Bellerophon Formation Research Articles

FIRST REPORT ON THE UPPERMOST PERMIAN OSTRACODS FROM THE MASORE SECTION (EXTERNAL DINARIDES), SLOVENIA

The ostracod assemblages from the Upper Permian and Permian-Triassic transitional strata of the Masore section in the External Dinarides (Slovenia) were studied. Altogether 13 genera and 20 species of the orders Palaeocopida, Platycopida and Podocopida are identified and illustrated. All recovered ostracods belong to shallow marine taxa. The older fauna from the uppermost Permian and the younger fauna from the Permian-Triassic boundary strata are distinguished. The obtained fauna from the Permian Bellerophon Formation corresponds to the “benthonic ostracod Eifelian Mega-assemblage” occupying the shelf sea floors. This study presents the first report of ostracod faunas from the uppermost Permian and Permian-Triassic boundary interval of Slovenia. The recovered ostracod fauna display a distinct faunal change and yield important paleobiogeographic implications as it reveals similarity with stratigraphical equivalent faunas from some other neighboring localities in the western Paleotethys, such as Bulla in Italy, Komirić in Serbia, and the Bükk Mountains in Hungary.

Bivalves from the Changhsingian (upper Permian) Bellerophon Formation of the Dolomites (Italy): ancestors of Lower Triassic post‐extinction benthic communities

AbstractDiverse shallow marine fossil assemblages from the Changhsingian Bellerophon Formation (Dolomites) record late Palaeozoic marine life immediately before the end‐Permian mass extinction. We classified c. 6500 bivalves from western Dolomites localities, identifying 26 species including one new family (Ladinomyidae), three new genera (Ladinomya, Lovaralucina, Gardenapecten) and 10 new species: Acharax frenademezi, Bakevellia (Bakevellia) preromangica, Edmondia hautmanni, Etheripecten stuflesseri, Ladinomya fosteri, Lovaralucina covidi, Palaeolima badiotica, Promytilus merlai, Tambanella? stetteneckensis and Volsellina carinata. The occurrence of three Eumorphotis species with different stratigraphic distributions, leads us to propose an upper Permian ‘Lower Eumorphotis Zone’, divided into E. praecurrens, E. striatocostata and E. lorigae subzones, and distinct from the existing Lower Triassic Eumorphotis Zone (here renamed ‘Upper Eumorphotis Zone’). Palaeoecological analysis produced six biofacies and four ecofacies, based on richness, dominance and ecological lifestyle. The bivalves inhabited lagoonal to nearshore environments affected by stressed conditions: high temperatures, high salinity, shallow water depths, low oxygen and high terrigenous input. The upper Bellerophon Fm is characterized by increasingly fully marine conditions, although eurytopic taxa still suggest stressed conditions. Bivalve richness of the upper Permian Bellerophon and Lower Triassic Werfen formations was compared to estimate the genus‐level extinction rate. The disappearance of almost half (47%) of Bellerophon Fm genera is remarkably low compared with other, coeval bivalve faunas. Pre‐extinction bivalve faunas were dominated by stress‐adapted taxa (Unionites, Eumorphotis, Bakevellia, Towapteria) able to thrive in extreme environmental conditions, survive the end‐Permian mass extinction, and become the dominant biotic component of Lower Triassic benthic communities globally.

Calcareous algae and foraminifers across the Permian-Triassic boundary interval (uppermost Bellerophon Formation and basal Werfen Formation) in the Dolomites (South Tyrol – Trentino, Italy)

Calcareous algae and foraminifers across the Permian-Triassic boundary interval (uppermost Bellerophon Formation and basal Werfen Formation) in the Dolomites (South Tyrol – Trentino, Italy)

Isotopic time-series (δ13C and δ18O) obtained from the columnar layer of Permian brachiopod shells are a reliable archive of seasonal variations

In this paper, we develop a robust palaeo-proxy technique for inferring seasonal fluctuations in Phanerozoic seawater temperature. Specifically, we report δ13C and δ18O values across the columnar layer (inner shell) of Permian brachiopods, including five genera of the Order Spiriferida (Ingellarella, Martinia, Permophricodothyris, Cartorhium, and Trigonotreta) and two genera of the Order Athyridida (Araxathyris and Comelicania). These brachiopod specimens are inferred to have inhabited varied palaeo-depths, based on facies analysis, and were collected from low, middle and high palaeolatitudes. To obtain high-resolution ontogenetic isotopic time-series, a handheld microdrill was used to collect low-magnesium calcite samples along the longitudinal axis of the mid-valve for each specimen. Intrageneric and intergeneric comparison of statistics (mean values, variance, and range) reveals that δ18O values are consistent within and between genera although δ13C values are more variable. In specimens obtained from low palaeolatitudes (Julfa Formation, Iran; Bellerophon Formation, Italy; Late Permian), the range of δ18O values is small and consistent with weak seasonal temperature variations, irrespective of water depth. In specimens obtained from middle palaeolatitudes (Qarari Formation, Oman; Early-Middle Permian), we found a range of δ18O values dependent on inferred water depth, possibly reflecting a change in thermocline structure between warm and cold seasons. In specimens obtained from high palaeolatitudes (Wasp Head and Wandrawandian Siltstone formations, Australia; Early-Middle Permian), brachiopods from glacial and interglacial climate phases show significant variations of δ18O values, probably caused by seasonal changes in the seawater surface temperature. Based on these findings, the technique developed in this paper appears to provide reliable paleoclimate and paleoenvironmental data for Permian sites, and should be also applicable for Phanerozoic studies in general. However, we caution that δ18O values vary dependent on the growth direction, resulting in differences of up to 5 °C in seawater paleotemperature calculations, and emphasise that a consistent sampling strategy accounting for shell structure and growth direction is required.

Strontium isotope stratigraphic insights on the end-Permian mass extinction and the Permian-Triassic boundary in the Dolomites (Italy)

The Dolomites (Southern Alps, Italy) is a most significant region to investigate the evolution of shallow-marine ecosystems during the end-Permian mass extinction (EPME). Shallow-marine ecosystems are complex places from an oceanographic viewpoint and combine high biological productivity and ecological diversity. Therefore, establishing the timing and correlation of globally recognisable events in this region are fundamental to interpreting the biological crisis that followed.We took advantage of the Strontium Isotope Stratigraphy (SIS) concept to correlate our stratigraphic succession, ranging from the upper Bellerophon (Bulla Member, upper Changhsingian) to the lower Werfen (Tesero Member, upper Changhsingian - lower Induan) Formations of the Dolomites, to the Meishan (Zhejiang Province, China), the Global Stratotype Section and Point (GSSP) for the Permian–Triassic boundary. We integrated new and previously published 87Sr/86Sr data from well preserved brachiopods and show that the topmost part of the Bellerophon Formation (the Bulla Member) correlates with beds 24 e-f of the GSSP section, while the Tesero Member, where the Permian-Triassic boundary is located, is characterised by more radiogenic Sr isotope ratios than expected. Differences in Sr isotope ratios may be due to small-scale variations in local paleoenvironmental and paleogeographic conditions/settings. Continental weathering of sedimentary or igneous rocks, distance from terrestrial environment and nearby occurrence of radiogenic rocks might also produce locally variable Sr isotope signatures especially in shallow water environments complicating the application of SIS principles.

Permian-Triassic biofacies of the Teočak section, Bosnia and Herzegovina

The Teočak section in Bosnia and Herzegovina (Sava-Vardar Zone) composed of the Upper Permian Bellerophon Formation and the Lower Triassic “Werfen Formation” was studied sedimentologically and micropaleontologically by using foraminifers and conodonts. The Bellerophon Formation was deposited in a shallow subtidal lagoon rich in biota characterized by typical Changsingian foraminiferal species. Deposition on a shallow epicontinental ramp with pronounced long-term transgression is proposed for the Lower Triassic strata. The recovered conodont faunas are assigned to the Late Permian praeparvus (Changhsingian) and to the Early Triassic isarcica-staeschei (Griesbachian), costatus (? latest Dienerian-early Smithian) and hungaricus (early Spathian) Zones. The studied strata include the Permian-Triassic Boundary as well as the Induan-Olenekian Boundary. The introduced conodont biozonation in the Teočak section is for the first time proposed for the region and is an important contribution for paleobiogeographic correlation of Western Tethys. • Uppermost Permian and Lower Triassic strata of the Teočak section were studied. • The section is composed of the Bellerophon Formation and the “Werfen Formation”. • The recovered conodont faunas enabled identification of four conodont zones. • Foraminifers of the Bellerophon Formation are marked by typical Changhsingian taxa. • A deposition on a shallow epicontinental ramp is proposed for the Triassic strata.

BIOSTRATIGRAFIA CON 1 FORAMINIFERI DEL LIMITE FORMAZIONE A BELLEROPHON FORMAZIONE DI WERFEN FRA RECOARO E LA VAL BADIA (ALPI MERIDIONALI)

In thc Southern Alps the boundary between the marine Upper Permian Bellerophon Formation and the Scythian Werfen Formation was believed to coincide with the Permo—Triassic boundary. Almost everywhere in the area from Recoaro (Vicenza) to the Badia Valley (Northern Dolomites) (Fig, l) the lower part of the Wcrfen Fm. is represented by the Mazzin Member dated as Early Griesbachian (Broglio Loriga et al., 1980, 1982; Mostler et al., 1982). The Mazzin Member begins with the Tesero oolitic Horizon (Bosellini, 1964, 1968), which consists of oolitic grainstones with dolomitized ooids and it ig considered to be trasgressive on the Bellerophon Fm. (Bosellini, 1964; Assereto et al., 1973; Cassinis et al., 1979; Farabegoli & Vicl, 1982; etc.). The Upper Bellerophon Fm. has been correlated with the Caucasian Phisonites—comelicania zone (Assereto et al., 1973), today referred to Lower Dorashamian (Rostovtsev & Azaryan, 1973).

PERMIAN-TRIASSIC BOUNDARY AND EARLY TRIASSIC CONODONTS FROM THE SOUTHERN ALPS, ITALY

The Bellerophon (Late Permian) and Werfen (Lower Triassic) Formations were investigated on the basis of conodonts. Fifteen sections were sampled from Carnic Alps and Dolomites area in the Southern Alps. Ten were productive.
 The Bellerophon Formation yielded a few specimens of Hindeodus typicalis, Ellisonia agordina and Ellisonia sp.
 In the Werfen Formation were collected Hindeodus typicalis, Ellisonia agordina, E. triassica, Hadrodontina anceps, Xaniognathus gradatus, Isarcicella isarcica, Pachycladina obliqua, Ellisonia delicatula, Neospathodus triangularis.
 In describing the conodont fauna, multielement taxonomy is applied.
 Ellisonia agordina is a new species found at the top of the Bellerophon Formation and from the Tesero to the Siusi Members of the Werfen Formation, i, e. at the Permian — Triassic boundary and in the Lower Triassic. The apparatus of this new species is described. In the Southern Alps the range of Hindeodus typicalis, previously known in the Werfen Formation, extends down into the uppermost Bellerophon Formation. All species confirm the ranges found elsewhere in the world.
 On the basis of only the conodont fauna, it is not possible as yet to recognize the position of the Permian — Triassic boundary more precisely in the Bellerophon/Werfen Formations in the Southern Alps. It is obvious, however, that the recovery of Isarcicella isarcica allows the certain identification of the Triassic.

Biostratigraphy and sedimentology of Upper Permian and Lower Triassic strata at Masore, Western Slovenia

Upper Permian and lowermost Triassic strata of the Masore section in western Slovenia have been restudied by means of bio- and lithostratigraphy. This section is mainly characterized by a carbonate succession of the Bellerophon Formation deposited in a shallow marine ramp environment that was located in the western part of the Paleotethys. The Permian-Triassic boundary (PTB) transition is marked by laminated microbialites – stromatolites interpreted to reflect a deeper ramp environment. The conodont elements recovered enabled the recognition of the Hindeodus praeparvus Zone of the uppermost Permian (Upper Changhsingian) in the Bellerophon Formation. Gondolellids are documented in the PTB transitional interval with microbial microfacies, whereas the Isarcicella isarcica Zone (Lower Griesbachian, Lower Triassic) is recognized in the tectonically separated Werfen Formation just above the microbial microfacies part of the section. The lowermost part of the microbialites is characterized by Late Permian species of foraminifers indicating that at least this part of the section is still Upper Permian.

Equatorial Palaeotethys as the last sanctuary for late Permian metazoan reef-builders: New evidence from the Bellerophon Formation of Slovenia

The rise and demise of warm-temperate Permian reefs and biostromes reflect the complex geologic history of this dynamic period. Environments suitable for reef-builders were devastated by the Guadalupian/Lopingian crisis, and Lopingian reefs have only been recorded at a small number of localities. The uppermost Permian limestones of the Bellerophon Formation, on the Vojsko Plateau (Slovenia), contain small, lenticular biostromes within a bioclastic wackestone/packstone lithofacies. The major biostrome builders are medium-sized coralline sponges (Demospongea and Calcarea), encrusted by smaller sponges, tube worms, sessile foraminifera, calcareous algae (Archaeolithoporella) and Shamovella (i.e., Tubiphytes), all of which are typically covered by microbial crusts. The biostromes are characteristically composed of bafflestone and bindstone, incorporating sporadic framestone. Narrow belts of floatstone surround the buildups, and sponge debris is also present in lenses within the mud matrix between metazoan bafflestones. The fossils are generally well-preserved, although the fine skeletal microstructure has been partially recrystallized. Sponges are heavily calcified, and ontogenic thickening of the skeleton can be observed in some encrusters. Framboidal pyrite, forming thin films on the inner walls of sponge chambers, suggests the presence of sulphate-reducing bacteria. These microbial symbionts may have enabled the sponges to survive in the anoxic marine environments of the uppermost Permian. The Changshingian sponge biostromes of the Vojsko Plateau represent the westernmost known occurrence of contemporary metazoan boundstones in the Palaeotethys.

SYSTEMATICS OF LINGULIDE BRACHIOPODS FROM THE END-PERMIAN MASS EXTINCTION INTERVAL

The systematics of lingulide brachiopods, from the end-Permian mass extinction interval, is here studied and discussed. The material has been collected from upper Permian (Changhsingian) beds of Southern Alps and Lower Triassic beds of several Tethyan localities, where the surviving phase following the peak the end-Permian mass extinction is recorded. The study contributes to fill the gap of knowledge regarding the lingulide systematics during a time lapse crucial for the fate of the Mesozoic and Cenozoic marine organisms. The systematics is based both on inner shell morphology and shell microstructure, which are considered to be the most useful taxonomical characters to study the lingulide phylogeny. The specimens have been referred to species of the new genus Trentingula, which is characterized by a shell with a secondary layer virgose fabric and a primitive disposition of the ventral muscle umbonal scar in the Lingulidae phylogeny. Trentingula n. gen. comprises four species: T. lorigae n. gen. n. sp . , type-species, T. borealis (Bittner), T. mazzinensis n. gen. n. sp . , and T. prinothi n. gen. n. sp. The type-species is late Griesbachian – Dienerian in age and has a wide geographic distribution in the western Tethys (Southern Alps and Hungary). Trentingula prinothi n. gen. n. sp. occurs in the Upper Permian Bellerophon Formation of the Dolomites; it has a large shell with a short mantle cavity. Trentingula mazzinensis n. gen. n . sp. occurs in the Griesbachian Mazzin Member of Werfen Formation and is characterized by a small sized shell, about half of the type species, which records the “Lilliput effect” related to the aftermath of the end-Permian mass extinction.

Palynology of the Permian and Triassic of the Tesero and Bulla sections (Western Dolomites, Italy) and consideration about the enigmatic species Reduviasporonites chalastus

A palynological study of two Permian–Triassic sections of the Southern Alps (Tesero and Bulla sections) was carried out in order to correlate the palynological data with the available conodont zones. Both the sections crop out in the Western Dolomites, the Tesero section in Fiemme Valley and the Bulla section in Badia valley.The two sections include the uppermost Bellerophon Formation and the overlying Werfen Formation. In the latter the Permian/Triassic boundary (Farabegoli et al., 2007) has been defined by conodonts. The palynological assemblages collected in both sections throughout the Bellerophon up to the Werfen formations show compositional variation marked by: a) a dominance of taeniate and non-taeniate bisaccates in the Bellerophon Formation dated as Late Permian; b) a bloom of the organic microfossil incertae sedis Reduviasporonites chalastus in the lower Tesero Member (Werfen Formation), found only in the Tesero section. This interval should stratigraphically lie below the Permian/Triassic boundary, as defined by conodonts recorded in the Bulla section; c) poorly preserved acavate and bisaccate taxa in the upper Tesero Member, above the Permian/Triassic boundary, and in the overlying Mazzin Member of the Tesero section. The origin and the ecological preferences of Reduviasporonites chalastus and the implications of its worldwide distribution across the Permian/Triassic boundary are also discussed.

A low-temperature ductile shear zone: The gypsum-dominated western extension of the brittle Fella-Sava Fault, Southern Alps

Based on structural and fabric analyses at variable scales we investigate the evaporitic gypsum-dominated Comeglians-Paularo shear zone in the Southern Alps (Friuli). It represents the lateral western termination of the brittle Fella-Sava Fault. Missing dehydration products of gypsum and the lack of annealing indicate temperatures below 100 °C during development of the shear zone. Despite of such low temperatures the shear zone clearly exhibits mylonitic flow, thus evidencing laterally coeval activity of brittle and viscous deformation.The dominant structures within the gypsum rocks of the Lower Bellerophon Formation are a steeply to gently S-dipping foliation, a subhorizontal stretching lineation and pure shear-dominated porphyroclast systems. A subordinate simple shear component with dextral displacement is indicated by scattered σ-clasts. Both meso- and microscale structures are characteristic of a subsimple shear type of deformation with components of both coaxial and non-coaxial strain. Shortening in a transpressive regime was accommodated by right-lateral displacement and internal pure shear deformation within the Comeglians-Paularo shear zone. The shear zone shows evidence for a combination of two stretching faults, where stretching occurred in the rheologically weaker gypsum member and brittle behavior in enveloping lithologies.

Adaptive strategies and environmental significance of lingulid brachiopods across the late Permian extinction

Linguliform brachiopods are traditionally considered a conservative group which seems to pass through the late Permian extinction without any significant loss and even appear to thrive immediately after the extinction peak. In the Southern Alps, lingulids are very common in the post-extinction Mazzin Member (early Induan) of the Werfen Formation. Sparse occurrences are also known in the overlying Siusi and Gastropod Oolite members (late Induan and early Olenekian in age respectively). The recent discovery of well preserved specimens from a pre-extinction bed of the Bellerophon Formation (Changhsingian) has permitted a detailed comparative analysis, mostly based on the interior characters, preserved in the lingulid succession from across the extinction beds. The following effects on the lingulid populations have been analyzed: i) change in taxonomic assessment; ii) adaptive strategies during the surviving and recovery phases; and iii) environmental proxy connected with the killing mechanisms of the late Permian extinction.The pre-extinction individuals belong to Lingularia? cf. smirnovae Biernat and Emig, a species that is characterized by large-sized shells with a short lophophoral cavity. The post-extinction populations belong to different species and, probably, even to a different genus. The first post-extinction population (early Induan), with small-sized shells and long lophophoral cavity, has been referred to Lingularia yini (Peng and Shi). It records the most severe effects of the late Permian extinction on the marine ecosystems. The late Induan–Olenekian Lingularia borealis (Bittner), with large sized shells and long lophophoral cavity, appears during the first phase of the Triassic biotic recovery.The main adaptive strategies of Lingularia yini, in comparison with the Permian species, include: i) shell miniaturization; ii) increasing of the lophophoral cavity surface (respiratory surface); and iii) increasing of shell width/length ratio. These modifications are interpreted as adaptations towards warming and hypoxia, two main killing mechanisms of the marine biota. The recovery species Lingularia borealis maintains a large lophophoral cavity, indicating an adaptation towards predominant low oxygenated bottom marine waters.The appearance and the great abundance of Lingularia yini in the Mazzin Member (early Induan) represent a proxy of dysaerobic conditions, which determined the appearance of the second phase of the Lilliput biota, characterized by the definitive disappearance of the rhynchonelliform brachiopods and calcareous algae in the Southern Alps.

Late Permian (Changsingian) ostracods of the Bellerophon Formation at Seis (Siusi) (Dolomites, Italy)

Abstract. Ostracod assemblages of the Upper Permian Bellerophon Formation at Seis near Bozen (South Tyrol, Italy) have been studied with respect to their taxonomy and palaeoecology. The investigations were concentrated on the Late Changsingian Casera Razzo Member which yielded five ostracod assemblages including more than twenty-four species. Twelve of these species are described herein and four species are new, including two species with strong affinity to taxa appearing in the Early Triassic. The lithofacies characteristics and low species diversity are suggestive of a protected shallow lagoonal environment with salinity fluctuations due to freshwater influx. Only four species are recorded from Late Permian localities outside of the Dolomites. This is due to the restricted environmental conditions which inhibited the immigration of more taxa from open shelf environments.

Stratigraphy of Upper Permian and Lower Triassic Strata of the Žiri Area (Slovenia)

The paper deals with the stratigraphy of Late Permian and Early Triassic strata of the Lukač section in the Žiri area of western Slovenia. This is the only section presently known in the External Dinarides where the Permian- Triassic boundary is defined following international criteria based on the first appearance of the conodont Hindeodus parvus. The following lithostratigraphic units have been formalized: the Bellerophon Limestone and Evaporite-dolomite Members of the Bellerophon Formation and the Lukač Formation with the three members, the Transitional Beds, Streaky Limestone and Carbonate-clastic Member. The paper presents the results of micropaleontological study based on foraminifers and conodonts as well as petrographic and sedimentologic research results. The investigation of conodont assemblages enabled the conodont biozonation of the Permian-Triassic interval of the studied Lukač section.

Conodont biostratigraphy and lithostratigraphy across the Permian-Triassic boundary at the Lukač section in Western Slovenia

Detailed conodont biostratigraphy and lithostratigraphy of the Late Permian and Early Triassic were studied at the LukaC section in western Slovenia. The analyzed section is composed of the Bellerophon Formation (evaporite-dolomite member) and the newly introduced Lukae Formation (transitional beds, streaky limestone member and carbonate-clastic member). The Permian-Triassic boundary interval is represented by transitional beds of carbonate facies deposited in shallow restricted marine conditions. The presence of H. parvus in sample L1 in the transitional beds marks the systemic boundary between Permian and Triassic. The studied interval is characterized by a diverse microfauna that contain conodonts, foraminifers, ostracods and gastropods. Six conodont zones have been recognized, in ascending order, the latest Changhsingian (uppermost Permian) praeparvus Zone, and the Griesbachian (lowermost Triassic) parvus, lobata, staeschei- isarcica , postparvus and anceps zones. This faunal succession represents the first known and the most complete conodont biozonation across the Permian-Triassic interval from the entire Dinaric region. The recognized conodont biozones can be correlated with the biozonation of the Southern Alps and of the GSSP Meishan D section.

Foraminifera from the Permian-Triassic transition in western Slovenia

Foraminifers from the Upper Permian Bellerophon Formation, Permian-Triassic "transitional beds" and lowermost Triassic "streaky limestone member" of the Luka Formation in the Luka dection, western Slovenia are described and illustrated. Four new species of foraminifers are described: Multidiscus zhiriensis, M. dinaridicus and Globivalvulina lukachiensis from the Upper Permian, and Lingulonodosaria slovenica from the lowermost Triassic. The assemblage of Late Permian foraminifers consists of species characteristic of the Changhsingian of many regions in the Tethys: northwestern Caucasus, Transcaucasia, Iran, Turkey, northern Italy, northwestern Serbia, northeastern Hungary, and South China. Unfortunately, the uppermost part of the Bellerophon Formation in the Luka section is represented by dolomite and does not contain foraminifers. The Permian-Triassic boundary interval is represented by carbonate "transitional beds" deposited in a shallow restricted marine environment that contains foraminifers and conodonts. The species "Cornuspira" mahajeri, "Earlandia" gracilis, and "E." tintinniformis, marking the lower boundary of the Triassic worldwide based on foraminifers, are found both below and above the first appearance of the conodont species Hindeodus parvus in the Luka section. These species appear to be ecological species and their appearance coincideswith a stressful shallowwater environment. The first intervalwith nodosariid foraminifers appears 2mabove the P/T boundary and a second one is approximately 5m above the boundary. Both of these intervals with nodosariids are within the range of the conodont species H. parvus and within the I. staeschei – I. isarcica conodont Range Zone.

The Lower Triassic Werfen Formation of the Karawanken Mountains (Southern Austria) and its disaster survivor microfossils, with emphasis on Postcladella n. gen. (Foraminifera, Miliolata, Cornuspirida)

A relatively poorly known sedimentary succession (uppermost Bellerophon Formation and overlying Werfen Formation) including the Permian-Triassic Boundary (PTB) is exposed in the South-Alpine part of the Karawanken Mountains of Southern Austria. As in the Dolomites, sedimentation of the Werfen Formation mainly occurred in a subtidal shelf environment between normal and storm wave base. Muddy sedimentation was periodically interrupted by storm events resulting in the deposition of storm layers. Three sections are accurately studied. All contain the same assemblage of Foraminifera and events from the PTB to the late Early Triassic Meandrospira pusilla zone. Between these two great events, only the cornuspirid foraminiferan Postcladella n. gen. is present. Its populations are described and illustrated here under the name Postcladella kahlori n. comb. In the geological record, many taxa such as P. kahlori, i.e., undivided, tubular, initially planispirally evolute coiled, and later uncoiled, appeared successively. A reappraisal is attempted in order to discriminate the different taxa. These forms are often disaster survivors.

Late Permian Nautiloids from the Bellerophon Formation of the Dolomites (Italy)

Late Permian Nautiloids from the Bellerophon Formation of the Dolomites (Italy)