Plant evolution in the Late Cretaceous (Turonian) of the southern Negev, Israel

The fossil flora from the Late Cretaceous (Turonian) localities Gerofit and Qetura with 46 species is presently the most representative for the northern Gondwana realm. The remains of terrestrial and aquatic plants occur in the Upper Shale Member of the Ora Formation bracketed between carbonate sequences with mid-Turonian ammonites. The orders Ranunculales, Nymphaeales, Nelumbonales, Trochodendrales, Hamamelidales, Juglandales, Rosales, Myrtales, and Sapindales are recognized, with various degrees of confidence, among the dicotyledons; the Najadales, Pontederiales, Arales, Cyclanthales, Arecales, and Typhales, among the monocotyledons. A peculiar Gerofitia group, including five genera, is considered as possibly representing a new extinct order of proangiosperms or early angiosperms. The modern aspect of the Turonian angiosperms from the southern Negev suggests a high rate of morphological macroevolution accompanied by ecological differentiation. The earliest angiosperm mangroves are inferred on the basis of taphonomic evidence, root morphology, and cryptoviviparous propagules. The flower/fruit remains indicate the combretaceous and rhizophoraceous affinities of the Cretaceous mangrove species. A diversification center for these groups might have occurred at that time on the northern edge of the Gondwana realm. Instead of decreasing with a supposed convergence of the landmasses, the floristic disparity of the Laurasian and Gondwanic realms steadily increased during the Cretaceous.