A new species of <i>Cyathocarpus</i> with <i>in situ</i> spores from the lower Permian of Gansu, northwestern China

<p>Well-preserved Marattialean fertile fronds are analyzed in this paper that come from the Cisuralian Shanxi Formation of Yongchang, Gansu Province, northwestern China. In particular, synangium in fronds and <i>in situ</i> spores are analyzed in the lab. Data show that the synangium of this species contains between four and five radially arranged pedicellate sporangia. The spores of this plant are small, between 21 and 30 μm, monolete and microgranulate with no visible annule. The fossils presented in this study are included within the genus <i>Cyathocarpus</i>. Furthermore, these spore masses and spores <i>in situ</i> of this genus are described in detail at the first time as a component of the Cathaysian flora. Based on comparisons with previously reported fossil records of these plants, we determined a series of differences. Thus, the fossils presented here are referred to a new species. In addition, the reproductive organs of the new fossils described in this paper provide some valuable taxonomic information. Based on the paleogeographic distribution of <i>Cyathocarpus</i> and the position of paleoplates in Late Paleozoic, we speculated that one of the possible migrated routes of <i>Cyathocarpus</i> is from the Euramerica to the North China Block and Alashan Terrane, terminating in the South China Block.</p>