ISSN 0031-0301, Paleontological Journal, 2006, Vol. 40, No. 3, pp. 328–338. © Pleiades Publishing, Inc., 2006. Original Russian Text © T.M. Kodrul, M.V. Tekleva, V.A. Krassilov, 2006, published in Paleontologicheskii Zhurnal, 2006, No. 3, pp. 93–102. A New Conifer Species, Mesocyparis rosanovii sp. nov. (Cupressaceae, Coniferales), and Transberingian Floristic Connections T. M. Kodrula, M. V. Teklevab, and V. A. Krassilovc aGeological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 109017 Russia e-mail:
[email protected] bPaleontological Institute of Russian Academy of Sciences, ul. Profsoyuznaya 123, Moscow, 117997 Russia cInstitute of Evolution, University of Haifa, Mount Carmel 31905, Haifa, Israel Received October 25, 2005 Abstract—A new species, Mesocyparis rosanovii sp. nov. from the Lower Paleocene of the Amur Region, Rus- sia, is characterized by a combination of advanced and primitive features: mixed opposite-alternate branching of vegetative shoots, leafy microsporophylls, as well as a relatively high number of sporangia per microsporo- phyll and seeds per cone scale. The Late Cretaceous–Early Paleogene genus Mesocyparis McIver et Basinger, which obviously embraces a natural group of closely related species, was a significant component of the vege- tation in the middle and high latitudes of eastern Asia and western North America. The range of the genus tes- tifies to terrestrial Transberingian connections between the continents during the Cretaceous warming phases. DOI: 10.1134/S0031030106030142 Key words: conifers, Cupressaceae, Paleocene, Amur Region, Beringia, phytogeography. INTRODUCTION from each other, which would have virtually excluded the possibility of migration. The problem of floristic exchanges between eastern In this context, phytogeographic relations between Asia and western regions of North America has long Asia and North America should be revised using mod- attracted the attention of phytogeographers.