A REVIEW OF RECENT AND FOSSIL SERPULID REEFS - ACTUOPALAEONTOLOGY ANDTHE UPPER MALM SERPULID LIMESTONES IN NW GERMANY

Serpulidae (Polychaeta) are benthic, suspension-feeding worms, mostly marine, secreting their own calcareous habitation tubes. Serpulid 'ree fs' include banks deposited on shallow parts of continental shelves, a nd primary frame reefs at intertidal and subtidal depths. Sheltered ba ys harbour the largest reefs, up to a few metres in height and kilomet res in length. A review of habitats with Recent serpulid mass-occurren ces allows interpretation of the palaeoenvironment in which the serpul id limestones in the 'Upper Malm' (Upper Jurassic-Lower Cretaceous) of NW Germany may have been laid down. The Lower Serpulid Limestones rep resent concentrations of re-deposited serpulid tubes. In the Upper Ser pulid Limestones ('Serpulit') the re-deposited tubes are embedded in s tromatolitic algae. Both limestones were formed in lagoons fringing an inland sea. Several records of Recent and fossil 'serpulid' buildups are erroneous and can be referred to algae, vermiform 'gastropods' or non-serpulid polychaetes. Differences and similarities between calcare ous tubes of serpulids and vermetids (Gastropoda) are summarized.