Permian smaller foraminifers: taxonomy, biostratigraphy and biogeography

Abstract

AbstractThis review has been undertaken in order to present some interpretations about the biostratigraphy of the smaller foraminifers belonging to four classes present during the Permian: Fusulinata, Miliolata, Nodosariata and Textulariata. Biostratigraphic markers of these classes are principally known in the orders and superfamilies of Lasiodiscoidea, Bradyinoidea and Globivalvulinoidea (Fusulinata), Cornuspirida (Miliolata), and in the entire class Nodosariata. The class Textulariata is too little known during the Permian to play a significant biostratigraphical role: nevertheless, the appearance of the order Verneulinida is probably an important bioevent. The main genera among the lasiodiscids are Mesolasiodiscus, Lasiodiscus, Lasiotrochus, Asselodiscus, Pseudovidalina, Xingshandiscus and Altineria; the bradyinoids Bradyina and Postendothyra; the globivalvulinoids Globivalvulina, Septoglobivalvulina, Labioglobivalvulina, Paraglobivalvulina, Sengoerina, Dagmarita, Danielita, Louisettita, Paradagmarita, Paradagmaritopsis and Paremiratella; the miliolates Rectogordius, Okimuraites, Neodiscus, Multidiscus, Hemigordiopsis, Lysites, Shanita and Glomomidiellopsis, and the tubiphytids and ellesmerellids, which might be specialized miliolate and cyanobacterium consortia, with reference to microstructures and phylogenies of these groups. The Nodosariata markers belong to Nodosinelloides, Tezaquina, Polarisella, Geinitzina, Pachyphloia, Rectoglandulina, first true Nodosaria, Langella, Pseudolangella, Calvezina, Cryptoseptida, Cylindrocolaniella, Colaniella, Frondina and Ichthyofrondina, but their lineages are too poorly understood to permit an accurate biostratigraphic use at the present time. The superfamily Geinitzinoidea is emended. Finally, palaeobiogeographical implications based on Shanita, Colaniella and Altineria are given.