Fossil Pagiophyllum from the Lower Cretaceous of Jiuquan Basin, Gansu Province, and its palaeoenvironmental implications.

Pagiophyllum compressum (Deng and Lu) was described based on the leaf morphological and cuticular features from the Lower Cretaceous (late Aptian—early Albian) Zhonggou Formation of Jiuquan Basin, Gansu Province, North‐west China. P. compressum has helically and tightly arranged leaves appressed on the ultimate shoots, which are imbricated shapes. The epidermal cells are square or rectangular, without papillae on the periclinal walls. The stomatal apparatus is elliptic and composed of 4–7 subsidiary cells arranged in two or three longitudinal rows on the middle part of the leaves. The present specimens may be related to Araucariaceae based on the cluster analysis of morphological features. By summarizing the global distribution of the Pagiophyllum in the Late Jurassic and Cretaceous, it has been found that Pagiophyllum can live in both tropical‐equatorial hot arid belt and humid climate zone of middle and high latitudes, confirming that Pagiophyllum has an extensive habitat. [ABSTRACT FROM AUTHOR]