Late Carboniferous bryozoans from La Hermida, Spain

Abstract

Fifteen bryozoan species belonging to thirteen genera have been identified from an outcrop of the Picos de Europa Formation (Moscovian, Upper Carboniferous) at La Hermida in northern Spain. Three species and one genus are new— Coscinium hermidensissp. nov., Cystodictya pustulosa sp. nov., and Cystocladia hispanica gen. et sp. nov. Rhabdomesid bryozoans are the most diverse order with seven species, followed by cystoporids (four species), fenestellids (three species) and trepostomids (one species). Bryozoans with erect branched or reticulate colonies dominate in the studied assemblage; only two species possess encrusting colonies. Together with associated crinoids, the bryozoan assemblage indicates a subtidal environment below the zone of vigorous water movement. The La Hermida bryozoan fauna confirms the Upper Carboniferous age of the Picos de Europa Formation and allows various biogeographical interpretations. All previously known species of the genus Coscinium were reported from the Lower Permian of Russia. Clausotrypa monticola is known from the Lower Permian of Russia and Arctic as well as from the Upper Carboniferous of Carnic Alps (Austria). Rhabdomeson cf. propatulissimum and Penniretepora pseudotrilineata are known from the same level of Italian Carnic Alps. Streblotrypa (Streblascopora) nikiforovae and Rhombocladia punctata are known from the Upper Carboniferous (Moscovian) of Ukraine. Fistulipora petaloida is known from Kasimovian Stage of Russian Plate. Several other species show connections with North America