Taxonomy and zoogeography of marine nematodes
Nematodes are considered to be the most numerous multicellular animals on Earth. This is also true for the marine environment. Among multicellular animals inhabiting marine sediments, the quota of nematodes usually accounts 60-100%, and the density of them at one square meter of sea floor can amount to more than one million. Species diversity of marine free-living nematodes is immense. About 5.000 species of marine nematodes are known to date, but, according to the most conservative estimation, the total number of marine nematode species is about 10-20.000 and a considerable part of them is supposed to inhabit the deep sea. However, less than 15% of all known valid marine nematode species have been found in the deep sea, whereas the deep sea makes up for 91% of seabed surface. This shows clearly that deep-sea nematodes as the most common and most dominate meiobenthic taxon in deep-sea sediments are greatly understudied. Besides, the diversity of marine nematodes is very high. For instance, among 1.000 examined deep-sea individuals, about 100-200 species can be found, and most of them are new, unknown.
Our interest is to find and describe new nematode species. Samples collected by Senckenberg scientists stem from different parts of the World Ocean. For the taxonomic work, there is a great amount of uninvestigated nematodes in Wilhelmshaven.
On the photo: New nematode species (family Camacolaimidae) parasitizing a deep-sea foraminifera Vanhoeffenella sp. (North-Western Atlantic, depth 5300 m). It is an only known case when multicellular animal parasitizes protists.