Stable isotope and trace element geochemistry of Upper Cretaceous carbonates and belemnite rostra (Middle Campanian, north Germany)

Trace element contents and stable isotopic composition of Middle Campanian marl-limestone rhythmites and belemnite rostra of Belemnitella mucronata were investigated. High strontium and low iron as well as manganese and magnesium contents of belemnite calcite and bulk rock samples suggest no diagenetic overprint. However, the orange-coloured cathodoluminescence of coccolith-rich sediments indicates diagenetic cementation and/or recrystallization. The non-luminescent belemnite rostra reveal an extraordinary preservation of the microstructures that is interpreted to have been favoured by a silification of the outer rim of the belemnite rostra. Carbon isotope ratios of the coccolith limestones and belemnite rostra are comparable, with higher δ¹³C variations observed for belemnite calcite. The 1.5-2‰ depletion in δ¹⁸O of the marl-limestone rhythmites relative to belemnite calcite is explained by diagenetic alteration of the sediments. Palaeotemperatures, calculated from the δ¹⁸O values of the well-preserved belemnite rostra, are around 12.5 ± 2 °C and suggest rather low sea-surface temperatures for the Middle Campanian epicontinental sea of north Germany assuming a water depth of less than 100 m.     

Environmental stress and diagenetic modifications in inoceramids and belemnites from the Upper Cretaceous James Ross Basin, Antarctica

Summary New petrographic and isotopic data from inoceramid bivalve shells and belemnite rostra from the lower Campanian and belemnite rostra from the mid-upper Maastrichtian of the Marambio Group, James Ross Basin, Antarctica are presented. Most of the inoceramid data were processed from shell fragments of the large formAntarcticeramus rabotensis (Crame and Luther) at the stratigraphic level marking the extinction of the inoceramids in the James Ross Basin (uppermost early Campanian-basal late Campanian). Standard transmitted light microscopy and cathodoluminescence (CL) studies in thin sections ofA. rabotensis show clear evidence of environmental stress, which is reflected as marked growth breaks in the shell banding of this large inoceramid bivalve. At Redonda Point, CL and the mean oxygen isotopic value (δ¹⁸O=-3.11‰ 3 (PDB); n=11; t°=25.4°C) indicate a varied degree of diagenetic modification, but without any evidence of neomorphism along the prismatic microstructures. Early Campanian belemnite rostra are much less diagenetically modified (at the Brandy Bay section; and the Santa Marta section; δ¹⁸O=-0.50‰ (PDB); n=5; t°=14.0°C and 3 δ¹⁸O=-0.94‰ (PDB); n=21; t°=15.8°C) and are non luminescent 3 except for localized, organic-rich bands. The mean oxygen isotopic value for mid-late Maastrichtian belemnite rostra (at the Seymour Island section; δ¹⁸O=-0.11‰ 3 (PDB); n=5; t°=12.5°C) indicates a substantial drop in the sea-water paleotemperature, suggesting a causal relationship between the early extinction of the inoceramid bivalves in high latitudes of the Southern Hemisphere and the falling sea-water temperature.     

A new species of the sclerorhynchid sawfish Borodinopristis from the Campanian (Upper Cretaceous) of North Carolina,USA

Elasmobranch fossils recovered from Campanian marine exposures at Elizabethtown, Bladen County, NC, include species from at least seven genera of sharks and four genera of batoids. Of particular interest is the recovery of multiple isolated rostral spines from a new sclerorhynchid sawfish, Borodinopristis shannoni, sp. nov. Species of Borodinopristis are known from oral teeth and/or rostral spines (‘rostral teeth’ for some authors). In species known from the latter, the spines differ from those of other sclerorhynchids by the presence of one or more ‘collared’ barbs on the posterior margin of the crown. Unlike the previously described B. schwimmeri, the rostral spines of the new species have well-developed hooked barbs with collars (curved, connected crests) extending asymmetrically onto the dorsal and ventral surfaces of the spine, as well as small, rudimentary barbs. Also unlike B. schwimmeri, the anterior margin of the spine is strongly convex and there is no enamelled collar at the base of the crown. The new species also occurs in the Upper Cretaceous of the Gulf Coastal Plain.     

New biostratigraphic data from Cretaceous planktic foraminifera in Sahlabad province, eastern Iran

The foraminiferal content of two stratigraphic sections, located in eastern Iran within the Sahlabad province, between the Lut and Afghan blocks and ranging in age from Turonian to Campanian is investigated. Previous studies were general and only indicated the presence of planktonic foraminifera in this province. This paper presents a detailed study of planktonic foraminifera of the Shirshotor unit and establishes for the first time a local biostratigraphy consisting of five biozones. Biozones from the upper Turonian to lower Campanian are recognized, but the upper lower Campanian to lower upper Campanian strata are missing, as demonstrated by the lack of the Globotruncana ventricosa biozone. Tectonic activity in this region during the late early Campanian and mid-Campanian resulted in the presence of an unconformity together with debrites (debris flow deposits) in the lower upper Campanian. About twenty-five planktonic foraminiferal species are reported and illustrated. The largest faunal diversity is encountered in the upper Santonian. The planktonic foraminiferal biozones are precisely defined in selected stratigraphic sections and allow age determinations for the deepest marine sediments (pelagic limestones and bedded cherts) before the collision of the Lut and Afghan blocks.     

Reconstructing the palaeoenvironment of the Middle Russian Sea during the Middle–Late Jurassic transition using stable isotope ratios of cephalopod shells and variations in faunal assemblages

Oxygen and carbon isotope data of well-preserved belemnite rostra and ammonite shells are presented from the Callovian–Oxfordian boundary (uppermost Lamberti to lowermost Cordatum zones) of the Dubki section near Saratov in the Russian Platform. Palaeotemperatures calculated for nektobenthic belemnites (averages of 5 °C and 8 °C for cylindroteuthids and belemnopseids, respectively) show the presence of cold bottom waters in the central part of the Middle Russian Sea during the studied interval. Palaeotemperatures calculated for ammonites, which are assumed to have lived in near-surface waters, are considerably higher (average 13 °C). The presented data show a vertical thermal gradient in the Middle Russian Sea. The belemnite oxygen isotope record and the relative abundances of ammonite families in the Dubki section do not correlate with each other probably as a result of different depth habitats of ammonites and belemnites. A review of literature isotope data shows the climatic zonation in European seas at the Middle–Late Jurassic transition. Despite the flux of cold polar waters to the Middle Russian Sea and the area of Scotland there is no evidence for glaciation at the Middle–Late Jurassic transition. Changes in water circulation during a sea-level highstand were likely a source of spreads of cold bottom waters and cardioceratid ammonite fauna in this time period.The belemnite isotope record of the Callovian–Oxfordian boundary in the Russian Platform is characterized by significant scatter of δ¹³C values. No temporal carbon isotope trend is observed. The δ¹³C values of Russian belemnite rostra average 2.6‰ VPDB being 1 to 2‰ higher than the values of coeval Lower Oxfordian belemnites from the area of the Submediterranean ammonite province. Higher (than Submediterranean) δ¹³C values of Russian belemnite rostra are likely related to high biologic productivity and/or high organic matter burial in semi-isolated Boreal–Subboreal marine basins.     

Belemnite battlefields

Mass accumulations of belemnite rostra ('belemnite battlefields') are common in Mesozoic sediments, and accumulations of belemnoids are also known from older rocks. Many Recent teuthid species suffer mortality immediately after spawning, and some authors have suggested that belemnite accumulations record a similar phenomenon. Conversely, it is clear that many belemnite battlefields actually formed in an environment of net sediment loss, with current alignment and winnowing. A proposed model for the production of belemnite battlefields involves five possible pathways: post-spawning mortality, catastrophic mass mortality, predation concentration, stratigraphical condensation, and resedimentation. Although accumulations that have not been reworked are rare, it is possible to recognise the generating agents of belemnite accumulations through their intrinsic features. A genetic classification of belemnite battlefields, based on the identified pathways, is tested through field examples in Britain and Antarctica, as well as through published examples. □ Belemnites, fossil accumulations, palaeoecology, Mesozoic, Antarctica, Yorkshire.     

Selachian teeth from Campanian sediments (Upper Cretaceous) of the Münsterland Cretaceous Basin (NW-Germany)

Selachian teeth obtained from trial samples of the Bosenberg quarry near Vorhelm (Beckumer Beds; lower Upper Campanian) and from outcrops along the Hamelbach brook near Stromberg/Oelde (Stromberger Beds; upper Lower Campanian) are presented. Both sites are located in the central southeast of the Münsterland Cretaceous Basin. Fifteen different taxa were identified but only seven could be assigned to a known species. Compared with other taxa the fauna is clearly dominated by squaliform selachians in terms of the number of species and number of specimens. The mixture of selachians presumed to inhabit both deep and shallow waters corresponds with typical taphonomic assemblages of turbiditic deposits and fits very well with the geological setting of the sampled locations.     

Small Theropod Teeth from the Late Cretaceous of the San Juan Basin,Northwestern New Mexico and Their Implications for Understanding Latest Cretaceous Dinosaur Evolution

Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian – Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately co-eval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost during the Maastrichtian in New Mexico. The same pattern seen in northern faunas, which may provide evidence for an abrupt dinosaur extinction.     

Late Campanian to late Maastrichtian bryozoans encrusting on belemnite rostra from the Aktolagay Plateau in western Kazakhstan

Twenty species belonging to fifteen genera of cyclostome and cheilostome bryozoans encrusting belemnite rostra are described from the late Campanian to Maastrichtian of the Aktolagay Plateau, in western Kazakhstan. Due to the moderate to poor preservation of the material, only four cheilostome species are identified down to the species level: Wilbertopora? besoktiensis (Voigt, 1967), ‘Aechmellina’ stenostoma Voigt, 1930, and two new species, ‘Aechmellina’ viskovae and Cheethamia aktolagayensis. All remaining species are left in open nomenclature. Type material of Wilbertopora? besoktiensis from the early Maastrichtian of the Mangyshlak Peninsula in Kazakhstan, has been re-examined. Palaeobiogeographical and implications are discussed. Cheilostomes slightly dominated over cyclostomes in the Aktolagay Plateau fauna encrusting on belemnites in terms of diversity. The dominant colony forms observed were spots and sheets.     

First record of a belemnite preserved with beaks,arms and ink sac from the Nusplingen Lithographic Limestone (Kimmeridgian,SW Germany)

Klug, C., Schweigert, G., Fuchs, D. & Dietl, G. 2009: First record of a belemnite preserved with beaks, arms and ink sac from the Nusplingen Lithographic Limestone (Kimmeridgian, SW Germany). Lethaia, 10.1111/j.1502‐3931.2009.00203.x A recent discovery of an unusually preserved belemnite from Nusplingen comprises the extraordinarily rare remains of beaks and nearly in situ arm hooks, as well as the ink sac and an incomplete phragmocone. So far, Hibolithes semisulcatus ( Münster, 1830 ) is the only belemnite known from the Nusplingen Lithographic Limestone (Upper Jurassic, Late Kimmeridgian, Beckeri Zone, Ulmense Subzone; SW Germany) that has the same phragmocone shape and size, and thus we assign the new specimen to this taxon. The rostrum was probably lost due to a lethal predation attempt in which the prey was killed but not entirely eaten. For the first time a specimen reveals details of the belemnite beak morphology, which we compare with the beaks of other Jurassic coleoids. This specimen presently represents the only known rostrum‐bearing belemnite of post‐Toarcian age with preserved non‐mineralized body parts. With the new discovery, Nusplingen now represents the only locality which has yielded complete beak apparatuses from all major Jurassic cephalopod groups. □Beaks, Belemnitida, Coleoidea, Germany, Late Jurassic, morphology, taphonomy.     

Revision of Habrosaurus Gilmore (Caudata; Sirenidae) and relationships among sirenid salamanders

The sirenid salamander Habrosaurus is revised and redescribed based on skull elements and vertebrae from the middle Campanian–middle Palaeocene of the North American Western Interior. Habrosaurus differs from the Cenozoic (Eocene–Recent) sirenids Siren and Pseudobranchus in a suite of cranial and vertebral plesiomorphies, one vertebral character of uncertain polarity and five apomorphies describing the structure of the dentary, atlas and tooth crowns. Two species are identified based on dental characters: the type species H. dilatus (late Maastrichtian–middle Palaeocene) has stout marginal and palatal teeth with bulbous crowns and prominent wear facets, whereas H. prodilatus sp. nov. (middle Campanian) has chisel-like marginal teeth (palatal teeth unknown) with weaker wear facets. Habrosaurus is argued to be the geologically oldest, undoubted sirenid and the sister-taxon of Siren  +  Pseudobranchus . Replacement of marginal teeth with a broad, horny beak in Siren and Pseudobranchus and the broad, bulbous marginal and palatal teeth in H. dilatus are proposed to be convergent strategies for achieving a crushing bite. The chisel-like teeth of H. prodilatus are interpreted as being transitional to the more specialized, crushing dentition of H. dilatus .     

The Function of the Belemnite Guard

A reconstruction of the belemnite animal was performed onCylindroteuthis puzosiana (d’Orbigny) to locate the centres of buoyancy and mass. The gas inclusion was found to be sufficient to provide neutral buoyancy. The reconstruction was modified to represent a belemnite without a guard, and its mechanics compared with the real belemnite. A model of a belemnite was tested in a wind tunnel, and showed that fins on the rostrum could have been used to generate dynamic lift.     

Short-necked plesiosaurs of the family Polycotylidae from the Campanian of the Saratov Region

Fragments of the anterior part of a mandibular rostrum and a maxillary bone of the plesiosaur Polycotylidae indet. from the Karyakino and Beloe Ozero localities of the Saratov Region (Upper Cretaceous, Campanian) are described. The specimens belong to a relatively long-snouted polycotylid with a mandibular symphysis incorporating 13 pairs of teeth. A unique feature of this plesiosaur is the fact that, in the symphysis, the splenial extends to the very anterior end of the rostrum. The polycotylid from the Campanian of the Saratov Region is probably closely related or identical to Georgiasaurus from the Santonian of the Penza Region, in which structural details of the mandibular symphysis remain uncertain.     

New species of Early Bajocian Megateuthididae (Belemnitida) from the Pacific coast of Russia

The belemnite rostrum from the upper Lower Bajocian of the Russian Far East that was earlier attributed to the Family Cylindroteuthididae, the species Cylindroteuthis confessa Nalnjaeva, and considered as the most ancient representative of the genus Cylindroteuthis is here placed in the family Megateuthididae. This belemnite is here described as Mesoteuthis soloniensis Nalnjaeva et Dzyuba, sp. nov. The analysis of belemnite distribution suggests that only representatives of the family Megateuthididae (genera Megateuthis, Mesoteuthis, and Paramegateuthis) inhabited the Far East seas in the Bajocian.     

Paleoenvironmental and paleoclimatic changes during the Late Cretaceous and Cretaceous–Paleogene (K/Pg) boundary transition in Tattofte,External Rif,northwestern Morocco: implications from dinoflagellate cysts and palynofacies

This paper presents a quantitative study of dinoflagellate cysts (dinocysts) and palynofacies of the Campanian–Danian marly succession at the village of Tattofte (western External Rif, northwestern Morocco). The paleoenvironmental and paleoclimatic interpretations, inferred from this palynologic analysis, are compared to coeval sequences of other areas in the Northern Hemisphere. Changes in the relative abundances of dinocyst taxa, which are paleoenvironmental indicators, throughout the section suggest a deposition in a marine inner to outer neritic setting. The upper Campanian dinocyst assemblage is characterized by the presence of outer neritic-oceanic and low productivity indicator taxa (e.g., Spiniferites spp., Odontochitina spp.) and cold-water taxa (e.g., Manumiella spp., Chantangiella spp., Laciniadinium spp.), whereas, the lower Maastrichtian assemblage is characterized by inner neritic, high productivity and warm-water indicator taxa (e.g., Palaeocystodinium spp., Andalusiella spp.). The upper Maastrichtian dinocyst assemblage displays a return to an outer neritic environment under a transgressive regime, but with a cooling pulse and a moderate productivity. However, the Cretaceous–Paleogene (K/Pg) boundary interval records remarkable changes in the relative abundances of dinocyst taxa, indicating an inner neritic (coastal) setting, which is the most proximal in the study section; such changes reflect instable paleoenvironmental conditions which may be related to global cooling periods, likely caused by the Deccan volcanism in India and/or the Chicxulub asteroid impact in Mexico at the K/Pg boundary. In the Danian, the dinocyst relative abundances indicate a gradual return to stable environmental conditions.A quantitative analysis of the kerogen plots (palynomorphs, phytoclasts and amorphous organic matter (AOM)) reveals five types of palynofacies, generally indicating oxic to suboxic marine environments. The upper Campanian and upper Maastrichtian (lowermost part) strata are characterized by a playnofacies (V), indicating a distal shelf, while the lower Maastrichtian and lower Danian (uppermost part) strata record a playnofacies (III), reflecting an intermediate inner-outer neritic environment. However, the K/Pg boundary transition is characterized by playnofacies types (I) and (II), indicating a proximal (coastal) environment.     

Chondrichthyan and actinopterygian remains from theLower Permian Copacabana Formation of Bolivia

Two horizons of the marine Lower Permian (Leonardian) Copacabana Formation have yielded fish remains, on the south-western slope of the Jacha Khatawi Hill, Yaurichambi, La Paz department, Bolivia. This fish fauna consists of teeth and scales of chondrichthyans (Eugeneodontida, Petalodontida, ? Bradyodonti, Elasmobranchii) and actinopterygians (? Plastysomidae). The Eugeneodontida are represented by a new species of a large Agassizodontidae, Parahelicoprion mariosuarezi n.sp., based on a large symphysial tooth series which resembles P. clerci from the Lower Permian Arta beds of the Urals. The Petalodontida are represented by a fragment of a large symphysial tooth which may be referred to the pristodontid genus Megactenopetalus, known else-where from the Lower Permian of the U.S.A. and China. Some isolated crushing teeth may questionably be referred to a bradyodont, possibly Helodus or Lagarodus. Some elasmobranch teeth of «Cladodus type also occur in this locality. Some hemispherical teeth of «phyllodont type and some scales are tentatively referred to the actinopterygian family Platysomidae. These findings are the first record of determinable marine Permian fishes in the Andean region of South America. The overall composition of this fauna agrees fairly well with the fish fauna known from the Marine Lower Permian of United States and eastern Asia.     

Environmental significance of gypsum-bearing layers at the “Lo Hueco” paleontological site (Upper Cretaceous,Cuenca, Spain): petrography,fluid inclusions,and isotopic relations

“Lo Hueco” (Cuenca, Spain) is an upper Campanian–lower Maastrichtian Fossil-Lagerstätte that has provided more than 8,500 well-preserved macrofossils, including titanosaur sauropod dinosaurs. Although the facies and fossil record point to both fresh and brackish or marine water influences, a detailed study of the sulphate-bearing layers of the site through petrography, fluid inclusions, and isotopes has been undertaken to evaluate the possible marine influence. The two main sulphate units of the “Lo Hueco” site consist chiefly of bimodal micro- to meso- lenticular gypsum crystals that grew displacively in a clayey-carbonate sediment. The well-preserved lenticular gypsum crystals are primary, as demonstrated by the presence of the original twinning and the absence of hydration textures or anhydrite relicts. Primary fluid inclusions of the lenticular gypsum crystals indicate a vadose environment of formation, with salinities between 1,800 and 14,000 ppm, pointing to a brackish but non-marine environment. Furthermore, gypsum exhibits ⁸⁷Sr/⁸⁶Sr values between 0.708034 and 0.708120, which are higher than those from marine evaporites of Campanian–Maastrichtian age, indicating a clear influence of fresh water. Gypsum δ ³⁴S _VCDT values (18.1 to 19.0 ± 0.5 ‰) and δ ¹⁸O_VSMOW values (11.0 to 15.2 ± 0.5 ‰), on the other hand, are typical isotopic values recorded in marine evaporites of this age. This apparent contradiction between fluid inclusion and Sr isotopic data is probably the result of some recycling from Upper Cretaceous evaporites. Based on all these observations, the sulphate-bearing layers are interpreted as probably formed in a near-coastal saline mudflat of a playa lake. As a whole, this study highlights the importance of combining different proxies when dealing with evaporites formed in brackish-water environments.     

The First Dinosaur from Washington State and a Review of Pacific Coast Dinosaurs from North America

We describe the first diagnostic dinosaur fossil from Washington State. The specimen, which consists of a proximal left femur, was recovered from the shallow marine rocks of the Upper Cretaceous (Campanian) Cedar District Formation (Nanaimo Group) and is interpreted as pertaining to a large theropod on the basis of its hollow medullary cavity and proximally placed fourth trochanter. The Washington theropod represents one of the northernmost occurrences of a Mesozoic dinosaur on the west coast of the United States and one of only a handful from the Pacific coast of Laramidia during the Cretaceous. Its isolated nature and preservation in marine rocks suggest that the element was washed in from a nearby fluvial system. If the femur pertains to a tyrannosauroid, which seems likely given its size and the widespread occurrence of the group across Laramidia during Late Cretaceous times, then it would represent an earlier occurrence of large body size than previously recognized (complete femur length estimated at 1.2 meters). Uncertainty surrounding the latitude of deposition of the Nanaimo Group (i.e., the Baja-British Columbia hypothesis) precludes assigning the Washington theropod to either of the putative northern or southern biogeographic provinces of Laramidia.