New data on some type-species of Maastrichtian-Paleocene Dasycladales (Green algae) from Iran. Part I. Pseudocymopolia Elliott , 1970

[摘要] Pseudocymopolia anadyomenea , the type-species of the genus, was described by Elliott ( 1959 ) from the Maastrichtian of Iraq. Besides the type-locality, it was also recorded from the upper Maastrichtian Tarbur Formation of Iran, from Afghanistan and Tibet. A rich but moderately preserved material is analyzed herein, evidencing the presence of two discrete species: P. anadyomenea and P. acuta n. sp. The new species is characterized by its thallus morphology displaying tapering, keeled segment margins. Besides the morphology, both are also distinguished by biometric parameters such as the outer diameter (D), inner diameter (d), and the d/D ratio. All other Lower Cretaceous species of Pseudocymopolia as well as the Maastrichtian P. anadyomenea have rounded segment margins. Both taxa from the Tarbur Formation occur in inner platform quiet water depositional settings whereas the Lower Cretaceous representatives typically characterize platform margin deposits.

[学科分类] 地质学