Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China

Harvestmen (Arachnida: Opiliones) are familiar animals in most terrestrial habitats but are rare as fossils, with only a handful of species known from each of the Palaeozoic, Mesozoic, and Cenozoic eras. Fossil harvestmen from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China, are described as Mesobunus martensi gen. et sp. nov. and Daohugopilio sheari gen. et sp. nov.; the two genera differ primarily in the relative length of their legs and details of the pedipalps. Jurassic arachnids are extremely rare and these fossils represent the first Jurassic, and only the fourth Mesozoic, record of Opiliones. These remarkably well-preserved and modern-looking fossils are assigned to the Eupnoi, whereby M. martensi demonstrably belongs in Sclerosomatidae. It thus represents the oldest record of a modern harvestman family and implies a high degree of evolutionary stasis among one of the most widespread and abundant groups of long-legged, round-bodied harvestmen.     

The oldest haplogyne spider (Araneae: Plectreuridae), from the Middle Jurassic of China

New fossil spiders (Arachnida: Araneae) from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China are described as Eoplectreurys gertschi gen. et sp. nov. and referred to the modern haplogyne family Plectreuridae. This small family is restricted to southwestern USA, Mexico, and the adjacent Caribbean area today and hitherto has only a sparse Cenozoic fossil record. The morphology of Eoplectreurys is remarkably similar to modern forms and thus demonstrates great evolutionary conservatism. This new discovery not only extends the fossil record of the family by at least 120 Ma to the Middle Jurassic but also supports the hypothesis of a different distribution of the family in the past than today and subsequent extinction over much of its former range.     

Potential ZnS fossilization of gastropods (Middle Jurassic claystones from Central Poland)

The rich fossil fauna in the Middle Jurassic claystones that crop out in the Krakow-Czestochowa Upland is extensively replaced by sulfide minerals, mainly pyrite. Sphalerite (ZnS) is rare and restricted to the internal casts of gastropods, often together with framboidal and euhedral pyrite and calcite. Scanning electron microscopy-energy dispersive spectrometer study was undertaken to explain this curious association. The results show that although direct infilling of the carbonate shell, similar to processes occurring during pyritization, is probable, it does not explain all textures observed. We propose that the carbonate shells were initially infilled by calcite and iron sulfides and sphalerite subsequently replaced the calcite casts. Preferential occurrence of ZnS in gastropods could result from accumulation of higher concentration of zinc during the organisms' life. After death, this Zn was introduced into the carbonate making gastropods more prone to ZnS replacement. Formation of ZnS casts was probably a late diagenetic event as zinc content of the surrounding sediment does not appear to influence sphalerite formation.     

A Middle Jurassic heterodontosaurid dinosaur from Patagonia and the evolution of heterodontosaurids

Heterodontosauridae is a morphologically divergent group of dinosaurs that has recently been interpreted as one of the most basal clades of Ornithischia. Heterodontosaurid remains were previously known from the Early Jurassic of southern Africa, but recent discoveries and studies have significantly increased the geographical and temporal range for this clade. Here, we report a new ornithischian dinosaur from the Middle Jurassic Ca?adón Asfalto Formation in central Patagonia, Argentina. This new taxon, Manidens condorensis gen. et sp. nov., includes well-preserved craniomandibular and postcranial remains and represents the only diagnostic ornithischian specimen yet discovered in the Jurassic of South America so far. Derived features of its anatomy indicate that Manidens belongs to Heterodontosauridae, as the sister taxon of Heterodontosaurus and other South African heterodontosaurids. The presence of posterior dentary teeth with high crowns but lacking extensive wear facets in Manidens suggests that this form represents an intermediate stage in the development of the remarkable adaptations to herbivory described for Heterodontosaurus. The dentition of Manidens condorensis also has autapomorphies, such as asymmetrically arranged denticles in posterior teeth and a mesially projected denticle in the posteriormost teeth. At an estimated total length of 60?C75?cm, Manidens furthermore confirms the small size of basal heterodontosaurids.     

An enormous Jurassic turtle bone bed from the Turpan Basin of Xinjiang, China

A spectacular new terrestrial Konzentratlagerst?tte is introduced from the Turpan Basin of Xinjiang, China that probably belongs to the late Middle Jurassic Qigu Formation. It contains a mass accumulation of “xinjiangchelyid” turtles preliminarily identified as Annemys sp. In the zone with the highest turtle concentration, complete and articulated turtle skeletons are tightly packed at a density of up to 36 turtles per square meter. The fossiliferous layer is thickened here and shows an erosional base. This high concentration zone outcrops approximately 10?m in length and shows no decrease in turtle density after exposing 2?m of the layer into the hillside. Adjacent is a more expansive zone of at least 10?m by 30?m. In this region, the fossiliferous layer is evenly thick, and approximately five, fully disarticulated turtles are present per square meter. A conservatively estimated 1,800 turtles may, therefore, have been deposited at this site. It is likely that these aquatic turtles gathered in a retreating water hole in a riverine environment during a drought, much as some aquatic turtles will do today, but perished when the habitat dried up completely. A following catastrophic rainfall event caused a debris flow, possibly channelized in a dry river bed, which transported complete turtles, disarticulated turtles, and mudstone clasts and deposited them after a short distance. This taphonomic model is consistent with previous environmental reconstructions of the Turpan Basin during the late Middle Jurassic in predicting the episodic breakdown of regional monsoonal circulation resulting in a seasonally dry climate with severe episodic droughts.     

A previously unrecognized group of Middle Jurassic triconodontan mammals from Central Asia

Ferganodon narynensis gen. et sp. nov. is represented by a lower molariform tooth from the Middle Jurassic (Callovian) Balabansai Svita in Kyrgyzstan. The new genus is allied with Klamelia zhaopengi Chow and Rich 1984 from the Middle Jurassic Shishugou Formation in Xinjiang, northwest China to the new family Klameliidae based on parallelogram-shaped lower molariforms, imbricating rather than interlocking of cusps e-d-f, by a peculiar distolabial cingulid cusp, and by vertical folding of the enamel on the labial crown side. The new family Klameliidae fam. nov. is most similar to Gobiconodontidae by the structure of the molariform teeth and represents a previously unrecognized radiation of eutriconodontan mammals possibly endemic to Central Asia.     

A molecular phylogenetic analysis of the neotropical dart-poison frog genus Phyllobates (Amphibia: Dendrobatidae)

 A phylogenetic analysis of the Neotropical dart-poison frogs, genus Phyllobates, was performed based on mitochondrial cytochrome b sequences. Members of Phyllobates from South and Central America were found to form each an evolutionary lineage. Among the South American lineage, species with uniform dorsal coloration as adults form a derived monophyletic clade. Received: 26 June 2000 / Accepted in revised form: 8 November 2000     

A new basal galeomorph shark (Synechodontiformes, Neoselachii) from the Early Jurassic of Europe

Palaeospinacids are a group of basal galeomorph sharks and are placed in the order Synechodontiformes (Chondrichthyes, Neoselachii) ranging from the Permian to the Eocene. Currently, there is a controversy concerning the identity of diagnostic characters for distinguishing palaeospinacid genera because of very similar dental morphologies and the scarcity of articulated skeletal material. The most notable character for distinguishing species within the Palaeospinacidae is, however, the dental morphology. The main dental character uniting all palaeospinacids is the very specialised pseudopolyaulacorhize root vascularisation. A re-examination of articulated neoselachian skeletons from the Lower Jurassic of Lyme Regis (England) and Holzmaden (S Germany), and recently discovered specimens from the Upper Jurassic of the Solnhofen area and Nusplingen (S Germany) has yielded several hitherto unrecognised complete skeletons of the palaeospinacids Synechodus and Paraorthacodus enabling a re-evaluation of characters. These specimens indicate that the number of dorsal fins and the presence or absence of dorsal fin spines represent important features for identifying palaeospinacids. Synechodus bears two dorsal fins without fin spines, whereas Paraorthacodus only has a single dorsal fin lacking a fin spine directly in front of the caudal fin. All palaeospinacids from the Early Jurassic have two spines supporting the dorsal fins and are consequently assigned to a new genus, Palidiplospinax nov. gen. Three species are placed into the new taxon: Synechodus enniskilleni, S. occultidens and S. smithwoodwardi.     

准噶尔盆地南缘新生代构造演化研究进展

新生代印度-欧亚板块碰撞的远程效应是理解中亚构造格局变化的主要机制。随着其远程效应的北移,位于中亚腹地的准噶尔盆地在周边山脉抬升的影响下,南北缘发生构造活动。基于前人的研究成果,将盆地新生代以来的构造演化概括如下：古新世,因基底断裂复活,盆地北部开始发生逆冲推覆活动;渐新世末期,博格达山脉恢复隆升,古牧地背斜发生构造变形;中新世以来,盆地南缘逐渐形成了三排构造带;上新世末期—更新世以来,北部基底断裂活动,南缘西段和东段分别形成浅层背斜和断裂。目前,由于印度-欧亚板块碰撞远程效应的传播模式仍处于探索阶段,因此需要更多的地质证据来证实它在不同阶段的传播方式以及使盆地发生构造变形的机制。     

A giant spider from the Jurassic of China reveals greater diversity of the orbicularian stem group

A large female spider, Nephila jurassica, was described from Middle Jurassic strata of north-east China and placed in the modern genus Nephila (family Nephilidae) on the basis of many morphological similarities, but, as with many ancient fossils, the single specimen lacked synapomorphies of the family (Selden et al. 2011). In order to test the placement within the nephilid phylogenetic tree, Kuntner et al. (2013) calibrated the molecular phylogeny using N. jurassica in three different scenarios based on inferred mitochondrial substitution rates. They concluded that N. jurassica fitted better as a stem orbicularian than a nephilid. Now, a giant male spider has been discovered at the same locality that yielded N. jurassica. The two sexes are considered conspecific based on their similar morphological features, size, and provenance. The male cannot be accommodated in Nephilidae because of its pedipalp morphology, so the new genus Mongolarachne and family Mongolarachnidae are erected for the species. Comparison with possibly related families show that Mongolarachnidae is most likely on the orbicularian stem, close to other cribellate orbicularians (e.g., Deinopoidea), which suggests a greater diversity of cribellate orbicularians during the Middle Jurassic.     

A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers

Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have involved four wings (Xu et al. Nature 421:335–340, 2003; Hu et al. Nature 461:640–643, 2009; Han et al. Nat Commun 5:4382, 2014). Here, we describe Serikornis sungei gen. et sp. nov., a new feathered theropod from the Tiaojishan Fm (Late Jurassic) of Liaoning Province, China. Its skeletal morphology suggests a ground-dwelling ecology with no flying adaptations. Our phylogenetic analysis places Serikornis, together with other Late Jurassic paravians from China, as a basal paravians, outside the Eumaniraptora clade. The tail of Serikornis is covered proximally by filaments and distally by slender rectrices. Thin symmetrical remiges lacking barbules are attached along its forelimbs and elongate hindlimb feathers extend up to its toes, suggesting that hindlimb remiges evolved in ground-dwelling maniraptorans before being co-opted to an arboreal lifestyle or flight.     

Detection and Characterization of Hepatitis A Virus and Norovirus in Mussels from Galicia (NW Spain)

Shellfish are recognized as a potential vehicle of viral disease and despite the control measures for shellfish safety there is periodic emergence of viral outbreaks associated with shellfish consumption. In this study a total of 81 mussel samples from Ría do Burgo, A Coruña (NW Spain) were analysed. Samples were collected in seven different harvesting areas with the aim to establish a correlation between the prevalence of norovirus (NoV) and hepatitis A virus (HAV) in mussel samples and the water quality. In addition, the genogroup of the detected HAV and NoV strains was also determined. The HAV presence was detected in 18.5 % of the samples. Contamination levels for this virus ranged from 1.1 × 10² to 4.1 × 10⁶ RNA copies/g digestive tissue. NoV were detected in 49.4 % of the cases reaching contamination levels from 5.9 × 10³ to 1.6 × 10⁹ RNA copies/g digestive tissue for NoV GI and from 6.1 × 10³ to 5.4 × 10⁶ RNA copies/g digestive tissue for NoV GII. The χ²-test showed no statistical correlation between the number of positive samples and the classification of molluscan harvesting area based on the E. coli number. All the detected HAV strains belong to genogroup IB. NoV strains were assigned to genotype I.4, II.4 and II.6.     

A relict basal tetrapod from Germany: first evidence of a Triassic chroniosuchian outside Russia

Chroniosuchians are basal tetrapods nesting within the paraphyletic anthracosaurs and were so far only well known from the Permian and Triassic of Russia. In this study, we present evidence for their existence in the upper Middle Triassic of Germany, based on diagnostic osteoderms and vertebrae from the Kupferzell and Vellberg localities in southern Germany. The finds are most similar to Synesuchus, a Middle Triassic bystrowianid chroniosuchian from the Northern Ural Pechora region. They demonstrate that by Middle Triassic time, chroniosuchians were much more widespread than previously thought.     

Unexpected skeletal histology of an ichthyosaur from the Middle Jurassic of Patagonia: implications for evolution of bone microstructure among secondary aquatic tetrapods

During the Mesozoic, one of the most significant evolutionary processes was the secondary adaptation of tetrapods to life in water. Several non-related lineages invaded from the terrestrial realms and from the oceans of the entire world. Among these lineages, ichthyosaurs were particularly successful. Advance parvipelvian ichthyosaurs were the first tetrapods to evolve a fish-shaped body profile. The deep skeletal modifications of their bodies, as well as their biology, depict advance ichthyosaurs as the paradigm of secondary adaptation of reptiles to marine life. Functional inferences point to them as off-shore cruising forms, similar to a living tuna, and some of them were capable of deep diving. Bone histology of some genera such as Temnodontosaurus, Stenopterygius, Ichthyosaurus, and Caypullisaurus, characterized by overall cancellous bone, is consistent with the idea of a fish-shaped ichthyosaurs as fast and far cruisers. Here, we provide histological examination of the ribs of the Middle Jurassic parvipelvian Mollesaurus. Contrasting with the bone histology of other parvipelvian, Mollesaurus ribs are characterized by a compact and thick cortex. Our data indicate that the rib cage was heavy and suggest that not all advanced ichthyosaurs were fast cruisers. The compact and dense ribs in these parvipelvian show that advance ichthyosaurs were ecologically more diverse than previously thought and that the lightening of the skeleton reversed, as also occurred in the evolution of cetacean, at least once along the evolutionary history of ichthyosaurs.     

First Castorid (Mammalia,Rodentia) from the Middle Miocene of Southeast Asia

Today and in the Tertiary, the geographical distribution of castorids is limited throughout all of the northern continents. Fossils of the Castoridae genus Steneofiber are abundant in many localities of Eurasia from the late Oligocene to Pliocene period. Recently, Steneofiber fossils were discovered in two localities of northern Thailand, Mae Moh and Chiang Muan coal mines, in layers of late middle Miocene age. These discoveries represent the first records of castorids from Southeast Asia and correspond to their southernmost known range. The focus of this study is to describe this new Thai species of Steneofiber and to define its wear stages from the molar occlusal surfaces by using micro-CT scan analysis. The CT scan technique permits the analysis of the virtual occlusal surface changes from wear, allowing easier comparison to related species of Steneofiber cheek teeth without destroying the teeth. The new species, Steneofiber siamensis n. sp., can be distinguished from the other species of Steneofiber by several distinct characters, longer mesostriid on p4, presence of premesostria and metastria on P4, which are smaller than most of the other known species. The occurrence of this new castorid also supports a subtropical to tropical paleoclimate for these two localities of northern Thailand.     

A new neosuchian with Asian affinities from the Jurassic of northeastern Brazil

Phylogenetic relationships near the origin of extant crocodylians are weakly supported, and this lack of resolution makes for poor estimates of taxonomic and morphological diversity. Previously known taxa are found throughout the Cretaceous in Laurasia and at a few sites from Brazil, Australia, and northern Africa. Here, we report Batrachomimus pastosbonensis gen. et sp. nov. from the Late Jurassic of northeastern Brazil, which is deeply nested within Neosuchia and associated to the Cretaceous Asian paralligatorids. The new taxon predates all other members of Paralligatoridae and its immediate sister group (including Eusuchia) by 30 million years. A nearly complete skull, osteoderms, and limb bones were recovered, and autapomorphies of B. pastosbonensis include a scalloped lateral margin of the rostrum in dorsal view, unsculpted alveolar margin at the caudalmost portion of the maxilla, blunt lateral prongs on the jugal at the base of the postorbital bar, hourglass shaped choanae, and pterygoid choanal septum extended between the palatal shelves of the palatines. The crocodyloid-like skull proportions and the slender, conical teeth suggest an amphibious and piscivorous life history to this 1 m long animal.

     

Last Glacial mammals in South America: a new scenario from the Tarija Basin (Bolivia)

The chronology, sedimentary history, and paleoecology of the Tarija Basin (Bolivia), one of the richest Pleistocene mammalian sites in South America, are revised here based on a multidisciplinary study, including stratigraphy, sedimentology, geomorphology, paleontology, isotope geochemistry, and ¹⁴C geochronology. Previous studies have indicated a Middle Pleistocene age for this classic locality. We have been able to obtain a series of ¹⁴C dates encompassing all the fossil-bearing sequences previously studied in the Tarija Basin. The dated layers range in age from about 44,000 to 21,000 radiocarbon years before present (BP), indicating that the Tarija fauna is much younger than previously thought. Glacial advances correlated to marine isotopic stages (MIS) 4 and 2 (ca. 62 and 20 ka BP, respectively) are also documented at the base and at the very top of the Tarija–Padcaya succession, respectively, indicating that the Bolivian Altiplano was not dry but sustained an ice cap during the Last Glacial Maximum. The results of this multidisciplinary study enable us to redefine the chronological limits of the Tarija sequence and of its faunal assemblage and to shift this paleontological, paleoclimatological, and paleoecological framework to the time interval from MIS 4 to MIS 2.     

Tectonic evolution of the Aravalli orogen (NW India): an inverted Proterozoic rift basin?

The Aravalli mountain range (AMR) in the northwestern part of the Indian Peninsula consists of two main Proterozoic metasedimentary and metaigneous sequences, the Aravalli and Delhi Supergroups, respectively, which rest over the Archaean gneissic basement. A synthesis and reinterpretation of the available geological, geochronological and geophysical data, including results of own field work and geophysical interpretations pertaining to the AMR, indicate its origin as an inverted basin: rifting into granitoid basement began ca. 2.5; Ga ago with Aravalli passive rifting (ca. 2.5–2.0 Ga) and Delhi active rifting (ca. 1.9–1.6 Ga). Associated mafic igneous rocks show both continental and oceanic tholeiitic geochemistry and are comparable with Phanerozoic, rift-related magmatic products. Available data showed no conclusive evidence for oceanic lithoshere and island-arc/active margin magmatic activity in the AMR. Subsequent inversion and orogeny (Delhi orogeny, ca. 1.5-1.4 Ga) lead to complex deformation and metamorphism. Only in the western and central zones has the basement been involved in this mid-Proterozoic (Delhi) deformation, whereas it is unaffected in the eastern part, except for local shear zones mainly along the basement/cover interface. The grade of metamorphism increases from the greenschist facies in the east to the amphibolite facies in the west with local HP assemblages. These latter are explained by rapid burial and exhumation of thin and cool continental lithosphere. Subsequently, during a final, mild phase of inversion, the Vindhyan basins consisting mainly of sandstones, limestones and shales, flanking the AMR formed which are comparable to foreland basins. The tectonic evolution of the AMR is therefore interpreted as an example of a major inverted continental rift and of a Proterozoic intra-continental orogen.     

准噶尔盆地夏盐11井区三工河组沉积相特征

本文在对准噶尔盆地夏盐11井区各井所取的侏罗系三工河组岩芯观察描述及室内粒度分析的基础上,根据沉积相标志确定夏盐11井区侏罗系三工河组为水下分流河道沉积;通过单井划相、剖面相分析及平面相分析,编制出夏盐11井区侏罗系三工河组沉积相图,解决了夏盐11井区储集层的沉积相问题。