Sequence stratigraphic significance of sedimentary cycles and shell concentrations in the Upper Jurassic-Lower Cretaceous of Kachchh, western India

Upper Jurassic and Lower Cretaceous siliciclastic shallow water sediments of the Kachchh Basin, western India, form strongly asymmetric coarsening-upward cycles, which are interpreted as recording changes in relative sea level (deepening-shallowing cycles). These cycles correspond to depositional sequences, in which deposits of the lowstand systems tract are not present, the sequence boundary coinciding with the transgressive surface. Shell concentrations are found in the transgressive lags at the base of the transgressive systems tract (TST), in the maximum flooding zone (MFZ), and at or close to the top of the highstand systems tract. They belong to six assemblages, five of them dominated by large bivalves such as Seebachia, Herzogina, Gryphaea, Gervillella, Megacucullaea, Pisotrigonia and Indotrigonia, the sixth by the coral Amphiastraea. Three types of shell concentrations can be distinguished that differ from each other in a number of ecological and taphonomic features, such as species diversity, preservation quality, orientation in cross-section, percentage of disarticulation, and degree of biogenic alteration. Characteristic features of concentrations at the base of the TSTs are moderate time-averaging, sorting, a preferred convex-up orientation, and nearly total disarticulation of shells. They are suggestive of an environment in which reworking and local transport were frequent events. Similar features are shown by concentrations near the tops of the HSTs, except that there shells were largely concentrated in lenses and in pavements rather than in beds as in the transgressive lags. Associated sedimentary structures indicate deposition above fair weather wave base in a high-energy environment. Concentrations occurring in the MFZ, in contrast, are autochthonous and highly time-averaged, having accumulated during times of low rates of sedimentation below storm wave base. This is supported by their high preservation quality (comparatively high percentage of articulated shells, shells of infaunal organisms commonly preserved in life position), biogenic alteration being the most important taphonomic agent. The dominant elements of these shell concentrations, i.e. Seebachia, Megacuccullaea, and Indotrigonia in the Upper Jurassic, and Pisotrigonia in the Lower Cretaceous, are endemic to the Ethiopean faunal province and belong to lineages that rapidly evolved during this time period.     

Taphonomy and palaeoecology of Hauterivian–Barremian nerineoid shell beds from the Neuquén Basin,west‐central Argentina

Nerineoid shell beds are described for the first time from Lower Cretaceous deposits of southern South America. These come from carbonates near the top of the Agrio Formation in southern Mendoza Province, west‐central Argentina. To envisage the origin of the nerineoid shell beds, a taphonomic study was carried out, which indicated that these represent within‐habitat time‐averaged, primary sedimentological concentrations with a secondary biogenic imprint related to a relatively high local production of nerineoid shells. The associated palaeoenvironments were studied through a facies analysis of the carbonate succession including the shell beds. The carbonates were deposited in a homoclinal ramp system and depict a shallowing upward trend from mid to inner ramp. The individuals lived and accumulated in oolitic shoals within the inner ramp, in a shallow, well‐lit, high‐energy setting above fair‐weather wave base. Substrate was oxygenated and loose. The nerineoids are shown to belong to one species of the genus Eunerinea, and through the functional morphology of the shells they are tentatively interpreted as infaunal or semi‐infaunal. It is suggested that the recorded monospecific nerineoid shell beds indicate that the palaeoenvironmental conditions may have been favourable for the development of abundant populations of these gastropods in the northern part of the Neuquén Basin during a short time interval in the Hauterivian–Barremian boundary. This could have been related to a brief warming episode, but other factors may have also been involved. □Argentina, Early Cretaceous, Gastropods, nerineoids, Neuquén Basin, shell beds, taphonomy.     

Microstratigraphy and taphonomy of rudist shell concentrations in Upper Cretaceous limestones,Cilento area (central-southern Italy)

Rudist bed type and distribution has been investigated in Upper Cretaceous limestones cropping out in the northern Cilento area (southern Italy). These limestones are dominated by fine-grained, peloidal, silty packstone in which rudist-rich beds are intercalated. An inner shelf environment may be inferred on the basis of the recognized sedimentary and taphonomic features. The rudist shell beds are characterized by low species diversity, with slight differences in abundance of a few species belonging to the Durania, Bournonia, Sauvagesia, Gorjanovicia and Biradiolites genera, which usually form oligo- or monospecific congregations. The internal fabric of these levels (i.e. orientation, arrangement, packing and sorting of the skeletal elements; internal microstratigraphy) has permitted us to distinguish two broad shell bed categories: (a) shell beds considered as “Primary Shell Concentration”, in which the shell concentration is essentially created by the behaviour of local shell producers, preserved in situ and in growth position; (b) shell beds considered as “Hydraulic Shell Concentration”, which were deposited under the influence of hydraulic processes and/or input of surrounding bioclastic sediments. The taphonomic analyses allowed us to highlight the role of some of the biotic and abiotic factors that controlled the distribution of the rudists in the various habitats. The increase of physical disturbance (especially hydrodynamism) is the primary difference between these shell bed categories. The establishment and development of the densest rudist congregations appear to be related to the accommodation space made available by means of relative sea level rise. The lowering of the sea level was often accompanied by the increased influence of waves and/or currents on the seabed and the consequent sediment disturbance and demise of the rudist lithosome, although other factors cannot be excluded.     

Late Pliocene benthic foraminifera and mollusks from the Atsipades Section, Central Crete; Palaeoecological distribution and use in palaeoenvironmental assessment

Changes in benthic foraminiferal and mollusk assemblages from the lower part of the Upper Pliocene of the Atsipades Section (Iraklion Basin, central Crete) were studied. The Atsipades Section represents a shallowing-upward sequence from outer shelf blue-gray clays at the bottom of the sequence, deposited below the storm wave base, to shallow inner shelf deposits affected by storm waves at the top. The foraminiferal assemblage at the bottom of the sequence is dominated by Bolivina spathulata, Bolivina dilatata and Uvigerinidae, a microfossil assemblage corresponding to the deepest deposits formed under dysoxic sea-floor conditions. Foraminiferal assemblages of the middle part of the section are highly diversified, predominantly Haynesina depressula, Cassidulina carinata and Reusella spinulosa. The top of the section is mainly characterised by Asterigerinata planorbis, Bolivina pseudoplicata, Cibicides lobatulus and Elphidium sp., a typically epiphytic foraminiferal assemblage which can be correlated with the presence of an algal covered sea-bottom. Within this general environmental trend, a minor shallowing cycle can be differentiated. The boundaries of this cycle can be inferred, based on a substantial microfossil assemblage change and on the coincidence of species diversity maximum and a planktonic/benthic (P/P + B) ratio peak. Nonetheless, upwelling currents and/or over-abundance of nutrients due to continental outflow could also contribute to increased diversity and P/P + B ratio. The character of the mollusk assemblages is in accordance with these trends. Moreover, the increase in diversity and in sculpture constitutes a clear indication of an increase in hydrodynamic energy related to a shallowing-upward trend.     

Tenacity and shell shape in six Patella species: Adaptive features

Measurements were made of te forces necessary to detach various South African Patella spp. These ranged from 5.18 to 1.95 kg/cm², with significant differences between the species. P. cochlear Born. had the highest value, followed in sequence by P. argenvillei Kr., longicosta Lam., P. granularis L., P. granatina L., and P. oculus Born. Adhesion is the only mechanism capable of providing forces of this magnitude.Differences between the species are related to differences in their morphology, high tenacity being associated with low mucus secretion, small number of mucocytes, and inflexibility of the foot. This is associated with a large area of muscle attachment on the shell and the size of basal haemocoelic spaces.Features favouring high tenacity conflict with those favouring mobility, and the limpets fall into two groups. P. granularis, P. oculus, and P. granatina occur on the upper shore and the last two usually occur in areas which are sheltered from strong wave action. They a rapid growth and high gonadal output, demanding extensive foraging and hence mobility at the cost of tenacity. P. cochlear and P. longicosta are territorial and together with P. argenvillei, remain low on the shore, grow slowly, and have a low reproductive output. Feeding is localized and mobility sacrificed for high tenacity which is essential in P. cochlear and P. argenvillei as they occur in areas of strong wave action.Shell height is not correlated with tenacity nor with the intensity of wave action normally experienced by each species, but P. cochlear, P. argenvillei and to a lesser extent P. granularis, are subjected to strong wave action and have proportionally narrower shells (increasing streamlining) and low coefficients of drag. The latter are low due to the rough but regular texture of the shells creating a turbulent boundary layer and hence reducing drag.     

Über triassische »Loxonematoidea« und ihre beziehungen zu rezenten und paläozoischen schnecken

The Triassic Loxonematoidea represent a polyphyletic group of gastropods. Among these Ctenoglossa can be traced into Paleozoic time. Triphoroidea and Janthinoidea as modern representatives are well documented throughout the Tertiary into the Upper Cretaceous. In the Triassic fauna Ctenoglossa are represented by the Zygopleuroidea which merge with modern forms during the Late Mesozoic time. The ctenoglossan units can be defined by the morphology of their larval shell. Paleozoic Pseudozy-gopleuridae have given rise to the Triassic Protoculidae n. fam. In addition to the Zygopleuroidea the “Loxonematoidea” contain species similar to DevonianLoxonema, likePolygyrina. Its larval shell is unlike that of the Ctenoglossa. Relation of the Triassic Loxonematoidae can be suggested with Paleozoic fossils. There may also be a connection with post-Triassic Stromboidea. Zygopleuroidea are thus separated from Loxonematoidea and placed into the Ctenoglossa. Loxonematoidea are newly defined and provisionally placed within the Mesogastropoda.     

Paleoecology of Auloporida: an example from the Devonian of the Holy Cross Mts., Poland

Substrate specificity of Auloporida (Tabulata) from the Ska?y Fm. (Upper Eifelian-Lower Givetian) of the Holy Cross Mts., Poland, has been recognized. Kyrtatrypa sp., a rare species in the formation (under 5%), was the most often encrusted brachiopod (59% of investigated specimens), while the most often occurring brachiopod, Aulacella eifeliensis (de Verneuil) was nearly not encrusted. The majority of encrusted brachiopods were larger than 20 mm, while smaller brachiopods occur abundantly in the Formation. The substrate specificity has been caused mainly by the ornamentation of the host's shell. The position of corallites along the commissure of the brachiopod shell proves that auloporids often encrusted living hosts. The epizoan probably used water currents produced by brachiopod's lophophore impoverishing the host's food composition, their relationship can therefore be described as scramble competition.     

Linking taphonomy to community-level abundance: Insights into compositional fidelity of the Upper Triassic shell concentrations (Eastern Alps)

Although actualistic live/dead comparisons lead to robust estimates of fidelity of modern death assemblages, quantitative evaluation of fidelity of fossil assemblage remains uncertain. In this paper, effects of storm reworking on compositional fidelity of the Upper Triassic shell concentrations (Eastern Alps, Austria) are evaluated. An exploratory approach is based on comparison of reworked and non-reworked assemblages in ordination analyses. Non-reworked assemblages of one or more communities provide a baseline for evaluation of fidelity of reworked assemblages. In siliciclastic-rich intervals of the Kössen Formation, shell concentrations are represented by (1) packstones with small, shallow infaunal bivalves, (2) floatstones and pavements with large semi-infaunal bivalves, and (3) bioclastic marlstones. In carbonate-rich intervals, bioclastic floatstones with bivalves and brachiopods occur. Analyzing all shell concentrations, eight sample groups sharing similar species composition are discriminated. Limited effect of storm reworking on composition of shell concentrations is indicated by (1) a general persistence of six sample groups when only non-reworked assemblages are analyzed, (2) similarity in composition between reworked and non-reworked assemblages within sample groups, and (3) compositional segregation between non-reworked assemblages of distinctive sample groups, mostly without any reworked assemblages of intermediate composition.Depth-related variations in dead-shell production, shell destruction and body size governed preservation and distribution of the shell concentrations along onshore-offshore gradient in the Kössen Basin. First, at times when environmental conditions were unfavorable for shell producers, coupled with high background shell destruction rates, limestone beds formed during storm events were shell-poor. Second, less common shell concentrations in upper than in lower parts of siliciclastic intervals can be related to higher environmental stress in shallower habitats. Third, the difference between shell concentrations dominated by small and large bivalves is driven by between-habitat differences in body size and is not due to a differential sorting of small and large shells. Combining community analysis based on species abundances with taphonomic analysis can thus be helpful in tracking fidelity of fossil assemblages.     

Larval shell morphology of <Emphasis Type="Italic">Inoceramus pictus</Emphasis>: all suspicions confirmed

Inoceramids were eurytopic bivalves and have a wide application as biostratigraphic index fossils in the Upper Cretaceous. Their paleoecology, however, is far from being understood. Here the prodissoconch of Inoceramus pictus is described. It was found in an upper Cenomanian shallow water methane-seep deposit in the Tropic Shale, southern Utah, USA. The larval shell consists of a small prodissoconch-1 and a large prodissoconch-2. The shell morphology indicates a planktotrophic larval phase with wide dispersal potential, and which confirms previous hypotheses of inoceramid larval ecology. Comparison with other inoceramid prodissoconchs shows that larval shell morphology cannot generally explain dispersal, and that more factors must have played a role in the distribution of species.     

A New Approach for the Determination of Ammonite and Nautilid Habitats

Externally shelled cephalopods were important elements in open marine habitats throughout Earth history. Paleotemperatures calculated on the basis of the oxygen isotope composition of their shells can provide insights into ancient marine systems as well as the ecology of this important group of organisms. In some sedimentary deposits, however, the aragonitic shell of the ammonite or nautilid is poorly or not preserved at all, while the calcitic structures belonging to the jaws are present. This study tests for the first time if the calcitic jaw structures in fossil cephalopods can be used as a proxy for paleotemperature. We first analyzed the calcitic structures on the jaws of Recent Nautilus and compared the calculated temperatures of precipitation with those from the aragonitic shell in the same individuals. Our results indicate that the jaws of Recent Nautilus are secreted in isotopic equilibrium, and the calculated temperatures approximately match those of the shell. We then extended our study to ammonites from the Upper Cretaceous (Campanian) Pierre Shale of the U.S. Western Interior and the age-equivalent Mooreville Chalk of the Gulf Coastal Plain. In the Pierre Shale, jaws occur in situ inside the body chambers of well-preserved Baculites while in the Mooreville Chalk, the jaw elements appear as isolated occurrences in the sediment and the aragonitic shell material is not preserved. For the Pierre Shale specimens, the calculated temperatures of well-preserved jaw material match those of well-preserved shell material in the same individual. Analyses of the jaw elements in the Mooreville Chalk permit a comparison of the paleotemperatures between the two sites, and show that the Western Interior is warmer than the Gulf Coast at that time. In summary, our data indicate that the calcitic jaw elements of cephalopods can provide a reliable geochemical archive of the habitat of fossil forms.     

Trilobites from the Silurian “Lower Red Beds” of Wuhan,South China: stratigraphic and paleogeographic implications

The age of the Silurian “Lower Red Beds” (LRBs), which occur widely in South China, has long been controversial because of the scarcity of index fossils. Here, we report a fauna with abundant trilobites from the LRBs in Wuhan, Middle Yangtze region, consisting of Aulacopleura (Paraaulacopleura) pijiazhaiensis, ‘Encrinuroides’ yichangensis, Gaotania hubeiensis, Hyrokybe gaotanensis, Japonoscutellum yichangense, Latiproetus latilimbatus, and Ptilillaenus lojopingensis. These trilobites are common in the Leijiatun, upper Xiangshuyuan, Shihniulan, and Lojoping formations in the Upper Yangtze region, and belong to the middle to upper Aeronian Ptilillaenus or ‘Encrinuroides’–Ptilillaenus–Latiproetus assemblages. The discovery of this trilobite assemblage suggests that the LRBs are probably partly of middle–late Aeronian age in the Middle Yangtze region. Thus, the lower boundary of the LRBs is likely diachronous in the Yangtze region, ranging from the middle–late Aeronian to the early Telychian. The discovery of the Ptilillaenus assemblage in the Wuhan LRBs expands the paleogeographic distribution of this assemblage and provides evidence of deeper depositional environment of the LRBs in the study area versus shallow waters in other areas of the Yangtze region.     

Trepostome bryozoans from the Zahořany Formation (Upper Ordovician) of Loděnice,Prague Basin,Czech Republic

Three trepostome bryozoan species are described from the Upper Ordovician Zaho?any Formation of Loděnice, Prague Basin, Czech Republic. One genus is new—Lodenicella gen. nov. One species is described in open nomenclature. The described fauna contains ramose colonies or ramose branched projections from encrusting tubular-shaped colonies which inhabited shallow environment with moderate wave energy and significant influx of clastic material.     

Thick brachiopod shell concentrations from prodelta and siliciclastic ramp in a Tortonian Atlantic–Mediterranean strait (Miocene, Guadix Basin, southern Spain)

Carbonate production by brachiopods in shallow-water habitats is generally expected to be not sufficiently high and temporally persistent to allow them to form very thick and densely packed shell concentrations. The formation of thick brachiopod concentrations requires long-term persistence of populations with high density of individuals, and such circumstances are assumed to be rare especially during the Cenozoic. However, here we show that the large-sized brachiopod Terebratula terebratula, the most common species in benthic assemblages with epifaunal bivalves and irregular echinoids, formed several decameter- to meter-thick, densely packed concentrations in shallow siliciclastic, high-energy environments, in a seaway connecting the Atlantic Ocean with the Mediterranean Sea during the Latest Tortonian (Late Miocene, Guadix Basin, southern Spain). This brachiopod formed (1) meter-scale, thick, parautochthonous concentrations in a prodelta setting and (2) thin, mainly allochthonous, tide- and storm-reworked concentrations in megaripples and dunes. The abundance of brachiopods at the spatial scale of the Guadix Basin seems to be mainly related to intermediate levels of sedimentation rate and current velocity because abundance and thickness of shell concentrations decline both (1) in onshore direction towards delta foresets with high sedimentation rate generated by debris flows and (2) in offshore direction with increasing levels of tide- and storm-induced substrate instability. Although brachiopods in dune and megaripple deposits are more fragmented, disarticulated, and sorted, and have a higher pedicle/brachial valve ratio than in prodelta deposits, taphonomic damage is still relatively high in prodelta deposits. Terebratula terebratula thus formed thick concentrations in spite of that disintegration processes were relatively intense along the whole depositional gradient. Therefore, population dynamic of this species was probably characterized by production maxima that were comparable to some Cenozoic molluscs in terms of their productivity potential to form thick shell concentrations in shallow subtidal environments. We suggest that temporal changes in brachiopod carbonate production have a significant spatial and phylogenetic component because multiple large-sized species of the family Terebratulidae, which underwent radiation during the Cenozoic, attained high abundances and formed shell concentrations in temperate regions.     

Upper Pliocene bivalve shell concentrations from the Lower Chelif basin (NW Algeria): Systematics,sedimentologic and taphonomic framework

Sedimentologic and palaeontological investigation of the Upper Pliocene Slama Formation in the Lower Chelif Basin (NW Algeria) led us to collect important bivalve assemblages for taxonomic and taphonomic purposes. A rather comprehensive inventory list of Upper Pliocene bivalves from northwestern Algeria is now available and consists of 30 species, 17 of which are extinct ones. Four principal taphonomic attributes were analysed: bioerosion, encrustation, fragmentation, and abrasion. Physical and biogenic sedimentary structures are used for palaeoenvironmental interpretations. The taphonomic, sedimentologic and ichnological characteristics of most of the deposits suggests they originated from discontinuous processes of winnowing and bypassing of sediments, probably due to the action of storms in shallow waters, mainly in the shoreface depositional environment. The bivalve assemblage is dominated by disarticulated valves and displays significant taphonomic alteration in the shells. Sclerobionts traces in shells particulary affect the oyster shells. Bioerosion traces are predominately those of clionid sponges (Entobia isp.), polychaetes (Maeandropolydora isp. and Caulostrepsis isp.), bivalves (Gastrochaenolites isp.), and of predatory gastropods (Oichnus isp.). Among the sclerobionts, the identified encrusters were juvenile oyster recruits, barnacles, polychaetes (serpulid tubeworms), bryozoans (Microporella sp. and Acanthodesia sp.), and vermetid gastropods (Petaloconchus intortus).     

Elucidation of tellurium biogenic nanoparticles in garlic,Allium sativum,by inductively coupled plasma-mass spectrometry

BackgroundBiosynthesis of Te nanoparticles may occur in higher plants exposed to Te, as reported on microorganisms. However, unambiguous observations of the biogenic nanoparticles (BgNPs) of Te in plants are lacking. Hence, in this study, we investigated the formation of insoluble BgNPs of Te in garlic (Allium sativum) as a model plant.MethodWe performed elemental analysis based on inductively coupled plasma-mass spectrometry (ICP-MS) technique, and obtained Te concentration and distribution in various parts of garlic. In addition, insoluble Te particles were detected by fast time-resolved ICP-MS. Direct observation of the insoluble Te particle was also conducted by scanning electron microscope (SEM) and transmission electron microscope (TEM).ResultsA part of the roots and clove from Te-exposed garlic showed black coloration. Te concentrations in the black-colored parts were significantly increased compared with the non-colored parts. Transient signals of Te unique to nanoparticles were detected from the insoluble fractions of the black-colored parts. Finally, rod-shaped biogenic Te nanoparticles consisting of highly crystalline elemental Te was observed by SEM and TEM.ConclusionOur data provide new insights to the metabolic pathway of Te in higher plants for the formation of insoluble biogenic nanoparticles, which is extremely important for the detoxification of Te.     

Encrusting micro-organisms and microbial structures in Upper Jurassic limestones from the Southern Carpathians (Romania)

Late Jurassic–Early Cretaceous ?tramberk-type reef limestones are known from some parts of the Southern Carpathians in Romania. The Upper Jurassic deposits mainly consist of massif reef limestones including a variety of microbialites associated with micro-encrusters. They played an important role in the formation and evolution of the reef frameworks and thus are of significant importance for deciphering the depositional environments. For our study, the most important encrusting organisms are Crescentiella morronensis, Koskinobullina socialis, Lithocodium aggregatum, Bacinella-type structures, Radiomura cautica, Perturbatacrusta leini, Coscinophragma sp., and crust-forming coralline sponges such as Calcistella. Based on microscopic observations, microbial contribution to reef construction is documented by the abundance of dense micrite, laminate structures, clotted, thrombolithic or peloidal microfabrics, constructive micritic cortices, biogenic encrustations and cement crusts, as well as by other types of microbial structures and crusts. Most of the investigated carbonate deposits can be classified as “coral-microbial-microencruster boundstones” which are characteristic for the Intra-Tethyan domain. Their paleogeographical significance is indicated by the presence of many features comparable with carbonate deposits of rimmed platform systems from the Northern Calcareous Alps or Central Apennines. Based on the distribution of the facies and facies associations within the carbonate sequences under study we can distinguish slope and external shelf margin environments. The microbial crusts, the encrusting micro-organisms, and in some cases the syndepositional cements have stabilized and bound the carbonates of the slope facies types. Subsequently, the stable substrate favored the installation of coral-microbial bioconstruction levels.     

Palaeobiology of an offshore molluscan fauna from the California Oligocene

Oligocene molluscs of the Kreyenhagen Formation lived in bathyal and shallower bottoms of diatomaceous mud. Four communities, dominated by the bivalves Delectopecten, Thyasira, Macrocallista, and Nuculana, occur in two stratigraphic cycles representing an environmental gradient of shallowing depth and increasing levels of energy and turbidity. Shallowing in each cycle is accompanied by a succession from epifaunal suspension feeders to infaunal suspension feeders to deposit feeders, by increase in shell density, and by decrease in species diversity. Modern Delectopecten and Thyasira Communities around northwestern Europe are related to Kreyenhagen associations by community evolution. Species diversity in the Delectopecten community lineage appears to have increased since the Oligocene, whereas diversity in the Thyasira community lineage has remained the same. Six species of the deep-water Kreyenhagen fauna also occur in shallow, sandy-bottom Oligocene faunas of northerly latitudes; these species produced smaller shells in the deeper environment. For Macrocallista and Nuculana, counts of external concentric lines and ridges suggest that smaller size resulted from a slower growth rate.     

Les Rhynchonelles du Bathonien du domaineprovencal: Liaison entre l'installation des peuplements et les modalités de la transgression bathonienne dans les Alpes-Maritimes

In the Maritime Alps, the Middle and Upper Bathoniancorresponds to a transgressive episode on the Provençal platform. The advancement of the marine invasion is very noticeable between Grasse and Antibes. The sediment shows the existence of a shallow marine environment in which benthic organisms were predominant.The deposits are at first varied: marly layers withbivalves (burrowers for the most part) and calcareous layers with monospecific populations of brachiopods (Burmirhynchia mediterranea nov. sp. in a calm environment, and B. turgidaBuckman in a more turbulent environment).The deposits then become uniform and show theexistence of very shallows environments: B. decorata kiliani nov. subsp. is the only representative of macrofauna in the micritic limestones that can be attributed to the Upper Bathonian.The Rhynchonellids, as on the other Bathonian carbonateplatforms of Western Europe, seem to be the only organisms likely to stay alive and proliferate in the specific environments in which entirely carbonate sediments are deposited in shallow water. Due to their relationships to those existing in other platforms, the species described in this article permit the clarification of biostratigraphic correlations.     

Oldest scleractinian coral reefs on the North American craton: Upper Triassic (Carnian), northeastern British Columbia,Canada

Bioclastic accumulations composed of crinoids, brachiopods, molluscs, spongiomorphs and scleractinian corals occur within Upper Triassic strata of the lower Baldonnel Formation at Pardonet Hill in northeastern British Columbia Canada. These small buildups (∼100 to 500 m³) have planar bases and broadly convex tops. These mounds are interpreted as small patch reefs composed of packstone, bioclastic floatstone/rudstone and carbonate breccia intercalated with mixed siliciclastic carbonate sediments deposited in a shallow subtidal setting (i.e. above fairweather wave base). Amalgamated hummocky cross-stratified to current ripple-laminated, quartz-dominated sandstone beds and numerous sharp-based, normally graded bioclastic (commonly encrinitic) packstone/grainstone — quartz–sandstone couplets characterize inter-reef lithologies.Conodont biostratigraphy indicates that the Pardonet Hill patch reefs occur within strata dated as earliest Upper Carnian (lower nodosus zone). The Pardonet Hill patch reefs originated and developed during an interval of regional sea level lowstand. Strata within which these patch reefs occur represent the westernmost migration of the Triassic shoreline in western Canada. Disappearance of coral reefs in the study area may have been affected by rapid marine transgression and failure of reef faunas to recolonize the new shore zone further to the east.The Pardonet Hill locality occurred on the western margin of the North American craton during the Triassic. Prior to their discovery reef-like structures dominated by corals in the western Panthalassa were limited to allochthonous terranes (now part of the Cordillera). The Pardonet Hill patch reefs occur at approximately 30° Triassic paleolatitude. In modern settings, this is at the extreme latitudinal margin of subtropical zooxanthellate reef development. The presence of benthic faunas characteristic of low-paleolatitude settings on the northwestern coast of Pangea has significant implications in paleotectonic and paleoenvironmental reconstructions.     

Lindholmemydid turtles (Cryptodira: Testudinoidea) from the Late Cretaceous of Shandong Province,China

A new genus and new species of lindholmemydid turtle (Cryptodira: Testudinoidea), Shandongemys dongwuica n. g. and n. sp. are described on the basis of a partial skeleton with incomplete shell and skull, complete lower jaws and disarticulated limb bones from the Upper Cretaceous Wangshi Group of Zhucheng, Shandong Province, China. Among Lindholmemydidae, the new species is closely related to Mongolemys elegans from the Late Cretaceous of Mongolia. An incomplete shell from the same locality is referred as Lindholmemydidae indet. Glyptops sp. from the Upper Cretaceous Wang Group of Jingangkou, Laiyang, Shandong is revised and assigned to Lindholmemydidae.