Siphodinarella costata n. gen., n. sp., a new benthic foraminifer from the Coniacian of the Adriatic Carbonate Platform (Slovenia, Croatia)

A new benthic foraminifer is described as Siphodinarella costata n. gen., n. sp. from Coniacian shallow-water platform-interior carbonates of Slovenia and Croatia. The new foraminifer is found in skeletal wackestone in association with small benthic foraminifera, thaumatoporellaceans, and calcimicrobes (Decastronema, Girvanella-type tubes). The existence of an internal siphon in Siphodinarella n. gen. is interpreted as an entosolenian tube and discussed in terms of its generic and suprageneric importance.     

On Late Jurassic and Early Cretaceous oysters (Bivalvia,Ostreidae) from northern Siberia

The morphology and taxonomic value of morphological features of Late Jurassic and Early Cretaceous oysters from northern Siberia are considered. A new species, Deltoideum exoticum Kosenko, sp. nov. is described.     

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.     

Palaeogeography and geodynamic evolution of the Gosau Group of the Northern Calcareous Alps (Late Cretaceous, Eastern Alps, Austria)

The sedimentation of the Late Cretaceous Gosau Group of the Northern Calcareous Alps records the complex geodynamic evolution of the northern part of the Austroalpine microplate. The tectonically controlled sedimentation and facies distribution were mainly governed by the oblique subduction of the Pennic-Ligurian ocean below the Austroalpine margin. Most of the Gosau successions comprise two distinct sedimentary complexes. The Lower Gosau Subgroup (upper Turonian-Campanian) is characterized by terrestrial to shallow-marine facies associations: alluvial fan and fan delta deposits, shallow-marine sandstones and sandy limestones, and storm-influenced nearshore and shelf deposits. During the early Santonian sea-level highstand, a great part of the Northern Calcareous Alps was covered by a shallow shelf sea. Palaeotransport directions point to source areas situated both to the north and to the south of the Northern Calcareous Alps.

The Upper Gosau Subgroup (upper Santonian-Eocene) comprises deep-water hemipelagic and turbiditic deposits. Rapid subsidence into bathyal to abyssal depths started diachronously from the northwest (Santonian) to the southeast (Maastrichtian) after a short phase of deformation and erosion. Abyssal deposits in the northern parts of the Northern Calcareus Alps and north-directed palaeotransport indicate a tilting of the slope towards the north. This subsidence pulse is attributed to an event of subcrustal tectonic erosion, probably triggered by the subduction of a topographic high of the South Penninic ocean. The relationships of the Gosau Group of the Austroalpine unit to Late Cretaceous deposits of the Carpathians and Southern Alps are discussed in the framework of a plate tectonic model.     

Giant Bathysiphon (Foraminiferida) from Cretaceous turbidites, northern California

Straight-sided, tubular fossils occur together with a diverse assemblage of deep-water trace fossils in linegrained Franciscan turbidites at Point Saint George. Pacific Coast of California. Based on comparison with living abyssal organisms and on skeletal microstructure, these tubes are interpreted as recrystallized siliceous tests of the large abyssohenthic foraminiferid, Bathysiphon. Tubes found preserved in-place show that life orientation of the Franciscan species was vertical with the broader, mature end protruding several millimetres above the muddy seafloor. Positioned in this way the organisms probably were suspension feeders or carnivores. Bathysiphon and trace fossils taken together reflect a diverse deep-water benthic community that was disrupted (or locally eliminated) repeatedly by turbidity currents reaching the outer margins of a submarine fan. ▭ Bathysiphon, deep-water benthos, outer fan/basin floor, trace fossils, Franciscan Complex, flysch, Cretaceous.     

The evolution and phytoplankton composition of mucilaginous aggregates in the northern Adriatic Sea

Recurrent occurrences of visible mucilage “clouds” that cover areas up to several hundred kilometres with vertical dimensions of 20–30 m have been recorded in the stratified water column in the northern Adriatic. In the past this was described as “mare sporco” phenomenon. Past studies of the phenomenon indicated that phytoplankton is an important component of mucilage. Our research revealed the composition of phytoplankton assemblages in different types of mucilaginous aggregates collected during the summers of 1997 and 2000 using pigment biomarkers (HPLC). Phytoplankton biomass in the mucilage samples was very high, ranging from 7.9 μg g⁻¹ to 390.8 μg g⁻¹ of chlorophyll a per unit of dry mass of mucilage. The phytoplankton community in the early, loose stage of mucilaginous aggregates was heterogeneous, as indicated by the diversity of detected pigments. The number of phytoplankton groups decreased as the aggregates aged and diatoms increased in relative biomass (up to 92.7%). Phytoplankton biomass in seawater was similar in years with and without mucilage; however, significantly higher contributions to the total biomass of 19′-hexanoyloxyfucoxanthin-containing phytoplankton (prymnesiophytes) were found in the upper 10 m in spring of the “mucilaginous years” (1997 and 2000) followed by prevalence of diatoms in summer. The F_p pigment index used to assess seawater trophic conditions reached lower values in April–May in mucilaginous years (1997 and 2000) compared to non-mucilaginous years (1998 and 1999). We conclude that the role of prymnesiophytes and other small flagellates is crucial for the initial phases of mucilage appearance. Aggregates represent a favourable environment for the secondary development of opportunistic diatoms that foster mucilage formation.     

Biostratigraphy and sedimentary evolution of Late Miocene and Pliocene continental deposits of the Granada Basin (southern Spain)

The Late Miocene and Pliocene continental sediments in the Granada Basin (southern Spain) have yielded large amounts of fossil small mammals in 37 localities from 11 sections. The aim of this paper is to integrate faunistic, stratigraphic, and sedimentary criteria to unravel the geological history of the continental infilling of the basin. The palaeontological study has led to a detailed biozonation on the basis of rodents, which helps to correlate in detail the different sedimentary units found in the basin, and to follow the changes of the different sedimentary systems and their palaeogeographical evolution through time. Combination of the proposed biostratigraphy and the reinterpretation of the magnetostratigraphic analyses of the Barranco del Purcal section allows us to assign an absolute age slightly older than 5.23 Ma to the Turolian–Ruscinian boundary (MN13‐MN14).     

Skeletal anatomy of the Late Cretaceous shark,Squalicorax (Neoselachii: Anacoracidae)

The paleobiology of the Cretaceous neoselachian shark,Squalicorax, has largely been based on isolated teeth. We examined partial and nearly complete skeletons of three species ofSqualicorax, S. falcatus (Aoassiz),S. kaupi (Agassiz), andS. pristodontus (Agassiz), that were collected from the U.S.A. These specimens suggest that the total body length (TL) ofS. falcatus typically measured 1.8–2.0 m, and probably did not exceed 3 m. Moderatesized individuals ofS. kaupi andS. pristodontus perhaps measured about 3 m TL. AlthoughS. pristodontus was the largest form among the three species examined, this taxon possessed a set of large jaws (with large but fewer teeth) relative to its body size compared toS. falcatus orS. kaupi. This suggests that tooth size is not an accurate indicator of the TL if one compares oneSqualicorax species to another. Neurocranial features suggest that the vision ofSqualicorax was not as acute as that of a contemporaneous macrophagous lamniform shark,Cretoxyrhina mantelli (Agassiz) , but olfaction ofSqualicorax may have been better thanC. mantelli. The morphology of placoid scales suggests thatSqualicorax was capable of fast swimming. New skeletal data support the view that the feeding dynamics ofSqualicorax was similar to the modern tiger shark (Galeocerdo Müller & Henle). The present data do not allow for exact ordinal placement, but, contrary to some previous interpretations,Squalicorax can be excluded from the Hexanchiformes and Orectolobiformes. The taxon should more appropriately be placed within the Lamniformes or Carcharhiniformes.      

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.     

Late Triassic sedimentary evolution of Slovenian Basin (eastern Southern Alps): description and correlation of the Slatnik Formation

Successions of the Slovenian Basin structurally belong to the easternmost Southern Alps. During the Late Triassic, they were part of the Adriatic continental margin. Norian–Rhaetian successions of the Slovenian Basin are characterized mainly by dolomite of the Bača Dolomite Formation. However, in the northern part of the basin, Late Triassic limestone is preserved above Bača Dolomite Formation and is formalized as the Slatnik Formation. It is composed of hemipelagic limestone alternating with resedimented limestones. The succession documents an upward progradation of the slope environment composed of three high-frequency cycles. Most prominent progradation is referred to the second, i.e., Early Rhaetian cycle. The Slatnik Formation ends with thin-bedded hemipelagic limestone that records the end-Triassic productivity crisis, or rapid sea-level fall. The overlying resedimented limestones of the Early Jurassic Krikov Formation, document the recovery of production and shedding from the adjacent carbonate platform.     

A Late Cretaceous Chimaerid (Chondrichthyes, Holocephali) from Seymour Island, Antarctica

A chimaerid holocephalian, Chimaera zangerli sp. nov., is described from both palatine tooth plates, two tooth plate fragments, and part of the chondrocranium in a nodule from the Maastrichtian of Antarctica. Possibly the oldest known chimaerid, C. zangerli sp. nov. exhibits a tooth plate which is a morphological intermediate between that of the Jurassic Ganodus and the Oligocene C. rupeliensis . The presence of C. zangerli sp. nov. before the end of the Cretaceous is evidence of the early evolution of the Chimaeridae, considered the most derived of the chimaeroid fishes.     

New enantiornithine bird (Aves, Ornithothoraces) from the Late Cretaceous of NW Argentina

A new enantiornithine bird, Intiornis inexpectatus gen. et sp. nov, is described here. It is based on a partial hind limb found in beds of the Upper Cretaceous Las Curtiembres Formation (Campanian), North-West Argentina. The new taxon is referred to the family Avisauridae on the basis of its cranially convex third metatarsal. Several features suggest close relationships between Intiornis and the avisaurid Soroavisaurus, from the Lecho Formation (Maastrichtian; North-West Argentina). Intiornis was the size of a sparrow, thus representing the smallest Enantiornithes known from South America. The new species shows adaptations for a perching mode of life. Moreover, the hypothesis suggesting that the flying pterosaur reptiles decrease in taxonomic diversity due to competitive interaction with birds is discussed. The new species shows adaptations for a perching mode of life. Moreover, the hypothesis suggesting that the flying pterosaur reptiles decrease in taxonomic diversity due to competitive interaction with birds is discussed.     

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).     

Glandulocalyx upatoiensis, a fossil flower of Ericales (Actinidiaceae/Clethraceae) from the Late Cretaceous (Santonian) of Georgia, USA

Background and Aims

Ericales are a major group of extant asterid angiosperms that are well represented in the Late Cretaceous fossil record, mainly by flowers, fruits and seeds. Exceptionally well preserved fossil flowers, here described as Glandulocalyx upatoiensis gen. & sp. nov., from the Santonian of Georgia, USA, yield new detailed evidence of floral structure in one of these early members of Ericales and provide a secure basis for comparison with extant taxa.

Methods

The floral structure of several fossil specimens was studied by scanning electron microscopy (SEM), light microscopy of microtome thin sections and synchrotron-radiation X-ray tomographic microscopy (SRXTM). For direct comparisons with flowers of extant Ericales, selected floral features of Actinidiaceae and Clethraceae were studied with SEM.

Key Results

Flowers of G. upatoiensis have five sepals with quincuncial aestivation, five free petals with quincuncial aestivation, 20–28 stamens arranged in a single series, extrorse anther orientation in the bud, ventral anther attachment and a tricarpellate, syncarpous ovary with three free styles and numerous small ovules on axile, protruding-diffuse and pendant placentae. The calyx is characterized by a conspicuous indumentum of large, densely arranged, multicellular and possibly glandular trichomes.

Conclusions

Comparison with extant taxa provides clear evidence for a relationship with core Ericales comprised of the extant families Actinidiaceae, Roridulaceae, Sarraceniaceae, Clethraceae, Cyrillaceae and Ericaceae. Within this group, the most marked similarities are with extant Actinidiaceae and, to a lesser degree, with Clethraceae. More detailed analyses of the relationships of Glandulocalyx and other Ericales from the Late Cretaceous will require an improved understanding of the morphological features that diagnose particular extant groups defined on the basis of molecular data.     

Campanian-Maastricthian (Late Cretaceous) veneroids (Bivalvia: Heterodonta) from the Ariyalur Group,South India

Eleven veneroid (Bivalvia) species are systematically described from the Campanian-Maastrichtian (Late Cretaceous) sediments of Ariyalur sub-basin of South India. Among these, only Crassatella (Crassatella) macrodonta (Sowerby) and Arctica lacianata (Stoliczka) were earlier recorded by Stoliczka. Protocardia (Pachycardium) madagascariensis (Colignon), Protocardia (Pachycardium) pauli (Cocquand), Epicyprina angulata (Sowerby), Venilicardia truncata (Sowerby), and Calva (Egelicalva) buttensis (Anderson) were previously unknown from the Late Cretaceous horizons of the Indian sub-continent. The present record also includes a new species Palaeomoera stoliczkai n. sp. erected on the basis of its unique hinge characters and surface features. Lucina (Lucina) cf. fallax Forbes, Nicaniella (Nicaniella) aff. trigonoides (Stoliczka), and Corbicula? sp. indet., are tentatively identified because of their imperfect preservation. The present record may add useful information to the understanding of the Late Cretaceous palaeobiology of the region.     

Biodiversity of settled material in a sediment trap in the Gulf of Trieste (northern Adriatic Sea)

Phytoplankton succession and sinking rates were studied from January to December 2003 at a coastal station in the Gulf of Trieste (northern Adriatic Sea), 200 m offshore, in a relatively undisturbed area. A conical sediment trap, moored at 15 m depth (water depth 17 m), was used. The hypothesis if the presence of benthic and epiphytic diatoms can lead to an overestimation of the vertical fluxes was tested. To evaluate primary and secondary sedimentation contributions, planktonic, benthic and epiphytic diatoms were distinguished. Benthic species abundance varied throughout the year and it was related to resuspension that strongly influenced sinking rates. All over the year, diatoms were the prevailing class in the trap material accounting for 75.32% of the settled cells, while flagellates represented 24.11%. Dinophyceae and resting cells constituted minor components, accounting for 0.43% and 0.14%, respectively. The gross sedimentation rates ranged from 0.006 × 10⁸ cell m⁻² d⁻¹ in the second week of May to 6.30 × 10⁸ cell m⁻² d⁻¹ in the third week of January with a mean annual value of 1.09 ± 1.43 × 10⁸ cell m⁻² d⁻¹. To the primary sedimentation rate Pseudo-nitzschia seriata of the group “Nitzschia seriata complex” contributed for 49.77% followed by Chaetoceros spp. (23.88%). The major contributor to the secondary sedimentation rate was the diatom Paralia sulcata, accounting for 24.76%. Epiphytic diatoms contributed for 11.19% and 12.27% on annual average gross abundance and biomass, respectively, reaching even 72.04% of gross abundance and 56.06% of gross biomass in the second week of August. The correlation between temperature and the logarithm of the epiphytic biomass was statistically significant, with r = 0.66 and P < 0.001. Both in the cluster analysis and in the PCA four main groups were formed, where benthic and epiphytic species were separately gathered. Planktonic, benthic and epiphytic forms accounted for 50.78%, 36.95% and 12.27%, respectively, calculated on the annual average biomass. Therefore, vertical fluxes can be overestimated of 50% or more if benthic and epiphytic species are not rejected.     

Late Cretaceous (Santonian-Campanian) sea lilies (Echinodermata,Crinoidea) from the glacial rafts of northwestern Poland

Seven Santonian (Isocrinus? minutus, Tetracrinus jagti, Cyathidium senessei, Bourgueticrinidae indet., Notocrinidae indet., Glenotremites paradoxus, Marsupites testudinarius) and seven Campanian (Nielsenicrinus carinatus, Austinocrinus sp., Bourgueticrinidae indet., Bourgueticrinus cf. constrictus, B. ellipticus, B.? suedicus, Roveacrinina gen. et sp. indet.) crinoid taxa from the Cretaceous glacial rafts of northwestern Poland (near Wolin Island) are described for the first time. The taphonomy and palaeogeographic implications are discussed. The present assemblage differs taxonomically from the crinoid faunules recently described from the glacial rafts of eastern Poland. However, these faunules are similar to crinoids from the autochthonous Upper Cretaceous sediments of southern and eastern Poland (Miechów Trough, Kraków-Cz?stochowa Upland, Middle Vistula River valley). An update of Late Cretaceous crinoids from the Miechów Trough and Kraków-Cz?stochowa Upland is also given.     

A new baurusuchid crocodyliform (Archosauria) from the Late Cretaceous of Patagonia (Argentina)

A new baurusuchid, Wargosuchus australis gen. et sp. nov., coming from the Bajo de La Carpa Formation, Neuquén Province (Argentina), is described. This new taxon is based on a fragment of snout and a portion of the cranial roof. Wargosuchus differs from other crocodyliforms by possessing a deep median groove on the frontals, a contact between nasals and frontals extremely reduced, a large depression for the olfactory bulbs, three large foramina surrounding the large, smooth perinarial depression, and a hypertrophied, conical last premaxillary tooth followed by a large paracanine fossa. The finding of Wargosuchus in Patagonia (Argentina), a taxon with a strong resemblance to Brazilian baurusuchids, reinforces the hypothesis of a similar biota between both regions by the Late Cretaceous. Wargosuchus and Cynodontosuchus represent the only Argentinian mesoeucrocodylians to be included within Baurusuchidae. This finding extends the number of crocodyliforms from the Bajo de la Carpa Formation, which, in turn, corresponds to the most taxonomically diverse one in Argentina.