Dinosaur eggshells from the Santonian Milk River Formation of Alberta,Canada

The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous.     

Biostratigraphic and biogeographic implications of a hadrosaurid (Ornithopoda: Dinosauria) from the Upper Cretaceous Almond Formation of Wyoming,USA

The results of Barnum Brown's 1937 expedition to the Almond Formation of Wyoming consisted of two unidentified ceratopsian skulls and a partial hadrosaurid specimen (AMNH 3651). The hadrosaurid is here attributed to the Maastrichtian genus Saurolophus, verifying previous biostratigraphic correlations of this formation using ammonite zones. Fossiliferous lower Maastrichtian formations occurring latitudinally between those of Alberta, Canada, and southwestern Texas, USA, such as the Almond Formation, are essential for testing the effects and duration of apparent hadrosaurid faunal segregation earlier in the Campanian, and indirectly aiding in the placement of faunal boundaries that are currently unknown for the late Campanian. The discovery of Saurolophus in Wyoming, a close relative of the Campanian genus Prosaurolophus, affirms that the segregation of hadrosaurid faunas established in the late Campanian (～75 Ma) continued for at least 3 million years. Combining occurrences of Saurolophus from Mongolia and the Moreno Formation of California with those of Alberta, Canada, this genus appears to have had one of the largest geographic ranges of any equivalent clade of hadrosaurid dinosaur, although species level distributions are still uncertain.     

Magnetostratigraphy of Upper Cretaceous strata in Grand Staircase-Escalante National Monument,southern Utah: The Santonian–Campanian Stage boundary,reassessment of the C33N/C33R magnetochron boundary,and implications for regional sedimentation patterns within the Sevier Foreland Basin

Samples were collected for magnetostratigraphic analysis from the Upper Cretaceous Straight Cliffs and Wahweap formations within Grand Staircase-Escalante National Monument, southern Utah, in an attempt to locate the C34n–C33r and C33r–C33n boundaries; the former approximates the Santonian–Campanian Stage boundary. Locating both of these horizons within the Monument provides for refined temporal resolution of the many new fossil localities discovered in these units, while also adding to our understanding of the overall Straight Cliffs–Wahweap sequence stratigraphic architecture. Results indicate that the John Henry and Drip Tank members of the Straight Cliffs Formation are of normal polarity, and represent the later part of C34n, the Cretaceous Normal Polarity Super-Chron. The C34n–C33r boundary apparently resides in a significant hiatus determined to occur between the Drip Tank Member of the Straight Cliffs Formation and the lower part of the overlying Wahweap Formation. In stratigraphically ascending order, the informally named lower, middle, and most of the upper members of the Wahweap Formation are of reversed polarity. The C33r–C33n polarity change occurs in the upper part of the upper member, and C33n continues stratigraphically upward through the capping sand member of the Wahweap Formation and into the overlying Kaiparowits Formation. The presence of over 200 m of reversely magnetized strata above a level in the lower part of the middle member dated to 79.9 ± 0.3 Ma, which coincides with the GTS2012 date for the C33r–C33n boundary of 79.9 Ma, suggests that the published age of that boundary may be in error. A new date of approximately 78.91 Ma is proposed, in turn allowing for the thick sequence of reversely magnetized strata above the 79.9 Ma level. Age revision of the Kaiparowits Basin's Late Cretaceous record demonstrates that during late Santonian through early middle Campanian time, except in central Utah, a close correlation in time and facies successions with other successions throughout the Western Interior Basin suggests a eustatic influence on the depositional patterns. Starting in the late middle Campanian, the Kaiparowits record, along with those both to the north and south, appear to diverge in style and facies successions. We consider this to have resulted from a fundamental change in depositional controls triggered by the Laramide Orogeny. The anomalous central Utah record appears to have been profoundly influenced by a massive salient (Nebo-Charleston thrust system) in the Sevier Fold and Thrust belt that was active for much of the Late Cretaceous.     

A New Specimen of Crichtonpelta benxiensis (Dinosauria: Ankylosaurinae) from the Mid-Cretaceous of Liaoning Province, China

A new specimen of ankylosaurine dinosaur Crichtonpelta benxiensis is described. The new specimen is based on a nearly completely preserved skull from the same quarry as the holotype of the mid-Cretaceous Sunjiawan Formation in Shuangmiao, Beipiao City, Liaoning Province, China. Cladistic analysis incorporating new information from the new specimen resolves Crichtonpelta benxiensis is more advanced than basal members of Ankylosauridae (Kunbarrasaurus, Liaoningosaurus, Chuanqilong, Cedarpelta, Gobisaurus and Shamosaurus) and represents the first diverging branch of Ankylosaurinae. Comparisons to other mid-Cretaceous ankylosaurid-bearing dinosaur assemblages in northern China indicate a late Early Cretaceous to early Late Cretaceous age for the Shuangmiao dinosaur assemblage.     

Evidence of across-shelf transport of fine-grained sediments: turbidite-filled shelf channels in the Campanian Aberdeen Member, Book Cliffs, Utah, USA

The shore‐normal transport of fine‐grained sediments by shelf turbidity currents has been the focus of intense debate over the last 20 years. Many have argued that turbidity currents are unlikely to be a major depositional agent on the shelf. However, sedimentological, architectural, stratigraphic and palaeogeographic data from the Campanian Aberdeen Member, Book Cliffs, eastern Utah suggests otherwise and clearly demonstrates that storm‐generated and river flood‐generated underflows can transport a significant volume of fine‐grained sediments across the shelf. These across‐shelf flowing turbidity currents cut large subaqueous channel complexes up to 7 m deep, tens of kilometres basinward of their time‐equivalent shoreface. The shelf channels were filled with organic‐rich siltstones, mudstones and very fine‐ to fine‐grained Bouma‐like sandstone beds, including wave‐modified turbidites, hyperpycnites and classical turbidites. Deposition was above storm wave base. Palaeocurrent data reveal an overwhelmingly dominant across‐shelf (east–south‐east), offshore‐directed transport trend. Tectonic activity and/or concomitant palaeogeographic reorganization of the basin may favour the generation of these turbidite‐rich shelf deposits by altering the relative balance of wave versus fluvial energy. Increased erosion and sediment supply rates, because of tectonic uplift of the hinterland, may have increased the probability of fluvial dominance along the coastline and, hence, the possibility of submarine channelization in front of the river mouths. Additionally, the coastline may have become more sheltered from direct wave energy, thus allowing the fluvial processes to dominate. Seasonal increases in rainfall and storm activity may also favour the generation of across‐shelf underflows. On wave‐dominated shorelines, isolated shelf channels and lobes are most likely to be found down‐dip of fluvial‐feeder systems in relatively high sediment supply settings. These features are also most likely to occur in systems tracts that straddle a sequence boundary, especially those which are tectonically generated, as these would enhance the potential for altering basin morphology and, hence, the balance of fluvial and wave energy. Isolated shelf channels are recognized in older and younger strata in the Book Cliffs region, implying that wave‐supported gravity flows were a recurrent phenomena in the Campanian of Utah. It is probable that isolated shelf bodies are preserved in other stratigraphic intervals in the Cretaceous Western Interior of North America, and other basins worldwide, and are currently being overlooked or misidentified. Shoreface‐to‐shelf facies models should be revised to incorporate turbidite‐rich shelf deposits in some shelf settings.     

Shelf construction in a foreland basin: storm beds, shelf sandbodies, and shelf-slope depositional sequences in the Upper Cretaceous Mesaverde Group, Book Cliffs, Utah

The Upper Cretaceous (Campanian) Kenilworth Member of the Blackhawk Formation (Mesaverde Group) is part of a series of strand plain sandstones that intertongue with and overstep the shelfal shales of the western interior basin of North America. Analysis of this section at a combination of small (sedimentological) and large (stratigraphical) scales reveals the dynamics of progradation of a shelf-slope sequence into a subsiding foreland basin. Four major lithofacies are present in the upper Mancos and Kenilworth beds of the Book Cliffs. A lag sandstone and channel-fill shale lithofacies constitutes the thin, basal, transgressive sequence, which rests on a marine erosion surface. It was deposited in an outer shelf environment. Shale, interbedded sandstone and shale, and amalgamated sandstone lithofacies were deposited over the transgressive lag sandstone lithofacies as a wave-dominated delta and its flanking strand plains prograded seaward. Analysis of grain size and primary structures in Kenilworth beds indicates that there are four basic strata types which combine to build the observed lithofacies. The fine- to very fine-grained graded strata of the interbedded facies are tempestites, deposited out of suspension by alongshelf storm flows (geostrophic flows). There is no need to call on cross-shelf turbidity currents (density underflows) to explain their presence. Very fine- to fine-grained hummocky strata are likewise suspension deposits created by waning storm flows, but were deposited under conditions of more intense wave agitation on the middle shoreface. Cross-strata sets in this region are bed-load deposits that accumulated on the upper shore-face, in the surf zone. Lag strata are multi-event, bed-load deposits that are the product of prolonged storm winnowing. They occur on transgressive surfaces. While the graded beds are tempestites in the strict sense, all four classes of strata are storm deposits. The distribution of strata types and their palaeocurrent orientations suggests a model of the Kenilworth transport system driven by downwelling coastal storm flows, and probably by a northeasterly alongshore pressure gradient. The stratification patterns shift systematically from upper shoreface to lower shoreface and inner shelf lithofacies partly because of a reduction in fluid power expenditure with increasing water depth, but also because of progressive sorting, which resulted in a decrease in grain size in the sediment load delivered to successive downstream environments. The Kenilworth Member and an isolated outlier, the Hatch Mesa lentil, constitute a delta-prodelta shelf depositional system. Their rhythmically bedded, lenticular, sandstone and shale successions are a prodelta shelf facies, and may be prodelta plume deposits. Major Upper Cretaceous sandstone tongues in the Book Cliffs are underlain by erosional surfaces like that beneath the Blackhawk Formation, which extend for many tens of kilometres into the Mancos shale. These surfaces are the boundaries of Upper Cretaceous depositional sequences. The sequences are large-scale genetic stratigraphic units. They result from the arranging of facies into depositional systems; the depositional systems are in turn stacked in repeating arrays, which constitute the depositional sequences. The anatomy of these foreland basin sequences differs     

Integrated biostratigraphy and palaeoenvironments of an upper Santonian - upper Campanian succession from the southern part of the Eastern Carpathians, Romania

Study of an upper Santonian to upper Campanian hemipelagic succession from the southern part of the Romanian Eastern Carpathians enables us to establish an integrated biostratigraphy based on planktonic foraminifera and calcareous nannofossils and to compare this record with the agglutinated foraminiferal biozonation used for the Carpathians.Benthic foraminiferal assemblages were investigated using several methods, such as agglutinated and calcareous benthic foraminiferal morphogroups, and the benthic foraminiferal oxygen index in order to determine their response to environmental parameters in the basin (correlated with sea-level maxima documented by regional sea-level curves for the Tethys). A pattern of changes in benthic foraminiferal communities associated with increased organic carbon flux and rising sea-levels can be summarized as follows in the studied succession. As sea-level begins to rise there is an increase in the proportion of calcareous benthic foraminifera at the expense of agglutinated foraminifera within the benthic assemblages (earliest Campanian, mid-late Campanian). Once sea-level rises, an increase in the elongate keeled morphotype of agglutinated foraminifera (shallower water forms) can be observed, and if sea-level remains high for an extended period (as in the early Campanian) then an invasion of both agglutinated and benthic calcareous foraminifera characteristic of outer shelf-upper slope environments take place in the basin. The variations in tubular and deep infaunal morphotypes of agglutinated foraminifera are ascribed to varying levels of organic carbon flux.     

A diverse,high-latitude ichnofauna from the Late Cretaceous Wapiti Formation,Alberta, Canada

The Wapiti Formation in west-central Alberta preserves one of the most diverse Late Cretaceous terrestrial track records yet identified in Canada. At least seven morphotypes are recognized and attributed to mammals, small reptiles or amphibians, tyrannosaurids, medium-sized theropods, hadrosaurids, and ankylosaurs. Most tracks occur isolated on slump blocks associated with latest Campanian (Wapiti Formation unit 4) exposures found along Pipestone Creek and Red Willow River. With the possible exception of hadrosaurids, tracks provide some of the most compelling evidence for the occurrence of such taxa within the Wapiti Formation ecosystem. The apparent absence of ceratopsian tracks is surprising considering their bones are abundantly preserved in nearby monodominant bonebeds. The overall faunal signal represented by the Wapiti Formation trackmakers is typical of and consistent with other coeval assemblages in similar environments. The Wapiti Formation tracks, combined with the known fossil bone record, provide another data point in a growing palaeobiogeographical picture of the dinosaur faunas of high-latitude northwestern North America during the Late Cretaceous.     

New evidence for the possible occurrence of Tyrannosaurus in West Texas,and discussion of Maastrichtian tyrannosaurid dinosaurs from Big Bend National Park

Speculation regarding Tyrannosaurus in West Texas has been largely based upon a sub-adult tyrannosaurid maxilla from the Javelina Formation (Late Cretaceous–Maastrichtian) of Big Bend National Park. However, a very large anterior caudal vertebra, recently collected from the Javelina Formation, exhibits a morphology that can confidently be assigned to Tyrannosauridae and, because of its size, likely pertains to an adult Tyrannosaurus. The stratigraphic position of the specimen is closely bracketed by titanosaurid remains and further supports coexistence of these taxa. The stratigraphic position of the specimen possibly records one of the earliest occurrences of Tyrannosaurus. If so, Tyrannosaurus likely existed during roughly equivalent temporal intervals in disparate paleobiomes in both northern and southern late Maastrichtian faunal realms of North America.     

A protoceratopsid skeleton with an associated track from the Upper Cretaceous of Mongolia

The Djadokhta Formation of the Gobi Desert is known for the number and diversity of dinosaur and other vertebrate bones and skeletons found there, but only theropod, hadrosaur and supposed ankylosaurid footprints have been reported from this stratum. Dinosaur footprints are also noted from the Nemegt Formation, and occur as typical dinosaur track accumulations (tracksites). An articulated protoceratopsid skeleton - specimen ZPAL Mg D-II/3 - was collected by the Polish-Mongolian Expedition of 1965 from the Djadokhta Formation of Flaming Cliffs in Mongolia. Recently, the natural cast of a tetradactyl digitigrade footprint was found underneath the pelvic girdle while the skeleton and matrix were being prepared. This is possibly the first find of a dinosaur track in close association with an articulated skeleton. Although Protoceratops is an extremely common dinosaur in Mongolia, its footprints have never previously been reported from the Late Cretaceous of the Gobi Desert.     

Palynoassemblages associated with a theropod dinosaur from the Snow Hill Island Formation (lower Maastrichtian) at the Naze,James Ross Island,Antarctica

The Cape Lamb Member of the Snow Hill Island Formation at The Naze on the northern margin of James Ross Island, east of the Antarctic Peninsula, yielded a theropod dinosaur recovered near the middle of a 90 m thick section that begins at sea level, ends below a basalt sill, and is composed of interbedded green–gray massive and laminated fine-grained sandstones and mudstones. Sixteen palynoassemblages were recovered from this section, which yielded moderately diverse assemblages with a total of 100 relatively well-preserved species. The principal terrestrial groups (32%) are represented by lycophytes (8 species), pteridophytes (15 species), gymnosperms (13 species), angiosperms (21 species) and freshwater chlorococcaleans (3 species). Marine palynomorphs (68%) belong to dinoflagellates (61 species), chlorococcaleans (6 species), and one acritarch. The vertical distribution of selected species allows the distinction of two informal assemblages, the lower Odontochitina porifera assemblage from the base to its disappearance in the lower part of the section, and the remaining section characterized by the Batiacasphaera grandis assemblage. The global stratigraphic ranges of selected palynomorphs suggest an early Maastrichtian age for this section and the entombed dinosaur that is also supported by the presence of the ammonoid Kitchinites darwinii. These assemblages share many species with latest Campanian–early Maastrichtian palynofloras from Vega and Humps Islands, New Zealand, and elsewhere in the Southern Ocean, establishing a good correlation among them. The dominance or frequent presence of dinoflagellates throughout the section supports the general interpretation of a shelf marine depocenter. The consistent presence of terrestrial palynomorphs suggests contributions from littoral/inland environments.     

Upper Campanian-lower Maastrichtian planktonic foraminifers and biostratigraphy of the Moni Formation,southern Cyprus

The first data on the taxonomic composition and stratigraphic range of the late Campanian planktonic foraminifers encountered in the middle and upper parts of the Moni Formation, southern Cyprus, are reported. Finds of planktonic foraminifers are associated with the bentonitic clay that composes the matrix of the Moni Formation. The planktonic foraminiferal assemblages revealed are very similar to those from the Kannaviou Formation, western Cyprus, but they are more diverse and yield several key species missing in the Kannaviou sediments. The planktonic foraminiferal assemblages discussed are referred to the Globotruncana aegyptiaca Zone and to the lowermost Gansserina gansseri Zone of the upper upper Campanian of the standard scale. The intraregional correlation of the Moni sections, depth of erosion of the upper part of the formation, and its relationship with the Kannaviou Formation have been refined. When subdividing the upper Campanian sediments based on planktonic foraminifers it is suggested that additional datum planes are used, such as the FADs of Globotruncanella citae and Trinitella scotti. For tracing the Campanian-Maastrichtian boundary (GSSP), attention should be paid to the LADs of Globotruncana bulloides and Contusotruncana fornicata and the potential use of Globotruncanita (Elevatotruncana) eolita sp. nov. should be assessed. It is shown that subfamily Archaeoglobigerininae Salaj, 1987, emend. O. Korchagin is the older synonym of subfamily Archaeoglobigerininae Georgescu, 2005. Two poorly known and three new planktonic foraminiferal species are described.     

Slickenlines and the kinematics of the Crowsnest Deflection in the southern Rocky Mountains of Canada

In the vicinity of the Crowsnest Pass, in the southern Rocky Mountains of Canada, the strike of the structural grain deviates significantly from the regional 325° Bow Valley–northern Montana trend. This deviation is known as the Crowsnest Deflection.The preferred azimuths for slickenlines on bedding north and south of the deflection is 056°; that is almost exactly perpendicular to the Bow Valley–northern Montana trend. Within the deflection, however, the preferred azimuth appears to be composite, ranging from 051° (Beaver Mines) to 082° (Frank, Alberta). The temporal relations of intersecting striae in the coal measures of Bow Valley would suggest, moreover, that these preferred slip directions are not sequential but may be partially or wholly concurrent.These kinematic fabric data, in conjunction with the alignment of remanent magnetic dipoles in mid-Proterozoic (Helikian) rocks, support the hypothesis that within the Crowsnest Deflection the curviplanar shape of contraction faults in the eastern Cordillera of Canada was controlled by the ancestral shape of the Cordilleran shelf-miogeocline.The proposed origin and tectonic significance of the Crowsnest Deflection may be similar to that of other great arcs, including the northeastward salient of the Mackenzie Mountains in the northern Cordillera of Canada, and of the northwestward salient of the central Appalachians of Pennsylvania.     

Late Cretaceous paleoenvironmental evolution of the Tarfaya Atlantic coastal Basin,SW Morocco

Lithological evidence, benthic foraminiferal census counts, and X-ray fluorescence (XRF) scanner-derived elemental data were integrated with planktonic foraminiferal biostratigraphy and bulk carbonate stable isotopes to retrace the Turonian to early Campanian paleoenvironmental evolution and sea-level history of the Tarfaya Atlantic coastal basin (SW Morocco). The lower Turonian is characterized by laminated organic-rich deposits, which contain impoverished benthic foraminiferal assemblages, reflecting impingement of the oxygen minimum zone on the shelf during a sea-level highstand. This highstand level is correlated to the global transgressive pulse above the sequence boundary Tu1. The appearance of low-oxygen tolerant benthic foraminiferal assemblages dominated by Gavelinella sp. in the middle to upper Turonian indicates an improvement in bottom water oxygenation, probably linked to offshore retraction of the oxygen minimum zone during a regressive phase. This interval is marked by major regressive events expressed by a series of erosional truncations associated with the prominent sequence boundaries Tu3 and/or Tu4. Dysoxic–anoxic conditions recorded in the upper Santonian of the Tarfaya Basin coincide with the eustatic sea-level rise prior to Sa3 sequence boundary. The lower Campanian transgression, only recorded in the southern part of the Tarfaya Basin, coincided with substantial deepening, enhanced accumulation of fine-grained clay-rich hemipelagic sediments and improved oxygenation at the seafloor (highest diversity and abundance of benthic foraminiferal assemblages). Stable isotope data from bulk carbonates are tentatively correlated to the English Chalk carbon isotope reference curve, in particular the Hitch Wood Event in the upper Turonian, the Navigation Event in the lower Coniacian, the Horseshoe Bay Event in the Santonian and the Santonian/Campanian Boundary Event.     

河南恐龙蛋化石组合类型及其地层时代意义

根据恐龙蛋化石在河南省 10余个盆地中纵向上的分布特点 ,结合孢粉、轮藻、介形类、岩石同位素年龄及产蛋盆地的大地构造发展演化特征 ,研究认为其代表的地层时代为晚白垩世 ,并提出了 3种不同的蛋化石组合类型 ,进一步“三分”上白垩统 :即下部组合为长圆柱形蛋、蜂窝蛋、树枝蛋、网格蛋 ;中部组合为椭圆形蛋、副圆形蛋、树枝蛋 ;上部组合为长形蛋、巨形蛋 ,分别代表晚白垩世早、中、晚 3个时期     

A possible juvenile ceratopsoid ilium from the Cenomanian of central Utah,U.S.A.

We describe a small ilium, with fibrous texture characteristic of juvenile bone, from the lower Cenomanian of central Utah, U.S.A. The ilium was recovered from the upper part of the Mussentuchit Member of the Cedar Mountain Formation. The ilium most closely resembles that of immature ceratopsid ilia referred to Agujaceratops mariscalensis from the Campanian Aguja Formation of southern Texas, U.S.A. Both have everted dorsal margins over the iliac body, subhorizontal postacetabular processes, and laterally compressed, anteroventrally curved preacetabular processes. If correctly identified, the small ilium from the Cedar Mountain Formation is the oldest ceratopsid or ceratopsoid known, and shows that the diversity of early ceratopsians was greater than previously realized.     

New Data on Dinosaurs in the Late Cretaceous Sediments of the Southern Urals

Doklady Earth Sciences - We describe a new find of a dinosaur in the Southern Urals, a fragment of long bone of a large dinosaur from the Upper Cretaceous (Upper Santonian–Lower Campanian)...     

A tyrannosaur trackway at Glenrock,Lance Formation (Maastrichtian), Wyoming

During the Campanian and Maastrichtian ages (86–66 million years ago), tyrannosaurids were the predominant large carnivorous dinosaurs throughout the Northern hemisphere. Despite the abundance of skeletal material, the fossil-footprint record of tyrannosaurids has been limited. Here we report a tyrannosaurid trackway in the Lance Formation, Wyoming. The trackway consists of three sequential tracks on a sandstone surface. Based on the age and size of the footprints, the trackmaker can be identified as either a sub-adult Tyrannosaurus rex or a Nanotyrannus lancensis. The trackway offers a record of a tyrannosaurid pace length, which permits the speed of the trackmaker to be calculated at 4.5–8.0 km/h. This result discounts previous speculation that tyrannosaurid walking speeds were notably slower than those of other large theropods.     

Titanoceratops ouranos, a giant horned dinosaur from the late Campanian of New Mexico

At the end of the Cretaceous, 65.5 million years ago, the giant ceratopsids Triceratops and Torosaurus dominated North America’s dinosaur fauna. The origins of these giant ceratopsids, the Triceratopsini, are poorly understood. This paper describes Titanoceratops ouranos, a giant ceratopsid from the late Campanian (73-74 Ma) of New Mexico, and the earliest known triceratopsin. The holotype was previously interpreted as an aberrant and exceptionally large specimen of Pentaceratops sternbergi, but the animal does not show the diagnostic features of Pentaceratops. Instead, cladistic analysis shows that Titanoceratops is the sister taxon of a clade formed by Eotriceratops, Triceratops, and Torosaurus. With an estimated mass of 6.5 tons, Titanoceratops is among the largest dinosaurs known from the Campanian of North America, and rivaled Triceratops in size. The recognition of Titanoceratops suggests that giant chasmosaurines evolved once, among the Triceratopsini, and that the group evolved large size five million years earlier than previously thought. The giant horned dinosaurs probably originated in the southern part of the North American continent during the Campanian but only became widespread during the Maastrichtian.     

Upper Campanian-lower Maastrichtian sections of the northwestern Rostov region. Article 1. Description, paleontological assemblages, and lithobiostratigraphy

Four upper Campanian-lower Maastrichtian reference sections are described in the Glubokaya and Kalitva river basins and in the Znamenka 1-A Borehole located in the northwestern Rostov region. The sections are composed of the upper Campanian Kagal??nik, Belgorod, Pavlovka, Sukhodol and lower Maastrichtian Efremovo-Stepanovka formations. They are characterized by successive stratigraphically significant macro- and microfossil assemblages: belemnites, calcareous nannoplankton, benthic foraminifers, and radiolarians. The Pavlovka and, particularly, Sukhodol formations contain a specific assemblage of coarsely-agglutinated benthic foraminifers. The first data obtained on radiolarians in upper Campanian-lower Maastrichtian sections of the northwestern Rostov region revealed four assemblages, two of which were previously unknown from Upper Cretaceous sediments of the East European Platform. Most sections enclose a hiatus at the base of the Sukhodol Formation, which comprises two upper Campanian benthic foraminiferal zones. The problem of recognition of the lower Maastrichtian boundary on the East European Platform is considered in accordance with international GSSP requirements.