Beaussetithyris asymmetrica nov. sp. from the Early Santonian of Les Martigues (Basse-Provence, SE France). A–D. Paratype MNHN.F.A59948, dorsal (A), lateral (B), ventral (C) views; note the step-like asymmetrical anterior commissure (D). E–G. Adult specimen MNHN.F.A59947 with a shape intermediate between monoplicate anterior margin and translatory motion of the anterior margin on one side (sub-asymmetrical shape). H–J. Adult specimen MNHN.F.A70645 with a strong shifted anterior margin but with a slight translatory motion of the anterior margin. Scale bars = 5 mm. Photographs: P. Loubry.