Batomorphs (Elasmobranchii: Rhinopristiformes, Rajiformes, Torpediniformes, Myliobatiformes) of the middle to late Ypresian, early Eocene, in the Anglo-Belgian Basin (south-western North Sea Basin) – a review and description of new taxa
Author
Reinecke, T., Mollen, F. H., Gijsen, B., D’Haeze, B. & Hoedemakers, K.
Early Eocene batomorph faunas, represented by isolated teeth from the London Clay Formation, LCF (Division D, lower Sheppey Member, lower NP12) at Burnham-on-Crouch, Essex, UK, and the Tielt Formation (Egemkapel Clay Member) and overlying Hyon Formation (Egem Sand Member, middle to upper NP12) at Egemkapel, western Flanders, Belgium, are described and illustrated. Whereas the Burnham fauna is from an outer neritic, deep-water environment, the faunal assemblages recovered from different stratigraphic levels in the Egemkapel Clay and Egem Sand Members are characteristic of mid to inner neritic settings. We also examined a small batomorph fauna from the upper levels of the Roubaix Clay Member of the Kortrijk Clay Formation exposed in the Koekelberg Clay Pit at Marke, Belgium. The upper Roubaix Clay Member is considered penecontemporaneus with Division D of the LCF, but was deposited in a mid-neritic environment. In all, we identified 13 batomorph taxa in the Sheppey Member, 12 in the Roubaix Clay Member, 23 in two different beds of the Egemkapel Clay Member, and 21 taxa in five beds of the Egem Sand Member. Three new species are described: Essexraja ypresiensis gen. et sp. nov., Casierabatis lambrechtsi gen. et sp. nov., and Eurasiabatis occlusostriata gen. et sp. nov. Based on detailed comparisons with the dentition and dental morphology of living stingrays, four species previously included in the genus ”Dasyatis” are re-allocated to new dasyatoid genera: Casierabatis jaekeli (Leriche, 1905) comb. nov., Sheppeytrygon davisi (Casier, 1966) comb. nov., Serratodasyatis tricuspidata (Casier, 1946) comb. nov., and Belgabatis thierryi (Smith, 1999) comb. nov. The rhinopristiform ”Rhinobatus” bruxelliensis Jaekel, 1894 is transferred to the new genus Glaucopristis. A stratigraphic range chart for batomorph taxa in the late Paleocene, Ypresian, and Lutetian of the North Sea Basin is presented. This chart may be considered as a starting point for additions and updates in future works, because identifications of some small-toothed rhinopristiform and dasyatoid species reported in the literature appear doubtful and the stratigraphic coverage of several species, especially those from outer neritic habitats, is insufficiently known.
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