Abstract: In 1841, Murchison coined the term Permian for strata in the Russian Urals. Recognition of the Permian outside of Russia and central Europe soon followed, but it took about a century for the Permian to be accepted globally as a distinct geological system. The work of the Subcommission on Permian Stratigraphy began in the 1970s and resulted in current recognition of nine Permian stages in three series: the Cisuralian (lower Permian) – Asselian, Sakmarian, Artinskian and Kungurian; the Guadalupian (middle Permian) – Roadian, Wordian and Capitanian; and the Lopingian (upper Permian) – Wuchiapingian and Changhsingian. The 1990s saw the rise of Permian conodont biostratigraphy, so that all Permian Global Stratigraphic Sections and Points (GSSPs) use conodont evolutionary events as the primary signal for correlation. Issues in the development of a Permian chronostratigraphic scale include those of stability and priority of nomenclature and concepts, disagreements over changing taxonomy, ammonoid v. fusulinid v. conodont biostratigraphy, differences in the perceived significance of biotic events for chronostratigraphic classification, and correlation problems between provinces. Further development of the Permian chronostratigraphic scale should focus on GSSP selection for the remaining, undefined stage bases, definition and characterization of substages, and further integration of the Permian chronostratigraphic scale with radioisotopic, magnetostratigraphic and chemostratigraphic tools for calibration and correlation.

Abstract: Permian palynostratigraphic schemes are used primarily to correlate coal- and hydrocarbon-bearing rocks within basins and between basins, sometimes at high levels of biostratigraphic resolution. Up to now, their main shortcoming has been the lack of correlation with schemes outside the basins, coalfields and hydrocarbon fields that they serve, and chiefly a lack of correlation with the international Permian scale. This is partly because of phytogeographical provinciality from the Guadalupian onwards, making correlation between regional palynostratigraphic schemes difficult. However, local high-resolution palynostratigraphic schemes for regions are now being linked either by assemblage-level quantitative taxonomic comparison or by the use of single well-characterized palynological taxa that occur across Permian phytogeographical provinces. Such taxa include: Scutasporites spp., Vittatina spp., Weylandites spp., Lueckisporites virkkiae , Otynisporites eotriassicus and Converrucosisporites confluens . These palynological correlations are being facilitated and supplemented with radiometric, magnetostratigraphic, independent faunal and strontium isotopic dating.

Abstract Early Jurassic plesiosaurian fossils are rare in the Scandinavian region, with a few isolated bones and teeth known from Bornholm, and anecdotal finds from East Greenland. The only other identifiable specimens derive from Toarcian-aged (based on ammonites) erratics deposited during Late Pleistocene glacial advances near the town of Ahrensburg, NE of Hamburg in northern Germany. The geographical source of these transported clasts is debated, but reconstructed ice-flow directions and lithofacies comparisons implicate either the offshore Baltic Sea between the Island of Bornholm and Mecklenburg–Vorpommern (Germany) or, less probably, south of the Danish Archipelago (Mecklenburg Bay). These regions collectively bordered the Fennoscandian landmass and adjacent Ringkøbing-Fyn Island in the late Early Jurassic, and were dominated by near-shore marine deltaic to basinal settings. The Ahrensburg plesiosaurian remains include postcranial elements reminiscent of both the microcleidid Seeleyosaurus and the rhomaelosaurid Meyerasaurus . These occur alongside other classic ‘Germanic province’ marine amniotes, such as the teleosaurid crocodyliform Steneosaurus and ichthyosaurian Stenopterygius cf. quadriscissus : thus, advocating faunal continuity between Scandinavia and southern Germany during the Toarcian, and a less pronounced marine reptile faunal provinciality than previously assumed.

A computerized file of approximately twenty thousand records of conodont occurrences was used in a quantitative study of conodont provincialism. Although biases in the fossil record, in specimen collection, and in data collection preclude any rigid statistical testing, study of quantitative measures of similarity between faunas, when combined with paleogeographic reconstructions, can give insight into provincial patterns and their possible causes. Conodonts showed strong provinciality three times during Paleozoic time. In each instance, temperature is a plausible control of the provincial distribution. In the Ordovician, one fauna inhabited the low to mid latitudes in Laurentia, China, Siberia, and northern Gondwana. Another fauna inhabited high latitudes in Baltica. Cooler high-latitude temperatures as compared to warmer low-latitude temperatures could have been the factor controlling distribution. In the Early Devonian, the Aurelian-province fauna (in present-day Europe and Turkey) inhabited a semirestricted seaway, while the Tasman-Cordilleran-province fauna (in present-day western North America, Siberia, and Australia) occupied the shores of a larger ocean. Eastern North America had a seemingly transitional fauna. These provinces were all in low to mid latitudes, but reconstructed current patterns suggest a warmer temperature in the Aurelian seaway than in the larger ocean. In the Pennsylvanian and Permian, the fauna in western Pangea (present-day North America) differed from that in eastern Pangea (present-day Eurasia). Again both provinces were in low to mid latitudes, but a stronger westward equatorial current due to the Pennsylvanian-Permian glacial episode could have contributed to a warming of the eastern (Tethyan) coast relative to the western coast.

Conodonts are divided into three groups with different histologies: protoconodonts (most primitive), paraconodonts, and euconodonts (most advanced). The first is poorly known, but paraconodonts included a Westergaardodina and a coniform evolutionary lineage, and each was the ancestor of one or more euconodont lineages. Early euconodonts are thus polyphyletic and included the Proconodontus and Tendonitis Lineages, which appeared in the middle Late Cambrian, and the Fryxellodontus and Chosonodina Lineages, which appeared in the Early Ordovician. Major changes in conodont evolution, biofacies adaptation, and development of provincialism coincided with sea-level fluctuations near the end of the Cambrian (here named the Lange Ranch Eustatic Event, or LREE) and similar fluctuations recorded at the Lower/Upper Tremadoc boundary (here named the Black Mountain Eustatic Event, or BMEE). Protoconodonts and paraconodonts were probably pelagic and cosmopolitan. Genera of the Proconodontus Lineage were probably also pelagic. Some genera of the latter lineage are found only in low- to mid-paleolatitude areas; others were cosmopolitan, including Cordylodus . Genera of the Teridontus and Fryxellodontus Lineages may have been nektobenthic. Some were adapted to warm, high-salinity environments that existed during the LREE, but younger genera probably were adapted to normal salinity and were more widely distributed. No apparent provincialism existed until the appearance of euconodonts, after which two broad faunal realms are distinguishable. The warm faunal realm included shallow seas in low to middle paleolatitudes; the cold faunal realm included high-paleolatitude seas and open-ocean areas. Early euconodonts of the Proconodontus Lineage appeared and quickly became dominant in the warm faunal realm during the latest Cambrian. Much of the preexisting protocondont-paraconodont fauna was displaced from the warm faunal realm but continued to dominate the cold faunal realm through the Early Tremadoc. Major faunal changes occurred in the warm faunal realm as a result of the LREE, and after this event conodonts in this ream consisted for the most part of genera from the Teridontus Lineage. During the BMEE a different euconodont fauna of uncertain ancestry became adapted to the cold faunal realm, after which most of the previously dominant primitive fauna became extinct. Cosmopolitan Cordylodus lived in both faunal realms during much of the Tremadoc, but after it became extinct prior to the Arenig, provincialism was extreme because few species were adapted to both faunal realms. Oneotodus tenuis Müller is reclassified as the type species of a new genus, Phakelodus.

R- and Q-mode cluster analysis of data on the occurrence and distribution of 43 conodont species enables delineation in North America of warm-water Red River and Ohio Valley provinces during the Late Ordovician Velicuspis Chron, and suggests recognition of six major biofacies that represent a continuum from nearshore, shallow-water biotopes with numerous endemics to offshore, deeper-water biotopes characterized by more cosmopolitan species. Approximately coeval conodonts from Great Britain, Baltoscandia, and continental Europe are assignable to at least 36 taxa, which are less well known than those of equivalent age in North America but represent cold-water faunas whose Late Ordovician distribution and frequency of occurrence may be used to characterize British, Baltoscandic, and Mediterranean provinces, within which we recognize only three distinct biofacies. Only a third of the taxa in the Late Ordovician cold-water region are also represented in warm-water areas, where they characterize relatively deeper-water biofacies or have a distribution that indicates they were eurythermal cosmopolites. Late Ordovician conodonts are treated as components of warm- and cold-water pelagic faunas, not because their distribution demands that interpretation, but because the pelagic model is simpler than a benthic or nektobenthic one and squares readily with available distributional data.

Many conodont lineages that appear in the Ludlovian on Gotland and elsewhere have no known earlier record anywhere. The closest relatives are found not in the earliest Ludlovian but in the latest Llandoverian-earliest Wenlockian or in still older beds. Ordinary biofacies and lithofacies models fail to explain the observed distribution, since such lineages appear in all of the different facies identified. Either these lineages evolved in an as yet unsampled province, the isolation of which broke down gradually during the Ludlovian, or their appearance reflects changes in the chemistry of the seawater. If the latter interpretation applies, then it indicates that conodonts can be used as sensitive indicators of fluctuations in the marine realm.