Late Miocene Pseudolarix amabilis bract-scale complex from Zhejiang, East China

Abstract

Previously, the identification of fossil Pseudolarix at the species level has been based on the morphology of the bract-scale complex of the seed cone. The morphological consistence of fossils through most of the Cenozoic with extant P. amabilis has led them to be considered conspecific, suggesting that P. amabilis is an extraordinary example of morphological stasis. However, the lack of cuticular evidence, especially for the leaf-homologous bract, reduces the accuracy of fossil identification based on morphology, thus weakening the evidence for morphological stasis in P. amabilis. For the first time, we provide cuticular evidence of the bract-scale of fossil P. amabilis based on the bract-scale complex from the late Miocene Shengxian Formation, Zhejiang, East China, which improves the identification accuracy and reinforces the concept of morphological stasis in this species. Second, we preliminarily reveal the niche stability of P. amabilis, which corresponds to its morphological stasis. Finally, we infer that the late Miocene forest containing P. amabilis in Zhejiang was an evergreen sclerophyllous broad-leaved or mixed mesophytic forest, which combined with the evergreen broad-leaved forest suggested by previous megafossil studies, indicates the occurrence of vertical vegetation zonation.