Waarnemingen van Ensis directus (Conrad, 1843) tussen Boulogne-Sur-Mer en le Touquet
Severijns, N.; Gilles, S. (1993). Waarnemingen van Ensis directus (Conrad, 1843) tussen Boulogne-Sur-Mer en le Touquet. De Strandvlo 13(2-3): 56-67 In: De Strandvlo: Driemaandelijks Tijdschrift van De Strandwerkgroep België. De Strandwerkgroep België: Ursel. ISSN 0773-3542, more |  |
| Authors | | Top | - Severijns, N., more
- Gilles, S.
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| Abstract | On 19-07-1993 fresh specimens of Ensis directus (CONRAD, 1843) were found on the beach of Equihen, about 6 km south of Boulogne-sur-Mer, in France. A study of Ensis-material collected on 19-07-1993 on the beaches of Equihen and Hardelot, and on 20-07-1993 on the beach of Le Touquet (about 22 km south of Boulogne-sur-Mer), showed that E. directus is a common species there already. In Equihen, 14 of the 23 collected Ensis-shells belonged to E directus, the rest to Ensis arcuatus. In Hardelot 19 of the 30 collected Ensis-shells were from E. directus and in Le Touquet 9 out of 52. All collected shells of E. directus are fresh and have a glossy periostracum. About two-third or more are more than one year old, while the large specimens are clearly more than two years old, indicating that E. directus arrived in this region already in 1991. Its presence in 1992 is undoubtedly confirmed by the finding of two damaged doublets (the largest being 71 mm long and showing at the damaged end a complete pallial sinus) in material collected on the beach of Hardelot on 12-08-1992. No shells with living or dead animals or with fleshy parts have been found yet. The observations reported here constitute the most southern findings of E. directus in Europe up to now and show that even the Cap Griz-Nez did not form a serious obstacle for the rapid spread of this species. The nature of the material collected in Le Touquet moreover suggests that it is probably present al ready more south than Le Touquet. |
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