Emendation of the Triassic plant species Glossophyllum shensiense (Ginkgoales) with a review of the genus Glossophyllum Kräusel

An amended species, Glossophyllum shensiense (Sze) Sun et Deng emend. nov. is described here based on the leaf macromorphology and cuticular structures of new materials from the Middle Triassic Tongchuan Formation in Huating County, Gansu Province, China. The species is characterized by large and lanceolate-shaped leaves, as well as regularly orientated stomata. Based on morphology and epidermal structure, all records under the specific name Glossophyllum shensiense (Sze) are re-examined, and three species were proposed, including one newly amended species and two new species: Glossophyllum panii Sun et Deng sp. nov. and Glossophyllum lanceolatum Sun et Deng sp. nov. Following a systematic re-examination of all species of the genus Glossophyllum published in the literature, a total of 12 species were recognized. The spatio-temporal distribution of Glossophyllum indicated that the genus first appeared in the Induan of the Early Triassic in Siberia, and spread to the southern Fergana in Central Asia and China during the Middle-Late Triassic. Its diversification and geographical distribution flourished during the Late Triassic, and declined and disappeared within the Late Triassic. Paleoclimate reconstruction suggested that Glossophyllum inhabits areas with warm and humid climates and is restricted to the temperate and subtropical zones of the Northern Hemisphere.