An early Late Cretaceous (Cenomanian) sturgeon (Acipenseriformes) from the Dunvegan Formation, northwestern Alberta, Canada

2014 ◽  
Vol 51 (7) ◽  
pp. 677-681 ◽  
Author(s):  
Matthew J. Vavrek ◽  
Alison M. Murray ◽  
Phil R. Bell
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Recent Survey ◽  
Peace River ◽  
Northern Regions ◽  
Early Late

A recent survey of the middle Cenomanian Dunvegan Formation along the Peace River, Alberta, has yielded a partial skull of a large acipenseriform fish. The fossil was from an animal approximately 5 m in length, based on comparisons with living relatives. Though incomplete, this represents an important record of mid-Cretaceous fish from northern North America, as formations of this age are virtually unexplored in northern regions. This fossil is the oldest acipenserid from North America, and one of the most northerly known.

?Tethyaster albertensis, a Late Cretaceous (Turonian) sea star from the Cardium Formation, Alberta, Canada

1990 ◽  
Vol 64 (6) ◽  
pp. 1045-1049 ◽  
Author(s):  
Russell L. Hall ◽  
Suzan Moore
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Sea Star ◽  
Sea Stars ◽  
Peace River ◽  
The North ◽  
The Family ◽  
Cardium Formation ◽  
Northern Alberta ◽  
Limited Change

Although many of the surviving lineages of sea stars appeared during an early Mesozoic radiation of the class and have undergone limited change since then, they have left a very poor fossil record, particularly in the Mesozoic of North America (Blake, 1981). This record from the Late Cretaceous of Alberta is made more significant by the fact that it is apparently only the second occurrence of a member of the family Astropectinidae in the Cretaceous of North America; Lophidiaster silentiensis was described by McLearn (1944) from the Lower Cretaceous (Albian) Hasler Formation, from a now-submerged locality on the Peace River in northern Alberta. All previously recorded fossil sea stars from the North American Cretaceous are representatives of the family Goniasteridae.

scholarly journals Dinosaurs from the Santonian–Campanian Atlantic coastline substantiate phylogenetic signatures of vicariance in Cretaceous North America

2021 ◽  
Vol 8 (8) ◽  
pp. 210127
Author(s):  
Chase Doran Brownstein
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Coastal Plain ◽  
Fossil Record ◽  
Atlantic Coastal Plain ◽  
Terrestrial Vertebrates ◽  
Small Juvenile ◽  
The Poor ◽  
Atlantic Coastal ◽  
Early Late

During the Cretaceous, diversifications and turnovers affected terrestrial vertebrates experiencing the effects of global geographical change. However, the poor fossil record from the early Late Cretaceous has concealed how dinosaurs and other terrestrial vertebrates responded to these events. I describe two dinosaurs from the Santonian to Early Campanian of the obscure North American paleolandmass Appalachia. A revised look at a large, potentially novel theropod shows that it likely belongs to a new clade of tyrannosauroids solely from Appalachia. Another partial skeleton belongs to an early member of the Hadrosauridae, a highly successful clade of herbivorous dinosaurs. This skeleton is associated with the first small juvenile dinosaur specimens from the Atlantic Coastal Plain. The tyrannosauroid and hadrosaurid substantiate one of the only Late Santonian dinosaur faunas and help pinpoint the timing of important anatomical innovations in two widespread dinosaur lineages. The phylogenetic positions of the tyrannosauroid and hadrosaurid show Santonian Appalachian dinosaur faunas are comparable to coeval Eurasian ones, and the presence of clades formed only by Appalachian dinosaur taxa establishes a degree of endemism in Appalachian dinosaur assemblages attributable to episodes of vicariance.

scholarly journals A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5883 ◽  
Author(s):  
Haviv M. Avrahami ◽  
Terry A. Gates ◽  
Andrew B. Heckert ◽  
Peter J. Makovicky ◽  
Lindsay E. Zanno
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Western North America ◽  
Western Interior Seaway ◽  
Cedar Mountain Formation ◽  
New Information ◽  
Asian Clade ◽  
Quantitative Analyses ◽  
Dinosaur Teeth ◽  
Early Late

The vertebrate fauna of the Late Cretaceous Mussentuchit Member of the Cedar Mountain Formation has been studied for nearly three decades, yet the fossil-rich unit continues to produce new information about life in western North America approximately 97 million years ago. Here we report on the composition of the Cliffs of Insanity (COI) microvertebrate locality, a newly sampled site containing perhaps one of the densest concentrations of microvertebrate fossils yet discovered in the Mussentuchit Member. The COI locality preserves osteichthyan, lissamphibian, testudinatan, mesoeucrocodylian, dinosaurian, metatherian, and trace fossil remains and is among the most taxonomically rich microvertebrate localities in the Mussentuchit Member. To better refine taxonomic identifications of isolated theropod dinosaur teeth, we used quantitative analyses of taxonomically comprehensive databases of theropod tooth measurements, adding new data on theropod tooth morphodiversity in this poorly understood interval. We further provide the first descriptions of tyrannosauroid premaxillary teeth and document the earliest North American record of adocid remains, extending the appearance of this ancestrally Asian clade by 5 million years in western North America and supporting studies of pre-Cenomaninan Laurasian faunal exchange across Beringia. The overabundance of mesoeucrocodylian remains at the COI locality produces a comparatively low measure of relative biodiversity when compared to other microvertebrate sites in the Mussentuchit Member using both raw and subsampling methods. Much more microvertebrate research is necessary to understand the roles of changing ecology and taphonomy that may be linked to transgression of the Western Interior Seaway or microhabitat variation.

The early evolution of the Tyrannosauridae in Asia

1999 ◽  
Vol 73 (6) ◽  
pp. 1176-1178 ◽  
Author(s):  
M. Manabe
Keyword(s):  
Body Size ◽  
North America ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Early Evolution ◽  
Land Bridge ◽  
Early Late

An isolated premaxillary tooth of a tyrannosaurid from the Lower Cretaceous section of the Tetori Group, Central Honshu, Japan, complements Siamotyrannus, which is based upon an incomplete postcranium for existence of tyrannosaurids in the Early Cretaceous of Asia. The occurrence of a tyrannosaurid tooth in the Japanese early Early Cretaceous further supports the possibility that tyrannosaurids originated during the Early Cretaceous in Asia and migrated to North America when the two continents were connected via a land bridge during the early Late Cretaceous. Thickening of the premaxillary teeth might have predated the increase in body size in tyrannosaurid evolution.

Early Cretaceous (?early late Albian) echinoderms from northeastern British Columbia, Canada

2015 ◽  
Vol 52 (4) ◽  
pp. 235-243 ◽  
Author(s):  
William I. Ausich ◽  
Charles R. Stelck ◽  
A. Guy Plint ◽  
Robin A. Buckley ◽  
Piotr J. Angiel
Keyword(s):  
British Columbia ◽  
North America ◽  
Gulf Of Mexico ◽  
Early Cretaceous ◽  
Water Depth ◽  
Deep Water ◽  
First Report ◽  
Peace River ◽  
Stalked Crinoids ◽  
Early Late

An echinoderm association is reported from the ?early late Albian Paddy Member of the Peace River Formation of British Columbia, Canada. The association includes Frasericrinus mauricensis gen. et sp. nov., two additional distinctive crinoid column types, a poorly preserved asteroid, and an umbilical fragment of the cephalopod Stelckiceras. This is the first report of a Cretaceous isocrinid from North America. The echinoderm fossils are from the top of a succession of storm-deposited sandstones and mudstones (Boulder Creek Formation) that can be correlated southward into nearshore and terrestrial facies of the Paddy Member of the Peace River Formation. The echinoderm fossils were buried (and probably lived) about 12–14 km from the contemporaneous shoreline in an estimated water depth of 10–20 m. Integration of biostratigraphic and allostratigraphic schemes suggests that the echinoderms are of earliest late Albian age. The association of the echinoderm fauna with ammonites of Boreal affinity indicates deposition in northern waters, although the presence of Tethyan inoceramids in apparently coeval Paddy Member strata 270 km to the east suggests that northward-advancing water from the Gulf of Mexico had reached northwestern Alberta, if not actually merged with the Boreal embayment. The nearshore occurrence of Cretaceous stalked crinoids is indicative of an asynchronous, gradual migration of stalked crinoids to deep-water habitats, to which they are restricted in modern oceans.

Earliest occurrence of the Pteranodontidae (Archosauria: Pterosauria) in North America: new material from the Austin Group of Texas

2010 ◽  
Vol 84 (6) ◽  
pp. 1071-1081 ◽  
Author(s):  
Timothy S. Myers
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Taxonomic Diversity ◽  
Left Wing ◽  
North Texas ◽  
Diagnostic Features ◽  
Eagle Ford ◽  
New Material ◽  
Early Late

Remains of a pteranodontid pterosaur are recorded in the basal Austin Group of North Texas. The specimen described here comprises a partial left wing and strongly resemblesPteranodonalthough diagnostic features of that genus are lacking. With an estimated early Coniacian age, this specimen represents the earliest occurrence of the Pteranodontidae in North America and the second earliest occurrence worldwide, predated only byOrnithostomafrom the Cambridge Greensand of England. Pterosaur material recovered from the Eagle Ford and Austin groups of Texas records an early Late Cretaceous change in the composition of North American pterosaur communities between the late Cenomanian and the early Coniacian. This faunal transition appears to be primarily a decrease in morphological disparity rather than a significant reduction in taxonomic diversity. However, the lack of Early CretaceousLagerstättenin North America may produce underestimates of true pterosaur richness during this interval, thereby obscuring a subsequent drop in diversity.

NOVEL INSECT HERBIVORY FROM THE LATE CRETACEOUS OF WESTERN NORTH AMERICA

2018 ◽  
Author(s):  
S. Augusta Maccracken ◽  
◽  
Ian M. Miller ◽  
Conrad C. Labandeira
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Insect Herbivory ◽  
Western North America

scholarly journals Isolated pliosaurid teeth from the Albian–Cenomanian (Cretaceous) of Annopol, Poland

2017 ◽  
Vol 67 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Daniel Madzia ◽  
Marcin Machalski
Keyword(s):  
Cross Section ◽  
Late Cretaceous ◽  
Type Species ◽  
Late Jurassic ◽  
Morphological Variability ◽  
Original Material ◽  
Tooth Crown ◽  
Similar Morphology ◽  
Faunal Turnover ◽  
Early Late

AbstractBrachauchenine pliosaurids were a cosmopolitan clade of macropredatory plesiosaurs that are considered to represent the only pliosaurid lineage that survived the faunal turnover of marine amniotes during the Jurassic- Cretaceous transition. However, the European record of the Early to early Late Cretaceous brachauchenines is largely limited to isolated tooth crowns, most of which have been attributed to the classic Cretaceous taxon Polyptychodon. Nevertheless, the original material of P. interruptus, the type species of Polyptychodon, was recently reappraised and found undiagnostic. Here, we describe a collection of twelve pliosaurid teeth from the upper Albian-middle Cenomanian interval of the condensed, phosphorite-bearing Cretaceous succession at Annopol, Poland. Eleven of the studied tooth crowns, from the Albian and Cenomanian strata, fall within the range of the morphological variability observed in the original material of P. interruptus from the Cretaceous of England. One tooth crown from the middle Cenomanian is characterized by a gently subtrihedral cross-section. Similar morphology has so far been described only for pliosaurid teeth from the Late Jurassic and Early Cretaceous. Even though it remains impossible to precisely settle the taxonomic distinctions, the studied material is considered to be taxonomically heterogeneous.

scholarly journals Depositional setting and limiting factors of early Late Cretaceous glaucony formation: implications from Cenomanian glauconitic strata (Elbtal Group, Germany)

Facies ◽  
2021 ◽  
Vol 67 (3) ◽  
Author(s):  
Markus Wilmsen ◽  
Udita Bansal
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Time Scales ◽  
Late Cretaceous ◽  
Limiting Factors ◽  
High Accumulation ◽  
Spatio Temporal ◽  
Facies Types ◽  
Facies Succession ◽  
Early Late

AbstractCenomanian strata of the Elbtal Group (Saxony, eastern Germany) reflect a major global sea-level rise and contain, in certain intervals, a green authigenic clay mineral in abundance. Based on the integrated study of five new core sections, the environmental background and spatio-temporal patterns of these glauconitic strata are reconstructed and some general preconditions allegedly needed for glaucony formation are critically questioned. XRD analyses of green grains extracted from selected samples confirm their glauconitic mineralogy. Based on field observations as well as on the careful evaluation of litho- and microfacies, 12 glauconitc facies types (GFTs), broadly reflecting a proximal–distal gradient, have been identified, containing granular and matrix glaucony of exclusively intrasequential origin. When observed in stratigraphic succession, GFT-1 to GFT-12 commonly occur superimposed in transgressive cycles starting with the glauconitic basal conglomerates, followed up-section by glauconitic sandstones, sandy glauconitites, fine-grained, bioturbated, argillaceous and/or marly glauconitic sandstones; glauconitic argillaceous marls, glauconitic marlstones, and glauconitic calcareous nodules continue the retrogradational fining-upward trend. The vertical facies succession with upwards decreasing glaucony content demonstrates that the center of production and deposition of glaucony in the Cenomanian of Saxony was the nearshore zone. This time-transgressive glaucony depocenter tracks the regional onlap patterns of the Elbtal Group, shifting southeastwards during the Cenomanian 2nd-order sea-level rise. The substantial development of glaucony in the thick (60 m) uppermost Cenomanian Pennrich Formation, reflecting a tidal, shallow-marine, nearshore siliciclastic depositional system and temporally corresponding to only ~ 400 kyr, shows that glaucony formation occurred under wet, warm-temperate conditions, high accumulation rates and on rather short-term time scales. Our new integrated data thus indicate that environmental factors such as great water depth, cool temperatures, long time scales, and sediment starvation had no impact on early Late Cretaceous glaucony formation in Saxony, suggesting that the determining factors of ancient glaucony may be fundamentally different from recent conditions and revealing certain limitations of the uniformitarian approach.

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