Les ostracodes de la collection de P. Margerie et l’âge des couches à Laffittéines du Mont Aimé (bassin de Paris, France)

Ostracodes described by P. Margerie (1967, 1968) from the Laffitteina layers of the “Mont Aimé”, east of Paris, are revisited and re-illustrated. Among the 74 species, 34 are exclusively known from the Upper Cretaceous or belong to genera known to occur only in the Cretaceous, 17 are new or not determined with precision but are nearer of Maastrichtian than Paleocene species, and 23 species are representated only by indetermined valves or carapaces. Cytherelloidea biloculata Van Veen, 1932, Amphicytherura chelodon (Marsson, 1880), Veenidea hendriki Deroo, 1966, Planileberis? corrosa (Van Veen, 1936), Kingmaina hagenowi (Bosquet, 1854), Mauritsina hieroglyphica (Bosquet, 1847), Aysegulina? cuvieri (Van Veen, 1936), Aysegulina depressa (Deroo, 1966), Occultocythereis? complanata (Bosquet, 1854), Acuticytheritta infundibuliformi (Van Veen, 1936), Neocythere virginea (Jones, 1849), Sphaeroleberis saccata (Marsson, 1880) and Crassacythere sherborni (Jones & Hinde, 1890) are particularly interesting because morphologically well-characterised. Cytherelloidea biloculata Van Veen, 1932 is known out of the Reims country only in the Maastrichtian of Maastricht but one nearby species is present in the Paris Basin Paleocene. Amphicytherura chelodon (Marsson, 1880) is mentioned in the Maastrichtian from England, Ireland and north Germany (Kaye 1964; Herrig 1966; Neale 1978; Slipper 2009). Veenidea hendriki Deroo, 1966 was described in the upper Maastrichtian of Maastricht likewise as Planileberis? corrosa (Van Veen, 1936), Dumontina? cuvieri (Van Veen, 1936), Aysegulina depressa (Deroo, 1966), Occultocythereis? complanata (Bosquet, 1854) and Acuticytheritta infundibuliformi (Van Veen, 1936). Kingmaina hagenowi (Bosquet, 1854) is known in the upper Maastrichtian of Limbourg and in the Orbitoides media strata of the lower Maastrichtian of Charente-Maritime (Deroo, 1966). Neocythere virginea (Jones, 1849) is one species from the Kent upper Cretaceous. Sphaeroleberis saccata (Marsson, 1880) was described in the upper Maastrichtian but is also mentioned in the upper Campanian of the Paris basin (Babinot et al. in Oertli 1985). Crassacythere sherborni (Jones & Hinde, 1890) is present in the upper Campanian and in the lower Maastrichtian of Great-Britain (Neale 1978). At last, Montian ostracodes species of Mons and of the Paris basin are totally absent. These ostracodes are not reworked: even the most fragile valves are not broken and no size- or shape-related sorting has been observed. Also, the characteristic foraminifer Laffitteina mengaudi (Astre, 1923), only known in the upper Cretaceous, is not reworked. Thus, the early Danian age assumed until now cannot be accepted.