Visbyella - a new genus of resserellid brachiopod

A new genus of resserellid brachiopod, Visbyella, is erected based on Orthis visbyensis Lindström 1861 as type species. Visbyella is distinguished from both Resserella and Fascicostella by its hypercline dorsal interarea, its extroverted (dorsally facing) trilobed cardinal process, the presence of an apical plate, and by its tendency to have the median ridge in the brachial valve elevated anteriorly. Fascicostella is distinguished from both Visbyella and Resserella by its distinctly fasciculate ribbing. Dalmanella wisbyensis var. nana McLearn 1924 and Parmorthis visbyensis var. pygmaea Whittard and Barker 1950 are both considered to be distinct species and are assigned to Visbyella together with a new species V. cumnockensis, which is here described from New South Wales.The known distribution of Visbyella is in beds of Silurian (Upper Llandovery and Wenlock) age from Gotland, Britain, Nova Scotia, southern New Brunswick, and New South Wales. Both Resserella and Visbyella make their first appearance in the Upper Llandovery. The more complex morphology of Visbyella seems to us to be more easily derived from Resserella than vice versa.