First record of Rellimia Leclercq & Bonamo (Aneurophytales) from Gondwana, with comments on the earliest lignophytes

Abstract

The lignophytes (Embryophytes that possess a bifacial cambium) evolved during the Devonian period and include seed plants. Their advent was a major event in the history of life and had a profound impact on terrestrial environments. Recent reinvestigations of a Devonian locality, Dechra Aït Abdallah in Central Morocco, led to the discovery of a rich assemblage of fossil plants and Tentaculita. This paper focuses on a single specimen of the lignophyte Rellimia Leclercq & Bonamo. Rellimia (Aneurophytales) is a monospecific genus reported from a large number of Middle Devonian localities from western Europe (Belgium, Czech Republic, Germany and Scotland) and America. Its fertile organs are highly distinctive and borne helically on branches. They consist of a basal stalk that dichotomizes once near the base, the resulting branches dividing pinnately and bearing elongated sporangia terminally on ultimate divisions. According to the late Emsian age indicated by our sample of Tentaculita, this Moroccan specimen is to date the earliest representative of both the genus and the lignophytes. If confirmed, this occurrence suggests a possible origin of the Aneurophytalean lignophytes in Gondwana and their rapid and widespread colonization in the Middle Devonian towards Laurussia. © 2010 The Geological Society of London.