New data about the Turonian–Coniacian sponge assemblage from Central Europe

Abstract

Siliceous sponges are common fossils in Turonian-Coniacian deposits of Central Europe. Despite numerous studies, the sponge fauna of this age is not sufficiently recognised, due to common poor preservation of the sponge skeletons. The presented taxonomic description of 16 species belonging to Hexactinellida and six species of Demospongiae from Opole area (southern Poland) aims to complete the knowledge of the taxonomic diversity of sponge fauna from the Late Cretaceous basins of Central Europe. Two new species of Hexactinellida – Centrosia clavata sp. nov. and Crateromorpha opolensis sp. nov. and one new species of Demospongiae – Pachastrella rara sp. nov. have been described. The lyssacinosid genus Crateromorpha was previously known only from Recent records. The extant genus Pachastrella, first documented in the Cretaceous based on a bodily preserved specimen, is a representative of non-lithistid demosponges, which are rarely noted in fossil assemblages. The Opole region is the second region in Europe from which the following Turonian/Coniacian species are known: Placotrema cretaceum, Polyptycha becksioides and Pyrospongia vrbaei. The species Eurete halli, Calyptrella bertae, Sporadoscinia micrommata and Theneopsis steinmanni are reported from Turonian strata for the first time. The vertical distribution of sponge assemblages in the Turonian-Coniacian of the Opole Basin reflects the general pattern of sponge distribution in the Circum Sudetic-Trap Basins. The occurence of the aforementioned sponge assemblages has been discussed in light of global sea level changes noted in Circum Sudetic-Trap basins and other Cretaceous basins of epicontinental Europe.