Permian and early Triassic isotopic records of carbon and strontium in Australia and a scenario of events about the Permian‐Triassic boundary

The negative shift in δ¹³C values of carbonate carbon at the Permian/Triassic boundary is one of the better documented geochemical signatures of a mass extinction event. The similar negative shift in δ¹³C values in organic carbon from Permian/Triassic boundary marine sediments in Austria and Canada is shown to occur also in marine and non‐marine sediments from Australian sedimentary basins. This negative shift in δ¹³C values is used to calibrate Australian sections lacking diagnostic faunal elements identifying the Permian/Triassic boundary. The minimum in the carbonate ⁸⁷Sr/⁸⁶Sr seawater curve from carbonates across the Guadalupian/Ochoan Stage boundary, mainly from North America, is shown to occur also in brachiopod calcite mainly from the Bowen Basin of eastern Australia, hence providing a second calibration point in the Australian sedimentary record. These two geochemical events support a model of a runaway greenhouse developing about the Permian/Triassic boundary; this is inferred to have contributed to the end‐Permian mass extinction.     

Sedimentological and paleoecological aspects of the Norian–Rhaetian transition (Late Triassic) in the Xuanhan area of the Sichuan Basin,Southwest China

The end-Triassic mass extinction is one of the five big extinction events in the Phanerozoic, and its impact on marine organisms has been extensively studied. However, whether the terrestrial ecosystem had begun to deteriorate or even collapsed prior to the end-Triassic mass extinction remains controversial and the related studies in Asia are very limited. In this study, we provide a comprehensive investigation of the sedimentary environments, their implications for floral changes, and the paleoecology during the Norian–Rhaetian transition in Xuanhan area, northeastern Sichuan Basin, Southwest China. The sedimentary environments and climatic conditions changed coupling the transgression and regression caused by the tectonic movements. Climatic oscillations were identified during the Norian–Rhaetian transition in the Xuanhan area, including a short-term cooling event. The diversity and composition of the plant communities changed through the Norian–Rhaetian transition in Xuanhan area, but the terrestrial ecosystem as a whole didn’t collapse or deteriorate prior to the end-Triassic mass extinction.     

A traversodont cynodont from the Middle Triassic (Ladinian) of Baden-Württemberg (Germany)

Nanogomphodon wildi n. gen., n. sp. is based on a tiny lower postcanine tooth from the lower Lettenkeuper (Lower Keuper or Erfurt Formation; Ladinian) of Michelbach an der Bilz (Baden-Württemberg). It represents the first record of a traversodont cynodont from the Middle Triassic of Europe and exhibits a distinctive combination of dental features. Along with recent discoveries of other traversodont taxa from the Upper Triassic of eastern North America,Nanogomphodon indicates the existence of a distinct lineage of these cynodonts in the Northern Hemisphere.      

New grylloblattid insects (Insecta: Grylloblattida) from the Grès à Voltzia of the Vosges (Middle Triassic of France)

New grylloblattid insects (Grylloblattida) are described from the Grès à Voltzia of the Vosges (Anisian of Alsace and Lorraine, France): Chauliodites anisicus, sp. nov. (Chaulioditidae), Palaeomesorthopteron pullus gen. et sp. nov. (Mesorthopteridae), Megakhosarodes vosgesicus sp. nov. (Megakhosaridae), Dorniella elcanoides sp. nov., D. apectinata sp. nov., D. diluta sp. nov., D. ovalis sp. nov., Baharellinus umbrosus sp. nov. Embigryllus shcherbakovi gen. et sp. nov., and Vosgesopterum arzvillerensis gen. et sp. nov. (Blattogryllidae).     

Lithostratigraphy and carbonate microfacies across the Permian–Triassic boundary near Julfa (NW Iran) and in the Baghuk Mountains (Central Iran)

Permian–Triassic boundary sections in the Julfa (NW Iran) and Abadeh (Central Iran) regions display a succession of three characteristic rock units, (1) the Paratirolites Limestone with the mass extinction horizon at its top, (2) the ‘Boundary Clay’, and (3) the earliest Triassic Elikah Formation with the conodont P–Tr boundary at its base. The carbonate microfacies reveals a facies change, in the sections near Julfa, within the Paratirolites Limestone with an increasing number of intraclasts, Fe–Mn crusts, and biogenic encrustation. A decline in carbonate accumulation occurs towards the top of the unit with a sponge packstone in the sections, and finally resulting in a complete demise of the carbonate factory. The succession of the ‘Boundary Clay’ differs in the two regions; thin horizons of sponge packstone are present in the Julfa region and ‘calcite fans’ of probably inorganic origin in the Abadeh Region. The skeletal carbonate factory of the Late Permian was restored with the deposition of microbial carbonates at the base of the Elikah Formation, where densely laminated bindstone, floatstone with sparry calcite spheres, and oncoid wackestone/floatstone predominate.     

Facies and diagenetic evaluation of the Permian–Triassic boundary interval and basal Triassic carbonates: shallow and deep ramp sections,Hungary

The Permian–Triassic boundary and basal Triassic shallow-marine successions were studied and correlated in sections of two structural units in Hungary (Transdanubian Range and Bükk units). Core sections in the Transdanubian Range unit recovered inner ramp deposits whereas outcrops in the Bükk unit expose deposits of the deeper ramp area of the western Tethys. The inner ramp section (studied ca. 10 m in thickness) is characterized by a succession of dolomites overlain by bioclastic limestones, peloidal grainstones (which recorded the biotic decline) and oolites with finely crystalline limestone interlayers. The deeper ramp section (studied ca. 15 m in thickness) is characterized by a succession of bioclastic limestones and marlstones, mudstone beds (recording the first biotic decline), the ‘boundary shales’ (recording the second biotic decline and the stable carbon isotope marker), mudstones with wackestone laminae, and stromatolite boundstones. Accordingly, oolite formation and microbial micrite precipitation represent carbonate sedimentary responses of end-Permian mass extinction on the carbonate shelf. In both successions, mudstones predominate the upsection, suggesting a relative sea-level rise. The succession of the deep ramp area exhibits a continuous sediment accumulation and the diagenesis here was influenced by marine and marine-derived pore water. The δ¹³C curve shows a continuous change towards more negative values, starting in bioclastic limestones, followed by a sharp symmetric negative peak at the second biotic decline that is a chemostratigraphic marker of the boundary event. Facies and microfacies trend of the inner ramp carbonates in the Transdanubian Range unit exhibits close similarities to that found in many South Alpine sections. Relict peloidal deposits, formed cemented submarine hardground substrate, indicate the extinction level. Sedimentary and diagenetic features of the overlying oolite bedset revealed slightly different depositional environments in the two studied Transdanubian Range unit sections. Petrography of the oolites highlighted shallow burial diagenetic alterations which includes marine cementation, marine-burial replacement and dolomitization. A lack of the specific negative peak in the δ¹³C values is most likely due to the multiple redeposition events of the sedimentary grains. This led to the conclusion that the deeper ramp deposits (e.g., in Bükk unit) have greater potential for recognizing trends in processes, affecting the marine environments and related to the end-Permian mass extinction, at the western Tethys.     

Pot casts in the Upper Muschelkalk (Middle Triassic) of Weimar/Thuringia—Composition,microfabrics and diagnesis

Summary A horizon with pot casts (potholes) is described from shallow-marine limestones of thespinosus-zone (‘Discitesschichten’, Upper Muschelkalk) near Weimar/Thuringia. The erosional structures are not developed as sole marks but occur as isolated structures. They differe distinctly in size and composition from pot casts described from the Muschelkalk of Southern Germany. Vertical sedimentary zonation and varying sediment infill in the structures suggest continuous erosion and deposition contemporaneous with the background sedimentation. Deposition may have been caused by oscillatory and unidirectional flows as well as a long period of micrite deposition. Early diagenetic deformations (e.g. dewatering, brecciation, pressure solution) have controlled by a higher continuous water flux inside the pot casts and higher intergranular dispersal pressure.     

Phylogeny of the Alismatales (Monocotyledons) and the relationship of Acorus (Acorales?)

A phylogenetic analysis of the early branching lineages of the monocotyledons is performed using data from two plastid genes (rbcL and matK), five mitochondrial genes (atp1, ccmB, cob, mttB and nad5) and morphology. The complete matrix includes 93 terminals representing Acorus, the 14 families currently recognized within Alismatales, and numerous lineages of monocotyledons and other angiosperms. Total evidence analysis results in an almost completely resolved strict consensus tree, but all data partitions, genomic as well as morphological, are incongruent. The effects of RNA editing and potentially processed paralogous sequences are explored and discussed. Despite a decrease in incongruence length differences after exclusion of edited sites, the major data partitions remain significantly incongruent. The 14 families of Alismatales are all found to be monophyletic, but Acorus is found to be included in Alismatales rather than being the sister group to all other monocotyledons. The placement is strongly supported by the mitochondrial data, atp1 in particular, but it cannot be explained as an artifact caused by patterns of editing or by sampling of processed paralogues.     

Late Triassic and Lower Jurassic Foraminifera of the carbonate platform of the Beyaz Aladağ Group (Eastern Taurus,Turkey): New stratigraphic implications

Foraminifera have proven to be reliable biostratigraphic indicators. Accordingly, Triassic and Early Jurassic benthic Foraminifera allow us to define a biostratigraphic zonation within the carbonate platform of Kayseri (Yahyal?), Göksun (Kahramanmara?) and Sivas (Delikta?) regions in the Eastern Taurus (Ceviz, Alada?, Kaman and Felfan Mountains). Seven new stratigraphic sections are described in detail and the first precise inventory and illustration of the benthic foraminifer assemblages from the Triassic successions are presented over a large geographic area. The stratigraphic and palaeontological features of the Lower Mesozoic carbonate units of these mountains include several synchronous transgressive–regressive events that suggest continuity of the Lower Mesozoic environments over a large parautochthonous Taurus zone. Palaeogeographic considerations about the Eastern Taurus carbonates are given, evidencing three stages of development underwent by the studied area: 1) a stable continental margin from Lower Triassic to Lower Cretaceous; 2) a dismantling of the continental margin and first emplacement of ophiolites in the Upper Cretaceous; and 3) a deformation of the continental margin and emplacement of the Peridotite Nappe in the uppermost Cretaceous (Maastrichtian).     

Sudden origin of ribbing in Jurassic Paracenoceras (Nautiloidea) and its bearing on the evolution of ribbing in post‐Triassic Nautiloids

Ribs appeared cryptically in the Middle Jurassic nautiloid Paracenoceras. These ribs were produced by crowding of growth lirae as a corollary of change in body size during paedomorphic evolution. Initially, they had no direct functional significance. Some other contemporary genera are found to have similar ribbing patterns, partially developed on either the flanks or venter of the adult body chamber.

Subsequently in nautiloid phylogeny, ribs spread all around the whorl, becoming analogous to those of contemporary ammonites. Shell rugosity is observed to occur with increasing frequency in post‐Triassic nautiloids, paralleling the trend in ammonites. This is believed to be an outcome of the ‘arms race’ known as the Mesozoic marine revolution. Ribbing that was not at first adaptive in these nautiloids was subsequently co‐opted as a defensive adaptation. The evolution of this structure is a good example of exaptation.     

Phylogenetic Relationships of the Triassic Archaeosemionotus Deecke (Halecomorphi,Ionoscopiformes) from the ‘Perledo Fauna’

The lagerstätten in the Monte San Giorgio have provided excellent fossils representing one of the most important windows to the marine life during the Triassic. Among these fossils, fishes are abundant and extraordinarily well preserved. Most of these fishes represent extinct lineages and were difficult to understand and classify during the early years after discovery. These difficulties usually led to a mixture of species under the same taxonomic name. This is the case of fishes referred to the genus Archaeosemionotus. The name bearing type of A. connectens, the type species of this genus, represents a basal halecomorph, but most other fishes referred to this genus represent basal ginglymodians. Therefore, we conducted this study to clarify the taxonomic status and phylogenetic relationships of A. connectens, which is a member of the family Furidae (Halecomorphi, Ionoscopiformes) representing the second cladistically supported evidence of ionoscopiforms in the Triassic and it is thus one of the two oldest reliable records of this group. Ionoscopiforms have a long stratigraphic range, though their fossil record is rather patchy. In our analysis, the sister taxon of Archaeosemionotus is Robustichthys from the Anisian of China, and they together form a clade with Furo, which is known from several localities ranging from the Early to the Late Jurassic. Other ionoscopiforms are so far known from the Kimmeridgian to the Albian and it is thus evident that recent efforts have concentrated on the later history of the group (Late Jurassic to Cretaceous). The phylogenetic relationships obtained for the Ionoscopiformes do not show a clear palaeobiogeographic pattern, but give important new insights into the origin, divergence date and early history of this clade.     

Sequence of Permian Tetrapod Faunas of Eastern Europe and the Permian–Triassic Ecological Crisis

Eastern Europe shows the most complete in the world continuous sequence of continental Permian and Triassic deposits, which allows the development of tetrapod faunas over more than 17 successive stages to be traced. The newly obtained data on transitional Vyazniki and Sundyr tetrapod faunas provide more complete characteristics of the Severodvinian (Late Guadalupian, pre-Lopingian) and Permian-Triassic ecological crises and the ways of replacement of the dominant vertebrate groups of Eastern Europe.     

Taxonomic and biochronological significance of specimens of the Triassic dicynodontDinodontosaurus Romer 1943 in the Tübingen collection

Two species of the dicynodontDinodontosaurus from the Middle Triassic interval of the Santa Maria Formation in Rio Grande do Sul, southern Brazil,D. tener (von Huene 1935) andD. turpior (von Huene 1935), are based on undiagnostic lectotypes and thus arenomina dubia. The oldest valid, available name for a species ofDinodontosaurus isD. oliveirai Romer 1943, the type species of the genus. (The unused senior subjective synonymDiodontosaurus pedroanum Caldas, 1936 has been suppressed by the International Commission on Zoological Nomenclature).Chanaria platyceps Cox 1968 andDinodontosaurus brevirostris Cox 1968 are junior subjective synonyms ofD. oliveirai Romer 1943.Dinodontosaurus thus is a monospecific genus known from the Santa Maria Formation and the Ischichuca (= Chañares) Formation of northwestern Argentina. This dicynodont and associated tetrapods characterize the Chanarian land-vertebrate faunachron, which is of Middle Triassic age, probably Ladinian.     

Spinicaudata (“Conchostraca,” Crustacea) from the Middle Keuper (Upper Triassic) of the southern Germanic Basin,with a review of Carnian–Norian taxa and suggested biozones

The Coburg Sandstone member of the Hassberge Formation, Middle Keuper, Carnian, Upper Triassic, in the Germanic Basin of Central Europe contains spinicaudatan branchiopods which considerably broaden the known spectrum and provide important data on the phylogenetic history and intercontinental correlation of this systematic group. The spinicaudatan fauna for this lithostratigraphic unit is described in detail and includes Euestheria kozuri sp. nov., E.? sp. nov. A, Gregoriusella striatula sp. nov., Laxitextella freybergi Kelber and Kozur in Kozur and Weems, 2007, L. dorsorecta (Reible, 1962), and Laxitextella? sp. A. Additional discussions deal with Euestheria multicostata (Geyer, 1987), E. winterpockensis (Bock, 1953a), Laxitextella laxitexta (Sandberger in Jones, 1890), Laxitextella multireticulata (Reible, 1962), and “Laxitextella? hausmanni (Schmidt, 1938),” as well as problems with (sub)global zonations that are based on spinicaudatans and suggested to be of Carnian and Norian age.     

Hypercalcified segmented sponges (“sphinctozoans”) from the Upper Triassic (Norian) reef boulders of Taurus Mountains (southern Turkey)

Upper Triassic Norian reef boulders, exposed in a locality near the fountain “Tavuk Cesme” (“Chicken Fountain”) in Taurus Mountains, southern Turkey yielded a large number of hypercalcified sponges, including “sphinctozoans”, “inozoans”, “spongiomorphids”, and “chaetetids”. The sphinctozoans from this locality are described in this paper. Geologically, this locality belongs to the Anamas-Akseki autochthonous. The reef boulders of this locality are exposed near the “Tavuk Cesme” fountain, located at the road, leading from the town of Aksu to Yenisarbademli. The following taxa are described: Amblysiphonella taurica nov. sp., Anthalythalamia riedeli Senowbari-Daryan, Calabrisiphonella sphaerica nov. sp., Calabrisiphonella cuifi nov. sp., Cinnabaria minima Senowbari-Daryan, Colospongia recta nov. sp., Colospongia sp. 1, Colospongia sp. 2, Colospongia sp. 3, Cryptocoelia compacta nov. sp., Cryptocoelia? sp., Deningeria crassireticulata Senowbari-Daryan, Zühlke, Bechstädt and Flügel, Discosiphonella minima Senowbari-Daryan and Link, Gigantothalamia ovoidalis Senowbari-Daryan, Hajarispongia dipoyrazensis nov. sp., Hajarispongia cortexifera nov. sp., Kashanella irregularis Senowbari-Daryan, Kashanella cylindrica nov. sp., Parauvanella ferdowsensis Senowbari-Daryan, Parastylothalamia cylindrica nov. gen., nov. sp., Asiphothalamia polyosculata nov. gen, nov. sp., Sollasia norica nov. sp., and Thaumastocoelia sphaeroida Senowbari-Daryan. The most abundant sponge is Amblysiphonella taurica nov. sp. followed by Hajarispongia dipoyrazensis nov. sp., Colospongia and Discosiphonella minima Senowbari-Daryan and Link are also relatively abundant. The stylothalamid sponge Parastylothalamia nov. gen. is an abundant sponge genus in other Norian reefs of the Taurus Mountains, but is rare at the “Tavuk Cesme” locality.     

Middle Triassic carbonate-platform break-up and formation of small-scale half-grabens (Julian and Kamnik–Savinja Alps, Slovenia)

In the Julian Alps (Mt. Prisojnik, NW Slovenia) and in the Kamnik–Savinja Alps (Mt. Kri?evnik, N Slovenia), both of which form part of the eastern Southern Alps, several meters of Upper Anisian pelagic red nodular, radiolarian-rich limestone (Loibl Formation) were deposited on the drowned platform carbonates of the Contrin Formation. The time of the platform drowning is dated with radiolarians and conodonts to the Illyrian, more precisely to the upper part of the Paraceratites trinodosus Ammonoid Zone. The red limestone is overlain by pyroclastics and volcanics (rhyolites) or carbonate (mega)breccia (Uggowitz Formation). The following unit consists of thin-bedded limestone, grainstone and subordinate marl (Buchenstein Formation) deposited during the final filling of the basin from the adjacent prograding carbonate platform (Schlern Formation) in the Ladinian. Map-scale geometry, neptunian dykes, the onset of volcanism, the presence of (mega)breccia and related paleo-escarpments, the lateral variations in thickness and the wedge-shaped geometry of the lithological units provide evidence of syn-sedimentary block faulting and the formation of small-scale, relatively shallow half-grabens within the previously uniform Slovenian Carbonate Platform. This analysis indicates a clear tectonic control over the development of the Middle Triassic stratigraphy. The described extensional event is well correlated and genetically connected with the syn-rift formation of the neighboring Slovenian Basin and other Southern Alpine basins that formed in connection with the opening of the Meliata-Maliac branch of the Neotethys Ocean.     

Platform margins, microbial/serpulids bioconstructions and slope-to-basin sediments in the Upper Triassic of the ‘Verbicaro Unit’ (Lucania and Calabria, southern Italy)

Summary  The Upper Triassic carbonates of the area comprised between Maratea (Lucania) and Praia a Mare (Calabria) have been studied. They have been grouped into six facies assemblages which, in turn, define two depositional systems.

Reinvestigation of conchostracans (Crustacea: Branchiopoda) from the Permian–Triassic transition in Southwest China

Sedimentary deposits of the Permian–Triassic transition are well-exposed in numerous outcrops of South China. Depending on the palaeogeographic positions of the sections, their lithofacies vary from fully marine, shallow marine, lagoonal, lacustrine, and fluvial to alluvial. In the present study, conchostracans (Crustacea: Branchiopoda) were newly collected from the continental deposits of the Kayitou and Jialingjiang formations around the Kangdian Highland elevated by the Emeishan Basalt in the southern Sichuan, western Guizhou, and northeastern Yunnan provinces. The conchostracan fauna of the Kayitou Formation is composed of Pseudestheria chatangensis, Euestheria fuyuanensis, and Euestheria sp. aff. E. gutta. These species occur in varying lithofacies types of different sections. In particular, the late Permian Pseudestheria chatangensis occurs in grey siltstones interbedded with pebbly sandstones, which are interpreted as lacustrine deposits. Euestheria fuyuanensis and Euestheria sp. aff. E. gutta were obtained from yellowish to greenish–grey clay- and siltstones, interpreted as coastal plain deposits. In comparison to other regions, occurrences of Euestheria gutta are indicative of an early Induan to Olenekian (Early Triassic) age. The fossil record of Euestheria fuyuanensis is so far restricted to a few occurrences in the Kayitou Formation of Southwest China and, therefore, using this species for long-distance biostratigraphic correlation requires further investigation. The distribution of late Permian pseudestheriid and Early Triassic euestheriid species in the respective sections possibly depends on the local lithofacies and, therefore, a diachronous age of the Kayitou Formation within the study area can be assumed. Additionally, Magniestheria sp. aff. M. mangaliensis and Magniestheria sp. aff. M. subcircularis were recorded in the Jialingjiang Formation, which represents a lithostratigraphic unit considered as late Early Triassic (Olenekian). Further investigations of both taxonomy and the real stratigraphic ranges of the conchostracan species as well as cross-correlations with other age data are recommended, in order to better constrain the position of the Permian–Triassic boundary and the specific timing of the terrestrial end-Permian mass extinction in continental deposits of Southwest China.