An advanced peltasperm Permoxylocarpus trojanus Naug. from the Lower Permian of the Urals (Russia): An ancient case of entomophily in gymnosperms?

The evolutionary advanced gymnosperm of peltaspermalean affinity Permoxylocarpus trojanus Naug. from the Lower Permian deposits of the Urals (Russia) is described. Female reproductive organs of P. trojanus are spherical, semi-closed, peltate capsules with 15-16 enclosed seeds. Both macromorphology and microstructure, including epidermal-cuticular characters and the anatomical structure of conducting tissues, are characterized. Sterile leaves of Praephylladoderma leptoderma Naug., provisionally belonging to the same parent plant, are also described. Some aspects of peltasperm evolution during the Late Palaeozoic-Early Mesozoic are briefly summarized. The occurrence of enclosed ovuliferous organs (capsules) in some peltasperms, the structure of their pollen grains as well as some palaeoentomological evidences suggest the gradual shift from anemophily to entomophily in evolution of these gymnosperms.