the Museum of Natural History at Humboldt University Berlin (“Berlin specimen”). In 1978 a second and well preserved find was made on Hiddensee island in the Baltic Sea. This specimen found its way into the collections of the “Geiseltalmuseum” (today: Geological and Palaeontological Collections of Martin Luther University Halle- Wittenberg; “Halle specimen”; Fig. 1) as a donation (KRUMBIEGEL, DEICHFUSS & DEICHFUSS 1980, DZIK & KRUMBIEGEL 1989, KRUMBIEGEL 1992). Both finds are therefore of special interest because in the “Berlin specimen” the back part of the fossil is preserved, and in the “Halle specimen” its front part, thus allowing a reconstruction of the animal (Fig. 2). Fig. 1: Xenusion auerswaldae POMPECKJ 1927, the “Halle specimen“. Preserved is the front part with the proboscis-like anterior end (right) and the middle part of the fossil with the dorsal cone-shaped humps and some of the lobopod limbs. Scale 2 cm. Fig. 2: Reconstruction of Xenusion auerswaldae. The occurrence of jellyfish in the sedimentary environment of Lower Cambrian Kalmarsund Sandstone is hypothetical. Drawing: S. KRETSCHMER. 1 Dr. Norbert Hauschke, Sophie Kretschmer, Martin-Luther-Universität Halle-Wittenberg, Institut für Geowissenschaften und Geographie, Von-Seckendorff-Platz 4, D-06120 Halle (Saale), E-Mail: norbert.hauschke@geo.uni-halle.de