Bennettitales, Erdtmanithecales e Gnetales do Cretácico Inferior da Bacia Lusitânica (litoral Centro–Oeste de Portugal): síntese e enquadramento estratigráfico

This paper presents a synthesis of the occurrence of extinct gymnosperms related to the Bennettitales, Erdtmanithecales and Gnetales group and discusses the stratigraphic setting of previously described specimens. These plants are represented by small fossil seeds collected from Lower Cretaceous (Berriasian to Lower Albian) fluvial siliciclastic deposits of the Lusitanian Basin, western Portugal, and probably constitute a monophyletic group, the BEG complex. The fossil seeds are composed of an innermost membranous nucellus preserved as a delicate cuticle. The nucellus is evolved by a membranous integument surrounded by a sclerenchymatic outer envelope. Plants from the BEG complex were contemporary of the earliest angiosperm having shared ecosystems with similar environmental characteristics, what reinforces its paleoecological importance.