Regional Substage Research Articles

Conodont biostratigraphy of the Famennian Makarovian Regional Substage in the Kuk-Karauk section, west slope of the Southern Urals

The Makarovian Regional Substage (Famennian Stage) stratigraphic interval is defined more accurately in the Kuk-Karauk stratotype section (Sikasya River, west slope of the Southern Urals) by conodonts. It is equal to the Pa. minuta minuta, Pa. crepida, Pa. rhomboidea, Pa. marginifera marginifera conodont zones. The absence of intervals equal to the Pa. termini, Pa. glabra prima, Pa. glabra pectinata and Pa. gracilis gracilis zones is testifies to a hiatus. The Pa. crepida and Pa. rhomboidea zones are revealed in the studied section for the first time. Conodont complexes are characterized by rich taxonomic and quantitative diversity (six genera and 48 species). Species of the genus Palmatolepis (up to 92%), which are representatives of deepwater palmatolepid biofacies, predominate.

Palmatolepis abramovae sp. nov.—A New Conodont Species from the Makarovo Regional Substage (Lower Famennian, Upper Devonian) of the Western Slope of the South Urals

Palmatolepis abramovae sp. nov.—A New Conodont Species from the Makarovo Regional Substage (Lower Famennian, Upper Devonian) of the Western Slope of the South Urals

New Givetian Conodonts of the Genus <i>Icriodus</i> from the Kolyvan-Tom Folded Area (South of West Siberia)

New species Icriodus alchedatensis sp. nov., I. kuzbassiensis sp. nov. I. lebedyankensis sp. nov. and Latericriodus sp. E are described from stratotype sections of the Mazalovy Kitatian regional Substage of the Middle Givetian from the Kolyvan-Tom folded area. The taxa of the genus Icriodus belong to two phylolines of the genus Icriodus: the I. struvei phylolines and the I. regularicrescens phylolines according to the concept of Weddige (1977).

THE KUYALNYKIAN REGIONAL STAGE OF THE EUXINIAN AREA OF THE EASTERN PARATETHYS AND THE POSSIBILITY OF DETERMINING THE NEOGENE-QUATERNARY BOUNDARY (PIACENZIAN-GELASIAN) IN THE SOUTHERN UKRAINIAN DEPOSITS

The Kuyalnykian regional stage is a stage of evolution of the Euxine Basin of the Eastern Paratethys with its own conditions for the existence of biota. During that time, the estuarine-marine conditions in southern Ukraine prevailed, leading to the development of various geological formations. However, to date, the Kuyalnykian does not have the official status of a regional stratigraphic unit, either in the Neogene stratigraphic scheme of the Eastern Paratethys or in the Neogene stratigraphic scheme of southern Ukraine, also there is no generalised (formal) description of it as a separate regional stratigraphic unit. The lowering of the Neogene–Quaternary boundary from 1.8 to 2.595 Ma led to a discussion about tracing it in the middle of the Kuyalnykian deposits. This study provides a comprehensive analysis of lithofacies, biostratigraphy (molluscs, ostracods, nannofossils, small mammals), palaeomagnetic and paleogeographic data to obtain a holistic view of the stratigraphy of the Kuyalnykian deposits in southern Ukraine. As a result, we acquired a generalized description and regional stratigraphic scheme of the Kuyalnykian, introduced new local stratigraphic units, obtained criteria for tracing the Neogene-Quaternary boundary, and clarified which part of the Kuyalnykian deposits are of Pliocene age and remain on the pre-Quaternary geological maps, and which of them are already of Pleistocene age and should be transferred to the Quaternary geological maps. The Euxine Basin of the Eastern Paratethys during Kuyalnykian was characterised by euryhaline brackish water, freshwater mollusc assemblages, brackish water and freshwater ostracods assemblages that existed in estuarine-marine environments. The Kuyalnykian deposits are divided into two regional substages and be determinated in the Northern Peri-Black Sea Region, Northern Azov Region, the northern part of the Crimean Peninsula and the Kerch Peninsula. We established the following lithostratigraphic units of the Kuyalnykian for southern Ukraine: the Zamorske Formation in the central and eastern part of the Kerch Peninsula; The Mysove Formation in the northwestern part of the Kerch Peninsula and the eastern part of the Crimean Peninsula is partly Kuyalnykian; the upper part of the Bekhtery Formation on the Left Bank of the Lower Dnieper in the Skadovsk and Holoprystan districts belongs to the lower regional substage of the Kuyalnykian; the Kuyalnyk Formation in the Northern Peri-Black Sea region and Northern Azov region, in the north of the Crimean Peninsula belongs to the upper regional substage of the Kuyalnykian. The age of the Kuyalnykian deposits has been determined based on palaeomagnetic and faunal data. The lower boundary of the Kuyalnykian regional stage is 3.6 Ma which coincides with the boundary of the Hilbert-Gauss palaeomagnetic epochs. The boundary between the Lower and Upper substages is 2.59 Ma (the Gauss-Matuyama boundary). The upper boundary of the Kuyalnykian is set at different stratigraphic levels; it dates 1.780 Ma (the upper boundary of the Olduvai Subchron) in the Indol structural facies zone and also ~1.500 Ma (perhaps above the Gils Subchron, based on small mammal data) or ~0.990 Ma (above the Jaramillo Subchron, based on palaeomagnetic data) in the Western and Eastern structural facies zones of the Northern Black Sea Region, the Northern Azov Region, and the Sivash structural facies zone. This diachrony of the upper Kuyalnykian boundary is explained by environmental difference: while in more marine and “deep water” conditions (Indol structural facies zone) the Kuyalnykian molluscs have already changed to “Gurian (sensu lato)”, in relatively remote estuaries (the Northern Black Sea Region, Northern Azov Region) the Kuyalnykian fauna still “survived”. In addition, it should be noted that the palaeomagnetic dates obtained from studied sections of the Northern Black Sea region are not “absolute” and therefore may be reinterpreted in the future.

The challenge of relating the Kasimovian to west European chronostratigraphy: a critical review of the Cantabrian and Barruelian substages of the Stephanian Stage

Abstract For the west European regional chronostratigraphic framework, the Cantabrian substage was conceived as covering a widely apparent stratigraphic gap between the top of the Westphalian and the base of Stephanian A, the lowest unit of the Stephanian. A continuous depositional history covers this time gap in the Cantabrian region of Spain; the upper limit of this interval was defined by the succeeding Barruelian substage, equivalent to Stephanian A. Intense tectonic and magmatic activity characterizes this period; the Iberian orogenic belt was an essentially linear feature buckled through the Late Pennsylvanian into the tightly folded Cantabrian Orocline. This evidences an extensive southern foreland to the Variscides, in which the coal-swamp biome persisted through the Late Pennsylvanian, supporting biostratigraphical correlation with the Donbass. New high precision U–Pb CA-ID-TIMS radiometric dating of tonstein horizons supports a preliminary time-framework of regional substages: base of the Asturian (proposed, ex-Westphalian D) c. 310.7 Ma; base of the Cantabrian c. 307.5 Ma; base of the Barruelian (ex-Stephanian A) c. 304.9 Ma; base of the Saberian (proposed) c. 303.5 Ma. The Cantabrian and Barruelian embrace the entire Kasimovian of the global time-scale, and the top of the Barruelian is essentially coincident with the base of the Gzhelian.

Foraminifers in the Holkerian Stratotype, regional substage in Britain: key taxa for the Viséan subdivision

Foraminiferal revision of the Holkerian Stratotype of Britain at Barker Scar, Holker Hall, south Cumbria, UK, allows the subdivision of the section into the Cf4δ, Cf5α and Cf5β subzones (the latter being further subdivided into lower Cf5β1 and upper Cf5β2 intervals). The base of Cf5α subzone at the base of bed C and base of Cf5β subzone from the middle part of bed C, occur at 14 m and 10.5 m, respectively, below the traditional basal boundary of the Holkerian at bed K. The lower boundaries of these foraminiferal subzones occur within the main interval affected by dolomitization in the section, which poses problems in defining precisely the bases for these subzones. Nevertheless, in spite of the dolomitization, a more or less continuous foraminiferal record allows a solid correlation of the base of the Cf5β with the preserved succession in the Livian Substage (defined in Belgium, but also used in France), and it is assumed that the base of this substage should correspond to the base of the Cf5α subzone. The base of the Cf5α subzone can be correlated with the base of the Russian Tulian Substage, since it contains many taxa in common with the Holkerian. However, further investigation is needed to establish other levels of correlation (e. g., base of the Cf5β subzone) higher up in the Holkerian substage. All of these problems suggest that the Holkerian, as it is currently recognised, and the Barker Scar stratotype section, in particular, should be reconsidered, and a new para-stratotype section, ideally devoid of dolomitization, should be located and investigated, in order to corroborate the occurrence of the Cf5α and Cf5β foraminiferal subzones compared to those recognised in the Barker Scar Stratotype. These modifications would allow identification of an apparent synchronous faunal event forming the basis of a future subdivision of the Visean.

A summary of upper Pennsylvanian regional substages defined in NW Spain – the chronostratigraphic legacy of Robert H. Wagner

A summary of upper Pennsylvanian regional substages defined in NW Spain – the chronostratigraphic legacy of Robert H. Wagner

The earliest occurrence of the ichnogenus Psilonichnus: a new record from the Mississippian of the West of Ireland

The ichnogenus Psilonichnus Fürsich, 1981 is recorded for the first time from the Mississippian (Brigantian regional substage) limestones of the Slievenaglasha Formation from the west coast of County Clare, Ireland. This record extends the known range of Psilonichnus which has previously been recorded from rocks of Jurassic or younger age. The trace maker of the burrows described herein has not been preserved and remains unknown; however, the ichnogenus Psilonichnus is generally ascribed to the burrowing activities of decapod crustaceans such as crabs or shrimp. Decapods from the Paleozoic are poorly known and assigning the traces to a maker must be treated with caution. However, this record indicates that burrowing organisms using a similar life strategy to modern decapods were established by Brigantian times. These examples are assigned to the Glossifungites ichnofacies, as they occur on an omission surface in a shallow marine carbonate firmground. The burrows were subsequently infilled with deposits of possible storm origin. Glacioeustatic sea-level fluctuation related to the onset of the Late Paleozoic Ice Age is a common feature of Carboniferous sedimentary successions at this level, and the Irish (Mississippian) Psilonichnus horizon occurs just below a significant regional sequence boundary at the top of the Slievenaglasha Formation.

ON THE POSITION OF THE BOUNDARY BETWEEN THE MOSCOVIAN AND KASIMOVIAN GLOBAL STAGES OF THE CARBONIFEROUS IN THE DONETS BASIN

Detailed new data on paleontology and stratigraphy were obtained in the process of fulfilling the tasks of the International Carboniferous Subcommission on definition of the scopes of the Moscovian and Kasimovian global stages and the precise position of the boundary between them. The analysis of these data has shown that the position of this boundary in the type area and in the other regions needs the revision. Recently the investigation of the conodonts from the Moscovian–Kasimovian boundary deposits in the Donets Basin revealed that the boundary between the Moscovian and Kasimovian stages in the official Ukrainian Carboniferous Stratigraphic Scheme does not correspond to this boundary in the type area of these stages in the Moscow Basin. To correct this situation the lower boundary of the Kasimovian in the Ukrainian Scheme must be downgraded by two conodont zones — Swadelina subexcelsa and Sw. makhlinae. To update this boundary in the type area to fulfill the task of the Carboniferous Subcommission four conodont species were proposed as potential index-species for the definition of the boundary between the Moscovian and Kasimovian global stages. These conodont species are as follows Sw. subexcelsa, Idiognathodus sagittalis, I. turbatus and I. heckeli. One of these species, which is selected, will be used as a marker of the studied boundary. None of these species is officially selected as a marker. If Sw. subexcelsa will be selected, the position of the Moscovian–Kasimovian boundary will remain at the present position. In this case this boundary in the Donets Basin has to be downgraded by two conodont zones. If one of three Idiognathodus will be selected, this boundary in the type area will be upgraded by one and a half regional substage. In the Donets Basin it will be upgraded by less than a cycle. Keywords: Carboniferous, stratigraphy, conodonts, extinction event, index-­species.

Microcomputed tomography of the holotype of the early tetrapodIchthyerpeton bradleyae(Huxley in Wright and Huxley, 1866) from the Pennsylvanian of Ireland

AbstractIchthyerpeton bradleyae(Huxley in Wright and Huxley, 1866) is one of the seven tetrapods originally described by Huxley from the Jarrow Assemblage (Pennsylvanian, Langsettian Regional Substage equated with the Bashkirian International Stage) in south-eastern Ireland. The holotype, one of only two specimens considered to represent the taxon, consists of the postcranial skeleton, which has been highly compressed and has undergone extensive replacement of bone by carbonaceous material. The holotype is studied using microcomputed tomography, which reveals that the vertebral column has at least 25 diplospondylous vertebrae with cylindrical centra. Neural arches and a haemal arch are described for the first time. Neural arches in the caudal region are paired and neural spines only contact one another dorsally. The hemal arch is fused and wraps around the ventral margin of the centrum. A stout femur and tibia are described. The morphology of the femur is unique for early tetrapods, with fibular and tibial condyles of similar length and lacking an adductor crest. The morphology of the femur, and its length relative to the tibia, suggests that the holotype ofI. bradleyaepreserves an immature individual. The tibia is a flat bone characteristic of stem tetrapods. Phalanges from the right and left pes are present. Because the phalanges are disarticulated, a phalangeal count cannot be determined. Despite the new anatomical information, the systematic position ofI. bradleyaeis still difficult to establish; however, it does not belong within the colosteids, temnospondyls, or embolomeres, to which it has previously been assigned.

Radiolarian Biostratigraphy of the Bazhenovo Regional Substage (Upper Jurassic–Lower Cretaceous) of Western Siberia

On the basis of published and new data, the features of the history of study of radiolarians and their stratigraphic distribution in the Upper Jurassic–Lower Cretaceous Bazhenovo Regional Substage (Tithonian–Berriasian) of the West Siberian depositional basin are summarized and analyzed. A general geological characteristic of the Bazhenovo Formation is given. The previous regional schemes are briefly characterized. For the first time, radiolarians were studied using SEM. It is proposed to consider five radiolarian-based units: (1) Parvicingula antoshkinae–P. blowi Zone, the lower Volgian and the lower part of the middle Volgian (lower Tithonian–lower part of the middle Tithonian); (2) Parvicingula jonesi–P. excelsa Zone, the middle Volgian (the middle Tithonian–the lowermost upper Tithonian; (3) Parvicingula rotunda–P. alata Zone, the upper Volgian (the uppermost Tithonian, possibly including the lower part of the Berriasian); (4) Parvicingula khabakovi–Williriedellum salymicum Zone, the uppermost Volgian–Ryazanian (the Berriasian); (5) Williriedellum Bed, the uppermost Ryazanian–Valanginian (the Berriasian–Valanginian). The age of all units is confirmed by rare ammonite occurrences. However, the stratigraphic position of two units (Parvicingula antoshkinae–P. blowi Zone and Williriedellum Bed) still requires clarification and additional justification.

Socioeconomic Disparities in Colon Cancer Survival: Revisiting Neighborhood Poverty Using Residential Histories.

Residential histories linked to cancer registry data provide new opportunities to examine cancer outcomes by neighborhood socioeconomic status (SES). We examined differences in regional stage colon cancer survival estimates comparing models using a single neighborhood SES at diagnosis to models using neighborhood SES from residential histories. We linked regional stage colon cancers from the New Jersey State Cancer Registry diagnosed from 2006 to 2011 to LexisNexis administrative data to obtain residential histories. We defined neighborhood SES as census tract poverty based on location at diagnosis and across the follow-up period through 31 December 2016 based on residential histories (average, time-weighted average, time-varying). Using Cox proportional hazards regression, we estimated associations between colon cancer and census tract poverty measurements (continuous and categorical), adjusted for age, sex, race/ethnicity, regional substage, and mover status. Sixty-five percent of the sample was nonmovers (one census tract); 35% (movers) changed tract at least once. Cases from tracts with >20% poverty changed residential tracts more often (42%) than cases from tracts with <5% poverty (32%). Hazard ratios (HRs) were generally similar in strength and direction across census tract poverty measurements. In time-varying models, cases in the highest poverty category (>20%) had a 30% higher risk of regional stage colon cancer death than cases in the lowest category (<5%) (95% confidence interval [CI] = 1.04, 1.63). Residential changes after regional stage colon cancer diagnosis may be associated with a higher risk of colon cancer death among cases in high-poverty areas. This has important implications for postdiagnostic access to care for treatment and follow-up surveillance. See video abstract: http://links.lww.com/EDE/B705.

Effect of the Mid-Carboniferous event on the diversity of brachiopods in the Middle and Southern Urals

Research subject. In this study, the distribution of brachiopods in the Mid-Carboniferous boundary (MCB) sediments in the Middle and Southern Urals was investigated with the aim of determining the influence of the global Serpukhovian-Bashkirian minor mass extinction event on the diversity of these benthic organisms. Materials and methods . Brachiopods distributed over the most complete carbonate sections of the West-Uralian (Brazhka, Sokol, Martyanovo, Askyn, Lakly), Magnitogorskian (Khudolaz, Kalinino, Bolshoy Kizil) and the East-Uralian (Beklenishchevo, Cave gully, Brod-Klyuchiki, “Uralnerud-1” quarry) megazons were studies. Results. It was established that the diversity of the Giganto-productus-Striatifera brachiopod association reduced during the Late Serpukhovian, with the extinction of its dominant taxa having occurred during the Early and Middle Carboniferous boundary. During the Syuranian time of the Bashkirian Age, the Middle-Late Carboniferous Choristites association was formed. Further, in the Akavassian time, the diversity of brachiopods was restored. The consequences of the described event affected mainly the taxa of the species and genus taxonomic rank, and, to a much lesser extent, those of the family rank. On the western slope of the Urals, the maximum regression was recorded at the top of the Striatifera shell-rock layer of the Lower Carboniferous Staroutkinskian regional substage. On the eastern slope of the Urals, the brachiopod diversity characterizing the event in question can be clearly seen in the Late Serpukhovian. This dynamics was also manifested in the lowermost Pennsylvanian; however, it was obscured by the activation of regional tectonic factors. Conclusion. In the Middle and Southern Urals, the Mid-Carboniferous minor mass extinction event is recognized according to the dynamics of the genus and species diversity of bra-chiopods in the deposits of different facies.

Остракоды пограничных отложений девона и карбона из опорного разреза на р. Ыджыд-Каменка (Печорская гряда)

This article presents new data on ostracodes and their stratigraphic distribution in the boundary deposits of the Devonian and Carboniferous (D3-C1) in the reference section Kamenka River (Pechora Uplift). The positions of the Kamenka River section and stratotypic sections of the southern Urals relative to the transgressive-regressive sequence are considered. The ostracode assemblage of the Ps. venulosa — Cor. alba — Cr. primaris zone, which occurs in the section on the Kamenka River and appears in sections of the southern Urals from the base of this zone, is represented by the following taxa: Pseudoleperditia venulosa (Kummerov), Coryellina alba Kotschetkova, Bairdia zaninae Posner, Blessites feluyensis Tschigova, Shishaella alekseevae Tschigova, Knoxiella complanata (Kummerov), Cavellina subeichwaldi Buschmina. The taxonomic characteristics of the upper part of the Pseudoleperditia venulosa — Coryellina alba — Cribroconcha primaris ostracode zone (Gumerovian Regional Substage (Horizon)) are supplemented Acratia subordinaria Buschmina, Healdianella ex gr. alba Lethiers, Phlyctiscapha ? pusilla Gurevitsсh, Pustulobairdia ex gr. confragosa (S. et Sm.), Acanthoscapha pechorica Sobolev, Acratina romboiformis Sobolev, and Rectobairdia eleganta Sobolev first appear at this level A gradual and insignificant change in the ostracode association is observed during the transition from the Gumerovian Horizon to the Malevkian Horizon, which precludes drawing the boundary between them. It is suggested that it would have been more appropriate to draw the boundary at the base of the global Hangenberg transgressive event near the base of the Ps. venulosa — Cor. alba — Cr. primaris ostracode zone (South Urals), which coincides with the initial phase of this transgression.

Conodonts of the Krevyakinian and Khamovnikian Substages of the Kasimovian Stage in the Type Region (Moscow Basin)

The Kasimovian Stage is a stage in the Pennsylvanian Subsystem, originally recognized in Russia. Its type area, despite the stage name (which is after the town of Kasimov in the Ryazan Region), is in the vicinity of the Voskresensk Region in the lower reaches of the Moscow River for the Krevyakian and Khamovnikian regional substages and the former village of Dorogomilovo (Moscow Region) for the Dorogomilovian Regional Substage. The stratotypes of the subdivisions of the Krevyakinian and Khamovnikian regional substages were established in the Voskresensk Region and no longer exist. The conodont assemblages of the Krevyakian and Khamovnikian and the lower part of the Dorogomilovian were studied in the neostratotype of the Kasimovian Stage (Afanasievo Section) and the Perkhurovo Reference Borehole drilled near the town of Voskresensk.

Upper Viséan and Serpukhovian Biostratigraphy and Lithofacies of the Southeast of the East European Platform

This paper presents new data on the biostratigraphy and sedimentology of upper Visean and Serpukhovian deposits (Lower Carboniferous) from boreholes in the southeast of the East European Platform around the Sol-Iletsk Swell (Orenburg oblast). Using rock lithology, sublatitudinal facies zones are recognized in the studied area. The deposits are represented by open shallow shelf facies, up to 500 m thick, in the area of the Sol-Iletsk Swell and near-side zone of the Preuralian Foredeep. To the south, at the margin of the Northern Pericaspian, their thickness sharply decreases to 36 m, and the succession is composed of carbonate-clay sediments of the relatively deep shelf. On the basis of foraminifers and conodonts, the upper Visean and Serpukhovian are subdivided using the regional substages of the stratigraphic scheme of the East European Platform, and foraminiferal zones are recognized. The base of the Serpukhovian in the high-energy shallow-water facies of the open shelf is drawn by the entry of the foraminifers Janischewskina delicata and Endothyranopsis plana; in lower energy facies, it is placed at the level of the first appearance of Neoarchaediscus postrugosus; in the clay-carbonate facies of the relatively deep shelf, it is drawn according to the appearance of the conodont Lochriea ziegleri. The distribution of microfauna from five boreholes, the characteristics of the foraminiferal zonal assemblages, and the interregional correlation are discussed.

Distribution of brachiopods in the Lower Visean deposits in the Eastern Urals

Subject. This paper is aimed at investigating the distribution of brachiopods across the stratotypes of the Lower Visean regional substages and formations, as well as of the Upper Visean Zhukovsky regional substage, which are presently located in the East Uralian and Magnitogorskian megazones of the Eastern Urals. Materials and methods. Brachiopods were one of the most numerous groups of benthic organisms inhabiting the Early Carboniferous marine basins now located in the eastern Urals. This paper presents information on the distribution of brachiopods across the carbonate and carbonate-terrigenous facies of the Middle (Pokrovskoe, Zhukovo, Smolino, Brod-Kljuchiki) and Southern (Nizhnyaya Gusikha, Verkhnyaya Kardailovka, Kipchak, Ust-Grekhovka and Khudolaz) Urals sections.Results. It is found that Delepinеа lebedevi, D. comoides, Ovatia markovskii and Composita sp. were the domineering species during the Early Visean period. The Ust-Grekhovsky time marked the appearance of migrant species, which resulted not only in a decrease in the proportion of Delepinеа and Ovatia but also significantly changed the entire structure of the local brachiopod communities. The evolutionary transformation of the Ovatia genus at the Ust-Grekhovsky–Zhukovsky time boundary led to the appearance of the Linoprotonia genus and subsequently to the Globosoproductus genus (the first representative of the Gigantoproductini). The Zhukovsky period was characterized by a continuing reorganization of the composition and structure of the communities, featuring a change in the dominant taxa. The Linoprotonia and Globosoproductus genera became widespread. Rare representatives of the Gigantoproductus, Datangia and Semiplanus genera appeared.Conclusions. A direct correlation between the diversity of brachiopod associations and abiotic factors is found. The most diverse associations represented by the taxa of several orders, including Gigantoproductini, inhabited shallow-water environments with carbonate sedimentation. The evolution of brachiopods over the Early Visean and Zhukovsky periods of the Late Visean was characterized by natural succession in the composition of genera and species, with the most significant alteration having occurred in the Ust-Grekhovsky and Zhukovsky periods.

An evaluation of biostratigraphic markers across multiple geological sections in the search for the GSSP of the base of the Serpukhovian Stage (Mississippian)

This paper aims to evaluate potential biostratigraphic markers for the Viséan–Serpukhovian boundary in sections of Europe and Asia, to help identify the base of the global Serpukhovian Stage, which is a high priority task for Carboniferous biostratigraphy. Sections in the Serpukhovian stratotype area in the Moscow Basin contain a gap at the base of the Tarusian Regional Substage (basal in the classical Serpukhovian), so the traditional boundary defined in these sections cannot be precisely correlated with other successions worldwide. The IUGS Task Group to establish a GSSP close to the traditional Viséan–Serpukhovian boundary focused on the search for a new boundary marker, primarily on the first appearance datum (FAD) of the conodont Lochriea ziegleri in the lineage Lochriea nodosa to Lochriea ziegleri, considering it to be a suitable biostratigraphic event. The FOD (first occurrence datum) of L. ziegleri has been recognized in many successions worldwide, although only in a few sections the supposed evolutionary lineage of L. ziegleri was inferred. There are serious impediments to the FAD of L. ziegleri being universally accepted as the boundary marker. This paper presents a review of the FOD levels of L. ziegleri documented so far from multiple sections along with other correlatable markers (foraminifers and ammonoids) that can serve as additional points of reference in sections where a conodont record is poor or absent. The reviewed sections are Naqing Section (South China), Verkhnyaya Kardailovka and Kugarchi sections (South Urals, Russia), Mariinsky Log and Ladeinaya Mountain Sections (western slope of the Middle Urals, Russia), Novogurovsky Section (Moscow Basin, Russia), Vegas de Sotres Section (Cantabrian Mountains, Spain), Lugasnaghta Section (County Leitrim, Ireland), Wenne River Bank Section (Germany), and Milivojevića Kamenjar Section (Družetić, NW Serbia). We also included a compilation of data from sections of North England and southern Scotland. In this paper, we will mainly focus on newly described sections, while the discussion of most previously described sections was summarized by Nikolaeva et al. (2001, 2002, 2005, 2009b) and other publications, so they are only briefly mentioned in this review. It should be added that there is no such a thing as a perfect GSSP section, as each section has certain disadvantages, either lithological, paleontological, or both, so it is important to hear and discuss all the different opinions to develop the optimum strategy for future research. In addition, we analyze published records from several sites in North England and southern Scotland. We discuss the first appearances of the ammonoid genera Cravenoceras, Edmooroceras, Lyrogoniatites, Dombarites, and Platygoniatites, the foraminifers Neoarchaediscus postrugosus, Hemidiscopsis muradymica, H. hemisphaerica, species of Janischewskina and Monotaxinoides, Eostaffella pseudostruvei group, Eostaffellina decurta, and Endothyranopsis plana. We publish here for the first time the useful accounts of foraminifers and conodonts from the Mariinsky Log Section and Ladeinaya Mountain Section (Middle Urals, Russia), and re-figure several important type specimens from Europe and the Urals.

Основные черты стратиграфии и палеогеографии нижнедулгалахского регионального подъяруса пермской системы Якутии

Основные черты стратиграфии и палеогеографии нижнедулгалахского регионального подъяруса пермской системы Якутии

A late Pleistocene gastropod fauna from the northern Caspian Sea with implications for Pontocaspian gastropod taxonomy.

The present paper details a very diverse non-marine gastropod fauna retrieved from Caspian Pleistocene deposits along the Volga River north of Astrakhan (Russia). During time of deposition (early Late Pleistocene, late Khazarian regional substage), the area was situated in shallow water of the greatly expanded Caspian Sea. The fauna contains 24 species, of which 16 are endemic to the Pontocaspian region and 15 to the Caspian Sea. The majority of the species (13) belongs to the Pyrgulinae (Hydrobiidae), a group famous for its huge morphological variability in the Pontocaspian region. The phenotypic diversity has led to an inflation of genus and species names in the literature. New concepts are proposed for many of the genera and species found in the present material, with implications for the systematics and taxonomy of the entire Pontocaspian gastropod fauna. Laevicaspia vinarskii sp. n. is described as a new species. This contribution is considered a first step in revising the Pontocaspian gastropod fauna.