Belichnus Traces Produced on Shells of the Bivalve Lutraria lutraria by Gulls
In: Ichnos: an International Journal for Plant and Animal Traces. Harwood Academic Publishers/Taylor & Francis: Reading. ISSN 1042-0940; e-ISSN 1563-5236, meer
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| Trefwoorden |
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| Author keywords |
Belichnus; Ichnotaxonomy; Bivalves; Birds; Predators; North Sea |
| Auteurs | | Top |
- Cadée, G.C., meer
- de Wolf, P.
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| Abstract |
In February 2011, after a storm, thousands of adult, articulated, and still-living common otter shells Lutraria lutraria (L. 1758) were stranded on the North Sea beach of the Island Texel (NL). These 9 to12cm long bivalves were rapidly found and consumed by both herring- and lesser black-backed gulls. Holes, irregular in outline, were observed in some 10% of the articulated shells of these bivalves. These holes were always smaller on the outside of the valves than on the inside and varied in size from 1 to 20mm (outside) to 4 to 22mm (inside). Often the other valve was crushed indicating consumption by gulls. We concluded that these holes were made by the gulls probing the shells; in a few cases, we observed that valves were broken starting from such a hole. Such traces are described in the literature as the ichnogenus Belichnus and were until now attributed to Stomatopoda only. We also suggest that a separate ichnospecies name for two Belichnus holes in one shell should not be used, as we see them simply as a double injury due to two blows. Our findings stress once more the importance of avoiding premature phylogenetic interpretation of traces and the use of a separate ichnotaxonomy. |
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