6533b861fe1ef96bd12c4303

RESEARCH PRODUCT

Aegopinella bourdieri nov. sp. (Gastropoda: Zonitidae),une espèce nouvelle du Pléistocène normand (France)

subject

description

St Pierre-les-Elbeuf (Normandy, NE France) is a reference site for the middle and the upper Pleistocene of NW France. In the eastern part of the quarry, the paleosoils Elbeuf III and IV are truncated, white sands and a small tufa lay on Elbeuf IV. Similar deposits have been recognized at Vernon (Seine valley) and at Arrest (northern France). They are probably contemporaneous (Holsteinian) and each of them has yielded an interglacial malacological fauna. The faunal communities are interesting because they are composed by species living up to now in this country, by emigrated species and by fossil species. Among them, A. bourdieri is a new fossil taxa, endemic of Holsteinian tufas of Normandy. Associated with other species it characterizes homogeneous and well individualized communities. Nevertheless such moist interglacial open forest has been recognized also in tufas at Icklingham and at Hitchin (England). These occurrences lead to distinguish a biogeographical unit revealing particular paleoecological and paleoclimatological conditions during Holsteinian which has permitted the speciation of A. bourdieri in Normandy.