In the late seventies, ELLIOTT and KINGSTON (1987) discovered a polychaetous annelid in various North Sea estuaries that had previously been found only in North American estuaries. Further specimens of what appeared to be the same species were found in the mid-eighties in the coastal waters of the Baltic Sea (BICK and BURCKHARDT, 1989). The distribution of these events in time and space led to the assumption that a North American species had immigrated to the North Sea and then extended its range of distribution to the Baltic. Within several years this species became one of the most dominant species in these estuaries. Identification of the immigrant was beset with problems from the start. It was identified as M. wireni AUGENER, 1913 or as M. viridis (VERRILL, 1873). It was the population genetic studies by BASTROP et al. (1995) and ROEHNER et al. (1996a, b) that showed the presence of genetically distinct forms in the North and Baltic Sea as well as in different regions of the north eastern coast of America. The morphological studies undertaken against this background allowed a good discrimination between these species (BICK & ZETTLER, 1997). Though, all authors dealing with the two species immigrated into the European estuaries were unable to name these species. The main reasons for this uncertainty are: - species identification is difficult, because diagnostic characters vary with growth (BICK, 1995), - the geographical distribution of Marenzelleria species is far from clear, - type material no longer exists or it is in poor condition (BICK & ZETTLER, 1997). Specimens of the type species of the genus, Marenzelleria wireni, were recorded from the Arctic region, Franz-Joseph Land and Spitzbergen (WIREN, 1883 and von MARENZELLER, 1892). As mentioned above, these specimens deposited in the Zoologisches Museum Hamburg and the Swedish Museum of Natural History, Stockholm are in poor condition. As far as we know further material from these regions does not exist. In order to eliminate the taxonomic uncertainty it is necessary to investigate morphologically and genetically specimens from the type locality.
We intend to collect Marenzelleria specimens from Spitzbergen by means of corer, grab, dredge, plankton net or by digging. After sieving, specimens will be fixed in ethanol (for genetic studies), formalin (morphological studies) or glutaraldehyde (SEM studies). Further polychaetes, e.g. specimens of the genus Spio, will be collected, to start taxonomic investigations on some other problematical polychaetous groups.