A well‐preserved isopod from the Middle Jurassic of southern Germany and implications for the isopod fossil record

A new isopod species, Eonatatolana geisingensis gen. et sp. nov., is described from Middle Jurassic shallow‐water sediments of southern Germany. It shows not only the almost completely preserved dorsal morphology but, in addition, details of the cephalic appendages, the pereiopods, pleopods and uropods. The presence of ambulatory pereiopods I–VII of a wide tridentate mandibular incisor with prominently developed posteriormost tooth and a narrow frontal lamina indicates that the new species belongs to the subfamily Conilerinae of family Cirolanidae within the suborder Cymothoida. It is closer to the species of the modern genus NatatolanaBruce than to any fossil isopod hitherto described. The isopod fossil record as well as current practices of isopod taxonomy in palaeontology are discussed, and the facies distribution and fossilization of isopods is reviewed with examples from the Jurassic.     

Palaeobiology of tanaidaceans (Crustacea: Peracarida) from Cretaceous ambers: extending the scarce fossil record of a diverse peracarid group

Diverse assemblages of tanaidacean peracarid crustaceans from western Tethyan continental deposits suggest that the group was relatively common in or around ancient resin‐producing forests. Here we report the results of an examination of 13 tanaidacean specimens from three Cretaceous (Albian to Turonian) French amber deposits. Two new species of the fossil family Alavatanaidae are placed in the previously described Early Cretaceous genus Eurotanais: Eurotanais pyrenaensis sp. nov. from Cenomanian Pyrenean amber (Fourtou, Aude) and Eurotanais seilacheri sp. nov. from Turonian Vendean amber (La Garnache, Vendée). The remaining specimens are placed in three newly erected genera and species (but family incertae sedis): Arcantitanais turpis gen. et sp. nov. from Albian–Cenomanian Charentese amber (Archingeay, Charente‐Maritime), and Tytthotanais tenvis gen. et sp. nov. and Armadillopsis rara gen. et sp. nov. from Pyrenean amber. These are the first formally described fossils that might be related to the paratanaoidean families Nototanaidae and Paratanaidae, sharing with these some putatively derived features and providing possible evidence for the antiquity and morphological stability of these families and the suborder Tanaidomorpha. The distinctive features and character combinations of these fossil taxa are discussed in connection with possible relationships to the living lineages of tanaidaceans. Propagation phase‐contrast X‐ray synchrotron microtomography was used to obtain high‐quality 3D images for some fossils. A discussion is provided on the putative palaeobiology of tanaidaceans and the French resiniferous forest ecosystem. The discovery of these new tanaidaceans extends the palaeogeographical distribution and stratigraphical range of the family Alavatanaidae and sheds new light on the palaeoecology and diversity of tanaidaceans in pre‐angiospermous woodlands.     

Toarcian carbon isotope shifts and nutrient changes from the Northern margin of Gondwana (High Atlas, Morocco, Jurassic): Palaeoenvironmental implications

The Early Toarcian is marked by a global perturbation of the carbon cycle and major marine biological changes. These coincide with a general decrease in calcium carbonate production and an increase in organic carbon burial, and culminate in the so-called Toarcian Oceanic Anoxic Event. It is believed that the environmental crisis was triggered by the activity of the Karoo-Ferrar large igneous province. In order to further document the Early Toarcian palaeoenvironmental perturbations, carbon isotope, total organic matter, calcareous nannofossils and phosphorus content of the Amellago section in the High Atlas rift basin of Morocco were investigated. This section is extremely expanded compared to the well-studied European sections. Its position along the northern margin of the Gondwana continent is of critical importance because it enables an assessment of changes of river nutrient input into the western Tethyan realm. The carbon isotope curve shows two negative excursions of equal thickness and amplitude, at the Pliensbachian-Toarcian boundary and at the transition from the Polymorphum to the Levisoni Zone. This confirms the supra-regional nature of these shifts and highlights the possible condensation of the first “boundary” shift in European sections. Phosphorus content is used to trace palaeo-nutrient changes and shows that the two negative carbon isotope shifts are associated with increased nutrient levels, confirming that these episodes are related to enhanced continental weathering, probably due to elevated greenhouse gases in the atmosphere. In the High Atlas Basin, the increase in nutrient levels at the Pliensbachian-Toarcian boundary is moreover likely to be the main factor responsible for the coeval demise of the Saharan carbonate platform. A middle Toarcian event, centered on the boundary between the Bifrons and Gradata Zones, characterized by a positive carbon isotope excursion and nutrient level rise, is documented in the Amellago section.     

Tanaidaceans (Crustacea) from the Central Pacific Manganese Nodule Province. I. The genera Collettea, Robustochelia and Tumidochelia

Three new species of are described from the manganese nodule province between the Clarion and the Clipperton Fracture Zone of the equatorial North Pacific Ocean, and collected during the Nodinaut expedition on board the r/v l′Atalante in the summer of 2004. The new species belongs to three genera as: Collettea (Collettea longisetosa), Robustochelia (Robustochelia pacifica), and Tumidochelia (Tumidochelia tuberculata). A key to the genus Tumidochelia is presented and the validity of the genera Robustochelia and Collettea is discussed.     

Preservational modes of some ichthyosaur soft tissues (Reptilia,Ichthyopterygia) from the Jurassic Posidonia Shale of Germany

Konservat-Lagerstätten, such as the Toarcian (Early Jurassic) Posidonia Shale of southwestern Germany, are renowned for their spectacular fossils. Ichthyosaur skeletons recovered from this formation are frequently associated with soft tissues; however, the preserved material ranges from three-dimensional, predominantly phosphatized structures to dark films of mainly organic matter. We examined soft-tissue residues obtained from two ichthyosaur specimens using an integrated ultrastructural and geochemical approach. Our analyses revealed that the superficially-looking ‘films’ in fact comprise sections of densely aggregated melanosome (pigment) organelles sandwiched between phosphatized layers containing fibrous microstructures. We interpret this distinct layering as representing condensed and incompletely degraded integument from both sides of the animal. When compared against previously documented ichthyosaur fossils, it becomes readily apparent that a range of preservational modes exists between presumed ‘phosphatic’ and ‘carbonized’ soft-tissue remains. Some specimens show high structural fidelity (e.g. distinct integumentary layering), while others, including the fossils examined in this study, retain few original anatomical details. This diversity of soft-tissue preservational modes among Posidonia Shale ichthyosaurs offers a unique opportunity to examine different biostratinomic, taphonomic and diagenetic variables that potentially could affect the process of fossilization. It is likely that soft-tissue preservation in the Posidonia Shale was regulated by a multitude of factors, including decay efficiency and speed of phosphatic mineral nucleation; these in turn were governed by a seafloor with sustained microbial mat activity fuelled by high organic matter input and seasonally fluctuating oxygen levels.     

Signs of predation in the Middle Jurassic of south-central Poland: evidence from echinoderm taphonomy

Distinct faunal aggregates are described from the Middle Jurassic (uppermost Bajocian/lowermost Bathonian and Middle Bathonian) clay deposits of Częstochowa area, south-central Poland. These aggregates are composed of molluscs (scaphopods, gastropods, bivalves, ammonites and belemnites), articulate brachiopods and echinoderms (asteroids, crinoids and echinoids). A large percentage of the fossils, especially bivalves, are fragmented, but some fossils are complete. Although most of the fossils are crushed and fragmented, they are still identifiable to at least the genus level. Thorough statistical analysis of taphonomic features indicates that the preservation of asteroid marginal plates is distinct from the ossicles derived from the host clays. The high frequency of bite marks and the good state of preservation suggest that the accumulations are the products of predation activities and most probably are the effect of regurgitation. Taking into account the rich and diverse fauna, the predator was a bottom-feeding generalist. Possible predators include palaeospinacid sharks, a tooth of which was collected from the same bedding surface, but not associated with regurgitated remains. Although the bite marks on the asteroid ossicles point to sharks as potential producers of regurgitates, other vertebrates, like durophagous pycnodontiform fish, cannot be excluded.     

An ammonite–fish association from the Kimmeridgian (Upper Jurassic) of La Rochelle, western France

A partially disarticulated actinopterygian fish preserved in a large three-dimensional ammonite body chamber is described from the Kimmeridgian of western France. Taphonomic observations on the degree of preservation of the fish and the development of epibiont organisms on the inner wall of the shell indicate a rather long time interval before sediment totally filled the body chamber. The fish, referred to an indeterminate Macrosemiidae, probably used this empty ammonite ( Rasenioides , Aulacostephanidae) shell as a refuge, or possibly for spawning and/or brooding. It can be assumed that ammonite shells may have constituted common shelters for demersal fishes living in an open-marine shelf environment, near to a muddy bottom devoid of rocks.     

A sauropod dinosaur megatracksite from the Late Jurassic of northern Switzerland

The largest known sauropod trackway site from the Upper Jurassic in Europe has been found in the northern Jura Mountains of Switzerland. Since the initial discovery of the site in 1988, detailed ichno‐facies mapping of the sites has been undertaken and completed. Six separate sites (from 5 to 45km apart) have been located to date; the largest one, displaying 345 single imprints, extends over a surface of 7000 m². As all of the reported sites occur within the same bed, these vertebrate prints form a megatracksite covering an area of more than 360 km². All localities are stratigraphically within the Reuchenette Formation. Two biostratigraphically diagnostic ammonites have been found within the sequence (Aulacostephanus; Gravesia), indicating an Upper Kimmeridgian age (sensu gallico). In the easternmost sites, imprints occur on mud‐cracked tidal pond deposits, whereas the western tracksites are found in supratidal algal marsh deposits. The track‐bearing horizon is immediately below a trans‐gressive event at all the sites, suggesting that the ichnofaunas represent dinosaur activity during a relative sea‐level low‐stand. Footprint size and morphology, as well as trackway dimensions, suggest that the track producers belong to the largest sauropods yet recorded in the European Jurassic, closely resembling the Breviparopus tracks from the Middle Jurassic of Morocco.     

The callovian (Middle Jurassic) crinoids from northern Lithuania

Callovian strata in northern Lithuania (Papilė area) have yielded some crinoid taxa[Chariocrinus andreae (Desor),Balanocrinus berchteni Hess —Pugin,B. subteres (Münster inGoldfuss) andIsocrinus nicoleti (Desor)], which have not been described from this area. The only form known previously wasBalanocrinus pentagonalis (Goldfuss).Palaeocomaster jaegeri n. sp. is the first free-living crinoid recorded from the Callovian of eastern Europe. It is characterized by possessing a very low, strongly flattened and narrow radial cavity. A very similar crinoid assemblage is known from the Callovian glacially-derived clays exposed in the Łuków region (eastern Poland), which were originally located near the Baltic Sea during the Middle Jurassic. It is considered that the allochthonous Callovian deposits from Poland are facies equivalents of the deposits known from Lithuania. The sole significant exception is the domination of free-moving comatulids (Comatulida) in the sediments known from the Papilė region, which may suggest that the Lithuanian sea basin was a little shallower than that located farther west in the Baltic area.      

Poekilopleuron bucklandii, the theropod dinosaur from the Middle Jurassic (Bathonian) of Normandy

Poekilopleuron bucklandii , described by Eudes–Deslongchamps in 1838, is one of the earliest discovered dinosaurs. Although incomplete, it is one of the best preserved Middle Jurassic theropods known from Europe. Unfortunately, the only specimen of P. bucklandii , housed in the Musée de la Faculté des Sciences de Caen, was destroyed during World War II. However, casts of some parts of the type skeleton have been found in the collections of the Museum National d'Histoire Naturelle, Paris. These casts and Eudes–Deslongchamps' monograph are used to redescribe the specimen. Poekilopleuron shares one synapomorphy with the Spinosauroidea and we tentatively assign it to that clade. The possible synonymy between Poekilopleuron and Megalosaurus is examined and we conclude that Megalosaurus is a nomen dubium and that the name should be restricted to the type dentary.     

陕西彬县地区中侏罗世延安组孢粉植物群及其意义

报道了采自陕西彬县地区中侏罗世延安组的孢粉化石６０属,８３种。经研究表明,陕西彬县地区延安组的孢粉组合是以裸子植物花粉为主,蕨类植物孢子次之。银杏、苏铁类和松柏类花粉在组合中占优势;桫椤科孢子在蕨类中具有较高的含量。根据孢粉组合特征及其对比,延安组的时代应属中侏罗世早期。陕西彬县地区当时的植被是以银杏、苏铁类和松柏类等乔木为主,并伴有桫椤科为主体的树蕨植物及草本植物,古气候应属大陆性亚热带气候。     

Middle and Upper Jurassic bivalve associations from the Iberian Range (Spain)

The four sections richest in bivalves from the Middle and Upper Jurassic of the Iberian Range (Spain) were selected for a quantitative palaeoecological analysis of the bivalve fraction of the macrobenthos. Five bivalve associations and two assemblages were recognized with the help of a Q-mode hierarchical cluster analysis (Ward method). The main environmental factors controlling bivalve associations are thought to be substrate, water energy and distribution of organic matter. The bivalves exhibit a distinct spatial and temporal distribution pattern within the Aragonian Branch of the Iberian Range. Four of the bivalve associations occur in the Upper Oxfordian (Sot de Chera Fm) and one association in the Lower Callovian (Chelva Fm). In the Sot de Chera and Loriguilla formations, the abundance of bivalves decreases from NW to SE i.e., from relatively close to the shore line towards the distal-most part of the carbonate platform. In the Chelva Fm, bivalves are abundant in the Ariño region, interpreted as a palaeogeographic high. The spatial distribution of bivalves might have been largely controlled by the availability of nutrients.     

Neoselachian sharks and rays from the British Bathonian (Middle Jurassic)

Extensive sampling of Bathonian sediments from localities across southern and central England has produced over 8000 neoselachian teeth. These comprise diverse faunas, with over 25 species being represented in total, most of them previously undescribed. Seventeen new species and seven new genera are named: Palaeoscyllium tenuidens sp. nov., Praeproscyllium oxoniensis gen. et sp. nov., Eypea leesi gen. et sp. nov., Proheterodontus sylvestris gen. et sp. nov., Paracestracion bellis sp. nov., Palaeobrachaelurus mussetti sp. nov., Heterophorcynus microdon gen. et sp. nov., Dorsetoscyllium terraefullonicum gen. et sp. nov., Ornatoscyllium freemani gen. et sp. nov., Pseudonotidanus semirugosus gen. et sp. nov., Synechodus duffini sp. nov., Protospinax magnus sp. nov., P. bilobatus sp. nov., P. carvalhoi sp. nov., Belemnobatis kermacki sp. nov., B. stahli sp. nov. and Spathobatis delsatei sp. nov. In addition, a new family, the Pseudonotidanidae fam. nov., is defined and the status of Paranotidanus Ward and Thies, 1987, Hybodus levis Woodward, 1889 and Breviacanthus brevis (Phillips, 1871) are discussed. These taxa show strong facies specificity, with different species being restricted to different palaeoenvironments.     

A new species of Eretmophyllum (Ginkgoales) from the Middle Jurassic of Turpan-Hami Basin,Xinjiang, China

A few specimens previously assigned to Eretmophyllum, based on the gross leaf morphology, lack cuticular structures. In this paper, we describe a new species of Eretmophyllum from the Middle Jurassic Xishanyao Formation in the Turpan-Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, based on fossil leaves preserved as compressions, and characterized by paddle shapes with conspicuous petioles, retuse apices, entire margins and two veins dichotomously branched from near the base. Leaf amphistomatic, the cuticles are composed of stomatal and non-stomatal bands. Based on a detailed comparison of the gross morphology and cuticular structures with previously reported fossils, Eretmophyllum hamiensis n. sp. is erected. The presence of Eretmophyllum indicates that Middle Jurassic climate in the Turpan-Hami Basin was likely warm and humid. On the basis of the geological history and geographical distributions of Eretmophyllum, we conclude that the genus probably originated in Europe and migrated from Siberia to northwestern China during the Middle Jurassic.     

A new genus of the family Panfiloviidae (Insecta,Neuroptera) from the Middle Jurassic of China

Abstract: Epipanfilovia oviformis gen. et sp. nov. (Neuroptera: Panfiloviidae) is described from the Middle Jurassic locality of Daohugou (Inner Mongolia, China) based on six specimens. A revised diagnosis of this family is provided. It includes two genera, Panfilovia Makarkin and Epipanfilovia gen. nov.; Osmylogramma Ponomarenko is removed from the family. Panfiloviidae is most closely related to another Jurassic family Grammolingiidae, and both are provisionally assigned to the superfamily Osmyloidea.     

Palaeoenvironmental and biostratigraphical implications of selected Floian and Dapingian (Ordovician) chitinozoans of the South China Palaeoplate

Chitinozoans are widespread microfossils in the Ordovician to Devonian strata. Although they have been widely adopted in biostratigraphy, their environmental preferences are rarely discussed. In this study, the palaeoecological distribution of four Floian and Dapingian key chitinozoans in six coeval stratigraphical units based on 13 sections from the South China Palaeoplate is discussed in detail, including Bursachitina maotaiensis (Chen 2009a), Bursachitina qianbeiensis (Chen 2009a), Conochitina decipiens and Sagenachitina dapingensis (Chen 2009b). It appears that B. maotaiensis and B. qianbeiensis preferred inner shelf environments and could spread to near‐shore and shallow outer shelf settings. C. decipiens mostly favoured inner shelf and shallow outer shelf environments. S. dapingensis had the widest environmental tolerance and was adapted to almost all environments, with the exception of the near‐shore area on the Yangtze Platform. Biostratigraphically, the four species have relatively well‐constrained ranges, and their first appearances provide good bases for regional correlations. The endemic B. maotaiensis and B. qianbeiensis can be good markers for the upper Floian, but their relatively narrow environmental preferences should be taken into account. S. dapingensis proves to be a good marker for the Dapingian in the South China Palaeoplate, except in the near‐shore areas. The globally distributed C. decipiens also has a biostratigraphical significance in most areas of the Yangtze Platform. Our study indicates that well‐documented environmental preferences of key species help to provide more reliable and practical biostratigraphical correlations.     

Evidence of synsedimentary tectonics in the Northern Tabas Block,East-Central Iran: The Callovian (Middle Jurassic) Sikhor Formation

Summary The Sikhor Formation (new) is a predominantly siliciclastic sediment package intercalated between the marly-silty Baghamshah Formation (below) and the calcareous Esfandiar Limestone and Qal'eh Dokhtar Limestone formations (above). All stratigraphic evidence points to an Early Callovian age of the formation. The Sikhor Formation is restricted to the southern and central Shotori Mountains and consists of two members: The Kuh-e-Neygu Member (new) is composed of fluvialdeltaic conglomerates, sandstones, and siltstones grading into marly silt of the Baghamshah Formation. The overlying Majd Member (new) is characterised by mixed siliciclastic-carbonate sediments that record the interfingering of carbonate ramp sediments with fluvialdeltaic sands and silts. Evidence of erosional truncation of the underlying Baghamshah Formation and confinement of the siliciclastic sediment to a comparatively narrow, NNW-SSE elongated strip suggest that the formation had its origin in the asymmetric uplift of a westdipping tilted fault block in the southern Shotori Mountains that shed its sediment predominantly in a northern and eastern direction. After erosional levelling, the former uplifted areas were overgrown by the highly productive Esfandiar Carbonate Platform. The Sikhor Formation thus is evidence of an extensional tectonic pulse in the early Callovian and underlines that this area of the Tabas Block was a tectonically highly unstable area during most of the Jurassic.     

New Deep-sea Leptognathiid Tanaids (Crustacea, Tanaidacea) from the North-east Atlantic

Three new genera ( Araphura, Leptognathioides and Stenotanais ) and six new species of tanaid crustaceans from below 1000 m depth in the north-east Atlantic are described. Two of the new species belong to the genus Leptognathiella Hansen, 1913, which is redescribed and removed from synonymy with Leptognathia Sars, 1882 ( sensu Lang 1968). These species are relatively common in the tanaid material examined and have a widespread distribution in the area under study, i.e. the Rockall Trough, Porcupine Seabight and Bay of Biscay. All six species are found at depths between 2070 and 2892 m. A further nine species previously belonging to the genus Leptognathia are removed to the new genera or to Leptognathiella. New records of Leptognathioides polita (Hansen, 1913) comb.n. and Leptognathiella abyssi (Hansen, 1913) have been obtained.