The Geiseltal fossil collection from southern Sachsen-Anhalt Germany contains remarkably well-preserved fossils of middle Eocene age. These include several crocodylian skulls, representing at least four different genera with a fifth genus represented by two mandibular rami. As sites with this many crocodylian genera are unknown in modern ecosystems, it has been hypothesized that these crocodylians may have differences in habit as compared to living crocodylians. In order to test similarities between the Geiseltal crocodylians and extant species, an analysis was conducted using geometric morphometrics to quantify shape in crocodylian skulls of all living species (n = 218) and all well-preserved crocodylian skulls of the Geiseltal fauna (n = 28). A relative warps analysis was used to quantify and compare skull shape, revealing Allognathosuchus and Boverisuchus to be very distinct from each other as well as from Asiatosuchus and Diplocynodon. Overlap in shape alone exists between some Diplocynodon and some Asiatosuchus, but there was significant difference in adult size. When compared with extant crocodylians, three Geiseltal genera occupied distinctly non-modern morphospace in the first two relative warps axes. Comparison of the diets of living crocodylians with similarly shaped skulls was used to reconstruct the prey preferences of the Geiseltal crocodylians, revealing differences in specialization. During the middle Eocene high global temperatures, partitioning of prey preference may have allowed this group to attain its higher than usual diversity, reducing the amount of direct competition.

Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable minerals, such as pyroxene, olivine and Fe oxides, illustrate how the analysed sands preserve the source rock(s) provenance signals. Applying the concept of Sand Generation Index we see that these lithotypes have different propensities to create detritus, in terms of both grain-size and composition. Clastic contribution from pyroclastic rock outcrops such as pumice is not found in the size ranges studied, suggesting that these pumiceous source rocks probably only produce gravel or very fine sand and silt. This finding has implications for the stratigraphic record because pumice clasts, ranging from medium to fine grain-size, could be underrepresented in older volcaniclastic deposits and overrepresented in other size fractions.

Enigmatic chambered structures have been reported forming reef frames in Cryogenian interglacial carbonates, prior to the commonly acknowledged microbial-metazoan reefs at the terminal Ediacaran, and interpreted as fossils of possible sponge-grade organisms. A better constraint on the affinity of these structures is partly hindered by few analogues in other time periods. This study describes similar structures from peritidal dolostones of the Ediacaran Denying Formation from Yunnan, China. Samples were investigated using optical microscopy and three-dimensional (3-D) reconstruction based on grinding tomography. The Dengying chambered structures are comparable with Cryogenian structures in basic construction, but are not frame building, and show variations in overall shape and inhabiting facies. Two-dimensional (2-D) cross-sections show that thin, homogeneous micritic laminae are the basic building blocks of the chamber walls. Thick walls represent parallel accretion of these laminae, and thin walls developed from the angular growth of a single lamina or merging of multiple laminae. In 3-D space, the laminae primarily correspond to continuous surfaces which sometimes contain sub-circular holes, while a few represent filamentous elements connected to the surfaces. The morphological features and growth pattern of the Dengying chambered structures indicate that they are likely to be calcified microbial constructions rather than skeletal remains of basic metazoans. However, aside from the Cryogenian and Dengying examples, comparable chambered constructions with laminae-based architecture are yet unknown from other fossil or extant microbialites. Further work investigating related structures is needed to determine the microbial consortia and controlling environmental factors that produced these chambered structures.

A complete coral succession through the Ordovician–Silurian transition in South China reveals an adaptive phase during the Hirnantian glaciation, followed by an early survival phase and finally a late survival phase that persisted into the early Silurian. We demonstrate that a coral assemblage of latest Hirnantian to earliest Silurian age, remarkably similar to those from the Edgewood fauna known from Laurentia, occurs stratigraphically above the typical Hirnantian fauna. This, in combination with other evidence (e.g. brachiopods, lithology and chemostratigraphy), suggests the Edgewood fauna probably post-dated the early–middle Hirnantian glaciation, rather than being coeval with the older glacial-related Hirnantia fauna. Evidence from South China shows that the Edgewood fauna appeared in the very latest Hirnantian and extended into the middle Rhuddanian, considerably younger than previously believed. Such a new correlation necessitates a reassessment of the influence of the end-Ordovician glaciation on biotas. We argue that this major glaciation probably would have substantially affected the ecosystem even in tropical regions, as shown by the development there of the Hirnantia fauna or, alternatively, the presence of a conspicuous stratigraphic hiatus. This suggests a surprisingly rapid biotic recovery during the subsequent postglacial transgression, represented by the flourishing of comparatively diverse shelly faunas (e.g. the Edgewood fauna and the Cathaysiorthis brachiopod fauna) in nearshore shallow water environments from Laurentia to eastern peri-Gondwana terranes or blocks (e.g. South China).

The Cambrian Stage 4 upper Bastion Formation of Albert Heim Bjerge and CH Ostenfeld Nunatak, NE Greenland, yielded 34 excellently preserved sclerites of Lapworthella schodackensis among other small shelly fossils. Lapworthellids have been interpreted as members of the camenellans, a basal tommotiid group. Little is known about this group although the morphological and ultrastructural features of their sclerites allow a potential reconstruction of a lophophorate body plan. The exquisite material from Greenland provides significant new data for the revision of the species taxonomy, but also for the comprehension of the scleritome structure of lapworthellids and the mode of formation of their sclerites. Two morphotypes of L. schodackensis sclerites are identified: one with a simple apex, occurring in sinistral and dextral forms; and one bilaterally symmetrical sclerite with two apices. All bear a similar ornamentation constructed of repeated growth sets consisting of a reticulate inter-rib groove with tubercles, a densely denticulate rib and a striated sub-rib area. The new data on the ornamentation and observations of the laminar shell microstructure of L. schodackensis enable us to improve the reconstruction of growth in lapworthellids. Finally, the morphological features of the two types of sclerites provide new information for the reconstruction of the bilaterally symmetrical multi-component lapworthellid scleritome with evidence of the fusion of adjacent sclerites during early ontogeny.

Red Hills Road Cave, Jamaica is a remnant of a karstic feature quarried away during road building. It is the most important site for Late Pleistocene terrestrial palaeontology on the island. The site is c. 30 ka old. Many taxa were washed in during hurricanes and tropical storms, either as dead carcasses or live organisms that drowned as the cave filled with water. The invertebrate fauna includes snails and arthropods; none are obligate cave dwellers. The 62 species of land snails are the most diverse of any Jamaican cave; operculate taxa may be preserved with the operculum in situ. Arthropods include the only fossil millipedes, isopods and insects (fly puparia, beetle elytra) in the Jamaican fossil record, in addition to land crabs. Millipedes and isopods are well preserved because of a diagenetically early coating of calcite cement. The exoskeletons of these groups contain a small, but significant, calcite component not found in insects, spiders and scorpions. The vertebrate fauna remains understudied, but include: a rodent and three species of bat; a flightless ibis and various other birds; and reptile and amphibian remains. In contrast to the arthropods, the vertebrates are invariably disarticulated apart from rare crania, jawbones retaining teeth and bones that are fused in life. A dead millipede could be coated in calcite when floating in the cave immediately after death; a dead vertebrate carcass would have to rot to expose its bones after the cave dried out and would, most likely, disarticulate before or during the next inundation.

One of the few and most complete records of the MDICE (Middle Darriwilian Isotope Carbon Excursion) is herein documented from Baltoscandia. Based on a core section penetrating the condensed Lower–Middle Ordovician succession (~46 m) on the island of Öland, southeastern Sweden, we provide an integrated scheme for carbon isotope chemostratigraphy (313 samples) and conodont biostratigraphy (29 samples) for this period. The carbonate succession in the Tingskullen core records 12 conodont zones and 6 subzones, including the Oepikodus evae, Trapezognathus diprion, Baltoniodus triangularis, B. navis, B. norrlandicus, Lenodus antivariabilis, L. variabilis, Yangtzeplacognathus crassus, Eoplacognathus pseudoplanus (Microzarkodina hagetiana and Microzarkodina ozarkodella subzones), E. suecicus, Pygodus serra (E. foliaceus, E. reclinatus, E. robustus and E. lindstroemi subzones) and Pygodus anserinus zones in ascending order. The δ13Ccarb record reveals an apparently complete record of the MDICE, including a rising limb, a well-defined peak and a falling limb. The anomaly covers a thickness of c. 27 m in the core and spans the Eoplacognathus pseudoplanus, E. suecicus, Pygodus serra and P. anserinus conodont zones. Combined with the new, detailed conodont biostratigraphy, the MDICE in the Tingskullen core can be used for detailed correlation with successions from Baltica, North America, the Argentine Precordillera, South China and North China.

Microstructural, finite strain and vorticity analyses of quartz-rich mylonites were used in order to investigate kinematics of rock flow and deformation temperature in the Sirjan thrust sheet exposed in a structural window within the Sanandaj–Sirjan High Pressure – Low Temperature (HP–LT) metamorphic belt that forms part of the hinterland of the Zagros orogenic belt of Iran. A dominant top-to-the-SW sense of shear in the study area is indicated by several shear sense indicators such as asymmetric boudins, rotated porphyroclasts, mica fish and S/C fabrics. Quantitative analyses reveal approximately plane strain deformation conditions with Rxz values ranging from 2.5 to 4.3 and increasing towards the Sirjan thrust. Opening angles of quartz c-axis fabrics and recrystallization regimes suggest deformation temperatures vary from 430 to 625 ± 50°C in the hanging wall rocks. Oblique grain shape and quartz c-axis fabrics were used to estimate the degree of non-coaxiality during deformation. The obtained vorticity profile indicates a down-section increase in kinematic vorticity number (Wm) from 0.6 to 0.89. This range of vorticity numbers confirms contributions of both simple (41–68 %) and pure shear (32–59 %) deformation components. The structural characteristics of the study area ultimately were controlled by oblique motion of the Afro-Arabian plate relative to the Iranian plate.

Late Permian fluvio-lacustrine successions of the Çakraz Formation in the Zonguldak Terrane between the regions of Akçakoca and Ereğli were investigated in order to describe the litho- and biostratigraphic properties and explain the depositional environment. The studied succession with black, dark-grey to greenish-grey shales, siltstones and limestones is named the Alaplı Member to distinguish it from the classical red clastic successions, which are tentatively named the Ereğli Member of the Çakraz Formation. The organic-rich black shales, mudstones and limestones of the Alaplı Member yielded palynological assemblages suggesting a Lopingian (Tatarian) age. The lack of any marine macro- or microfossils, the fine-grained character of the lithofacies with abundant plant material and the association of poorly sorted conglomerates in the middle part of the succession indicate possible deposition in a broad range of fluvial and lacustrine environments. Successions of similar age and depositional environment are known from the East European Variscan Belt in Bulgaria and Romania. Common successions were also developed in actively extending shallow-marine platforms on the NW Palaeotethyan margin at the end of the Permian Period.

The first ophthalmosaurid ichthyosaur from the Upper Jurassic deposits of the Central–Northern Apennines (Marche, Italy) is here described for the first time. The specimen is relatively complete and is referred to Gengasaurus nicosiai gen. et sp. nov. based on a unique combination of characters, including a peculiar condition of the preaxial accessory facet on the humerus. The faunal association of the ichthyosaur-bearing level indicates a late Kimmeridgian – earliest Tithonian age, and its finding contributes significantly to our knowledge of the diversity of Late Jurassic ichthyosaurs from the Western Tethys. Two shark teeth assigned to the order Hexanchiformes were also recovered in association with the ichthyosaur specimen, suggesting that scavenging of the carcass might have occurred. Gengasaurus can be referred to Ophthalmosauridae based on the reduced extracondylar area of the basioccipital, and the presence of a preaxial digit. It differs from Ophthalmosaurus spp. in several respects, including the shape of the posterior basisphenoid, the shape of the supraoccipital, the anteriorly deflected preaxial facet of the humerus, and a proximodistally shortened ulna. The new taxon actually shares diagnostic characters with both members of the two main lineages recovered in previous phylogenetic analyses, more nested within Ophthalmosauridae. The affinities of Gengasaurus to genera from both the northern and southern hemispheres also suggest that connectivity between pelagic habitats was high during the early Late Jurassic, allowing dispersal of some forms, followed by local, endemic divergence.

The Podolsko complex, Bohemian Massif, is a high-grade dome that is exposed along the suprastructure–infrastructure boundary of the Variscan orogen and records snapshots of its protracted evolution. The dome is cored by leucocratic migmatites and anatectic granites that enclose relics of high- to ultrahigh-pressure rocks and is mantled by biotite migmatites and paragneisses whose degree of anatexis decreases outwards. Our new U–Pb zircon ages indicate that the leucocratic migmatites were derived from Early Ordovician (c. 480 Ma) felsic igneous crust; the same age is inferred for melting the proto-source of the metapelitic migmatites. The relics of high- to ultrahigh-pressure rocks suggest that at least some portions of the complex witnessed an early Variscan subduction to mantle depths, followed by high-temperature anatexis and syntectonic growth of the Podolsko dome in the middle crust at c. 340–339 Ma. Subsequently, the dome exhumation was accommodated by crustal-scale extensional detachments. Similar c. 340 Ma ages have also been reported from other segments of the Variscan belt, yet the significance of this tectonothermal event remains uncertain. Here we conclude that the 340 Ma age post-dates the high-pressure metamorphism; the high temperatures required to cause the observed isotopic resetting and new growth of zircon were probably caused by heat input from the underlying mantle and, finally, the extensional unroofing of the complex requires a minimum throw of about 8–10 km. We use this as an argument for significant early Carboniferous palaeotopography in the interior of the Variscan orogen.

Microbially induced sedimentary structures (MISS) are microbial traces in sandy deposits. They have been formed by various modes of microbial behaviour in response to the prevailing physical dynamics in shallow-marine environments since early Archaean time. An association of fossils, phosphatic structures and grains, stromatolites and microbial laminated levelling structures is documented from the Zhongyicun Member of Lower Cambrian strata in the Baideng section dated close to 535 Ma. SEM examination demonstrates that microbial laminated levelling structures are the result of the development of microbial mats composed of filamentous structures. We propose that there was a short hiatus after the dolomite layer deposited when the dolomite layer was weathered to form centimetre-scale valleys firstly, and then microbes accumulated in these valleys and formed the microbial laminated levelling structures.

Two crinoid pluricolumnals from Permian rocks of Timor show similar patterns of external pitting. Platycrinitid sp. preserves circular, parabolic pits that do not cross-cut between columnals, some have raised rims and at least one columnal shows a growth deformity. These pits are interpreted as the trace fossil Oichnus paraboloides Bromley. Crinoid sp. indet. has particularly dense pits cross-cutting columnals on one side of the pluricolumnal only and extending onto the contiguous limestone; it is a Holocene microkarstic solution feature. Care must be taken to separate true bioerosive trace fossils from modern microkarstic features in limestones in the tropics.

The large Late Cretaceous marine reptile Mosasaurus has remained poorly defined, in part owing to the unorthodox (by today's nomenclatural standards) manner in which the name was erected. The lack of a diagnosis accompanying the first use of either the genus or species names allowed the genus to become a catchall taxon, and subsequent diagnoses did little to refine the concept of Mosasaurus. We herein present emended diagnoses for both Mosasaurus and the type species M. hoffmannii, based solely on personal examination of the holotype, and a description of the type species based on personal examination of many specimens. Mosasaurus exhibits a premaxilla with a short, conical edentulous rostrum, a maxilla with little to no dorsal excavation for the external naris, posteromedial processes of the frontal that deeply invade the parietal, a quadrate taller than long with a short suprastapedial process and the stapedial pit dorsal to the mid-height of the shaft, an angular that is laterally visible for only a short length of the post-dentary unit, a very tall surangular, a humerus with the postglenoid process robust and offset and a distal width greater than the length, and a pubis with an anteriorly projecting tubercle. M. hoffmannii is distinguished from other species assignable to the genus by the anteroventral corner formed on the tympanic rim of the quadrate, the asymmetric carinae of the anterior marginal teeth dividing the tooth circumference into short labial and long lingual segments, and the proximal and distal expansion of the femur.

Correlation of lower Cambrian strata is often confounded by provincialism of key fauna. The widespread occurrence of the micromollusc Watsonella crosbyi Grabau, 1900 is therefore an important biostratigraphic signpost with potential for international correlation of lower Cambrian successions. Previous correlations of W. crosbyi from Australia (Normanville Group) suggested an Atdabanian- to Botoman-equivalent age. However, in the upper part of the Mount Terrible Formation, stratigraphic ranges of W. crosbyi and Aldanella sp. cf. golubevi overlap prior to the incoming of vertically burrowed ‘piperock’, which is indicative of an age no earlier than Cambrian Stage 2. The stratigraphic range of W. crosbyi in the Normanville Group, South Australia correlates with the ranges of the taxon in China, France, Mongolia and Siberia (though not Newfoundland). The new Australian data add further support for considering the first occurrence of W. crosbyi a good potential candidate for defining the base of Cambrian Stage 2. The stratigraphic range of W. crosbyi through the lower Cambrian Normanville Group has been determined based on collections from measured sections. Although rare, W. crosbyi is part of an assemblage of micromolluscs including Bemella sp., Parailsanella sp. cf. murenica and a sinistral form of Aldanella (A. sp. cf. A. golubevi). Other fauna present include Australohalkieria sp., Eremactis mawsoni, chancelloriids and Cupitheca sp.

Many previous studies have investigated the late Palaeozoic ophiolites, migmatites and high-pressure metamorphic belts of the Tibetan Plateau, whereas the early Palaeozoic evolution of the regions is relatively poorly understood. Lower Palaeozoic strata, including the Duguer quartz schist, occur in the Himalaya, Lhasa and South Qiangtang terranes of the Tibetan Plateau. In this study, we report the depositional age and sedimentary provenance of the Duguer quartz schist of the central South Qiangtang terrane, which enables us to interpret the tectonic affinity of the terrane. We obtained U–Pb ages, trace-element compositions and Hf isotopic data from zircons from the Duguer quartz schist. A total of 162 U–Pb analyses of detrital zircons from the schist yielded two pronounced age peaks at c. 600 Ma and c. 960 Ma. These results indicate that the provenance of the Duguer quartz schist is India Gondwana or the terranes that share an affinity with India Gondwana in the Tibetan Plateau, which include the South Qiangtang and Himalaya terranes. Detrital zircon crystals show large variations in Hf isotope compositions, with εHf(t), TDM and TDMC values of −52.5 to 13.2, 900–3300 Ma and 1010–4240 Ma, respectively. This suggests that the source area for the Duguer quartz schist included Precambrian rocks and, more specifically, Pan-African and Grenville–Jinning crustal material. During Pan-African and Grenville–Jinning events, crustal recycling and the addition of mantle material occurred in the source regions of the quartz schist, when the South Qiangtang, Lhasa and Himalaya terranes were all part of the northern margin of Gondwana.

The clade Triadophlebioptera within the Odonatoptera greatly diversified and became widely distributed worldwide during the Triassic. Although abundant insect fossils have been reported from the Triassic of China, no Triassic dragonflies have been recorded. In this paper, Zygophlebia tongchuanensis sp. nov., the first species of Zygophlebiidae discovered outside the Madygen Formation of Kyrgyzstan, is described from the Middle–Upper Triassic Tongchuan Formation of Shaanxi Province, northwestern China. The discovery extends the distribution of the family Zygophlebiidae in Asia, indicating a high diversity of Triadophlebioptera during Middle–Late Triassic times. Combined with the palaeontological and geochronological evidence, the age of the Tongchuan Formation is considered to be Anisian – Early Carnian, and the insect-bearing layers are considered to be Ladinian.

Discoidal macrofossils reported herein from the lower Cambrian Zabriskie Quartzite (Great Basin, western United States) record the oldest Phanerozoic medusozoan body fossils, as well as the oldest medusozoan stranding event on record. Moreover, these fossils provide evidence of a significant shift in the taphonomic mode characteristic of preservation of nonmineralized taxa in coarse-grained siliciclastic successions near the onset of the Phanerozoic. Taphonomic and sedimentological evidence recorded by these and younger examples of stranded Cambrian medusae is consistent in suggesting that several of the requirements for preservation of these fossils were holdovers from the Ediacaran Period, including the presence of microbial mats and a lack of carcass disturbance by scavenging and/or bioturbating taxa. To shed further light upon the taphonomic factors necessary for the preservation of Cambrian medusae, we compared the biostratinomy and sedimentology of Cambrian medusa strandings to those of Ediacara Biota assemblages from lithologically similar successions. We find key secular disparities in the taphonomic histories of these two types of fossil assemblage. Inconsistencies between the preservational styles characteristic of fossil assemblages preserved in sandstone lithofacies on each side of the Precambrian–Cambrian boundary are explained by a considerable change in the preferred depositional setting in which these macrofossil assemblages are preserved. Thus, rather than documenting a single taphonomic continuum through the Precambrian–Cambrian transition, the Zabriskie and younger medusozoan body fossil assemblages record the advent of an entirely new, yet still very rarely exploited, taphonomic window exclusive to the Cambrian Period.

The earliest fossil record of animal biomineralization occurs in the latest Ediacaran Period (c. 550 Ma). Cloudina and Sinotubulites are two important tubular taxa among these earliest skeletal fossils. The evolutionary fate of Cloudina-type fossils across the Ediacaran–Cambrian transition, however, remains poorly understood. Here we report a multi-layered tubular microfossil Feiyanella manica gen. et sp. nov. from a phosphorite interval of the lowest Cambrian Kuanchuanpu Formation, southern Shaanxi Province, South China. This newly discovered fossil is a conical tube with a ‘funnel-in-funnel’ construction, showing profound morphological similarities to Cloudina and Conotubus. On the other hand, the outer few layers, and particularly the outermost layer, of Feiyanella tubes are regularly to irregularly corrugated, a feature strikingly similar to the variably folded/wrinkled tube walls of Sinotubulites. The Feiyanella tubes additionally exhibit two orders of dichotomous branching, similar to branching structures reported occasionally in Cloudina and possibly indicative of asexual reproduction. Owing to broad similarities in tube morphology, tube wall construction and features presumably indicative of asexual reproduction, Cloudina, Conotubus, Sinotubulites and the here described Feiyanella may thus constitute a monophyletic group traversing the Ediacaran–Cambrian boundary. The tube construction and palaeoecological strategy of Feiyanella putatively indicate evolutionary continuity in morphology and palaeoecology of benthic metazoan communities across the Ediacaran–Cambrian transition.

Gravitational collapse occurs during the mature evolution of orogenic belts, but its signature is difficult to discriminate in macroscopic structures from that of pre-, syn- or late-/post-orogenic extension, so reliable mesoscopic examples are particularly useful. A composite fabric developed along a lateral thrust ramp in the Apennines reveals mesoscopic normal faults that truncate the thrust surface, overprint the S-fabric and merge downwards in a foreland-directed splay, leaving the thrust footwall undeformed. These relationships indicate syn-/late-thrusting extension, which we interpret as induced by hanging-wall gravitational collapse. Our study provides critical constraints for reconstructing the kinematic evolution of collapsing thrust fronts.