Taxonomic revision and new elasmobranch records from the Wemmel Sand and Asse Clay members, base of the Maldegem Formation (middle Lutetian, southern North Sea Basin)
De Schutter, P.J.; Steurbaut, E. (2025). Taxonomic revision and new elasmobranch records from the Wemmel Sand and Asse Clay members, base of the Maldegem Formation (middle Lutetian, southern North Sea Basin). Geol. Belg. 28(3-4): 117-131. https://dx.doi.org/10.20341/gb.2025.007
In: Geologica Belgica. Geologica Belgica: Brussels . ISSN 1374-8505; e-ISSN 2034-1954, more
|   |
| Keywords |
|
| Author keywords |
sharks, batoids, middle Eocene, bande noire |
| Authors | | Top |
- De Schutter, P.J.
- Steurbaut, E., more
|
|
|
| Abstract |
The elasmobranch fauna of the middle Lutetian Asse Clay Member (the lower part of the Maldegem Formation) has been updated and complemented with new material from a temporary outcrop at Papenboskant (Wolvertem), about 20 km north of Brussels. This faunal assemblage, which exclusively comes from its coarse-grained glauconitic base, traditionally known as the bande noire, comprises 22 taxa. Fourteen are mentioned for the first time in this horizon, including Abdounia lapierrei, which has never been recorded in Belgium before, and Casierabatis spp. The latter comprises dental morphologies deviating from these of the two nominal Casierabatis species known to date, although it is currently unclear if these reflect intraspecific variability or represent taxonomic novelties. The new records from Papenboskant consist predominantly of small-toothed taxa, mainly batoids, which are absent from the historical handpicked museum collections of the Wemmel Sand and Asse Clay members reviewed in this study. The composition of the elasmobranch fauna indicates that during the middle Lutetian, the area north of Brussels was covered by a tropical to warm-temperate shallow sea with sandy to muddy bottoms and an open connection to deeper waters. The pronounced similarities between the assemblages of the Belgian, Hampshire, and Paris basins indicate that, during the middle and late Lutetian, these three subareas of the southern North Sea remained interconnected and maintained marine exchange with the Atlantic Ocean, not only through the northern seaway but also via the southwestern English Channel. Virtually all of the newly recovered elasmobranch taxa existed over a considerable period of time and were reported from several Ypresian and/or Lutetian deposits across the North Sea Basin. Abdounia lapierrei appears to possess biostratigraphic significance, being so far confined to Lutetian strata. This may also apply to certain representatives of the Casierabatis species group, although this remains to be confirmed. The single tooth of Notorynchus figured in Leriche (1905) and recovered from the Wemmel Sand Member at Neder-Over-Heembeek is re-examined and refigured. This specimen represents the first occurrence of Notorynchus kempi in Belgium. |
|
