The taxonomy and biogeographic history of Glyptostrobus Endlicher (Cupressaceae)
- Glyptostrobus Endlicher is well represented in early Early Cretaceous to Pleistocene deposits in the middle to high latitudes of North America and Eurasia. Although the taxonomy and nomenclature of the genus is complicated, the fossil record indicates Glyptostrobus was represented by a small number of species. The genus first appears in Aptian age deposits from western Canada and Greenland, and achieved a wide distribution early in its evolutionary history. Exchange of Glyptostrobus between Asia and North America occurred across the Spitsbergen and Beringian corridors, which were functional about 110 and 100 million years ago, respectively The Late Cretaceous fossil record of Glyptostrobus shows that the genus had spread into Russia, China and the shores of the Turgai Strait. By the early Tertiary, Glyptostrobus was a prominent constituent of the polar broad-leaved deciduous forests. Paleocene age deposits across western Canada and the United States indicate the genus was present in great abundance in the lowland warm temperate and subtropical forests east of the Rocky Mountains. The broad distribution in North America and Russia during the Paleocene and Eocene indicates that Glyptostrobus grew and reproduced under a diverse range of climatic and environmental conditions, including the cold and unique lighting conditions of the polar latitudes. The presence of Glyptostrobus in Europe indicates the North Atlantic land bridges that extended between North America and Eurasia (Fennoscandia) and Europe during the early Tertiary were used. In Europe, extensive Glyptostrobus dominated swan1ps occupied the Central European Depression during the late Tertiary. Increasing global aridity and cooling, as well as landscape stabilization together with increasing competition for resources and habitat by representatives of the Pinaceae, seem to have forced the genus out of North America, Europe and most of Asia during the Miocene and Pliocene. In Japan, Glyptostrobus persisted until the early Pleistocene. After the early Pleistocene extinction in Japan, Glyptostrobus reappeared in southeastern China. Details of the taxonomic and biogeographic history of Glyptostrobus are examined.