Fossil seed cuticles from the Upper Cretaceous Whitemud beds of Alberta and Saskatchewan, Canada

摘要

Abundant fossil cuticles are associated with megaspores in the Upper Cretaceous Whitemud beds of the southern Alberta plains and in the Whitemud Formation of the Cypress Hills. Form generaSpermatitesMiner andCostatheca(Dijkstra) Hall are emended, and the new genusCarpothecais described. The three genera are differentiated by shape and orientation of cuticular cells. Ten new species of seed cuticles are described. The affinity ofSpermatiteswith the extant genusJuncusL. is reaffirmed, and it is suggested thatCostathecamay be related to extant species ofButomusL. In the Whitemud,Costathecais more abundant in the Alberta plains, whereasSpermatitesandCarpothecaare better represented in the Cypress Hills. The fossil microfloral assemblage indicates that these beds were deposited in a continental, fluviatile to lacustrine environment, having a subtropical climate, in agreement with previous sedimentological, isotopic, and palynological investigations.