Fruits ofHemitrapa(Trapaceae) from the Miocene of eastern China, their correlation withSporotrapoidites erdtmaniipollen and paleobiogeographic implications

Abstract

The fruits of the extinct genusHemitrapaMiki (Trapaceae) are described from the Miocene Shanwang Formation, representing its first fossil record in the Cenozoic of China. Bearing a fusiform, relatively small fruit body with a very long stalk and four sub-equal, strongly ascending, horn-like arms, the Chinese fossil fruits are described asH. shanwangensisQ. Wang new species. Prior to this discovery, a dispersed, trapaceous pollenSporotrapoidites erdtmanii(Nagy) Nagy was documented from the same formation. Recent paleobotanical and palynological studies in Europe demonstrated thatHemitrapawas closely related toS. erdtmanii, so the co-occurrence ofHemitrapafruits andS. erdtmaniipollen at Shanwang implies that they may stem from the same parental plant population.Hemitrapafruits have been widely recognized from the Miocene of mid-latitudes in France, Austria, the Czech Republic, Kazakhstan, Russia, Korea, Japan and the U.S.A. as well as from the late Oligocene–Miocene of Germany and the late Eocene of the Czech Republic. In contrast, dispersedS. erdtmaniipollen has been recovered from the Miocene in central Europe as well as from the late Eocene to the Pliocene of eastern Asiatic shelf basins near the Bohai Sea, Yellow Sea, East China Sea, and the Sea of Japan. Overall, the microfossil and macrofossil records demonstrate that the parental plants ofHemitrapamight have begun to diversify from the mid-latitudes of Eurasia since the Eocene, flourished in eastern Asia and Central Europe during the Miocene, and become extinct after the Pliocene.