Frasnian Atrypida (Brachiopoda) from Silesia (Poland) and the age of the eo-Variscan collision in the Sudetes

Frasnian (Late Devonian) Atrypida (Brachiopoda) from the Świebodzice Depression in the Sudetes (Silesia, south-western Poland) are revised. Three species are recognised. Kyrtatrypa barnimi n. sp. is the first described Late Frasnian species of the genus and one of the latest representatives of the genus before the atrypide extinction at the Frasnian-Famennian boundary. Pseudogruenewaldtia tschernyschewi Rzhonsnitskaya, 1960 is described for the first time outside the type area of the species, the Timan Mts. It allows to date the entire fauna to the Late Frasnian. Spinatrypa mariaetheresiae n. sp. is similar to coeval S. lambermontensis Mottequin, 2003 and S. rossica Rzhonsnitskaya in Rzhonsnitskaya et al., 1998 in having a high tongue (low in most representatives of the genus) but differs from them in ornamentation density. This species is represented by two morphotypes; an analogous dimorphism was described in some Spinatrypina Rzhonsnitskaya, 1964. A synoptic table of Devonian atrypides from the Sudetes is given. At present, given the lack of conodonts and unclear status of other diagnostic macrofauna, atrypide brachiopods are the best time markers giving a pre-Famennian terminus ante quem for the eo-Variscan collision of Bohemia and Saxothuringia.