Brachiopod Species Research Articles

Guadalupian brachiopods from western Taurus, Turkey.

Here we describe 41 brachiopod species belonging to the orders Productida, Orthotetida, Orthida, Rhynchonellida, Athyridida, Spiriferida, Spiriferinida, and Terebratulida coming from the Guadalupian lower-middle part of the Pamucak Formation at Curuk Dað, Antalya (Western Taurus, Turkey). Associated conodonts are also reported and illustrated. The brachiopod taxa are either pedicle attached genera, with one genus also stabilized by penetration of its elongate umbo, or free living concavo-convex semi-infaunal genera; this indicates that the energy of the environment was never very high, as in settings just below the fair weather wave-base or in a back-reef, more protected inner platform. The brachiopods from the Pamucak Formation are very similar to the Wordian fauna of southeastern Oman, and they are similar to the Guadalupian assemblages of Chios, North Iran, South Thailand, and Salt Range. In comparison they share only a few taxa with the Guadalupian faunas of Central Afghanistan and Karakorum. Therefore the biotic affinity of the Guadalupian brachiopods of the Pamucak Formation is clearly peri-Gondwanan. The brachiopod record at Curuk Dað has implications for understanding the pattern of the end-Guadalupian (pre-Lopingian) biotic crisis. The pre-Lopingian crisis assemblages are quite diverse and nearly totally consist of Guadalupian genera and species except for a single Lopingian incomer. Their stratigraphic range terminates rather abruptly and the following 120 metres of shallow water limestones are barren of brachiopods, after which there is the first occurrence of Lopingian brachiopod taxa, which show a much lower biodiversity. This pattern is different from that observed in South China and it shows that the end-Guadalupian crisis is not only characterized by taxonomic selectivity, but also by a strong local control on the extinction/recovery pattern of some groups.

The famennian-lower carboniferous reference section Geran-Kalasi (Nakhichevan Autonomous Region, Azerbaijan)

One of the most complete sections of the Upper Devonian-Lower Carboniferous in the Nakhichevan Autonomous Region in Azerbaijan is described bed-by-bed. The section is located on the northeastern slope of Geran-Kalasi Mountain. The section features a continuous succession of marine beds and abundant fossils, including foraminiferans, bryozoans, tabulates, rugoses, brachiopods, ostracodes, crinoids, conodonts, and algae. A few ammonoids found in the section have not yet been identified. In the process of composing the 1:25000 scale geological map, a complex brachiopod zone is for the first time accepted as a major stratigraphic unit (indicating the stratotype and an assemblage of zonal brachiopod species).

Mass extinction and recovery of the Early Toarcian (Early Jurassic) brachiopods linked to climate change in Northern and Central Spain

The Early Toarcian mass extinction event represented the most important Mesozoic and Cenozoic turnover of the population of brachiopods and severely affected other benthic fauna. Two main hypotheses have been proposed to explain the synchronous and global mass extinction: an oceanic anoxic event or a warming episode. To test both hypotheses, the dynamics of the brachiopod assemblages below and above the extinction boundary are analyzed and compared with the seawater paleotemperature variations, calculated from the δ 18O data recorded in belemnite rostra. Five sections from Northern and Central Spain, well dated with ammonites, have been selected for this study. The sections show no indication of sedimentary breaks and contain abundant brachiopods, which have been grouped into four assemblages. The changes observed in the brachiopod assemblages show a close correlation with the changes in the seawater paleotemperatures. The oldest assemblage (assemblage 1) coincides with a cooling interval recorded to have taken place in the latest Pliensbachian. Paleobiogeographical reconstruction shows that this assemblage was distributed at paleolatitudes between 30 and 45°N, with a preference for relatively cool waters. With the rise of temperatures that took place during the earliest Toarcian Tenuicostatum Zone, assemblage 1 was substituted by assemblage 2, which composed of different species of the same genera but considerably restricted to the warmer waters of lower paleolatitudes, between 28 and 35°N. Coinciding with the rapid and pronounced increase in seawater temperature, recorded at the Tenuicostatum–Serpentinum zonal boundary, all of these brachiopod species disappeared in the studied localities, marking clearly the extinction boundary. Predominant southward currents through the Laurasian Seaway precluded the possible migration of the brachiopods to cooler northern waters. The brachiopods' disappearance is independent from the oxygenation degree of the sea bottom, and therefore the rapid warming seems to be the most plausible cause of the mass extinction. After the extinction event, the recovery of the brachiopods was uneven. Subsequent to a brief pause, recovery was rapid in Central Spain and in other southern areas of Western Tethys, whereas in northern Spain and in the whole of Europe north of the French Central Massif, brachiopods did not recover until the Mid to Late Toarcian times.

Functional morphology and modifications on spine growth in the productid brachiopod Heteralosia slocomi

Spines are one of the most characteristic ornamenting features of many fossil brachiopod taxa. Despite several studies of spines in different species, there is still insufficient information about the development, functional morphology, and modifications of brachiopod spines. In particular, ontogenetic data are very rare and the understanding of the relationship between functional morphology and paleoecology is elusive. The present study analyzes the functional morphology and modifications on spines of the Pennsylvanian brachiopod species Heteralosia slocomi throughout ontogeny. Spines are tubular hollow and only displayed on the surface of the ventral valves, where they develop from a specific point at the margins of the growth lamellae and directed towards the antero-lateral margins. Modifications of up to 180° from this original direction of growth are observed in response to ecological pressure and biotic interactions. The function of these spines is primarily for attachment by clasping and cementatio...

Latest Changhsingian orthotetid brachiopods in the Dolomites (Southern Alps, Italy): ecological opportunists at the peak of the end-Permian mass extinction

The majority of Changhsingian orthotetid brachiopod species from the Southern Alps were described by the end of the nineteenth century, but were then neglected by subsequent authors who proposed further new species, giving rise to great taxonomical confusion. An examination of type-specimens and newly collected material permits the consideration ofOrthothetina ladina(Stache, 1878) andOmbonia tirolensis(Stache, 1878), type-species ofOmbonia, as the only valid species and describeTeserina neriias a new genus and species. The former two species are mostly located within a short stratigraphic interval, which is a few centimetres thick, limited by the trigger and peak of the end-Permian mass extinction.Teserina neriin. gen. n. sp. occurs 2–3 m above the extinction peak and represents one of the last Permian rhynchonelliform brachiopod holdovers in the Southern Alps.

Study of fossil and recent brachiopods, using a skyscan 1172 X-ray microtomograph

Fossil and recent brachiopods were studied with the aid of a Skyscan 1172 microtomograph. The capabilities of this method at different stages of studying, X-ray scanning and producing slices and 3D models are described. The method enables the study of punctuation, microornamentation, and inner structures of the brachiopod shells and soft tissues. The contrast of shell structures of fossil brachiopods is discussed; it depends on differences in the mineral composition of the shell and surrounding matter. This method allows studying the inner structure of the holotypes of brachiopod species without damaging their shells. The data on the efficiency of the method are provided.

Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) from the Silurian of Gotland, Sweden

Twelve species of Brachiopods are described from the Silurian of Gotland, six furcitellinines and six “strophodontids.” One is new—Strophodonta hoburgensis n. sp. The furcitellinines are moderately common and diverse in the lower part of the succession, but the last species disappears in the middle Hemse beds (~middle Ludlow). Three genera are represented: Bellimurina, Pentlandina and Katastrophomena, with the species and subspecies B. wisgoriensis, P. tartana, P. loveni, P. lewisii lewisii, K. penkillensis and K. antiquata scabrosa. Most of the taxa are confined to low energy environments, but P. loveni was evidently specialized for the high energy reef environments of the Hogklint Formation. B. wisgoriensis displays environmentally induced morphological variability in developing strong, frilly growth lamellae in high-energy environments. The “strophodontids,” although belonging to three different families, share a common morphology consisting of denticles along the hinge line, a semi-circular outline, unequally to finely costellate ornament and, most importantly, a concavo-convex profile with both valves of the same curvature, enclosing a very small body chamber. Two leptostrophiids are generalists, occurring in both high- and low-energy environments and with long stratigraphical ranges [Mesoleptostrophia filosa; latest Llandovery through the entire Ludlow. Brachyprion (Brachyprion) semiglobosa; latest Llandovery to latest Wenlock]. The third leptostrophiid (Brachyprion (Erinostrophia) walmstedti) is short ranged and occurs in low-energy environments in the latest Llandovery. The species belonging to the Strophodontidae (Strophodonta hoburgensis n. sp.) and Shaleriidae [Shaleria (Janiomya) ornatella and S. (Shaleriella) ezerensis] occur only in high-energy environments and have a short range within the late Ludlow.

Controls on body size during the Late Permian mass extinction event

This study examines the morphological responses of Late Permian brachiopods to environmental changes. Quantitative analysis of body size data from Permian-Triassic brachiopods has demonstrated significant, directional changes in body size before, during and after the Late Permian mass extinction event. Brachiopod size significantly reduced before and during the extinction interval, increased for a short time in more extinction-resistant taxa in the latter stages of extinction and then dramatically reduced again across the Permian/Triassic boundary. Relative abundances of trace elements and acritarchs demonstrate that the body size reductions which happened before, during and after extinction were driven by primary productivity collapse, whereas declining oxygen levels had less effect. An episode of size increase in two of the more extinction-resistant brachiopod species is unrelated to environmental change and possibly was the result of reduced interspecific competition for resources following the extinction of competitors. Based on the results of this study, predictions can be made for the possible responses of modern benthos to present-day environmental changes.

New brachiopod species from the order acrotretida from the Cambrian of central Kazakhstan

Four new brachiopod species from the order Acrotretida (class Lingulata): Picnotreta saryarkensis sp. nov., Stilpnotreta propria sp. nov., Anabolotreta firma sp. nov., and Batenevotreta variabilis sp. nov. are described from the Agyrek Mountains, northeastern Central Kazakhstan from two olistoliths of limestones, which contain the uppermost Middle and lowermost Upper Cambrian fauna and are located in the Upper Ordovician olistostrome. These new species supplement the described earlier brachiopod assemblage from this region (Koneva and Ushatinskaya, 2008). Strong age and intraspecific variability of some Kazakh acrotretids is shown.

Analyzing niche stability and biogeography of Late Ordovician brachiopod species using ecological niche modeling

Gauging the potential impacts of environmental change on the geographic distributions of species is a central area of modern biogeographic analysis, often involving complex models of species–environment interactions. The geographic distribution of fossil species can also provide a framework to test the impact of environmental change on biogeography and ecological niches of species, yet few paleontological analyses have attacked this question in deep time. Herein we present a quantitative biogeographic analysis to examine the stability of ecological niches and geographic ranges of rhynchonelliform brachiopods during an interval of sea level change preserved in Upper Ordovician strata of the Cincinnati Arch.The intensive sampling, excellent preservation, and numerous prior paleoecological and sedimentological analyses within the tri-state region of Kentucky, Indiana, and Ohio provide a robust framework for detailed paleobiogeographic study. Quantitative biogeographic modeling methods incorporating GIS (Geographic Information Systems) are utilized in order to spatially analyze the geographic ranges of brachiopod species of the Corryville and Mt. Auburn Formations of the C3 (uppermost Maysvillian) depositional sequence.This study employs the ecological niche modeling program GARP (Genetic Algorithm using Rule-set Prediction) to predict the geographic distribution of eight brachiopod species during three time slices within the C3 sequence. This method estimates a species’ geographic range by modeling the ecological niche of the species based on a set of known species occurrence data coupled with environmental data inferred from sedimentologic proxies. Once environmental tolerances for a species are modeled; the species is predicted to occur wherever its preferred set of environmental conditions occurs within the study region.Distributional patterns were reconstructed for three time slices during the C3 sequence. Recovered range predictions were quantitatively analyzed for evidence of temporal range changes. Results indicate that average species range within the study area decreased and species tracked their preferred niche with high fidelity during the transition from the early to middle portions of the C3 depositional sequence, an interval of rapid relative sea level change. However, during the transition from the middle to late portions of the sequence, gradual shallowing within the basin and development of discontinuous habitat patches correlates with niche evolution of five of the eight species modeled. The average area a species occupied within the basin increased during this interval, but there is a mixed response including both increases and decreases in range size within the study group. In general, the species that exhibit niche evolution increased their geographic range size while those that continue to track their niche with high fidelity experience a decrease in geographic range size. During the latter half of the C3 sequence, previously continuous habitats become fragmented, thereby isolating individual populations and providing a mechanism for niche evolution. The rate of sea level change and the corresponding fragmentation of previously continuous habitats into isolated patches appear to be the primary controls on both mean geographic range size and relative degree of niche evolution.

Within‐shell variations in carbon and oxygen isotope compositions of two modern brachiopods from a subtropical shelf environment off Amami‐o‐shima, southwestern Japan

This study examines the fidelity of carbon (δ13C) and oxygen (δ18O) isotope compositions of two modern brachiopod species (Kikaithyris hanzawai and Basiliola lucida) to use as proxies of δ13C values of total dissolved inorganic carbon and temperature and/or δ18O values of seawater, respectively. Well‐preserved shells of K. hanzawai and living individuals of B. lucida were collected from a subtropical shelf environment off Amami‐o‐shima, southwestern Japan. Some portions of the shells are in isotopic equilibrium with the ambient seawater, while other portions are not. The degree of disequilibrium differs between the two species and between different portions of each shell. Statistically significant positive correlations are recognized between the δ13C and δ18O values of these samples, which can be ascribed to a kinetic fractionation effect. Far from the posterior shell edge and along the axis of shell growth, the δ18O values of the secondary shell layer of K. hanzawai mostly fall within the expected range of equilibrium calcite. The δ13C values from the inner surface of the secondary shell layer in both species are relatively constant and are equivalent to or very close to equilibrium calcite. Therefore, these portions of the shells are most suitable for collecting reliable environmental proxy data. Although the δ13C and δ18O values of modern brachiopod shells are predominantly controlled by a kinetic fractionation effect, the appropriate selection of species and shell portions that reflect the isotopic composition of ambient seawater can facilitate the reconstruction of secular variations in oceanic δ13C or δ18O values.

A detailed 87SR/ 86SR isotopic curve for the mid-Cincinnatian (Upper Katian–Lower Hirnantian, Upper Ordovician), NE North American Shelf (Ontario, Canada) transition to the Hirnantian glaciation

We examined the Sr-isotopic composition of one species of well-preserved brachiopod species from the mid-Cincinnatian (Upper Katian–Lower Hirnantian, Upper Ordovician) in closely spaced samples from one borehole on the western shelf of the Upper Ordovician Appalachian low latitude retroarc basin in southwestern Ontario. The section spans the transition from passive margin carbonate ramp through anoxic shales into foredeep orogenic clastics and encompasses the transition into the late Ordovician glaciation. The primary nature of the Sr-isotopic composition of the shells shows several stable Sr-isotopic excursions that refine the Upper Ordovician Sr-isotopic curve, and indicate several marked changes that may be related to the competing influences of island arc and ophiolite nappe emplacement and erosion, increasing continental crust erosion during the Taconic orogeny and the glacio-eustatic drop in sea-level related to the onset of the late Ordovician Hirnantian glaciation. These changes begin with low Sr isotope ratios (~ 0.7090) consistent with the overall trends but the ratios then change to much more positive, reaching high Sr isotope ratios (~ 0.7084) not elsewhere attained until the end Silurian. These and other minor fluctuations are attributed to periodic increases in Sr isotope ratios in the semi-isolated Taconic retroarc basin caused by rivers draining unroofing continental thrust sheets and earlier Ordovician carbonate cover rocks, with their higher Sr isotope ratios, together with increased continental erosion during regression associated with the onset of the main phase of the late Ordovician glaciation and possible glacial/interglacial phases.

Using ecological niche modeling to assess biogeographic and niche response of brachiopod species to the Richmondian Invasion (Late Ordovician) in the Cincinnati Arch

Within the Cincinnati, Ohio region, the beginning stage of a large-scale biotic invasion is recorded in the C4 depositional sequence (Late Ordovician, Richmondian Stage), which includes the Arnheim Formation and its correlates. The fauna and strata of this region are well studied and the ecological changes present provide a unique opportunity to study biogeographic changes associated with the onset of a biotic invasion. In this study, GIS-based ecological niche modeling (ENM) is used to examine the biogeographic and paleoecological impacts of the biotic invasion during the C4 sequence. In particular, this study assesses whether species respond to invasion pressure through niche conservatism (exhibiting stasis and maintaining the parameters of their ecological niche through time) or niche evolution (altering the ecological parameters of their niche through adaptation). Ranges of ten rhynchonelliform brachiopod species were modeled for three temporal intervals within the C4 sequence. Modeled ranges provide the basis for quantitatively assessing the shifting roles of native and invasive species throughout the C4 sequence. GARP (Genetic Algorithm for Rule-set Prediction), a computer-learning based ENM program, was used to model species' ecological niches from environmental data as estimated from sedimentological variables associated with known species occurrence data. Once environmental parameters of the niche were modeled, the resulting rule set was used to project the geographic boundaries of potential habitat and estimate the spatial extent occupied by each species. Three prominent trends are apparent within the fauna. (1) Generalist species tended to track their preferred ecological niches closely from the early into the middle time slice and maintained or expanded the size of their geographic range during this transition. (2) Ecologically specialized species exhibited decreasing geographic range size through the sequence and were more likely to shift geographic areas inhabited within the study area. (3) The amount of niche evolution increased as the invasion progressed; species that adapted to the new biotic regime though niche evolution persisted through the invasion interval while species with high levels of niche conservatism did not. During early C4 sequence, species respond individualistically to changes in abiotic conditions (shallowing upward), but do so primarily by tracking their previously preferred environmental conditions laterally and maintain high fidelity of niche dimensions through time. This matches the null hypothesis that species will exhibit niche conservatism during intervals of slow or gradual environmental change. Following the geologically sudden introduction of the intrabasinal invaders in the second half of the C4 sequence, native species responded to the combined abiotic (shallowing upward) and biotic (invader introduction) changes in the Cincinnatian environmental by altering the parameters of their ecological niches and through fundamental changes in geographic distribution. Extrapolating these results to modern ecosystems, suggests that most species should exhibit niche conservatism and habitat tracking in response to gradual changes in environmental conditions, while species should exhibit niche evolution and adaptive response following rapid environmental changes. Furthermore, modern species with reduced potential for adaptive response may also be the most susceptible to extinction.

Biodiversity of shallow-water brachiopods from New Caledonia, SW Pacific, with description of a new species

SUMMARY: Twelve species of recent brachiopods belonging to the genera Lingula, Discradisca, Novocrania, Xenobrochus, Eucalathis, Frenulina, Argyrotheca, Campages, Thecidellina and Lacazella were identified in samples collected during shallow-water cruises around New Caledonia, southwest Pacific. Six genera, Lingula, Xenobrochus, Eucalathis, Frenulina, Campages and Thecidellina, have been already reported from the New Caledonian region, while four genera, Discradisca, Novocrania, Argyrotheca and Lacazella are the first records from this region. Additionally, Discradisca stella is the first discinid brachiopod recognized in the New Caledonia area. One new species is described, the megathyridid Argyrotheca neocaledonensis n. sp. The biogeographical affinities of the New Caledonia brachiopod faunas are briefly discussed.

Early Cambrian brachiopods and other shelly fossils from the basal Kinzers Formation of Pennsylvania

An assemblage of seventeen species of Small Shelly Fossils, dominated by the brachiopod Eothele tubulus and species of the mollusk Yochelcionella, is described from the basal Kinzers Formation of Thomasville, Pennsylvania. The occurrence extends southwards the distribution of an Early Cambrian fauna (Cambrian Series 2, Stage 4) that is otherwise characteristic of the eastern shelf of Laurentia from New York to Greenland. The poorly known acrothelid brachiopod Eothele tubulus is redescribed based on large collections of ventral valves. The shell structure of E. tubulus is characterized by orthogonal baculae, and represents the oldest known example of a baculate shell structure, indicating that this type of shell structure evolved already in the Early Cambrian.

Late Tournaisian (Carboniferous) brachiopods from Mouydir (Central Sahara, Algeria)

AbstractA small‐sized brachiopod fauna, representing an orthid, rhynchonellid and spiriferid community which lived in a low‐energy environment, is reported from the lower part of the Argiles de Teguentour and was collected around Oued Tamertasset (or Temertasset) and Oued Habadra in north‐western Mouydir (Algerian Sahara). Associated goniatites indicate an early Late Tournaisian age (Pericyclus–Progoniatites assemblage). Thirteen brachiopod species belonging to 12 genera and 5 orders (Productida, Orthida, Rhynchonellida, Athyridida and Spiriferida) are described. Mouydirhynchus is proposed as a new rhynchonellid genus and the species Rhipidomella prolifica, Mouydirhynchus quietus and Eomartiniopsis mouydirensis are new. The other described taxa are the following: Chonetipustula? sp., strophalosioid gen. et sp. indet., Schizophoria sp., trigonirhynchiid gen. indet. sp. A, trigonirhynchiid gen. indet. sp. B, Hemiplethorhynchus? sp., Coveenia? sp., Crurithyris cf. fissa, Punctothyris? sp., and elythid gen. et sp. indet. Copyright © 2009 John Wiley & Sons, Ltd.

Early Pleistocene sediments on Store Koldewey, northeast Greenland

Bennike, O., Knudsen, K. L., Abrahamsen, N., Böcher, J., Cremer, H. & Wagner, B. 2010: Early Pleistocene sediments on Store Koldewey, northeast Greenland.Boreas, Vol. 39, pp. 603–619. 10.1111/j.1502‐3885.2010.00147.x. ISSN 0300‐9483.Marine Quaternary deposits, here named the Store Koldewey Formation, are found at ∼120 m above sea level in northeast Greenland (76°N). The sequence is referred to the Olduvai normal polarity subchron at 1.95–1.78 Ma BP based on palaeomagnetic studies (palaeomagnetically reversed), amino acid epimerization ratios and evidence from marine and non‐marine fossils. The sediments and the fauna show that the sequence was deposited on a mid or inner shelf, and some elements of the marine mollusc and foraminiferal assemblages indicate water temperatures between −1 and +1 °C and seasonal sea ice cover during deposition. Mean summer air temperatures were around 6 °C higher than at present, as demonstrated by the occurrence of southern extralimital terrestrial species. Well‐preserved remains of land plants indicate that the adjacent land area was dominated by sub‐arctic forest‐tundra with the treesLarixandBetula, shrubs, herbs and mosses. Most of the species represented as fossils have recent circumpolar geographical ranges. An extinct brachiopod species and an extinct gastropod species have been found, but the other macrofossils are referred to extant species. The brachiopod is erected as a new genus and species,Laugekochiana groenlandica. Correlation of the Koldewey Formation with the Île de France Formation farther to the north is suggested. Member A of the Kap København Formation in North Greenland is referred to the Late Pliocene, whereas Member B of the Kap København Formation is suggested to be slightly older than the Store Koldewey Formation.

Bioerosion structures and their distribution on shells of the Lower Pleistocene terebratulid brachiopod Gryphus minor

We present an analysis of bioerosion structures occurring on the shells of a Gryphus minor fossil population from Reggio Calabria (S. Italy), Early Pleistocene (Calabrian) in age. This population belongs to a palaeobiocoenosis that can be compared with present-day detritic terrigenous mud outer circalittoral environment. The assemblage includes 5 different brachiopod species, but it is dominated by Gryphus minor. We analyzed all of the 4069 Gryphus individuals in search of shell damage due to biological activity (bioerosion). About 12% of the specimens were affected to some extent. Bioerosion traces were identified down to the ichnospecies level and ascribed to potential biological agents (predators, epibionts or endobionts). Evidence for predation (Praedichnia) is limited, whereas etchings for attachments (Fixichnia) are more common. In particular, 453 traces belong to Podichnus obliquus, an ichnotaxon that describes a distinctive etching scar due to the pedicle attachment of other brachiopods on the shell. In the case of Gryphus minor, Podichnus were caused by conspecifics. Podichnus distribution on the shells, and its shape, suggest that Gryphus minor had a somewhat short pedicle, and lived with the umbo close to the substrate.

Middle Devonian brachiopods from arctic Canada and some preliminary results of North American biogeography based on quantitative assessment

INTRODUCTION The upper Lower to Middle Devonian Bird Fiord Formation (late Emsian to late Eifelian) is a carbonate-siliciclastic succession that contains a diverse brachiopod-dominated fauna. A collection of over 45 000 brachiopod specimens, which came from 140 collections made at 34 locations throughout the outcrop belt of this formation, contains 22 species of brachiopods that belong to 21 genera. Among them, the atrypids form 52% of the biota, spiriferids ~13%, orthids ~8%, productids ~3%, rhynchonellids ~2%, terebratulids ~1% and the strophomenids, pentamerids, and athyridids each <1%. Spinatrypina, Schizophoria, Elythyna, Desqumatia (Independentrypa), Cupularostrum, and Atrypa collectively form more than 80% of the brachiopod biota. Biogeographically, the Devonian was a unique period because the high provincialism that was established during the Early Devonian was replaced by a very cosmopolitan biota during the Late Devonian (Boucot, 1988). Numerous worldwide and regional studies of Devonian biotas led to the qualitatively defined Old World, Eastern Americas (=Appalachian),

Marine biotic events in the Lopingian succession and latest Permian extinction in the Southern Alps (Italy)

AbstractThe Upper Permian in the eastern Southern Alps consists of an overall transgressive sedimentary succession of continental red beds (Val Gardena Sandstone), which are overlain and interfingered by the marine Bellerophon Fm, consisting of sulphate evaporites, dolomites and neritic limestones. In the western Dolomites, a key‐area for analysing the stratigraphic framework and biotic events connected with the Permian‐Triassic boundary and related mass extinction studies, the Bellerophon Fm is followed by oolitic limestone of the Werfen Fm, where the end‐Permian mass extinction and the erathem boundary, are located a few centimetres and a few metres, respectively, above the formational contact.The marine events presented here are located in three historical sections in the western Dolomites (Bletterbach, Seceda‐Monte Balest and Putia). Bioevents mostly concern brachiopod and cephalopod assemblages, discussed herein in terms of biodiversity changes and bio‐chronostratigraphic value. Recent data on cephalopod and conodont biostratigraphy have improved significantly the chronostratigraphic framework of the upper part of the succession and its correlation with other Tethyan localities. As far as nautiloids are concerned, the Tirolonautilus beds (T. crux and Tirolonautilus sebedinus lineage zone) are Changhsingian in age; while, all the Comelicania‐bearing brachiopod beds are late Changhsingian in age.The extinction pattern of the Dolomites is compared with that which occurred in the GSSP Meishan (South China) section. In both regions, the main extinction phase is probably synchronous, whereas the ultimate extinction of relicts is slightly diachronous. However, in the Dolomites the extinction seems to have been more catastrophic, because of the lack of the Chinese prelude phase, which is also characterized by miniaturization. On the other hand, the supposed coeval Dolomites assemblages have a high biodiversity, both in richness and abundance, and include gigantic brachiopod species. Copyright © 2010 John Wiley &amp; Sons, Ltd.