This paper presents new integrated micropaleontological data from two outcrops (the Agia Marina section) of the Kathikas Formation in southwestern Cyprus. Microfossil assemblages from pelagic interbeds within debris flow deposits are documented, including planktic foraminifera, benthic foraminifera, calcareous nannofossils and ostracodes. The biostratigraphic framework is primarily based on planktic foraminifera and calibrated with calcareous nannofossils zonations. Outcrop 21–32 contains a late Maastrichtian assemblage characterized by planktic foraminifera of the Abathomphalus mayaroensis Zone and calcareous nannofossils of the CC25c/UC20b Zone, consistent with previous age interpretations. Outcrop 21–31 yields microfossil associations including taxa indicative of the early Danian planktic foraminifera P1a Zone and the calcareous nannofossil NP1/CP1 Zone. The documented assemblages indicate that pelagic interbeds within the Kathikas Formation span the late Maastrichtian–early Danian interval. These results highlight the need to revise and extend the stratigraphic range of the formation. The new micropaleontological data indicate that deposition of the Kathikas Formation was contemporaneous with pelagic carbonates of the lower part of Lefkara Formation. Accordingly, the final stage of development of the Mamonia – Troodos nappe system occurred immediately prior to, or during, the late Maastrichtian.
The article provides a description of four type collections of Mesozoic ostracods stored in the Federal Core Material Fund (FCMF) of the FGBU VNIGNI Aprelevka Branch of All-Russian Geological Oil Institute (Russia, Moscow region, с. Aprelevka). Two collections were gathered by M.I. Mandelstam and P.S. Lyubimova from the Callovian-Maastrichtian deposits of Western Siberia for a collective monograph (1960); the other two collections were gathered by N.N. Kolpenskaya from the Berriasian of the North Caucasus (2000), from Upper Jurassic deposits of the Pechora River basin and the eastern part of the Russian Platform for an article and two collective monographs (1993, 1995, 1997). Besides type specimens (holotypes and paratypes), the original specimens of all characteristic species encountered in the published works are stored. The collections comprise in total 337 specimens, including 82 holotypes, 35 paratypes, and 220 originals. The taxonomic lists are provided for the four collections, including references to the original description of each species, type locality, age, specimen number, status, and revision.
The Rhaetian (Late Triassic) was a time of intense biological, climatic, and environmental change, culminating in the end-Triassic mass extinction (ETE). Recent advances in marine biostratigraphy and magnetostratigraphy have allowed a more precise reconstruction of the sequence of extinctions among major marine groups at the Norian/Rhaetian boundary (NRB). The chronology of the Norian-to-Rhaetian pelagic Panthalassan sediments in Japan is mainly constrained by radiolarian biostratigraphy. Although the chronostratigraphic framework of the Triassic is primarily based on conodonts, most Japanese radiolarian zones have not yet been calibrated with conodont biostratigraphy. Here we present an integrated conodont–radiolarian biostratigraphic framework across the NRB in the pelagic Panthalassa, based on bedded chert successions in the Mino belt, central Japan. Five conodont zones are defined: the Mockina bidentata, Parvigondolella andrusovi, Misikella hernsteini, Misikella onouei sp. nov., and Mi. posthernsteini zones, in stratigraphic order. The first occurrence (FO) of Mi. posthernsteini, the index species of the NRB, was identified above the last occurrence (LO) of the radiolarian species Betraccium deweveri, which has previously been used as a marker for this boundary in Japan. In contrast, the FOs of the Rhaetian radiolarian genera Paronaella, Pantanellium, and Proparvicingula coincide with the FO of Mi. posthernsteini. These radiolarian FOs are also documented around the NRB in Italian and North American successions. Our results provide the first conodont-based definition of the NRB in the Panthalassa Ocean and significantly refine the biostratigraphic framework for this critical interval.
