Largest fossil logs of Paraphyllanthoxylon-type from the Eastern Hemisphere (Upper Cretaceous, Czech Republic)

Abstract

The fossil genus Paraphyllanthoxylon is known from many localities around the world. In some cases, the fossilized logs can reach quite large proportions. We present the findings of large fossil logs (the two biggest logs have diameter 98 cm, length minimally 11 m, estimated height 34 m, and diameter 93 cm, length 7 m, estimated height 32.5 m) with Paraphyllanthoxylon type of wood from the Klikov Formation (Turonian–Santonian) in South Bohemia (Czech Republic). These are the largest documented logs from the Eastern Hemisphere from Upper Cretaceous. Our study clarifies for the first time the geological context of fossil wood finds from the South Bohemian Basins. The fossiliferous strata represent a bedload sedimentation in a series of low-sinuosity, braided stream channels. The palaeovegetation reconstruction indicates that trees of Paraphyllanthoxylon-type apparently dominated at the locality, but platanoids and plants of Normapolles complex were also present. No distinct growth ring boundaries were seen, but there were variations in vessel frequency. These changes in wood anatomy were unique and probably associated with rare events in the ecosystem, perhaps a major flood.