Subgenera of the Upper Triassic bivalve Monotis

摘要: Abstract A two-fold division into the subgenera Monotis Bronn s.s. and Entomonotis Marwick was never fully accepted because it too coarse associated together in M. (Entomonotis) species varying greatly size, inflation, sculpture. The five species-groups that were proposed by Westermann new data from New Zealand laid basis for present proposal of subgenera. resembles salinaria group; (type richmondiana Zittel) includes ochotica, subcircularis, zabaikalica groups; (Eomonotis) n. subgen. typica (Kiparisova ) is equivalent to (Maorimonotis subgen, routhieri Avias) covers calvata group Grant-Mackie; (Inflatomonotis) hemispherica Trechmann) erected a form previously included ochotica group. Two cannot be classified subgenerically. Lower Jurassic eastern U.S.S.R. Italy are tentativ...