Seeds of Weigela (Caprifoliaceae) from the Early Miocene of Weichang, China and the biogeographical history of the genus
Abstrakt
Seeds of the genus Weigela (Caprifoliaceae) are described from the Early Miocene Hannuoba Formation of Weichang County, Hebei Province, China. They are flat, elliptic, with translucent membranous wings on three sides.
Comparison with extant and fossil species of Weigela indicates that these seeds are different which therefore were assigned to a new species, Weigela weichangensis. On the basis of the fossil record, the distribution of Weigela through geologic ages is shown on a series of palaeogeographic maps of the Northern Hemisphere.
The oldest fossils of Weigela are seeds from the Oligocene of West Siberia, Asia. The genus later expanded into East Asia and Europe as well as into Arctic/Subarctic areas of North America via the North Atlantic Land Bridge and/or Bering Land Bridge in the Miocene.
Weigela disappeared from Europe and North America probably during the Pleistocene glaciations, but survived in Asia until now.