Aktuo-palaontologie of the common cuttlefish, Sepia officinalis, an endocochleate cephalopod (mollusca) in the North Sea

摘要

Following 3 days of gales in the North Sea off the Dutch coast, one part of the beach at Katwijk, Zuid-Holland, was littered with shells (cuttlebones) of the common cuttlefish, Sepia officinalis Linne. Over 100 specimens were collected. These Sepia may have died at the same time, with the storm as the probable cause of death (=life assemblage); alternately, did it just cause dead, floating cuttlebones to wash ashore as a monospecific death assemblage? The collected cuttlebones showed a great variation not only in their dimensions, but also in their preservation. All the cuttlebones were examined in detail. About one third of the shells were broken. Most of the cuttlebones have triangular holes and V-shaped scratches, which suggest that they were carried and attacked by birds; this kind of damage can only be made after the death of Sepia. One specimen preserved a bite mark of a fish. Some of the cuttlebones have algae or barnacles growing on them, suggesting they had a lengthy post-mortem residence floating in the North Sea. The diversity and common occurrence of evidence of interactions by other organisms with the cuttlebones, predatory, scavenging, and pseudoplanktonic, leads to a conclusion that these Sepia cuttlebones represent a death assemblage, possibly left over from the previous summer season and perhaps mixed with some older specimens.