First report of protoceratopsians (Neoceratopsia) from the Late Cretaceous Judith River Group, Alberta, Canada

1998 ◽  
Vol 35 (7) ◽  
pp. 820-826 ◽  
Author(s):  
Michael J Ryan ◽  
Philip J Currie
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Coastal Environments ◽  
First Report ◽  
Skeletal Material ◽  
First Occurrence ◽  
Dinosaur Park Formation ◽  
Milk River Formation

Protoceratopsians are best known in North America from associated skeletal material of Montanoceratops from the early Maastrichtian of Montana and Campanian of Alberta and Leptoceratops from the late Maastrichtian of Alberta and Wyoming. We report here the first occurrence of protoceratopsian elements from the middle Campanian (Dinosaur Park Formation) of Alberta. The specimens consist of a fragmentary right dentary and an almost complete left dentary which can be referred to Leptoceratops sp. Recent examination of Albertan microvertebrate material has identified cf. protoceratopsians teeth from the latest Santonian (Milk River Formation), extending the record of Albertan protoceratopsians back almost 20 million years. The rarity of these small ornithischians in the fossil record of Alberta may have been due to ecological exclusion from the wet, coastal environments that were preferred by the larger, more abundant ceratopsids.

A review of nonmarine turtles from the Late Cretaceous of Alberta

2003 ◽  
Vol 40 (4) ◽  
pp. 557-571 ◽  
Author(s):  
Donald B Brinkman
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Geographic Area ◽  
Hell Creek Formation ◽  
Diversity Gradient ◽  
The Family ◽  
Group A ◽  
Dinosaur Park Formation ◽  
Milk River Formation ◽  
Horseshoe Canyon Formation

The Late Cretaceous of Alberta preserves one of the most complete records of fossil turtles within a single geographic area in North America. The Cenomanian Dunvegan Formation contains the earliest record of the family Trionychidae in North America. The Santonian Milk River Formation contains a minimum of ten taxa with Adocus, a small trionychid, and a member of the Solemydidae being the most abundant. Diversity remains high in the mid-Campanian Judith River Group. The solemyidid last occurs in the basal beds of the Judith River Group. A member of the Macrobaenidae first occurs in the Dinosaur Park Formation, the uppermost formation in the Judith River Group. Turtles diversity is low in the late Campanian lower Horseshoe Canyon Formation, and they are absent in the early Maastrichtian upper Horseshoe Canyon Formation. Diversity increases in the late Maastrichtian Scollard Formation, although it is much less than in the contemporaneous Hell Creek Formation of Montana. Two of the taxa present in the Scollard Formation, Compsemys and Plastomenus, occur in late Campanian or early Maastrichtian formations in more southerly areas of North America. The changes in turtle diversity through the Campanian and Maastrichtian are interpreted as a result of shifts in a latitudinal turtle diversity gradient resulting from changes in climate. Based on this interpretation a decrease in temperature from the mid-Campanian to early Maastrichtian, followed by a rapid increase at the beginning of the late Maastrichtian is supported.

Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation

2021 ◽  
pp. 1-15
Author(s):  
Thomas M. Cullen ◽  
Lindsay Zanno ◽  
Derek W. Larson ◽  
Erinn Todd ◽  
Philip J. Currie ◽  
...  
Keyword(s):  
High Resolution ◽  
North America ◽  
Fossil Record ◽  
Upper Cretaceous ◽  
Environmental Changes ◽  
Morphometric Analyses ◽  
Variable Distribution ◽  
Taxic Diversity ◽  
Dinosaur Park Formation ◽  
Broad Scale

The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skeletons. Although small theropods are well documented in the assemblage, taxonomic assessments are frequently based on isolated, fragmentary skeletal elements. Here we reassess DPF theropod biodiversity using morphological comparisons, high-resolution biostratigraphy, and morphometric analyses, with a focus on specimens/taxa originally described from isolated material. In addition to clarifying taxic diversity, we test whether DPF theropods preserve faunal zonation/turnover patterns similar to those previously documented for megaherbivores. Frontal bones referred to a therizinosaur (cf. Erlikosaurus), representing among the only skeletal record of the group from the Campanian–Maastrichtian (83–66 Ma) fossil record of North America, plot most closely to troodontids in morphospace, distinct from non-DPF therizinosaurs, a placement supported by a suite of troodontid anatomical frontal characters. Postcranial material referred to cf. Erlikosaurus in North America is also reviewed and found most similar in morphology to caenagnathids, rather than therizinosaurs. Among troodontids, we document considerable morphospace and biostratigraphic overlap between Stenonychosaurus and the recently described Latenivenatrix, as well as a variable distribution of putatively autapomorphic characters, calling the validity of the latter taxon into question. Biostratigraphically, there are no broad-scale patterns of faunal zonation similar to those previously documented in ornithischians from the DPF, with many theropods ranging throughout much of the formation and overlapping extensively, possibly reflecting a lack of sensitivity to environmental changes, or other cryptic ecological or evolutionary factors.

An ornithurine bird coracoid from the Late Cretaceous of Alberta, Canada

2020 ◽  
pp. 1-7
Author(s):  
Sydney R. Mohr ◽  
John H. Acorn ◽  
Gregory F. Funston ◽  
Philip J. Currie
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Ct Scans ◽  
Micro Ct ◽  
Internal Structures ◽  
Postcranial Remains ◽  
Dinosaur Park Formation ◽  
Upper Campanian

The Cretaceous birds of Alberta are poorly known, as skeletal elements are rare and typically consist of fragmentary postcranial remains. A partial avian coracoid from the upper Campanian Dinosaur Park Formation of Alberta, Canada, can be referred to the Ornithurae, and is referred to here as Ornithurine G (cf. Cimolopteryx). Its structure is similar to previously described ornithurine coracoids from Alberta and other localities in North America, particularly those belonging to the genus Cimolopteryx. A comparison of these elements indicates that the new coracoid is distinct; however, its preservation prevents complete diagnosis. As other Cimolopteryx are Maastrichtian in age, Ornithurine G (cf. Cimolopteryx) also represents the earliest occurrence of a Cimolopteryx-like anatomy. A pneumatized coracoid is a diagnostic trait of Neornithes, identified by the presence of a pneumatic foramen. Ornithurine G (cf. Cimolopteryx) does not preserve this feature. CT and micro-CT scans of both pneumatic and apneumatic coracoids of modern birds show similar internal structures to Ornithurine G (cf. Cimolopteryx), indicating that pneumaticity of the coracoid cannot be determined in the absence of an external pneumatic foramen. A comparison between members of Cimolopterygidae, including Cimolopteryx and Lamarqueavis, raises questions about the assignment of Lamarqueavis to the Cimolopterygidae, and the validity of this family as a whole.

An enigmatic blastozoan echinoderm fauna from central kentucky

2009 ◽  
Vol 83 (5) ◽  
pp. 739-749 ◽  
Author(s):  
Colin D. Sumrall ◽  
Carlton E. Brett ◽  
Troy A. Dexter ◽  
Alexander Bartholomew
Keyword(s):  
North America ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Fossil Record ◽  
Foreland Basin ◽  
Late Ordovician ◽  
Upper Devonian ◽  
Range Extension ◽  
First Report ◽  
Appalachian Foreland

A series of small road cuts of lower Boyle Formation (Middle Devonian: Givetian) near Waco, Kentucky, has produced numerous specimens of three blastozoan clades, including both “anachronistic” diploporan and rhombiferan “cystoids” and relatively advanced Granatocrinid blastoids. This unusual assemblage occurs within a basal grainstone unit of the Boyle Limestone, apparently recording a local shoal deposit. Diploporans, the most abundant articulated echinoderms, are represented by a new protocrinitid species, Tristomiocystis globosus n. gen. and sp. Glyptocystitoid rhombiferans are represented by isolated thecal plates assignable to Callocystitidae. Three species of blastoids, all previously undescribed, include numerous thecae of the schizoblastid Hydroblastus hendyi n. gen. and sp., the rare nucleocrinid Nucleocrinus bosei n. sp., and an enigmatic troosticrinid radial. The blastoid Nucleocrinus is typical for the age; however, the callocystitid, schizoblastid, and protocrinitid are not. Hydroblastus is the oldest known schizoblastid. Middle and Upper Devonian callocystitids have been previously reported only from Iowa and Michigan USA with unpublished reports from Missouri USA and the Northwest Territories, Canada. This occurrence is thus the first report of a Middle Devonian rhombiferan from the Appalachian foreland basin. Tristomiocystis is the first known protocrinitid in North America and the only protocrinitid younger than Late Ordovician. This occurrence thus represents a range extension of nearly 50 million years for protocrinids. This extraordinary sample of echinoderms in a Middle Devonian limestone from a well-studied area of North America highlights the incompleteness of the known fossil record, at least in fragile organisms such as echinoderms.

scholarly journals A new Late Cretaceous iguanomorph from North America and the origin of New World Pleurodonta (Squamata, Iguania)

2017 ◽  
Vol 284 (1847) ◽  
pp. 20161902 ◽  
Author(s):  
David G. DeMar ◽  
Jack L. Conrad ◽  
Jason J. Head ◽  
David J. Varricchio ◽  
Gregory P. Wilson
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Fossil Record ◽  
New World ◽  
Cladistic Analysis ◽  
Arid Environment ◽  
New Taxon ◽  
Low Latitude ◽  
Anatomical Features ◽  
Parietal Foramen

Iguanomorpha (stem + crown Iguania) is a diverse squamate clade with members that predominate many modern American lizard ecosystems. However, the temporal and palaeobiogeographic origins of its constituent crown clades (e.g. Pleurodonta (basilisks, iguanas, and their relatives)) are poorly constrained, mainly due to a meagre Mesozoic-age fossil record. Here, we report on two nearly complete skeletons from the Late Cretaceous (Campanian) of North America that represent a new and relatively large-bodied and possibly herbivorous iguanomorph that inhabited a semi-arid environment. The new taxon exhibits a mosaic of anatomical features traditionally used in diagnosing Iguania and non-iguanian squamates (i.e. Scleroglossa; e.g. parietal foramen at the frontoparietal suture, astragalocalcaneal notch in the tibia, respectively). Our cladistic analysis of Squamata revealed a phylogenetic link between Campanian-age North American and East Asian stem iguanomorphs (i.e. the new taxon + Temujiniidae). These results and our evaluation of the squamate fossil record suggest that crown pleurodontans were restricted to the low-latitude Neotropics prior to their early Palaeogene first appearances in the mid-latitudes of North America.

Species composition of the Late Cretaceous eutherian mammal Paranyctoides Fox

2013 ◽  
Vol 50 (7) ◽  
pp. 693-700 ◽  
Author(s):  
Marisol Montellano-Ballesteros ◽  
Richard C. Fox ◽  
Craig S. Scott
Keyword(s):  
North America ◽  
Species Composition ◽  
Central Asia ◽  
Late Cretaceous ◽  
Geographic Range ◽  
Eutherian Mammal ◽  
The Past ◽  
Central Asian ◽  
Dinosaur Park Formation ◽  
Eutherian Evolution

Although the known record of Mesozoic eutherian mammals has been significantly enriched in recent years, early eutherian evolution is still not well understood. Among the more controversial of Mesozoic eutherians is Paranyctoides Fox, which was described in 1979 from the Judithian Dinosaur Park Formation, Alberta, Canada. It is a rare taxon and therefore has been identified in only a few other North American Late Cretaceous local faunas since. Within the past decade, dental and gnathic remains discovered in Central Asia have also been referred to Paranyctoides, thereby expanding the geographic range of the genus substantially and making it the only Late Cretaceous eutherian ostensibly occurring in both continents. As a result of our detailed study of Paranyctoides, however, we find that the Central Asian species lack the diagnostic characters of Paranyctoides and must be referred to other taxa. We conclude that this genus was limited to North America, ranging from Aquilan to Lancian time, and accordingly we recognize as valid only the following species: Paranyctoides sternbergi (Judithian, Alberta), P. maleficus (Aquilan, Alberta), Paranyctoides Wahweap sp. A and sp. B (Judithian, Utah), Paranyctoides Kaiparowits sp. A and sp. B (Judithian, Utah). Another purported species of Paranyctoides, P. megakeros, from the Lancian of Wyoming, is a junior synonym of Alostera saskatchewanensis.

scholarly journals A tyrannosauroid metatarsus from the Merchantville formation of Delaware increases the diversity of non-tyrannosaurid tyrannosauroids on Appalachia

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4123 ◽  
Author(s):  
Chase D. Brownstein
Keyword(s):  
Phylogenetic Analysis ◽  
North America ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Morphological Features ◽  
The West ◽  
Intermediate Grade

During the Late Cretaceous, the continent of North America was divided into two sections: Laramidia in the west and Appalachia in the east. Although the sediments of Appalachia recorded only a sparse fossil record of dinosaurs, the dinosaur faunas of this landmass were different in composition from those of Laramidia. Represented by at least two taxa (Appalachiosaurus montgomeriensis and Dryptosaurus aquilunguis), partial and fragmentary skeletons, and isolated bones, the non-tyrannosaurid tyrannosauroids of the landmass have attracted some attention. Unfortunately, these eastern tyrants are poorly known compared to their western contemporaries. Here, one specimen, the partial metatarsus of a tyrannosauroid from the Campanian Merchantville Formation of Delaware, is described in detail. The specimen can be distinguished from A. montgomeriensis and D. aquilunguis by several morphological features. As such, the specimen represents a potentially previously unrecognized taxon of tyrannosauroid from Appalachia, increasing the diversity of the clade on the landmass. Phylogenetic analysis and the morphology of the bones suggest the Merchantville specimen is a tyrannosauroid of “intermediate” grade, thus supporting the notion that Appalachia was a refugium for relict dinosaur clades.

scholarly journals The First Fossil Owl (Aves, Strigiformes) From the Paleogene of Africa

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 163
Author(s):  
N. Adam Smith ◽  
Thomas A. Stidham ◽  
Jonathan S. Mitchell
Keyword(s):  
North America ◽  
Fossil Record ◽  
Evolutionary History ◽  
Ecological Role ◽  
Avian Predator ◽  
First Occurrence ◽  
Stark Contrast

The relatively extensive fossil record of owls (Aves, Strigiformes) in North America and Europe stands in stark contrast to the paucity of fossil strigiformes from Africa. The first occurrence of a fossil owl from the Paleogene of Africa extends the fossil record of this clade on that continent by as much as 25 million years, and confirms the presence of large-sized owls in Oligocene continental faunas. The new fossil is tentatively referred to the Selenornithinae, a clade of large owls previously restricted to Europe. This new fossil owl was likely similar in size to the extant Eagle Owls of the genus Bubo, and suggests that the niche of large, volant, terrestrial avian predator, although relatively rare throughout avian evolutionary history, may be an ecological role that was more common among extinct owls than previously recognized.

The skeletal morphology of the solemydid turtleNaomichelys speciosafrom the Early Cretaceous of Texas

2014 ◽  
Vol 88 (6) ◽  
pp. 1257-1287 ◽  
Author(s):  
Walter G. Joyce ◽  
Juliana Sterli ◽  
Sandra D. Chapman
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Fossil Record ◽  
Posterior Margin ◽  
Late Jurassic ◽  
Evolutionary History ◽  
Ventral View ◽  
Skeletal Morphology ◽  
History Of

The fossil record of solemydid turtles is primarily based on isolated fragments collected from Late Jurassic to Late Cretaceous sediments throughout North America and Europe and little is therefore known about the morphology and evolutionary history of the group. We here provide a detailed description of the only known near-complete solemydid skeleton, which was collected from the Lower Cretaceous (Aptian–Albian) Antlers Formation of Texas during the mid-twentieth century, but essentially remains undescribed to date. Though comparison is limited, the skeleton is referred toNaomichelys speciosa, which is based on an isolated entoplastron from the Lower Cretaceous (Aptian–Albian) Kootenai (Cloverly) Formation of Montana. The absence of temporal emarginations, contribution of the jugals to the orbits, and a clear subdivision of the middle and inner cavities, and the presence of elongate postorbitals, posteriorly expanded squamosals, a triangular fossa at the posterior margin of the squamosals, an additional pair of tubercula basioccipitale that is formed by the pterygoids, foramina pro ramo nervi vidiani (VII) that are visible in ventral view, shell sculpturing consisting of high tubercles, a large entoplastron with entoplastral scute, V-shaped anterior peripherals, and limb osteoderms with tubercular sculpture diagnoseNaomichelys speciosaas a representative of Solemydidae. The full visibility of the parabasisphenoid complex in ventral view, the presence of an expanded symphyseal shelf, and the unusual ventromedial folding of the coronoid process are the primary characteristics that distinguishNaomichelys speciosafrom the near-coeval European taxonHelochelydra nopcsai.

A basal bird from the Campanian (Late Cretaceous) of Dinosaur Provincial Park (Alberta, Canada)

2010 ◽  
Vol 147 (3) ◽  
pp. 469-472 ◽  
Author(s):  
ERIC BUFFETAUT
Keyword(s):  
Late Cretaceous ◽  
High Latitude ◽  
Western Canada ◽  
First Report ◽  
Dinosaur Park Formation ◽  
Provincial Park

AbstractA fragmentary bone from the Dinosaur Park Formation (Campanian) of Dinosaur Provincial Park (Alberta, Canada), originally described as a pterosaur tibiotarsus, is reinterpreted as the distal end of the tibiotarsus of a basal bird, probably an enantiornithine, on the basis of several distinctive characters. It is the first report of such a bird from the Dinosaur Park Formation and shows that this group was present, together with various more derived ornithurines, in the relatively high-latitude environments of Late Cretaceous western Canada.

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