Nomenclatural status of Orbitolina pileus Fossa-Mancini 1928 (Foraminifera) (junior synonym Palorbitolinoides orbiculatus Zhang 1986) from the Lower Cretaceous of the Himalaya (Ladakh, Tibet)

The published literature concerning Lower to mid-Cretaceous (late Barremian-Albian, early Cenomanian) Tibetan Orbitolinidae suggests an apparent extreme high diversity with almost exclusive reference to taxa displaying a complex embryo (subfamily Orbitolininae). The majority of them, among Orbitolina pileus Fossa Mancini described in the late twenties from the border areas of Ladakh (India) and Tibet (China), however need taxonomic reconsideration. The original images of O. pileus are herein interpreted as a mixture of a high-conical mesorbitolinid (of unclear species identity) and a section of Palorbitolinoides orbiculatus Zhang described in the early 80ies from Tibet. The concluding new nomenclatural act considers P. orbiculatus a junior synonym of O. pileus validated herein as Palorbitolinoides pileus (Fossa-Mancini) comb. nov. with the designation of a lectotype. The present study refers to data from the literature and own material from the Albian Langshan Fm. of the northern Lhasa Block of Tibet.

Automated summary

This study focuses on the Lower to mid-Cretaceous Tibetan Orbitolinidae, which exhibits a high diversity and complex embryo structures. However, the taxonomy of Orbitolina pileus needs to be reconsidered, as the original images actually represent a mixture of an unidentified high-conical mesorbitolinid species and a section of Palorbitolinoides orbiculatus. The nomenclatural act reclassifies P. orbiculatus as a junior synonym of O. pileus and designates a lectotype. The study utilizes data from the literature and material collected from the Albian Langshan Formation in the northern Lhasa Block of Tibet.