Taxonomic revision and palaeoecological interpretation of the plant assemblage of Bernissart (Barremian, Belgium)

Abstract

The Lower Cretaceous plant assemblage of Bernissart (Mons Basin, Belgium) was studied in detail during the 1900s, but no recent revisions have been performed. The taxonomy of plant taxa recovered from this site is updated, which includes one undetermined “aquatic plant” taxon, nine fern taxa (Cladophlebis sp., Hausmannia dichotoma, Phlebopteris dunkeri, Matoniaceae indet., Ruffordia goeppertii, Onychiopsis psilotoides, Coniopteris sp., Korallipteris sp., and Weichselia reticulata), aff. genus Taeniopteris (of unknown affinity), and five undetermined conifer organs (one stem, two types of seed, one cone, and a dispersed bract). Two lithologies are identified, both consisting of grey clays, one with a smooth surface while the other is more irregular. The large number of available specimens has permitted the study of the species richness and relative abundance of the locality and both lithologies. The taphonomical analysis of the specimens including the preservation of the remains, fragment size, and associations between taxa, together with the diversity analyses, results in four assemblages: “algae” in the water column of the lake; a vegetation composed of Weichselia and Phlebopteris closest to the lake margin; Hausmannia, Onychiopsis and the other ferns further away from the margin; and Matoniaceae indet., conifers and aff. Taeniopteris even further away from the depositional site. In general, the plant assemblage at Bernissart consists of open vegetation, which probably belonged to an early successional stage that was burnt frequently by wildfires.