THE OCCURRENCE OF THE UPPER JURASSIC BIVALVE MALAYOMAORICA MALAYOMAORICA (KRUMBECK) ON THE ORVILLE COAST, ANTARCTICA

Malayomaorica malayomaorica is an important Upper Jurassic bivalvein the southern hemisphere: widely distributed in strata ofEarly - Middle Kimmeridgian age, it is a zone fossil of considerablepotential for regional biostratigraphic correlations. Its commonoccurrence in the Latady Formation of the Orville Coast, Antarctica,indicates that at least part of this stratigraphic unit hasa Kimmeridgian age. Although its precise taxonomic status remainsin some doubt, it would appear to be the earliest buchiid-likebivalve so far recorded from the southern hemisphere. Its verywide distribution around the margins of Gondwana is similarto that established for species of the Late Jurassic bivalvegenera Retroceramus, Buchia and Anopaea (Received 13 April 1981;     

A catshark (Neoselachii, Carcharhiniformes, Scyliorhinidae) from the Late Jurassic of Germany

A new genus and species of catshark (Neoselachii, Carcharhiniformes, Scyliorhinidae) —Bavariscyllium tischlingeri n. gen. n. sp. — is described from the Late Jurassic (Tithonian) Plattenkalke of South Germany. The new taxon is known from a single articulated skeleton having the skull, the trunk and all of the fins preserved. The position of the first dorsal fin in relation to the pelvic fins and the dental morphology shows that the specimen belongs into the neoselachian family Scyliorhinidae. Two isolated tooth crowns from the Kimmeridgian of North Germany are identified asBavariscyllium sp. and represent the oldest unambigious fossil record of the Scyliorhinidae known so far.     

The distribution of Late Kimmeridgian and Portlandian ostracoda in southern England

The vertical distribution of ostracods in the Upper Kimmeridgian and Portlandian (sensu anglico) succession in three cored boreholes at Hartwell, Tisbury and Fairlight, are compared to other successions in southern England. The Upper Kimmeridge Clay Formation yields rich, but low diversity ostracod faunas, characterised by stratigraphically restricted species of Aaleniella, Galliaecytheridea, Klentnicella, Macrodentina, Mandelstamia, Micrommatocythere, Paralesleya and Prohutsonia. Several continue into the Portlandian, but some species, belonging to genera such as Cytherelloidea, Paracypris, Fabanella, Galliaecytheridea, Klieana, Paraschuleridea, Eocytheridea, Paranotacythere, Procytheropteron, Rectocythere and Macrodentina, appear for the first time. Biostratigraphical subdivision is made difficult by provincialism caused by decreasing salinities and facies change during the Late Portlandian. Marine taxa such as Protocythere, Macrocypris, Paraschuleridea, Paranotacythere, Procytheropteron and Rectocythere were replaced by euryhaline forms, such as species of Fabanella and Mantelliana, and fresh-oligohaline species of the genera Cypridea, Scabriculocypris, Alicenula and Rhinocypris.     

Bone histology of the Middle Jurassic turtle shell remains from Kirtlington, Oxfordshire, England

The Middle Jurassic (Bathonian) turtle material from the Mammal Bed at Kirtlington, Oxfordshire, England, has recently been tentatively referred to the Pleurosternidae, although the known synapomorphies of this clade were absent from the specimens. Here we present new evidence from shell bone histology that corroborates reports of pleurosternids at Kirtlington and further reveal that two different histomorphs (= two different taxa) are present in this locality. The first histomorph presents the distinctive histological structure of pleurosternids, which is described herein for the first time: the external cortical bone layers are differentiated into an inner zone of coarse, irregularly interwoven structural fibre bundles and an outer fine-fibred zone. The second histomorph has a more plesiomorphic structure and can only be assigned to Cryptodira indet. A morphological reassessment of the Kirtlington material fails to recognize two different taxa and shows that only sparse evidence supports the presence of pleurosternids in this locality. Shell bone histology thus appears as a powerful tool to study poorly preserved specimens and may in some case (like with pleurosternids) help resolve phylogenetic relationships. According to our results, the stratigraphic appearance of the Pleurosternidae is adjusted from the Kimmeridgian (Late Jurassic) to the Bathonian (Middle Jurassic), which significantly reduces the ghost lineage of Paracryptodira.     Bone histology, turtles, Paracryptodira, Pleurosternidae, Middle Jurassic, Kirtlington.     

The locomotion system of Mesozoic Coleoidea (Cephalopoda) and its phylogenetic significance

A morphological comparison of shell‐muscle contacts in coleoid cephalopods mainly from the Early Jurassic (Toarcian) Posidonia Shales of Holzmaden (Germany), the Middle Jurassic (Callovian) Oxford Clay of Christian Malford (UK), Late Jurassic (Kimmeridgian‐Tithonian) plattenkalks of Solnhofen (Germany), and the Late Cretaceous (Cenomanian) of Hâdjoula and Hâkel (Lebanon) provides new and meaningful insights into their locomotion systems. The study shows that both pro‐ostracum‐ and gladius‐bearing coleoids are typified by a marginal mantle attachment and by distinctly separated fins, which usually insert (indirectly via the shell sac and basal fin cartilages) to posterior shell parts. While absent in gladius‐bearing forms, mantle‐locking cartilages might have existed already in pro‐ostracum‐bearing belemnoids. Similar to ectocochleate ancestors, funnel‐ and cephalic retractors are generally attached to the internal (ventral) shell surface. A comparison of Mesozoic and Recent gladius‐bearing coleoids shows that the locomotion system (most significantly the dorsal mantle configuration, and the presence of nuchal‐ and funnel‐locking cartilages) is fundamentally different. This does not support the concept of ‘fossil teuthids’, but suggests, owing to similarities with Recent Vampyroteuthis, placement of Mesozoic gladius‐bearing coleoids within the Octobrachia (Octopoda + Vampyromorpha). Classification of Mesozoic gladius‐bearing coleoids as octobrachians implies that: (1) unambiguous teuthids are still unknown in the fossil record and (2) the similarity between Recent and some fossil gladiuses represents a matter of homoplasy.     

Mineralization of soft-part anatomy and invading microbes in the horseshoe crab Mesolimulus from the Upper Jurassic Lagerstätte of Nusplingen, Germany

A remarkable specimen of Mesolimulus from the Upper Jurassic (Kimmeridgian) of Nusplingen, Germany, preserves the musculature of the prosoma and associated microbes in three dimensions in calcium phosphate (apatite). The musculature of Mesolimulus conforms closely to that of modern horseshoe crabs. Associated with the muscles are patches of mineralized biofilm with spiral and coccoid forms. This discovery emphasizes the potential of soft-bodied fossils as a source for increasing our knowledge of the diversity of fossil microbes in particular settings.     

First description of axymyiid fossils (Insecta: Diptera: Axymyiidae)

Two species of fossil insects from the Daohugou Formation of Chifeng City in Nei Monggol Autonomous Region, northeastern China are described, and recognized as Psocites pectinatus (Hong, 1983) nov. emend., nov. transl. and P. fossilis nov. sp. They are the oldest representatives of the family Callovian or Axymyiidae, and first described of this family in the Mesozoic. Although early the age of the fly-bearing beds is controversial, it is probably Oxfordian or Kimmeridgian (Late Jurassic) rather than Early Cretaceous or Middle Jurassic.     

Fossil coniferous wood from the Middle Jurassic of Liaoning Province, China

Silicified coniferous wood was collected from the Lanqi Formation (late Middle Jurassic in age) at Shebudaigou Village, Liaoning Province, China. Three taxa are identified, namely Pinoxylon dacotense Knowlton, Xenoxylon phyllocladoides Gothan, and Araucariopitys sp. Based on these new data, and those of other fossil plants reported previously from the same formation, we consider the climate during the deposition of the Lanqi Formation was subtropical, humid and seasonal. In this respect the Lanqi flora differs from the coeval Shimengou and Longmen floras from North China. The Longmen flora was deposited during more humid, subtropical conditions, while the Shimengou Formation indicates that the climate was warm temperate and dry. Our data would suggest that the Late Jurassic climatic pattern was initiated as early as the late Middle Jurassic.     

Factors controlling upper Jurassic ammonite assemblages in north-central Mexico

Lower Kimmeridgian to Lower Tithonian (Upper Jurassic) sections studied at Sierra de Palotes (Durango) and Sierra de Catorce (San Luis Potosí), Mexico, show low-energy deposits in which the composition of fossil macroinvertebrate assemblages, including megabenthos, reflects biostratinomic control. Monotonous siltstones provide continuous records of ammonite assemblages and reflect dominant deposition of shells in living areas; meanwhile, discontinues records were forced by episodic post-mortem transportation of shells, which was especially accentuated under storm influence. Rhythmic marly-silty limestones and marls illustrate a fossil record probably determined by minor transgressive-regressive pulses. The major changes in lithofacies are reflected by condensed silty and phosphatic mudstones deposited during significant floodings affecting areas under dominant terrigenous sedimentation. These changes determined more or less significant variations in the composition of fossil assemblages according to their relation to changing ecological conditions. However, shifting ecospaces exhibit no direct relationship to changes in lithofacies. Post-mortem transportation, operating in relation to both marine floodings and changes in the pattern of upper-water currents, was the main biostratinomic factor affecting the areal distribution of ammonite populations. Shell transportation and sedimentation rate controlled preservation and ultimately influenced diversity in recorded ammonite assemblages. The post-mortem behaviour (interpreted from shell structure and preservation), and therefore distribution, of ammonite shells points to shallow-water environments during the Kimmeridgian - Early Tithonian in areas (such as SE Durango and San Luís Potosí) close to the changing boundary between dominant carbonate and terrigenous sedimentation. No reworking affecting ammonite biostratigraphy has been identified in the sections studied.     

辽西义县下白垩统沙海组木化石新材料

辽西地区下白垩统沙海组是我国北方地区重要的白垩纪木化石产出层位,其产出的木化石数量丰富、类型多样.尽管前人开展了部分研究,但目前对沙海组木化石植物群组成特征的认识仍相对薄弱.本文报道了辽西义县上石洞沟地区沙海组产出的木化石新材料,共鉴定出2属3种,分别为:Phyllocladoxylon cf.eboracense(H...     

First record of Pliensbachian (Lower Jurassic) amber and associated palynoflora from the Monti Lessini (northern Italy)

The fossil record of amber dates back to the Palaeozoic, but it is only since the Mesozoic that amber became relatively common, probably because of the spreading of resin-producing plants. In Italy, the oldest ambers come from the Middle and Upper Triassic of the Dolomites. Cretaceous ambers come from some Albian sites in the Dolomites and from the Coniacian–Santonian of Vernasso, Julian Prealps, northern Italy. Until now, no Jurassic sites with amber have been reported in Italy, and this “Jurassic gap” seems generalized, since there are only a few Jurassic ambers described all over the world. Here, we report the first finding of Lower Jurassic (Pliensbachian) amber from the Bellori locality (Grezzana, Verona Province, Northern Italy). The amber was found in two clayey-coal levels containing plant remains and cuticles, with subordinate bivalves, foraminifera and ostracods. Palynomorphs of the amber levels are dominated by levigate and ornamented spores (ferns) and Circumpolles (conifers). Foraminiferal linings and algal cysts are also present. The freshwater alga Pseudoschizaea is reported for the first time from the Lower Jurassic. The amber shows different kinds of preservation, some peculiar features probably connected with the plant structure, and colours ranging from light yellow to blackish red. Moreover, it includes millimetre-sized wood structures (“mummified wood”) and gas bubbles. Fourier-transform–Infrared, thermogravimetric and differential thermogravimetric analyses were carried out and resulted in a clear characterization of this amber with respect to all others known so far. These data, together with sedimentological observations and fossil content analysis, suggest a coastal palaeoenvironment under rather wet conditions, comparable with the present-day Everglades, with the addition of a monsoonal climate as in the modern southern Asia.     

Two new theropod egg sites from the Late Jurassic Lourinhã Formation,Portugal

Two new Late Jurassic (uppermost Late Kimmeridgian) dinosaur eggshell sites are described, Casal da Rola and Porto das Barcas, both near Lourinhã, central-west Portugal. Casal da Rola yields eggshells with an obliquiprismatic morphotype comparable to those from a nest with the associated fossil embryos from Paimogo, tentatively assigned to the theropod Lourinhanosaurus antunesi. The Porto das Barcas eggshells have a dendrospherulitic morphotype with a prolatocanaliculate pore system. This morphotype was also recognised in eggshells from a clutch with associated Torvosaurus embryos at the Porto das Barcas locality. A preliminary cladistic analysis of eggshell morphology suggests theropod affinities for the Casal da Rola eggs, but is unable to resolve the phylogenetic position of the Porto das Barcas eggs. The eggshells at both sites are preserved in distal flood plain mudstones and siltstones. Carbonate concretions within the deposits indicate paleosol development.     

The oldest turtle from Portugal corresponding to the only pre-Kimmeridgian plesiochelyid (basal Eucryptodira) recognized at the generic level

A shell coming from an upper Oxfordian section of the Lusitanian Basin located in Alqueidão da Serra (Municipality of Porto de Mós, West Central Portugal) is here presented. It corresponds to the oldest remain of a turtle identified in Portugal. In fact, the record of Jurassic turtles identified in pre-Kimmeridgian levels of Europe is very scarce. The new specimen represents the second worldwide identification of a Plesiochelyid turtle (basal Eucryptodira) performed in pre-Kimmeridgian levels, being the only one recognized at generic level. Therefore, this specimen corresponds to the oldest identification of Craspedochelys, a genus well-represented in Kimmeridgian and Tithonian levels of several European countries. This finding contributes the first evidence on the synchronous coexistence of more than a member of Plesiochelyidae in pre-Kimmeridgian levels, which provides arguments to justify the relatively wide diversity known for this exclusively Jurassic clade during the Kimmeridgian and the Tithonian.     

Late Jurassic decapod crustaceans from northeast Japan

Abstract: Astacidean and thalassinidean macrurans (Glyphea sp., ?Eryma sp. and Protaxius sp.) and a new longodromitid crab, Planoprosopon kashimaensis, are recorded from the Upper Jurassic (upper Kimmeridgian to lower Tithonian) of Fukushima Prefecture, northeast Japan. Material was collected from the Tatenosawa Sandstone Member of the Nakanosawa Formation, Somanakamura Group, from which abundant Tethyan‐type marine invertebrates are known. Planoprosopon kashimaensis sp. nov. closely resembles P. heydeni (von Meyer), a common form in the Upper Jurassic of the Tethyan realm in Europe, and represents the oldest record of a brachyuran from the circum‐Pacific region. Similarities to contemporaneous decapod assemblages in southern Germany indicate that closely comparable, parallel decapod faunas in the Tethyan realm, inclusive of brachyurans, had already been established in the western circum‐Pacific region by the Late Jurassic.     

DUROPHAGOUS PREDATION ON MIDDLE JURASSIC MOLLUSCS, AS EVIDENCED FROM SHELL FRAGMENTATION

Abstract:  Durophagous (shell-crushing) predation is known from the beginning of the Phanerozoic, but it has been suggested that modern intensity was not reached until the Late Cretaceous and Early Cenozoic, when specialized marine durophagous taxa increased in diversity. In this paper, evidence of durophagous predation on Middle Jurassic communities of molluscan prey is presented on the basis of distinct accumulations of fossil remains in the Polish Jura (south-central Poland) that contain characteristic, angular shell fragments with sharp, non-abraded margins. The diverse fossil content of the accumulations studied, consisting of either benthic or nektic/nekto-benthic taxa, indicates that the potential predatory taxon was an opportunistic generalist, most probably fish. On the basis of taphonomic observations, the faunal accumulations are interpreted to represent regurgitated remains (pellets). The common occurrence of such accumulations in the Middle Jurassic clays of the Polish Jura indicates that durophagous predation has been intense since the mid-Mesozoic, at least locally.     

A MIDDLE JURASSIC FOSSIL FOREST FROM NEW ZEALAND

Abstract:  A Middle Jurassic fossil forest, thought to have been growing at high southern palaeolatitudes on the Gondwana margin, is described from New Zealand. Fossil stump horizons are exposed in stratigraphic section within the Urawitiki Measures Formation, Murihiku Supergroup. Tree bases were preserved by silica permineralisation in a sandy braided river setting. Fossil wood is referred to 'abietinean-type' and Agathoxylon . A total of 238 stumps were mapped with measured diameters allowing tree height estimates of 9–40 m. A two-dimensional area (102 m²) allows an interpretation of tree density (2353 trees/ha), biomass (579 t/ha) and stand basal area (146 m²). This horizon is interpreted as a highly productive, young, dense tree stand probably actively regenerating on a flood-cleared surface. Annual growth rings suggest a clearly defined growing season with a rapid onset of favourable temperature, light and water supply conditions at the start and a similarly rapid deterioration at the end. Mean ring width is 1·10 mm and the maximum 9·67 mm. Mean Sensitivity values suggest both 'complacent' and 'sensitive' growth patterns. Broad palaeoclimate interpretations suggest a humid, warm regional climate throughout the growing season.     

Palaeodiversity and formation counts: redundancy or bias?

A key question in palaeontology is whether the fossil record taken at face value is adequate to represent true patterns of diversity through time. Some methods of assessing data quality have depended on the commonly observed covariation of palaeodiversity and fossiliferous formation counts through time, based on the assumption that the count of formations containing fossils, to a greater or lesser extent, drives diversity; but what if diversity drives formations? Close study of two fossil records, early tetrapods (Devonian–Jurassic) and dinosaurs, shows how the relationship between new taxa and new fossiliferous formations varies through research time. Initially, each new find represents a new fossiliferous formation and discovery follows the ‘bonanza’ model (fossils drive formations). In unexplored parts of the world, new taxa are identified frequently in new regions/formations. Only after time, in well‐explored continents such as Europe and North America, does collecting style switch to a mix of exploration for new formations and re‐sampling of known fossiliferous formations. Data are most striking for dinosaurs, where the Triassic–Jurassic record largely comprises finds from Europe and North America, where new formation discoveries reached their half‐life in 1914. This contrasts with the Cretaceous, which is dominated by rapidly rising discoveries from regions outside Europe and North America and the formation half‐life for these ‘new’ lands is 1986, showing that 50% of new Cretaceous dinosaur‐bearing formations were identified only in the past 30 years. The relationship between dinosaur‐bearing formations and palaeodiversity then combines three signals in variable amounts, reflecting the original diversity (relative abundances of particular taxa in different formations), redundancy (new fossiliferous formations accruing because of new fossil finds) and sampling (intensity of exploration for new fossiliferous formations, and of search within already‐sampled formations). For fossil vertebrates at least, formation counts of various kinds are poor predictors of sampling, missing, for example, the bonanza samples of Lagerstätten such as the Yixian Formation in China: thousands of specimens, dozens of species, but counted as one formation. These observations suggest that formation count cannot be regarded as an unbiased metric of sampling.     

Microbial carbonate crusts-a key to the environmental analysis of fossil spongiolites?

Summary Morphological and geochemical comparisons between modern cryptic microbialites from Lizard Island/Great Barrier Reef and fossil counterparts in the Upper Jurassic (Southern Germany, Dobrogea/Romania) and late Lower Cretaceous (Aptian/Albian from Cantabria/Spain) spongiolitic environments show that there are common factors controlling the crust formations mostly independent of light despite of diverging (paleo-) oceanographic positions as well as relationships of competitors. Factors such as increased alkalinity, oligotrophy, and reduced allochthonous deposition are of major importance. Thrombolitic microbialites are interpreted as biologically induced and therefore calcified in isotopic equilibrium with the surrounding sea water. Corresponding with shallowing upward cycles, microbial mats which produce stromatolitic peloidal crusts become more important. Different biomarkers are introduced for the first time extracted and analyzed from spongiolitic limestones of Lower Kimmeridgian age from Southern Germany.