UPPER TOARCIAN (LOWER JURASSIC) MARINE GASTROPODS FROM THE CLEVELAND BASIN, ENGLAND: SYSTEMATICS, PALAEOBIOGEOGRAPHY AND CONTRIBUTION TO BIOTIC RECOVERY FROM THE EARLY TOARCIAN EXTINCTION EVENT

MARIEL FERRARI, CRISPIN T.S. LITTLE, JED W. ATKINSON

PAPERS IN PALAEONTOLOGY

The Palaeontological Association

Año: 2020

Here we describe a new late Toarcian (Lower Jurassic) marine gastropod fauna from rocks of the Cleveland Basin exposed on the North Yorkshire coast of England. Th fossil assemblage comprises sixteen species, of which three are new: Katosira? bicarinatasp. nov., Turritelloidea stepheni sp. nov. and Striactaenonina elegans sp. nov. Four speciesare described in open nomenclature as Tricarilda? sp., Jurilda sp., Cylindrobullina sp. andCossmannina sp. The other species have previously been described: Coelodiscus minutus(Schübler in Zieten), Procerithium quadrilineatum (Römer), Pseudokatosira undulata(Benz in von Zieten), Palaeorissoina aff. acuminata (Gründel, 1999b), Pietteia unicarinata(Hudleston), Globularia cf. canina (Hudleston), Striactaeonina cf. richterorum Schulbert& Nützel, Striactaenonina aff. tenuistriata (Hudleston) and Sulcoactaeon sedgvici (Phillips). Most of these species are the earliest records of their respective genera and show palaeobiogeographical connections with contemporary gastropod associations from otherregions of Europe and South America. The taxonomic composition of the late ToarcianCleveland Basin gastropod assemblage differs substantially from the faunas of the latePliensbachian and early Toarcian Tenuicostatum Zone, showing the strong effect of theearly Toarcian mass extinction event on the marine gastropod communities in the basin.Only a few gastropod species are shared between the late Toarcian faunas and the muchmore diverse Aalenian gastropod faunas in the Cleveland Basin, suggesting there was afacies control on gastropod occurrences at that time. This is also a potential explanation forthe taxonomic differences between the late Toarcian gastropod faunas in the ClevelandBasin and those in France, and Northern and Southern Germany.