Diversity and distribution of Devonian Protolepidodendrales (Lycopsida)

Abstract

A review of recent literature regarding Devonian Protolepidodendrales (Lycopsida) emphasises the progress that has been made in the understanding of this group of common fossils. They share complex microphylls, undifferentiated sporophylls and a presumed herbaceous habit. Maximum diversity occurred in the Middle and lowermost Upper Devonian. Usually only relatively well preserved materials can yield determinative characters. The genera Protolepidodendron, Colpodexylon, Haskinsia, Artschaliphyton, Minerodendron, Leclercqia, Archaeosigillaria and a new genus are discussed. A regional survey demonstrates that Leclercqia, Haskinsia and Colpodexylon are widely distributed across Laurussia, Siberia and Kazakhstan with more sporadic occurrences in Gondwana. Endemic forms may be found in South China and South Africa during the Middle and early Late Devonian.