Evolution, palaeobiogeography and palaeoecology of Eucommiaceae
Keywords:Eucommiaceae, Evolution, Palaeobiogeography, Palaeoecology
A comprehensive treatise incorporating morphology, ecology, stratigraphy and systematics of Eucommia belonging to family Eucommiaceae, based on extant and extinct records, is presented. Fifteen species of megafossil leaves and fruits of Eucommia and about one hundred localities from the northern hemisphere are known. Pollen of Eucommiidites troedssonii Erdtman was widely distributed in the Mesozoic sediments of Europe. Authentic pollen reocrds of Eucommia, Eucommiaceaopollenites eucommides Sun and E. minor Sun are known from China. They first appeared in East China in the Paleocene.
The validity of Eucommia leaves known from the Paleocene of the western United States is doubtful. Other records include Eucommia brevirostria from south China, Eucommia kobayashi from northern Japan, Eucommia sp. from Alaska. United States, E. brownie, E. Montana from the Oligocene of United States, E. sibirica from the Miocene and Oligocene of Siberia.
During the Miocene Eucommia species has widest distribution – E. japonica from Japan, E. caucasica from Caucasus, E. kryshtofovichii from Moldovia and Poland, E. palaeoulmoides from Caucasus, Ukraine, the Netherlands, Kazakhastan and western Russia and Eucommia sp. from Mexico are known.
Eucommia europaea is known from the Mio-Pliocene of Siberia, Germany, Poland, France, Italy, the Netherlands and Hungary, Some fossil specimens assigned to the living E. ulmoides were found from the Miocene and Pliocene of Germany, Poland, Romania. Several indeterminable species of Eucommia were recorded from the Neogene of Poland, Germany, France and Italy. One species of Eucommia was found in the Pleistocene of Italy. An evaluation of these records, their geographical distribution, endemism and environmental impact have been discussed.