Appendage anatomy contributes crucial data for understanding the evolution and ecology of Euarthropoda. The Palaeozoic trilobites show a great diversity of exoskeletons in the fossil record. However, soft parts, especially appendages, have only been discovered from a few trilobite species. Here we report extraordinarily preserved appendages in the trilobite species Hongshiyanaspis yiliangensis Zhang & Lin in Zhang et al. 1980 (Redlichiida, Metadoxididae) from a single mudstone layer of the Xiazhuang fossil assemblage within the Hongjingshao Formation (Cambrian Series 2, Stage 3) near Kunming, Yunnan, SW China. The appendages exhibit the common architecture revealed by other trilobites and artiopods by consisting of a pair of uniramous antennae followed by a series of paired homonomous biramous limbs. The antennae in holaspid individuals comprise up to 27 spinous podomeres and their ontogeny occurs by lengthening of the podomeres. The post-antennal biramous limbs are similar to those in other polymerid trilobites and artiopods by having a single-segmented protopodite and an endopodite comprising seven segments, but possess a unique wide tripartite exopodite with long setae. Sophisticated appendage anatomy, including the body–limb junction, fine setae, putative muscle bundles and duct-type tissues, are also revealed. Appendages of trilobites, artiopods and other upper stem-group euarthropods are compared and summarized. The H. yiliangensis appendages highlight the high morphological disparity of exopodites and the conservativeness of endopodites in trilobites and artiopods. This morphological pattern, together with similar body patterning seen in crustaceans but not in chelicerates, supports the mandibulate affinities of trilobites and at least some artiopods.

Diverse and well-preserved acritarchs are reported from the type section of the Cambrian Hanford Brook Formation at Hanford Brook, southern New Brunswick. This section fills an important gap in acritarch studies by providing the first detailed picture of changing acritarch associations close to the traditional lower–middle Cambrian boundary in Avalonia. Acritarchs from the St Martins Member, at the base of the succession, include Skiagia ciliosa, Heliosphaeridium notatum, H. longum and Liepaina plana and suggest attribution to Cambrian Stage 4. Acritarchs from the Somerset Street Member, in the middle of the formation, include Eliasum llaniscum and Comasphaeridium silesiense. This information adds new biochronological context to an ash bed in the Somerset Street Member previously dated as c. 510 Ma or 508 Ma, and to the endemic trilobites from the same member, including Protolenus elegans. It also places absolute ages on the basal range of stratigraphically important acritarchs. Both the acritarch assemblage and the radiometric age are consistent with a position very close to the traditional lower–middle Cambrian transition and likely within Cambrian Stage 5. Acritarchs from the Long Island Member, at the top of the succession, include additional taxa demonstrating assignment to Cambrian Stage 5. Both the Somerset Street and Long Island members probably correlate with the Morocconus notabilis Zone. The new acritarch species Retisphaeridium striatum Palacios is described. New data are presented on acritarchs from the upper part of the Hell's Mouth Formation, Wales, and correlation proposed with the Long Island Member.

Southwestern Europe is one of the best regions for characterizing the dinosaur assemblages that prevailed just before the end-Cretaceous extinction. Aiming to better document this scenario, we provide the first evidence of dinosaur skin impressions in the red-beds of the Tremp Formation (southern Pyrenees). The impressions are assigned to sauropods (probably titanosaurians) on the basis of their scale morphology, arrangement and size. They represent a valuable tool for analysing the last occurrences of the sauropod clade before the K–Pg extinction, as they fall within chron C29r (latest Maastrichtian), thus representing some of the last in situ remains of this clade worldwide.

We describe a study of the E–W-trending South Wagad Fault (SWF) complex at the eastern part of the Kachchh Rift Basin (KRB) in Western India. This basin was filled during Late Cretaceous time, and is presently undergoing tectonic inversion. During the late stage of the inversion cycle, all the principal rift faults were reactivated as transpressional strike-slip faults. The SWF complex shows wrench geometry of an anastomosing en échelon fault, where contractional and extensional segments and offsets alternate along the Principal Deformation Zone (PDZ). Geometric analysis of different segments of the SWF shows that several conjugate faults, which are a combination of R synthetic and R’ antithetic, propagate at a short distance along the PDZ and interact, generating significant fault slip partitioning. Surface morphology of the fault zone revealed three deformation zones: a 500 m to 1 km wide single fault zone; a 5–6 km wide double fault zone; and a c. 500 m wide diffuse fault zone. The single fault zone is represented by a higher stress accumulation which is located close to the epicentre of the 2001 Bhuj earthquake of Mw 7.7. The double fault zone represents moderate stress at releasing bends bounded by two fault branches. The diffuse fault zone represents a low-stress zone where several fault branches join together. Our findings are well corroborated with the available geological and seismological data.

A single specimen of a new species of the chasmataspidid Diploaspis Størmer, 1972 is described from the upper Silurian (Pridoli) Phelps Member of the Fiddlers Green Formation (Bertie Group) in Herkimer County, New York State, USA. Diploaspis praecursor sp. nov. is distinguished by the shape of the posterolateral margins of the buckler, which are drawn out into angular epimera, and by the lack of elongate tubercles on the postabdomen. This discovery increases the taxonomic diversity of the Bertie Group by extending the geographic extent of Diploaspididae into North America. D. praecursor pre-dates previously known species of Diploaspis by more than 10 million years.

This contribution deals with the record of the Ordovician genus Pygodus in Cuyania, Argentina. Several classical sections have been sampled for conodonts in the Precordillera and the San Rafael Block, involving diverse sedimentary deposits: coarse clastic rocks with carbonate cement, carbonate beds intercalated in fine clastic deposits, green shale, and black carbonate deposits. The recovered species of this genus are Pygodus lunnensis Zhang, P. anitae Bergström, P. serra (Hadding), P. protoanserinus Zhang and P. anserinus Lamont & Lindström. These key conodonts indicate middle to upper Darriwilian – lower Sandbian age for the bearing strata. The species P. protoanserinus is recorded for the first time from the Precordillera. Detailed observations were made on specimens of P. anitae, P. lunnensis and P. protoanserinus; the two last species are described for the first time from Cuyania.

During the middle Paleocene Laramide phase, several basins in Europe experienced subsidence, while others experienced uplift. Previous studies have shown that during the Laramide phase some basins surrounding the Brabant Massif experienced subsidence into shallow depocentres. This study discusses how the Brabant Massif simultaneously experienced uplift along its WNW–ESE Caledonian structural axis from central Belgium in the east up to the southeast coast of England (Ipswich) in the west. Uplift resulted in erosion of the formerly deposited Chalk Group on top of the axis of the Brabant Massif. The erosion products of the Chalk Group were reworked in the latest Danian to earliest Thanetian deposits that filled the surrounding depocentres. Early to middle Thanetian pulsed marine transgressions caused flooding and deposition across the entire region, including the previously uplifted axis of the Brabant Massif. The depositional thicknesses, however, indicate that the axis of the Brabant Massif remained a relative high up to the middle Thanetian.

Both the geometry and timing of the middle Paleocene vertical surface movements of the Brabant Massif and surrounding areas are very similar to those described for other structural entities in central and northern Europe, despite their often strongly differing Mesozoic tectonic evolutions. We discuss several mechanisms that might have triggered these vertical surface movements, of which lithospheric folding seems the most likely.

This paper is a contribution to the redefinition of the base of Carboniferous system. At present the criterion for the definition of the Devonian–Carboniferous boundary is the first occurrence of a conodont species. In order to evaluate the stratigraphic potential for new criteria for the definition of the Devonian–Carboniferous boundary, the distribution of conodont species of Bispathodus, Branmehla, Palmatolepis, Polygnathus, Protognathodus, Pseudopolygnathus and Siphonodella across the boundary is presented and discussed. An updated biozonation scheme across the boundary based on the First Appearance of Bispathodus ac. aculeatus, Bispathodus costatus, Bispathodus ultimus, Protognathodus kockeli, Siphonodella bransoni and Siphonodella duplicata is proposed, and it is suggested that the new criterion for the definition of the base of the Carboniferous system be the First Appearance Datum of Pr. kockeli or Si. bransoni.

A well-preserved fossil priapulid worm, Xiaoheiqingella sp., is reported from the early Cambrian Guanshan Lagerstätte (Cambrian Series II, Stage 4) near Kunming City, Yunnan Province, SW China. The body of the animal consists of four sections: a swollen introvert, a constricted neck, a finely annulated trunk and a caudal appendage. The body configuration exhibits a close resemblance to that of the crown group priapulid Xiaoheiqingella peculiaris from the early Cambrian Chengjiang Lagerstätte. The new discovery provides another striking example of crown group priapulids, representing the third occurrence of crown group fossil priapulids after the Chengjiang Lagerstätte (Cambrian Series II, Stage 3) and the Mazon Creek Lagerstätte (late Moscovian Stage, Pennsylvanian). The discovery also sheds new light on the early diversity and evolution of priapulid worms.

Utahcaris orion Conway Morris & Robison, 1988, from the lower middle Cambrian (Series 3, Stage 5) Spence Shale Member situated in Utah, USA, is redescribed based on a restudy of the original material. Newly recognized features, including ventral lateral eyes, trunk appendages, and a bulbous cephalic shield with subtriangular extension, reinforce similarities with Sanctacaris uncata from the middle Cambrian Burgess Shale. Both are assigned to the new family, Sanctacarididae. Sanctacaridids represent the oldest chelicerates. Their ecology and that of their nearest non-chelicerate relatives indicate that Chelicerata were plesiomorphically predatory.

The Mississippian volcano-sedimentary complex in the Toca da Moura – Cabrela areas represents remnants of intra-volcanic marine sedimentary basins, formed during the collision between the Ossa Morena Zone with the South Portuguese Zone. These rock units are unconformably overlain by the Pennsylvanian intramontane coal-bearing Santa Susana Basin. Vitrinite reflectance determinations from rocks of these two basins indicate two episodes of thermal maturation. During the first episode, the Toca da Moura – Cabrela volcano-sedimentary complexes attained high maturation levels, equivalent to anthracite coal rank (3.0–3.5% Roran), which pre-dates the middle Moscovian Santa Susana Basin. The Santa Susana Basin attained moderate maturation levels equivalent to bituminous coal rank (1.35–1.5% Roran) recording a second episode of thermal maturation. Here, peak thermal conditions did not overprint the first maturation episode. The observed effects of magmatic intrusion on the thermal maturity and the lack of any increase in vitrinite reflectance with depth through c. 400 m of section in borehole SDJ-1 indicate high geothermal gradients during the first maturation episode. A contemporaneous magmatic event associated with the c. 335–320 Ma Cuba-Alvito Gabbros/Diorites of the Beja Massif was the possible cause for the high geothermal gradients postulated for the first maturation episode. Burial under a post-upper Moscovian sedimentary cover was the most likely process to account for the maturation levels determined for the Santa Susana Basin and for the second episode of thermal maturation.

The Grenville Province forms the exhumed remnants of a 1.1 Ga collisional orogeny that telescoped an older continental margin. Terranes with distinct crustal formation ages can be mapped using Nd isotopes, revealing a ramp–flat thrust structure. The ramp is identified by the presence of retrogressed eclogites, and its trajectory is refined using Nd model ages. The main allochthon is locally overlain by the Parry Sound klippe, but is also underlain by a tectonic duplex. Northwest-directed nappes represent remnants of a corrugated thrust sheet, but a ring-shaped remnant was also preserved where the thrust sheet was down-buckled under the dense rocks of Parry Sound domain.

D. Plašienka, J. Michalík, J. Soták & R. Aubrecht comment: In their recent paper, Golonka et al. (2015) described the Cretaceous and Palaeogene olistostromes and other types of mass-transport deposits occurring within the Pieniny Klippen Belt (PKB) of the Western Carpathians. After a short introduction into the olistostrome concept and an overall description of the PKB structure, the authors presented their views on the composition and evolution of the PKB with olistostromes as the leading phenomenon. Although novel in some aspects, the model they present is largely oversimplified and partly erroneous in our opinion. In the following, we shall comment on the several most disputable statements and interpretations offered in the discussed paper.

The skeleton of a new vauxiid sponge (Order Verongida), Angulosuspongia sinensis gen. et sp. nov., described on the basis of material from calcareous mudstones of the Kaili Formation (Cambrian Stage 5), Jianhe area, Guizhou, South China, is composed of two layers of fused spicules outlining hexagonal or polygonal openings. These vauxiid remains are the first reported from outside Laurentia, and represent only the second genus attributed to the family. Its age is close to but still slightly older than the Burgess Shale Biota, and it appears to be a primitive relative of other members of the Vauxiidae. The morphological differences between Chinese and Laurentian vauxiid sponges may be a result of vicariance. These specimens not only extend the geographic distribution of vauxiids, but also help to fill a chronostratigraphical gap between North Greenland and North American material and provide additional evidence for understanding the evolutionary history of the Demospongiae.

Modern unvegetated rivers flowing through aeolian-dune fields demonstrate potential as analogues for pre-vegetation fluvial landscapes. A prominent example is contained in the Lençóis Maranhenses of Brazil, a coastal aeolian system hosting the semi-perennial Rio Negro. Remotely sensed images covering c. 45 years display the rhythmic expansion and wind-driven shift of single-threaded and sinuous fluvial trunks alternating with wider braided plains. Sinuous tracts feature mid-channel and bank-attached bars, including expansional point bars with subdued relief. The morphology, accretion and sediment transport of unvegetated point bars in the Rio Negro are compared to the morphodynamics of vegetated meandering rivers. Unvegetated point bars are composed of large coalescent unit bars, lack apparent scroll topography and are preferentially attached to channel banks located on the windward side of the river course. Unvegetated meanders have expansional behaviour related to downwind channel trailing. Point bars maintain an expansional planform despite spatial confinement induced by aeolian dunes. Channel-flow impingement onto cohesion-less banks favours scouring of deep pools along the bar tails, which host bank-collapse deposits subsequently reworked into new bars. Analogies to Precambrian rivers suggest that ancient unvegetated fluvial landscapes were not unequivocally featured by low sinuosity, especially if characterized by a low gradient and stable discharge. This inference is supported by ongoing studies on Proterozoic fluvial–aeolian systems in the Canadian Shield. Lack of scroll topography introduces overlap with low-sinuosity fluvial facies models, underscoring the value of observing ancient fluvial deposits in planform, or along 3D sections where the palaeodrainage of channel bodies and attached bars can be compared.

It remains unclear whether a crystalline basement exists in SE China (including Taiwan), whether the formation of the Tananao metamorphic belt in Taiwan was linked to subduction of the Palaeo-Pacific Plate, and whether the source rocks of the sedimentary sequences in the metamorphic belts are late Mesozoic or Palaeozoic in age. Field investigations and zircon age data in the present study indicate that there is no pre-Palaeozoic gneiss (crystalline basement) in Taiwan (although orthogneisses were produced during deformation and metamorphism of Mesozoic granites), and investigations of the metasediments show that the sedimentary sequences in the Tailuko and Yuli belts are similar. Moreover, LA-ICP-MS dating of detrital zircons from the Pingtan–Dongshan belt in Fujian Province yields a cluster of 206Pb–238U ages at ~ 210–190 Ma, and the Tailuko and Yuli belts in Taiwan have similar clusters of detrital zircon ages at 200 Ma, 160 Ma, 120 Ma and 110 Ma, as well as a later overprinting caused by arc–continent collision. The cathodoluminescence images and trace-element characteristics of the zircons show that they were originally magmatic in origin. This finding, combined with the Hf isotope data, indicates that the sources of sediments in the Tananao belt (Tailuko and Yuli belts) were relatively close to an active continental margin, and that both the Tailuko and Yuli belts have similar sedimentary sources. From the margin of the Chinese mainland to Taiwan, the metasediments seem to represent a continuous sequence of deposits ranging in age from Jurassic to Cretaceous, but with the sediments becoming progressively younger towards the east. It can be inferred that the sediments in the Tailuko and Yuli belts were continental-shelf sequences with sources in SE China.

A new dinosaurian track-bearing site, with tridactyl footprints from the Lower Jurassic (pre-middle Pliensbachian) volcanogenic and epiclastic rocks of the Marifil Volcanic Complex, Patagonia, Argentina, is presented and described. The best-preserved footprint, classified as cf. Anomoepus, confirms the utility of the Anomoepus-like tracks for the Early Jurassic biochronology. Palaeobiogeographically, this record supports the idea that the South American Early Jurassic dinosaur fauna presents elements of Pangaean distribution, and others with Gondwanan relationships with prevalent southern African affinities. Dinosaur records from South America between the Rhaetian and the Pliensbachian are very scarce, and this find contributes to the knowledge of early radiation and evolution of Dinosauria.