Taxonomy and paleobiogeographic implication of Glabrobournonia Morris and Skelton (Hippuritida,Radiolitidae) from the Late Cretaceous Yigeziya Formation,southwestern Tarim Basin

A re-examination of the specimens that were identified as Biradiolites minor Pojarkova from the late Campanian to early Maastrichtian middle member of the Yigeziya Formation of southwestern Tarim Basin reveals that they should be assigned to the genus Glabrobournonia Morris and Skelton. Glabrobournonia is a genus of radiolitids characterized by indented radial bands, salient ridges on the shell margins and absence of fine ribs on the surface of the right valve. Apart from southwestern Tarim Basin, Glabrobournonia minor (Pojarkova) has also been recorded from the late Campanian of Fergana and Alai basins. The central Asian, late Campanian to early Maastrichtian G. minor differs from the late Campanian to Maastrichtian, eastern Arabian type species Glabrobournonia arabica Morris and Skelton in the flat left valve and an additional fourth ridge on the junction of the dorsal and posterior sides of the right valve. Biradiolites ingens (Des Moulins) could be the direct ancestor of Glabrobournonia. The paleogeographic distribution of Glabrobournonia suggests that this genus dispersed to central Asia from the late Campanian time, becoming widely distributed in the eastern Tethyan region rather than endemic to eastern Arabia. Correspondingly, specimens belonging to Gyropleura yielded from the same bed as G. minor in southwestern Tarim Basin, are similar to the specimens which were attributed to the eastern Arabian Gyropleura sp.; Campanian to early Maastrichtian Osculigera specimens described from the Yigeziya Formation are comparable with those known from the Campanian–Maastrichtian of Iran, Afghanistan and eastern Arabia. The similarity of the rudist assemblages between central Asia and eastern Arabia suggests a faunal connection and affinity between the north and south margins of the eastern Tethyan realm during Campanian to early Maastrichtian times.     

A new kogaionid multituberculate mammal from the Maastrichtian of the Transylvanian Basin,Romania

The Latest Cretaceous (Maastrichtian) terrestrial sedimentary sequences of the Haţeg Basin in Transylvania are well known for the so-called “Haţeg Island” vertebrate faunas, which evolved in endemic (insular?) conditions. In addition to frogs, lizards, turtles, crocodilians, birds and dinosaurs, peculiar multituberculate mammals have been recorded, all belonging to the family Kogaionidae. Here, a new species of the genus Barbatodon is reported from the Maastrichtian Şard Formation in the Transylvanian Basin (Alba County, Romania). Barbatodon oardaensis n. sp. is characterized by M1 cusp formula 3:4:2 and is much smaller than the two other Maastrichtian kogaionids from Transylvania, Barbatodon transylvanicus and Kogaionon ungureanui. The origin and paleobiogeography of kogaionids are discussed.     

Faunal turnover at the end of the Cretaceous in the North Pacific region: Implications from combined magnetostratigraphy and biostratigraphy of the Maastrichtian Senpohshi Formation in the eastern Hokkaido Island,northern Japan

A combined magnetostratigraphic and biostratigraphic study has been performed on the Maastrichtian Senpohshi Formation in eastern Hokkaido Island, northern Japan, which is an approximately 1300 m thick section mainly composed of hemipelagic mudstone. The identification of magnetic polarity was possible at 51 horizons, whereby four magnetozones were recognized. These magnetozones were correlatable to geomagnetic polarity chrons C31r to C30n, suggesting that the age of the Senpohshi Formation is spanning from middle to upper part of the Maastrichtian (ca. 69–67 Ma).The magnetostratigraphy of the Senpohshi Formation established in this study enables a direct age correlation to the Maastrichtian successions in other regions. Thus, this detailed chronology of the formation contributes to paleontological studies of the Maastrichtian in the North Pacific region. For instance, this magnetostratigraphic age assessment implies the following: (1) the stratigraphic range of the ammonite Pachydiscus flexuosus contains polarity chrons from the lower part of C31r to the lower part of C31n, (2) the first occurrence (FO) of the calcareous nannofossil Nephrolithus frequens in the North Pacific region is correlatable to polarity chron C30n or below, and (3) the FO of the bivalve “Inoceramus” awajiensis is located within polarity chrons from C31r to the upper part of C31n. This suggests that the inoceramid extinction event in the North Pacific region might have occurred during polarity chrons from C31r to the upper part of C31n (ca. 70.5–67.8 Ma), which is 2.3–5.0 Myr prior to the Cretaceous/Paleogene boundary. The trend of the Maastrichtian faunal turnover in the North Pacific is well consistent with those of other regions, brings a new evidence for understanding the global faunal turnover in the Maastrichtian, just before Cretaceous/Paleogene mass extinction.     

Late Cretaceous (Cenomanian–Maastrichtian) calcareous nannofossils from Goban Spur (DSDP Sites 549, 551): Implications for the palaeoceanography of the proto North Atlantic

The early late Cretaceous (Cenomanian–early Turonian) is thought to have been one of the warmest periods of the Phanerozoic. This period was characterised by tropical sea surface temperatures of up to 36 °C and a pole-to-equator-gradient of less than 10 °C. The subsequent Turonian–Maastrichtian was characterised by a continuous climatic cooling, peaking in the Maastrichtian. This climatic cooling and the resulting palaeoceanographic changes had an impact on planktic primary producer communities including calcareous nannofossils. In order to gain a better understanding of these Cenomanian–Maastrichtian palaeoceanographic changes, calcareous nannofossils have been studied from the proto North Atlantic (Goban Spur, DSDP Sites 549, 551). In order to see potential differences between open oceanic and shelf dwelling nannofossils, the data from Goban Spur have been compared to findings from the European shelf (northern Germany).A total of 77 samples from Goban Spur were studied for calcareous nannofossils revealing abundant (mean 6.2 billion specimens/g sediment) and highly diverse (mean 63 species/sample) nannofossil assemblages. The dominant taxa are Watznaueria spp. (mean 30.7%), Prediscosphaera spp. (mean 18.3%), Zeugrhabdotus spp. (mean 8.3%), Retecapsa spp. (mean 7.2%) and Biscutum spp. (mean 6.6%). The Cenomanian assemblages of both Goban Spur (open ocean) and Wunstorf (shelf) are characterised by elevated abundances of high fertility taxa like Biscutum spp., Zeugrhabdotus spp. and Tranolithus orionatus. Early Turonian to Maastrichtian calcareous nannofossil assemblages of Goban Spur are, however, quite different to those described from European sections. Oceanic taxa like Watznaueria spp., Retecapsa spp. and Cribrosphearella ehrenbergii dominate in Goban Spur whereas the fertility indicators Biscutum spp. and T. orionatus are more abundant in the European shelf assemblages. This shift from a homogeneous distribution of calcareous nannofossils in the Cenomanian towards a heterogeneous one in the Turonian–Maastrichtian implies a change of the ocean circulation. The “eddy ocean” system of the Cenomanian was replaced by an oceanic circulation similar to the modern one in the Turonian–Maastrichtian, caused by the cooling. The increased pole-to-equator-gradients resulted in an oceanic circulation similar to the modern one.     

Diversity,Relationships, and Biogeography of the Lambeosaurine Dinosaurs from the European Archipelago,with Description of the New Aralosaurin Canardia garonnensis

We provide a thorough re-evaluation of the taxonomic diversity, phylogenetic relationships, and historical biogeography of the lambeosaurine hadrosaurids from the European Archipelago. Previously published occurrences of European Lambeosaurinae are reviewed and new specimens collected from upper Maastrichtian strata of the south-central Pyrenees are described. No support is found for the recognition of European saurolophines in the available hadrosaurid materials recovered so far from this area. A new genus and species of basal lambeosaurine, Canardia garonnensis, is described on the basis of cranial and appendicular elements collected from upper Maastrichtian strata of southern France. C. garonnensis differs from all other hadrosaurids, except Aralosaurus tuberiferus, in having maxilla with prominent subrectangular rostrodorsal flange; it differs from A. tuberiferus in a few maxillary and prefrontal characters. Together with A. tuberiferus, C. garonnensis integrates the newly recognized tribe Aralosaurini. Inference of lambeosaurine interrelationships via maximum parsimony analysis indicates that the other three known European lambeosaurines are representatives of two additional subclades (tribes) of these hadrosaurids: Tsintaosaurini (Pararhabdodon isonensis) and Lambeosaurini (the Arenysaurus ardevoli-Blasisaurus canudoi clade). The tribes Aralosaurini, Tsintaosaurini, Lambeosaurini, and Parasaurolophini are formally defined and diagnosed for the first time. Three event-based quantitative methods of ancestral range reconstruction were implemented to infer the historical biogeography of European lambeosaurines: Dispersal-Vicariance Analysis, Bayesian Binary MCMC, and Dispersal-Extinction-Cladogenesis. The results of these analyses, coupled with the absence of pre-Maastrichtian lambeosaurines in the Mesozoic vertebrate fossil record of Europe, favor the hypothesis that aralosaurins and tsintaosaurins were Asian immigrants that reached the Ibero-Armorican island via dispersal events sometime during the Maastrichtian. Less conclusive is the biogeographical history of European lambeosaurins; several scenarios, occurring sometime during the Maastrichtian, are possible, from vicariance leading to the splitting of Asian or North American from European ranges to a dispersal event from North America to the European Archipelago.     

Biostratigraphy and geodynamic impact in the uppermost part of the northeastern coastal basin of Togo

Lithological and micropaleontological studies of core-samples from five boreholes drilled in the northeastern part of the coastal basin of Togo allow for a specification of the stratigraphy and the paleogeography of this area during the Maastrichtian and Paleogene. A lithological analysis reveals a marine series consisting of a Lower Maastrichtian unit, a Middle Paleocene to Eocene unit, and an upper unit attributed to the Continental terminal sensu lato. The biostratigraphical study, based on planktonic foraminifera, has led to a characterization of the basin in terms of biozones ranging from the Globotruncana aegyptiaca to the Abathomphalus mayaroensis biozones and biozones P5 to P11, thus specifying a Middle to Upper Maastrichtian, an Upper Paleocene and a Lower to Middle Eocene units. The paleogeographical evolution of the area shows that the series recorded two sedimentary cycles: the first one stops at the end of the Cretaceous and the second one in the Paleogene.     

Description of a new species,Globotruncana pseudoconica and remarks on its relation to Globotruncana conicaWhite and Globotruncana falsostuartiSigal

A new, strongly spiroconvex Globotruncana species,Globotruncana pseudoconica nov. sp., is described from the Maastrichtian of Tunisia. It is distinguished from Globotruncana conicaWhite in morphology and phylogeny. Some Maastrichtian, strongly spiroconvex specimens referred to as Globotruncana conicaWhite, are shown to be identical to Globotruncana pseudoconica nov. sp. The new species reveals close affinity with Globotruncana falsostuartiSigal from which it has evolved during the middle Lower Maastrichtian.     

A strange new chelonioid turtle from the Latest Cretaceous Phosphates of Morocco

A new genus and species of huge marine turtle (superfamily Chelonioidea, epifamily Dermochelyoidae) is described from the Maastrichtian Phosphates of the Oulad Abdoun Basin of Morocco. A new type of feeding apparatus, adapted for a powerful crushing pattern, illustrates the noteworthy diversity of fossil vertebrates of the Maastrichtian-Ypresian Phosphates of Morocco. No other crushing cryptodire or bothremydid pleurodire has this morphology. During the Maastrichtian, the known crushing pattern of chelonioids was different, close to that of modern cheloniids, as illustrated in Morocco in the Maastrichtian Ganntour Basin and the Palaeogene Oulad Abdoun Basin. This new taxon exhibits unusual cranial characters (fusion of premaxillae associated with a backward and dorsal retraction of the naris, horizontal stretching of the dorsal meatus quadrati), that are shared only with another new turtle, known also from the same Maastrichtian Phosphates of Morocco.     

A new crocodylian from the late Maastrichtian of Spain: implications for the initial radiation of crocodyloids

Background

The earliest crocodylians are known primarily from the Late Cretaceous of North America and Europe. The representatives of Gavialoidea and Alligatoroidea are known in the Late Cretaceous of both continents, yet the biogeographic origins of Crocodyloidea are poorly understood. Up to now, only one representative of this clade has been known from the Late Cretaceous, the basal crocodyloid Prodiplocynodon from the Maastrichtian of North America.

Methodology/Principal Findings

The fossil studied is a skull collected from sandstones in the lower part of the Tremp Formation, in Chron C30n, dated at −67.6 to 65.5 Ma (late Maastrichtian), in Arén (Huesca, Spain). It is located in a continuous section that contains the K/P boundary, in which the dinosaur faunas closest to the K/P boundary in Europe have been described, including Arenysaurus ardevoli and Blasisaurus canudoi. Phylogenetic analysis places the new taxon, Arenysuchus gascabadiolorum, at the base of Crocodyloidea.

Conclusions/Significance

The new taxon is the oldest crocodyloid representative in Eurasia. Crocodyloidea had previously only been known from the Palaeogene onwards in this part of Laurasia. Phylogenetically, Arenysuchus gascabadiolorum is situated at the base of the first radiation of crocodyloids that occurred in the late Maastrichtian, shedding light on this part of the cladogram. The presence of basal crocodyloids at the end of the Cretaceous both in North America and Europe provides new evidence of the faunal exchange via the Thulean Land Bridge during the Maastrichtian.     

Paleocene coccoliths and coccospheres in deposits of the Maastrichtian stage at the `type locality' and type area in SE Limburg,The Netherlands

Three so-called `Tertiary Newcomer Coccoliths'—Cruciplacolithus primus, Neobiscutum parvulum and Neobiscutum romeinii—were found in what are generally believed to be upper Maastrichtian deposits at the ENCI quarry, St. Pietersberg near Maastricht, the CURFS quarry near Houthem and from the Maastrichtian part of the K/T boundary section of the cave system at Geulhemmerberg near Valkenburg, southeastern Limburg, The Netherlands. The mentioned species appear already far below The Berg en Terblijt Horizon at the CURFS quarry and Geulhemmerberg, which is actually supposed to mark the K/T boundary, at the ENCI quarry they range throughout the Maastricht Formation above the Horizon of Lichtenberg. The specimens are well preserved and originate from undisturbed sediment layers, thus it seems that they were not transported into the Maastrichtian sediments by water circulation or burrowing effects. The state of preservation and the presence of intact coccospheres indicate that they are autochthonous. C. primus, N. romeinii and N. parvulum are extremely small in size (800 nm to 2.0 μm), implying that a scanning electron microscope (SEM) must be set at least to 3 K magnification in order to detect them. With a light microscope (LM) at 1 K they cannot be classified, which is probably the reason why previous investigators who studied the same sections based on LM did not mention these species from the upper Maastrichtian. They furthermore appear in very low numbers contributing to around 1% of an associated calcareous nannoflora which is equivalent to the assemblage of the CC26 Nephrolithus frequens Zone of Cepek and Hay (1969). The biostratigraphic setting of the ENCI quarry, CURFS quarry and Geulhemmerberg have been the subject of a long and controversial discussion whether the exposed sediments still belong to the upper Maastrichtian or represent the lower Tertiary. Reworking of macrofossils and microfossils or autochthony of index fossils had been discussed and used to support the different opinions about the chronostratigraphy of these sections. Up to now there has not been any contribution which might lead to convincing data. If C. primus, N. romeinii, and N. parvulum are indeed `Tertiary Newcomer Coccoliths', the sediments exposed above the Horizon of Lichtenberg at the ENCI quarry, and the sediments below The Berg en Terblijt Horizon studied at CURFS quarry and Geulhemmerberg do belong to the NP 1 Biantholithus sparsus Zone, which means they are of Early Paleocene age. However, if these coccoliths already originate in the late Maastrichtian, the definition of the K/T boundary by calcareous nannoflora must be revised.     

Biostratigraphie,paléoécologie et zones d’acmé des foraminifères planctoniques au passage Crétacé-Paléogène dans la Téthys (Tunisie et Espagne) et l’Atlantique (France)

Biostratigraphical high-resolution analyses and quantitative data confirm that deposition is continuous across the K-Pg transition in several sections in Tunisia (El Kef, stratotype section) and Spain (Agost and Caravaca sections) located in the Tethyan realm and the Bidart sections in the Atlantic realm, without any relevant hiatus. The Upper Maastrichtian assemblages of planktic foraminifera from these sections are largely dominated by small biserial heterohelicids. They are associated to common species having planispiral test (i.e. globigerinelloids), trochospiral test (i.e. hedbergellids, rugoglobigerinids globotruncanids), to rare triserial heterohelicids (i.e. guembelitriids) and trochospiral species showing tubulospines (i.e. schackoinids). Stratigraphical ranges of these diverse taxa through the late Maastrichtian in the Tethyan and Atlantic realms show very few changes in the planktonic foraminiferal assemblages and most of the species are present in the Abathomphalus mayaroensis biozone. By our high-resolution sampling and the intensive research for the A. mayaroensis index species in the uppermost Maastrichtian samples, we confirm that this species is omnipresent up to the top of the Maastrichtian. Therefore, A. mayaroensis is present in almost all samples which are late Maastrichtian in age, but this species became very scarce in the uppermost Maastrichtian samples. This scarceness could be due to a climate cooling. A sharp decrease in relative abundance of the deep dwellers species, like as Abathomphalus intermedius and A. mayaroensis as well as in other keeled globotruncanids is observed at the studied sections from the Tethyan realm (indicative of low latitude) across the latest Maastrichtian. At the K/Pg boundary, all the globotruncanids disappeared. They are considered specialists living in tropical-subtropical deep seawater habitat. At this boundary, large and ornate heterohelicids also disappeared. Therefore, all the studied sections show that about 90 % of the Maastrichtian species became extinct according to a catastrophic mass extinction pattern. Only about 10 % crossed the K/Pg boundary and survived during the earliest Danian. The minor difference in the number of disappeared taxa is related to their latitude location or environment paleodepth. The changes in the species relative abundance, observed in the successive planktic foraminiferal assemblages, make it possible to recognize the Acme-stage 0 typical of the upper Maastrichtian interval. It is characterized by the highest species richness of Globotruncanids and heterohelicids specialists of tropical to subtropical marine conditions, the Acme-stage 1 typical of the Guembelitria cretacea Zone, and in particular of the Hedbergella holmdelensis Subzone dominated by “opportunists” species belonging to Guembelitria, the Acme-stage 2 which corresponds to the Pv. eugubina Zone dominated mainly by specimens belonging to Palaeoglobigerina and Parvularugoglobigerina and the Acme-stage 3 which characterizes mainly the Ps. pseudobulloides Zone dominated by biserial species belonging to Chiloguembelina and Woodringina.     

Phymosomatoid echinoids from the campanian and the maastrichtian of Belgium and the Netherlands

Phymosomatoid echinoids from the Campanian and the Maastrichtian of Belgium and the Netherlands are systematically revised. Ten species, belonging to four genera are identified and described. One new species is introduced:Gauthieria?mosae sp. nov.     

Organic-walled dinoflagellate cysts from the Upper Cretaceous–lower Paleocene succession in the western External Rif,Morocco: New species and new biostratigraphic results

Palynological investigation of the Upper Cretaceous–lower Paleocene succession from the Tahar section near Arba Ayacha in northwestern Morocco (westernmost External Rif Chain) reveals the presence of rich, diverse and well-preserved dinoflagellate cyst assemblages. For the first time in the study region, biostratigraphic interpretations based on the dinoflagellate cyst assemblages from the studied interval allow the recognition of the upper Maastrichtian and Danian. Relevant upper Maastrichtian–Danian global dinoflagellate cyst events include: the First Appearance Datum of the upper Maastrichtian species Disphaerogena carposphaeropsis, Glaphyrocysta perforata, and Manumiella seelandica; the Last Appearance Datum of the Cretaceous taxa Dinogymnium spp., Isabelidinium cooksoniae, and Pterodinium cretaceum; and the First Appearance Datum of the earliest Danian markers Carpatella cornuta, Damassadinium californicum, Membranilarnacia? tenella, and Senoniasphaera inornata. We formally describe the biostratigraphical range and potential of two new dinoflagellate cyst species, namely Nematosphaeropsis silsila Guédé and Slimani nov. sp., and Pterodinium ayachensis Guédé and Slimani nov. sp. Both species are found in the westernmost External Rif Chain and are restricted to the upper Maastrichtian.     

Rudist decline in the Maastrichtian Cardenas Formation (East-central Mexico)

Five sections of the Cardenas and Tabaco formations in east-central Mexico have been analyzed by means of bio-, Sr-isotope, and sequence stratigraphy, in order to evaluate their age as well as the timing of rudist decline.Ammonites [Pachydiscus (Pachydiscus) neubergicus (Hauer), Sphenodiscus pleurisepta (Conrad), Coahuilites sheltoni Böse] indicate an early Maastrichtian age for the topmost lower member of the Cardenas Formation and planktic foraminifera [e.g., Globotruncanita stuarti (de Lapparent), Archaeoglobigerina cretacea (d’Orbigny), Globotruncanella petaloidea (Gandolfi), Gansserina gansseri (Bolli), Globotruncana linneiana (d’Orbigny)] a late early Maastrichtian age for the middle member corresponding to the foraminiferal zones CF5 and CF6. Sr-isotope stratigraphic data yield an early late Maastrichtian age (66.93 Ma < 67.98 Ma < 68.96 Ma) for the last rudist assemblage in the topmost upper member of the Cardenas Formation, coinciding with the foraminiferal zone CF4.17 small-scale and 3 large-scale depositional cycles have been identified, which correspond to para- and depositional sequences. The progradational pattern of the large-scale cycles indicates an overall regression trend, which terminated in subaerial exposure of the area, indicated by paleosoils in the red beds of the Tabaco Formation. The correlation of the large-scale cycles with the global sea level charts indicate that eustatic sea level fall caused the regression and led to the exposure during the middle late Maastrichtian. This subaerial exposure resulted in the loss of habitat and thus the disappearance of rudists in east-central Mexico.     

Icriocarcinidae: a family of portunoid crabs from the Upper Cretaceous of North America

Icriocarcininae ?tev?i?, 2005, an extinct North American subfamily of portunoid decapods, is elevated to family level to contain two Late Cretaceous genera—Icriocarcinus Bishop, 1988, from the Pacific Coast, and Branchiocarcinus Feldmann and Vega, 1995, from the Gulf of Mexico and Atlantic Coast Plain. The family is centered on Icriocarcinus xestos Bishop, 1988, described from the Late Campanian of Baja California. Closely allied with this species are: “Eryma” flecta Rathbun, 1926, originally described from the latest Campanian of Tennessee and now known to occur throughout the Maastrichtian of the adjoining Mississippi; Branchiocarcinus cornatus Feldmann and Vega, 1995, from the Maastrichtian of San Luis Potosí, Mexico; and undescribed material from the latest Maastrichtian of New Jersey. The Gulf and Atlantic populations compose a single new species—Branchiocarcinus flectus (Rathbun). Provisionally regarded as a lobster, on the basis of a single, eroded chela, B. flectus is now known from complete bodies found at several locations in the eastern US. The additional material also clarifies the identity of B. cornatus, which is based on a distorted external mold of a lone dorsal carapace. Members of the family lack the typical portunoid flattened fifth pereiopod but share other characters that enable placement within the Portunoidea.     

Revised radiolarian zonation of the Upper Cretaceous Izumi inter-arc basin (SW Japan)

The radiolarian zonation of the Izumi Group is revised for an integrated biostratigraphy across the Campanian/Maastrichtian boundary, together with the ammonite occurrence, fission track and magnetostratigraphic calibration of the acidic tuff key beds. The significance of direct correlation in the same sections, between macro- and micro-fossils (i.e. between relatively near-shore nektonic and turbiditic planktonic-fauna) is discussed in relation to the litho- and bio-facies of the Izumi group. Late Cretaceous paleoceanographic changes inferred from the studied radiolarian fauna represent a regional marker event for the chronostratigraphic correlation of continental shelf to turbidite deep-sea sequences, which accumulated on a mid latitudinal margin facing towards the NW paleo-Pacific. The proposed Campanian/Maastrichtian boundary is at the limit between Pachydiscus awajiensis and Nostoceras hetonaiense ammonite zones. This boundary corresponds to the radiolarian last occurrence of Amphipyndax pseudoconulus (= A. enesseffi), Archaeodictyomitra sliteri, Dictyomitra formosa, D. koslovae and Rhopalosyringium magnificum at the top of the Myllocercion acineton Assemblage Zone (uppermost Campanian), and the first occurrence of Clathrocyclas gravis and Dorcadospyris sp. A, at the base of the Maastrichtian C. gravis Assemblage Zone. The new data settle partly a chronostratigraphic discrepancy between radiolarian and ammonite zonations in the Izumi Group, which was pointed out previously by Ishida et al. (2010).     

A new Late Cretaceous (Maastrichtian) serial planktic foraminifer (Family Heterohelicidae) with early planispiral coil and revision of Spiroplecta Ehrenberg, 1844

A new planktic foraminifer, Hartella harti nov. gen., nov. sp. is described from the Maastrichtian sediments of the Atlantic Ocean. H. harti likely evolved from Fleisherites glabrans (Cushman). Spiroplecta Ehrenberg is reviewed and considered monospecific. The only species assigned to this genus is Spiroplecta americana Ehrenberg, which evolved from Heterohelix globulosa (Ehrenberg). It is demonstrated that the early planispiral coil developed in at least three separate lineages of serial planktic foraminifera in the Late Cretaceous (late Campanian-early Maastrichtian).     

New Data on Dinosaurs of the Crimean Peninsula

Reexamination of the holotype of Riabininohadros weberae from the Upper Cretaceous (upper Maastrichtian) of the Crimean Peninsula (Besh-Kosh) allowed determination of previously unknown elements of the femur, astragalus, and calcaneus. This taxon shows a set of primitive characters observed in iguanodontids and basal ornithischians and is referred to as Styracosterna indet. The second dinosaur specimen from Crimea (Aleshino) is a fragmentary skeleton, including cervical and dorsal vertebrae. It possibly belongs to advanced iguanodontids or primitive hadrosauroids. Thus, in the Maastrichtian of the Crimean Peninsula, at least two dinosaur species coexisted.     

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.     

A new genus and species of raninoid crab from the Upper Cretaceous of Mississippi

A new genus and species of raninoid crab, Carinatus galebishopi, is described from the upper Maastrichtian Prairie Bluff and Owl Creek formations of Mississippi. Carinatus galebishopi gen. et sp. nov. fits best within the Raninidae, Subfamily Symethinae, based upon similar dorsal carapace characteristics of member genera. The new crab possesses distinctive dorsal carapace ornamentation setting it apart from described symethines and warrants establishment of a new genus. Carinatus galebishopi represents the first Cretaceous symethine crab and suggests the subfamily may have migrated eastward across the North Atlantic—Maastrichtian of Mississippi, Danian of New Jersey, and Ypresian of Spain—before dispersing to the Indo-Pacific.