Spores and cryptospores diversification from the Ordovician to the Lower Devonian

The oldest cryptospores are known from the Llanvirn. The sporomorph assemblages are very similar until the Llandovery. During this period, an important extinction affects the cryptospores. Most of the cryptospores enclosed in a membrane disappear. Trilete spores appear during the Ashgill. But it is only during the Wenlock that they really begin to diversify. This diversification continues until the Devonian. On the contrary, the cryptospores disappear progressively from the Wenlock - Ludlow to the Lochkovian. It seems to be a correlation between the eustatic sea level and the biodiversity of these sporomorphs. The Telychian/Sheinwoodian boundary could correspond to a bio-event which is the cause of the replacement of a flora dominated by hepatics by a flora dominated by rhyniophytoids. In addition, it seems that plant producing trilete spores and plant producing cryptospores occupied separated continental biotas.