The Eocene (Bartonian) marls of the La Guixa Member and Gurb Member, Vic Marls Formation (Ebro Basin, Catalonia, Spain), contain a very rich and diversified siliceous sponge fauna. The fauna is dominated by hexactinellids; lithistids and other demosponges are rare. It consists of 16 species representing 16 genera. Eleven new species and two new genera are proposed for these sponges: Reguantella cavernosa nov. gen. nov. sp., Regadrella concinna nov. sp. (both Hexactinellida, Lyssacinosa), Eurete clava nov. sp., Pleuroguettardia iberica nov. sp., Aphrocallistes almeriae nov. sp., Hexactinella informis nov. sp. (all Hexactinellida, Hexactinosa), Brachiolites munterensis nov. sp., Centrosia viquensis nov. sp., Callicylix eocenicus nov. sp., Rhizocheton robustus nov. sp. (all Hexactinellida, Lychniscosa), Propetrosia pristina nov. gen. nov. sp. (Demospongia, Haplosclerida). Some genera of sponges in this fauna are still extant, but, in general, the predominant ones are very close in morphology, and, without doubt, closely related to the Late Cretaceous sponges. This fauna also differs considerably, in terms of composition, from most other described faunas of Tertiary sponges from the Mediterranean region, which are dominated by lithistid sponges. Lithistid sponges are rare in this investigated assemblage, which seems most similar to an as yet undescribed Eocene fauna from Italy. There is ecological differentiation in the proportions of particular sponges in various outcrops and/or stratigraphical levels that is clearly associated with water-depth-related controlling factor(s): Munter, Tona and Sta. Cecilia represent the deepest facies, Gurb is intermediate, and St. Roc and Vespella are the most shallow. The exact bathymetric position of the sponge fauna is difficult to estimate, but it seems that 100 m (but probably 200 m and more in the case of the deepest parts) of water depth may be inferred for this facies.
Les marnes eocenes (Bartonien) des membres La Guixa et Gurb, de la formation Margues de Vic (Bassin de l'Ebre, Catalogne, Espagne), contiennent une faune d'eponges siliceuses tres riche et diversifiee. Cette faune est dominee par des hexactinellides. Les lithistides et autres demosponges sont rares. La faune consiste en seize especes qui representent seize genres. On propose deux nouveaux genres et onze nouvelles especes: Reguantella cavernosa nov. gen., nov. sp., Regadrella concinna nov. sp. (deux Hexactinellida, Lyssacinosa), Eurete clava nov. sp., Pleuroguettardia iberica nov. sp., Aphrocallistes almeriae nov. sp., Hexactinella informis nov. sp., (toutes Hexactinellida, Hexactinosa), Brachiolites munterensis nov. sp., Centrosia viquensis nov. sp., Callicylix eocenicus nov. sp., Rhizocheton robustus (toutes Hexactinellida, Lychniscosa), Propetrosia pristina nov. gen., nov. sp. (Demospongia, Haplosclerida). Quelques genres d'eponges de cette faune sont encore actuellement vivants, mais en general ceux qui predominent sont morphologiquement tres proches et sans doute directement lies phylogenetiquement aux spongiaires du Cretace superieur. La composition de cette faune differe beaucoup de celle d'autres faunes d'eponges tertiaires de la region mediterraneenne composees surtout des lithistides, tres rares dans l'ensemble de Bassin d'Ebro. La faune etudiee ressemble fortement a une faune eocene de l'Italie non encore decrite en detail. Il y a une differenciation ecologique parmi les assemblages d'eponges des differents affleurements et niveaux stratigraphiques. Cette differenciation est clairement associee aux facteurs lies directement a la bathymetrie. Les affleurements de Munter, Tona et Sta. Cecilia representent les facies les plus profonds; Gurb se situe a une profondeur intermediaire et St. Roc et Vespella sont les facies les moins profonds. La position bathymetrique exacte de cette faune d'eponges est difficile a preciser, mais correspond sans doute a une profondeur d'au moins 100 m, voire 200 m, ou plus dans le cas des facies les plus profonds.