Late Turonian (Cretaceous) climate cooling in Europe: faunal response and possible causes

Isochronous variations of δ¹⁸O curves within several European basins indicate a period of Late Turonian climate cooling, which is characterized by two distinct cooling phases, separated by a period of climate stability. Literature data for macrofauna (ammonites, echinoids, and belemnites) indicate that the cooling phases are associated with a southward shift of taxa. Concomitant Late Turonian events (volcanism and relative sea-level changes) suggest the migration to be triggered mainly by relative sea-level falls. The inferred cooling phases are seen in context with a general cooling trend due to the decrease in Mid-Cretaceous volcanogenic CO₂ emission. Short-term stagnation of cooling in the Late Turonian has been probably triggered by renewed volcanism. Due to the general high temperatures during Mid-Cretaceous times, a glacio-eustatic explanation for the coincidence of cooling and sea-level fall is considered unlikely.     

A new mosasauroid (Squamata) from the Late Cretaceous (Turonian) of Morocco

Tethysaurus nopcsai gen. et sp. nov. is described on the basis of both cranial and postcranial material from the Late Cretaceous (Early Turonian) of the Goulmima region, southern Morocco. This new mosasauroid is mainly characterized by a parietal table ending posteriorly in two pointed pegs; jugal with a large ascending ramus; splenial with a large and notched dorsomedial process; surangular exposed medially ventral to the coronoid; large paracotylar and parazygosphenal foramina on vertebrae. A phylogenetic analysis shows that Tethysaurus is the sister-group of Mosasauridae. It fills the gap between the aigialosaurids (mainly Cenomanian) and the mosasaurids (known from the Middle-Late Turonian to the Latest Maastrichtian). To cite this article: N. Bardet et al., C. R. Palevol 2 (2003).     

Paedomorphosis in the Turonian (Late Cretaceous) collignoniceratine ammonite lineage from the north Pacific region

Ontogenetic development and variation of shell ornament of the four Turonian collignoniceratine ammonites, Collignoniceras woollgari (Mantell 1822), Subprionocyclus neptuni (Geinitz 1850), S. normalis (Anderson 1958) and S. minimus (Hayasaka & Fukada 1951) have been compared on the basis of large population samples from Hokkaido (Japan), California and the US Western Interior Province. Our study revealed that the ornament types observed in the early-middle stage of C. woollgari occur in the middle-late stage of the three other species, and that those in the early-middle stage of S. neptuni appear in the middle-late stage of S. normalis and S. minimus. These species are generally regarded as closely related phylogenetically, because they share several common morphological features such as the presence of double ventrolateral tubercles and a serrated keel. If a postulated phylogeny starting from C. woollgari to S. normalis and S. minimus via S. neptuni is accepted, the mode of morphological evolution in the lineages can be explained by paedomorphosis. Available palaeobiogeographical data suggest that this paedomorphic evolution occurred independently on the northwestern and northeastern sides of the northern Pacific, where the C. woollgari – S. neptuni – S. minimus, and C. woollgari – S. neptuni – S. normalis sublineages evolved.     

Track analysis of the marine palaeofauna from the Turonian (Late Cretaceous)

Aim  To analyse the worldwide distribution patterns of Turonian marine biotas using a panbiogeographical approach.
Location  Turonian localities of southern and north-eastern Brazil, Mexico, Canada, central Europe, England and Morocco.
Method  Panbiogeographical track analysis.
Results  Nine generalized tracks and six nodes were found. The generalized tracks comprise two vicariant track patterns (one northern and one mid-southern) across the Atlantic.
Main conclusions  The generalized tracks show clearly two separate marine biotas, which were associated with the proto-South Atlantic and the proto-North Atlantic oceans. These generalized tracks, as well as the two vicariant track clusters between the north and south Atlantic, are identified by vicariant relationships shared by most of the taxa analysed, and illustrate the final break up of the Gondwana and Laurasia supercontinents and the consequences of vicariant events for the biogeography of the Atlantic Ocean.     

Cenomanian/Turonian sponge microbialite deep-water hardground community (Liencres,Northern Spain)

Summary A benthic community of sessile metazoans dominated by coralline sponges (e.g.Acanthochaetetes andVaceletia) is found within a Cenomanian-Turonian deep water hardground succession cropping out at the coastal area of the Bay of Biscay near Santander. The characteristic K-strategic community exhibits a very close taxonomic relationship with modern communities from the Pacific realm, which allows for a comparison with Recent environmental conditions. The sponge community was associated with automicrites, microbialites, and thin mineralized limonitic biofilms. This biofacies is typically found in cryptic niches of reefal buildups (“telescoping”). The iron-rich biofilms had a strong electrochemical corrosive ability which explains the distinct submarine dissolution patterns. The hardground conditions are controlled, in part, by strong contour current regimes linked with extremely oligotrophic water masses. This system was established during the drowning of a distal carbonate ramp during the early Middle Cenomanian (A.rhotomagenese zone). In the uppermost portion of the hardground (Late Cenomaian, upperR. cushmani zone) the coralline sponge community was replaced by thick limonitic stromatolites with numerous encrusting foraminifera (Miniacina-type) and by colonies of the problematic iron bacteriumFrutexites. This event is accompanied by an increase of terrigenous influx and detrital glauconite, indicating a fundamental change in food web, and terminates the sponge dominated basal hardground interval. Thehardground was buried by hemipelagic sediments during the Middle Turonian (upperR. kallesi zone). Dedicated to the memory of Prof. Dr. JostWiedmann     

Yaguarasaurus columbianus (Reptilia,Mosasauridae), a primitive mosasaur from the Turonian (upper cretaceous) of Colombia

New remains of Yaguarasaurus columbianus found in the Turonian beds of the upper valley of the Magdalena River, in Colombia, are described. Three aspects of the cranial morphology of Y. columbianus are of particular interest. First, its morphology is one of the most primitive among mosasaurs; second, it exhibits most similarities to the cranial morphology of the aigialosaurs; and finally, it exhibits some traits that are unknown in other mosasaurs, including certain cranial features that resemble those of the terrestrial varanoids.     

New Nemonychidae,Brentidae and Curculionidae (Coleoptera: Curculionoidea) from the Turonian of Kzyl-Dzhar (Kazakhstan)

Five new genera, Turononemonyxn. gen. (type species: Turononemonyxsamsonovin. sp.) (Nemonychidae: ? Cretonemonychinae: ? Cretonemonychini), Falsotanaosn. gen. (type species: Falsotanaos convexusn. sp.), Pretanaosn. gen. (type species: Pretanaosocularisn. sp.), Longotanaosn. gen. (type species: Longotanaosrasnitsynin. sp.) from Brentidae: Apioninae: Tanaini) and Turonerirhinusn. gen. (type species: Turonerirhinuskaratavensisn. sp.) from Curculionidae (Erirhininae: Erirhinini), and seven new species, Falsotanaosconvexusn. sp., Paratanaos samsonovin. sp., Pretanaos ocularisn. sp., Longotanaos rasnitsynin. sp., Turonerirhinus karatavensisn. sp., Turonerirhinuspunctatusn. sp. and Turonerirhinus poinarin. sp., are described from Kzyl-Dzhar locality (Kazakhstan, Upper Cretaceous, Turonian).http://www.zoobank.org/urn:lsid:zoobank.org:pub:13E0316E-C229-471A-90AA-2D71253B12F9     

Spinicaudatans and ostracods (Crustacea) from the Montceau Lagerstätte (Late Carboniferous, France): morphology and palaeoenvironmental significance

Spinicaudatans and ostracods form two components of the diverse arthropod fauna from the Montceau Lagerstätte (Stephanian, France). Spinicaudatans are represented by Montcestheria orri gen. and sp. nov. and Euestheria feysi sp. nov., and ostracods by a single species, Carbonita sp. aff. salteriana (Jones, 1862). Allied forms such as Montcestheria sp. aff. orri, Montcestheria sp. and Euestheria cebennensis (Grand'Eury, 1890), all from coeval localities in France, are also described. Montcestheria gen. nov. has carapace features, external (possibly sexual) dimorphism, preserved soft parts (e.g. appendages, gut) and resting eggs similar to those of Recent spinicaudatans, suggesting comparable lifestyles, reproductive strategies and feeding modes. Detailed anatomical comparisons are made with Cyzicus tetracerus from Recent ephemeral freshwater ponds. The ostracods belong to the Superfamily Carbonitoidea, which is a recurrent component of Carboniferous non‐marine biotas. Spinicaudatan‐rich assemblages typically occur in several Westphalian–Stephanian Lagerstätten (including Montceau) and localities from Europe and North America, where freshwater conditions prevailed, indicating that the group had already colonized continental waters by the Late Carboniferous. Similarities with the fauna from Recent temporary freshwater ponds (e.g. low diversity/high density spinicaudatan‐ostracod populations, synchronous spinicaudatan populations developing from resting eggs, high diversity/low density insects, amphibians) suggest the presence of temporary or ephemeral aquatic environments at Montceau as part of a complex limnic ecosystem. Flooding may have been the main driving force by which faunal and floral elements drifted away from their respective biotopes into the depositional areas, thus explaining the co‐occurrence of terrestrial (e.g. myriapods, scorpions, plants), amphibian and aquatic (e.g. conchostracans and syncarids from temporary and permanent settings, respectively) elements in fossil assemblages.     

A new fossil flower from the Turonian of New Jersey: Dressiantha bicarpellata gen. et sp. nov. (Capparales)

Recent discoveries of fossil reproductive structures from deposits of the Raritan Formation in New Jersey (Turonian, Upper Cretaceous, ~90 million years BP) include a previously undescribed representative of the Order Capparales. The fossils are usually charcoalified with three-dimensional structure and excellent anatomical details. In the present contribution, we introduce a taxon represented by fossil flowers that have a combination of characters now found in the families of the Order Capparales sensu Cronquist. The fossil species is characterized by an unique suite of characters, such as the presence of a gynophore, arrangement of the sepals, unequal petal size, monothecal anthers, and a bicarpellate gynoecium, that are found in extant families of the Order Capparales. This new taxon constitutes an important addition to our understanding of Cretaceous angiosperm diversity and represents the oldest known fossil record for the Capparales. Heretofore, the oldest known capparalean was from the Late Tertiary sediments of North America.     

Cyrtocrinids (Crinoidea) and associated stalked crinoids from the Lower/Middle Oxfordian (Upper Jurassic) shelfal deposits of southern Poland

Five cyrtocrinid crinoid taxa previously unknown from the epicratonic deposits of Poland, as well as associated millericrinids and isocrinids, are described. The studied materials were derived mainly from the Lower and Middle Oxfordian, but crinoids are also from uppermost Callovian and/or lowermost Oxfordian sediments of the Polish Jura Chain (southern Poland). The crinoids, preserved as more or less complete (e.g., basal circlets) cups, include Lonchocrinus dumortieri, Phyllocrinus belbekensis, Remisovicrinus polonicus, Remisovicrinus aff. polonicus, Tetracrinus moniliformis and Sclerocrinus sp. The occurrence of Remisovicrinus polonicus in the late Middle Oxfordian of the southern Poland is confirmed. Moreover, the present study extends the geographic range of all cyrtocrinid species studied and discusses their unusual environmental adaptations.     

Sorophores of<Emphasis Type="Italic">Lygodium</Emphasis> Sw. (Schizaeaceae) from the Late Cretaceous of New Jersey

We report here on a series of specimens of charcoalified sorophores with characteristics of the extant fern genusLygodium (Schizaeaceae) collected from sediments of the Raritan Formation (Late Cretaceous). Each elongate lobed fertile pinnule (sorophore) is flattened and bears alternately arranged sporangia on one surface. Each sporangium is covered by an indusium continuous with the margin of the lamina. Sporangia are oblong in shape, short stalked, and have an apical annulus formed by a single ring of radiating cells that dehisces longitudinally. The sporangial cap or distal face is formed by only one cell. All of these features are characteristic of the extant genusLygodium. Small numbers of trilete, psilate spores are found in the sporangia. Megafossils assignable toLygodium are known from the Upper Cretaceous of North America and Germany with worldwide distribution during the Tertiary. The newLygodium fossils are compared with others previously referred to the genus.     

A New Three-Dimensionally Preserved Xiphosuran Chelicerate from the Montceau-Les-Mines Lagerstätte (Carboniferous, France)

Excellent three dimensional preservation of 142 specimens of Alanops magnificus gen. et sp. nov. (Chelicerata: Xiphosura) from the Stephanian Konservat-Lagerstätte of Montceau-les-Mines (Saône-et-Loire, France), exposes the carapace design and hitherto unrecorded details of fossil xiphosuran ventral anatomy, and makes possible an interpretation of appendicular functional morphology. All legs are long, slender and chelate. The chelate condition of the fifth leg and the shape of the prosoma (highly vaulted with a subvertical frontal area) indicate that the animal was neither a burrower like Recent xiphosurans (e.g. Limulus ) nor an active swimmer as suggested for other extinct forms, but was more likely to have been a benthic crawler. The ability to fold up is attested by both partly enrolled specimens showing appendages withdrawn into the prosomal cavity, and by coaptive devices on the external and internal margins of both prosoma and opisthosoma. The low-level articulation system at the boundary between the two shields allowed both the carapace closure and the complete outstretching of the animal. The unusually small adult size of Alanops magnificus gen. et sp. nov. combined with the loss of ophthalmic ridges and spines is interpreted as indicating a paedomorphic derivation from a bellinurine stock. The depositional environment (limnic intramontane basin) and faunal association (dominated by syncarids and bivalves) of Alanops indicate that the animal probably lived in fresh water.     

A new polycotylid plesiosaur from the Late Cretaceous (Turonian) of Morocco

A new Polycotylidae (Plesiosauria) from the Late Cretaceous (Turonian) of southern Morocco is described. Thililua longicollis gen. et sp. nov. is based on a complete cranium and 37 associated vertebrae. It differs from other polycotylids in several cranial and especially vertebral characters, such as the occurrence of 30 cervical vertebrae, whose centra are nearly as long as high and bear laterally longitudinal ridges. Thililua is the first polycotylid hitherto found in Africa and under subtropical palaeolatitudes. To cite this article: N. Bardet et al., C. R. Palevol 2 (2003).     

New Dinosaur Footprints from the Upper Cretaceous of Poland in the Light of Paleogeographic Context

The Late Cretaceous track assemblage of southeastern Poland includes intriguing ichnotaxa with Asian or North American affinities. New finds of the ceratopsian-like ichnite and small hadrosauroid track refer directly to this problem, whereas the re-evaluation of foraminifer taxa estimates the stratigraphic positions of the track-bearing horizon and allowed to understand paleogeographic context of the studied and adjacent areas. The results demonstrate that during the Late Cretaceous times, migration of dinosaurs was possible from Asia through the East European Land to Kukeritz Island and the islands at peri-Tethys area.     

A new aquatic pythonomorph (Reptilia,Squamata) from the Turonian (Late Cretaceous) of France

Disarticulated vertebrae from the Turonian of France display a distinctive suite of characters and probably represent a new pythonomorph. This taxon displays some degree of vertebral pachyostosis s.s., often observed in varanoid squamates from the Cenomanian-Turonian interval of the ‘Mediterranean’ portion of the Tethys. The discovery of this new material highlights the importance of also describing possibly new taxa based on isolated remains.     

Reconstruction of Late Cretaceous coastal paleotemperature from halite deposits of the Late Cretaceous Nongbok Formation (Khorat Plateau,Laos)

Cretaceous evaporites of the Maha Sarakhan Formation in Thailand (e.g., the Nongbok Formation, Laos) have been studied for almost a century as the huge potash deposits in the world. The consistently high local paleotemperatures should lead to huge salt deposits during the evaporation process. Primary fluid inclusions in halite can provide surface brine water temperatures directly and quantitatively. Until now, there have been no data published from paleotemperature of primary fluid inclusions of Cretaceous halite. The non-marine halite from the Cretaceous Nongbok Formation (Laos) precipitated from shallow brine waters with temperatures of 17.7–42.3 °C.     

Aptychi microstructure in Late Cretaceous Ancyloceratina (Ammonoidea)

The microstructure of aptychi (bivalved calcareous coverings on lower jaws) of three genera of Late Cretaceous Ancyloceratina, Baculites, Polyptychoceras and Jeletzkytes is described for the first time on the basis of well-preserved and in situ material from the Western Interior of the USA and Hokkaido, Japan. Optical and scanning electron microscope observations of aptychi on polished median and cross-sections reveal some variation in their relative size, shape and microstructure among the three genera. The aptychus of Baculites is composed of two calcitic layers: one with tilted lamellae and the other one with horizontal lamellae, whereas those of Polyptychoceras and Jeletzkytes consist of a thin layer with horizontal lamellae. Comparison with aptychi (e.g. Laevaptychus) of Jurassic Ammonitina shows that the aptychi of Ancyloceratina differ from those of Jurassic Ammonitina in the smaller number of layers and the absence of a sponge-like structure. We propose for the first time growth models for a sponge-like aptychus of Jurassic Ammonitina and the lamellar aptychus of Cretaceous Ancyloceratina. The remarkable microstructural variation of aptychi observed in Mesozoic Ammonoidea is probably related to the diversity of their modes of feeding and the secondary function of the lower jaws as opercula.     

Fossil preservation in the Neoproterozoic Doushantuo phosphorite Lagerstätte, South China

Phosphorites of the late Neoproterozoic Doushantuo Formation exposed in the vicinity of Weng'an, Guizhou Province, and Chadian, Shaanxi Province, South China, contain exceptionally well-preserved algal thalli, acritarchs, and globular microfossils interpreted as animal embryos. Combined optical microscopic and SEM observations provide insights into the taphonomy of phosphatized fossils. Algal cells and tissues are variably resistant to decay, and within preserved populations permineralization began at varying stages of degradation. In consequence, there is a spectrum of quality in cellular preservation. Algal cell walls, acritarch vesicles, and embryo envelopes are commonly encrusted by an isopachous rim of apatite, with cell interiors filled by collophane and later diagenetic dolomite. In contrast, blastomere surfaces of animal embryos are encrusted primarily by minute phosphatic spherules and filaments, possibly reflecting an immediately postmortem infestation of bacteria that provided nucleation sites for phosphate crystal growth. Thus, the same processes that gave rise to Phanerozoic phosphatized Lagerstätten - phosphatic encrustation, and impregnation, probably mediated by microbial activity - effected soft-tissue preservation in the Doushantuo Lagerstätte. It remains unclear how phosphatic ions and organic macro-molecules interact at the molecular level and to what extent specific microbial metabolisms or microenvironmental conditions control the phosphatization of soft tissues. New observations of phosphatized Doushantuo fossils include: a second locality (Chadian) for Wengania globosa , interpreted as an algal thallus and previously known only from Weng'an; microtunnels in Weng'an phosphorites interpreted as pyrite trails; and new taxa described from Weng'an: Meghystrichosphaeridium reticulatum (acritarch), Sarcinophycus radiatus (algal thallus), and one unnamed problematic form.     

A brachiopod boring (Podichnus) in a Late Cretaceous oyster from a mangrove-like environment, Skåne, Sweden

A characteristic etching trace, comparable to those produced by pedicles of some Recent brachiopods, was found on a Late Cretaceous, Campanian oyster shell from a mangrove-like setting in the Åsen quarry, Sweden. The trace fossil belongs to the ichnospecies Podichnus centrifugalis Bromley & Surlyk, 1973 and is, together with a single specimen of Crania craniolaris Linnæus, 1758, the only evidence of brachiopods in the mangrove-like environment.     

Integrated stratigraphy and palaeoenvironment of the Cenomanian-Lower Turonian (Upper Cretaceous) of northern Westphalia, North Germany

Summary The present study provides an integrated stratigraphy of the Lower Cenomanian-Lower Turonian of the northwestern Münsterland Basin, Westphalia. This is important to establish a standard section allowing an interregional correlation as well as an interpretation of single environmental conditions, their changes through time and their geographical extent. Numerous sections have been investigated in northern Westphalia, in addition to data from other profiles in North Germany. Macrofossils and thin-sections have been sampled, stable isotope and gamma ray data have been obtained from a part of the sections. Investigation of the sedimentary sequence is based on a analysis of events. Many events are diachronous, whereas others are difficult to define and do not show a wide geographic distribution. For ecological or sedimentological reasons, correlation is not possible. The discussion of events leads to a compound picture of the evolution of the depositional sequence, allowing the reconstruction of palaeo-environmental changes. Sea-level changes and their influence on the fauna is discussed. During maximal sea-level rising, macrofossils occur more frequently for ecological reasons, however, some macrofossil accumulations are lag deposits. Some biostratigraphical problems find their origin in a tectonic separation leading to different habitats. The local tectonics was caused by the intial phase of transpression of the Osning Zone, that can be traced down to the Lower Cenomanian. A correlation of the Cenomanian-Turonian Boundary Event (CTBE) in Westphalia (Lengerich), Colorado (USA) and England (Eastbourne), is possible due to very dense sampling of carbon-isotopes (δ¹³C). In Westphalia, definition of the stage boundary is possible by correlation of carbon isotope curves only. A sequence from the upper Middle Cenomanian, up to the lower Upper Cenomanian, is investigated concerning the controlling factors of biogenic sedimentation. The cyclicity of lithology is investigated by Fast Fourier Trans-formation. It can be shown that sedimentation is forced by orbital cycles, mainly by the precession cycle of the Milankovitch band (P1 and P2, 18 500 and 22 300 years, respectively). This confirms the primary origin of the marlstone-limestone couplets that are obvious in the field. Calculation of sedimentation rates is based on these data. There is a high variability of sedimentation rates, maybe due to a strong variation of productivity in this epicontinental environment. Dedicated to the memory of Jost Wiedmann (1931–1993)