In Europe, the fossil record of the eutherian mammals is very scanty for the Late Cretaceous, as only two genera, documented by isolated teeth, are presently recorded in France and in Spain. Both genera, Labes and Lainodon, are considered to be representatives of the 'zhelestids', a paraphyletic unit regarded as being at the origin of Cenozoic ungulates within the Ungulatomorpha clade. We here describe Valentinella vitrollense gen. et sp. nov. from Vitrolles la Plaine (Maastrichtian, southern France). This species, represented by fragmentary remains of lower and upper dentitions, is tentatively assigned to the 'zhelestids' according to the hypoconulid-entoconid twinning and the antero-posteriorly short trigonid on m1-3. The occlusal surfaces are obliterated by dental attrition, but Valentinella could be an evolved 'zhelestid', more derived than Labes and Lainodon by its fully compressed trigonid. Valentinella is similar to Gallolestes by other derived characters such as a crushing specialization of the teeth, associated with a probably molariform p4 (or dp4) and slightly reduced m3. The enamel microstructure, showing a radial prismatic pattern combined with a reduced interprismatic matrix, in which cristallites are oriented at about 45° to the prisms axes, appears compatible with the ancestral morphotype for all ungulates; although no synapomorphy can be proposed for the ungulatomorphs.

Key words: Mammalia, Eutheria, “Zhelestidae”, enamel microstructure, Cretaceous, France.

Rodolphe Tabuce [rtabuce@isem.univ−montp2.fr], Monique Vianey−Liaud [movianey@isem.univ−montp2.fr], Laboratoire de Paléontologie, Institut des Sciences de l’Evolution, cc064, Université Montpellier II, place Eugène Bataillon, 34095 Montpellier cedex 05, France; Géraldine Garcia [geraldine.garcia@univ−poitiers.fr], Laboratoire de Géobiologie, Biochronologie et Paléontologie Humaine, Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France.