The late Palaeozoic brachiopod genus Yakovlevia Fredericks, 1925 and the Yakovlevia transversa Zone, northern Yukon Territory, Canada

The familial and superfamilial position, relationship with Muirwoodia Likharev, species composition, and stratigraphical and palaeogeographical distribution of Yakovlevia Fredericks are reviewed. Muirwoodia is considered to be a junior subjective synonym of Yakovlevia, which is placed in the Yakovleviidae Waterhouse within the Linoproductacea Stehli. Forty-five described species ranging from the Middle Carboniferous to the mid-Permian are assigned to Yakovlevia. The palaeogeographical implications of the occurrences of the genus in northeast China, Japan, and US - Central America are discussed. The Yakovlevia transversa Zone, most likely of Early Sakmarian (Tastubian) age, here established is based on material from the Jungle Creek Formation, northern Yukon Territory, and is correlated with several other faunas in the Arctic and western North America. -from Author