Sur la présence d'une nouvelle espèce d'Isoetites dans la flore du Crétacé inférieur de la région de Tataouine (Sud tunisien) : implications paléoclimatiques et phylogénétiques

Abstract

Fossil plant compressions belonging to Isoetales have been discovered, for the first time, in clay from the Lower Cretaceous of Merbah el Asfer, Tataouine area (south Tunisia). The study of leafy corms and sporophylls has permitted us to attribute the fossils to the genus Isoetites Münster. The comparison between the known Mesozoic material leads to the description of a new species : I. daharensis nov.sp. Its affinities with Isoetes and with Triassic species show that the Isoetales were differentiated before the beginning of the Mesozoic era, and since then this lineage has shown little morphological variation. The good preservation of fossils is evidence of short transportation in a deltaic plain with sufficient moisture to permit the growth and development of these plants.Key words: Isoetales, Isoetites, Lower Cretaceous, Tunisia, phylogeny, palaeoecology.