Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian–Turonian) of Uzbekistan

2013 ◽  
Vol 50 (3) ◽  
pp. 306-314 ◽  
Author(s):  
Hans-Dieter Sues ◽  
Alexander Averianov
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Theropod Dinosaurs ◽  
Kyzylkum Desert

Upper Cretaceous (Cenomanian–Turonian) formations in the Kyzylkum Desert of Uzbekistan, especially the Bissekty Formation at Dzharakuduk, have yielded a great diversity of continental vertebrates, including dinosaurs. Underwater screening of the sandy matrix has recovered many dinosaurian teeth. Here we describe and illustrate two types of enigmatic theropod teeth that are referable to Paronychodon and Richardoestesia, respectively. Both of these tooth taxa are well known from the Late Cretaceous of North America and possibly represent stages in the development of the teeth of various paravian theropods. Confirmation of this hypothesis awaits discovery of more complete jaws.

Parataxonomic classification of ornithoid eggshell fragments from the Oldman Formation (Judith River Group; Upper Cretaceous), southern Alberta

1996 ◽  
Vol 33 (12) ◽  
pp. 1655-1667 ◽  
Author(s):  
Darla K. Zelenitsky ◽  
L. V. Hills ◽  
Philip J. Currie
Keyword(s):  
Late Cretaceous ◽  
Shell Thickness ◽  
Upper Cretaceous ◽  
Theropod Dinosaur ◽  
Surface Sculpture ◽  
External Zone ◽  
Theropod Dinosaurs ◽  
Southern Alberta ◽  
The Family

Examination of a large number of eggshell fragments collected from the Oldman Formation of southern Alberta reveals a greater ootaxonomic diversity than is known from complete eggs or clutches. Three new oogenera and oospecies of the ornithoid-ratite morphotype and one of the ornithoid-prismatic morphotype are established, based on the eggshell fragments. Porituberoolithus warnerensis oogen. et oosp. nov. and Continuoolithus canadensis oogen. et oosp. nov. have a microstructure similar to that of elongatoolithid eggs of theropod dinosaurs. Tristraguloolithus cracioides oogen. et oosp. nov. and Dispersituberoolithus exilis oogen. et oosp. nov. possess an external zone and thus have a microstructure like modern avian eggshell. Tristraguloolithus has a shell thickness, microstructure, and surface sculpture similar to those of recent bird eggshell of the family Cracidae (order Galliformes). Dispersituberoolithus exhibits the primitive or normal eggshell condition of some recent neognathous avian taxa. The ootaxa described indicate a diversity of both avian and theropod dinosaur egg layers within Devil's Coulee and Knight's Ranch, southern Alberta, during the Late Cretaceous.

scholarly journals A new, transitional centrosaurine ceratopsid from the Upper Cretaceous Two Medicine Formation of Montana and the evolution of the ‘ Styracosaurus -line' dinosaurs

2020 ◽  
Vol 7 (4) ◽  
pp. 200284 ◽  
Author(s):  
John P. Wilson ◽  
Michael J. Ryan ◽  
David C. Evans
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Frames Of Reference ◽  
Unique Combination ◽  
Holotype Specimen ◽  
Intermediate Morphology ◽  
Northwestern Montana ◽  
Phylogenetic Framework ◽  
Stratigraphic Succession

Ceratopsids are among the most ubiquitous dinosaur taxa from the Late Cretaceous terrestrial formations of the Western Interior of North America, comprising two subfamilies, Chasmosaurinae and Centrosaurinae. The Two Medicine Formation of northwestern Montana has produced numerous remains of centrosaurine dinosaurs, which represent three taxa previously considered valid: Rubeosaurus ovatus , Einiosaurus procurvicornis and Achelousaurus horneri . Here, we reassess the previous referral of specimens to Rubeousaurus ovatus and demonstrate that this taxon is represented solely by its holotype specimen, which was first diagnosed as Styracosaurus ovatus . One of the specimens previously referred to ‘ Rubeosaurus ’ ovatus instead represents a new eucentrosauran centrosaurine taxon diagnosed here, Stellasaurus ancellae gen. et sp. nov. Stellasaurus expresses a unique combination of eucentrosauran centrosaurine characters, including an elongate nasal horncore, diminutive supraorbital horncores, and a parietal bearing straight, elongate P3 processes, semi-elongate P4 processes and non-elongate P5, P6 and P7 processes. Within the stratigraphic succession of Eucentrosaura, Stellasaurus occurs intermediate to Styracosaurus albertensis and Einiosaurus , and likewise reflects intermediate morphology. Assessed within the stratigraphic, geographical, taphonomic, ontogenetic and phylogenetic framework of Unified Frames of Reference, we fail to reject the hypothesis that Stellasaurus ancellae represents a transitional taxon within an anagenetic lineage of eucentrosauran centrosaurines.

Probable deinonychosaur tracks from the Upper Cretaceous Wapiti Formation (upper Campanian) of Alberta, Canada

2020 ◽  
pp. 1-14
Author(s):  
Nathan J. Enriquez ◽  
Nicolás E. Campione ◽  
Corwin Sullivan ◽  
Matthew Vavrek ◽  
Robin L. Sissons ◽  
...  
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
North American ◽  
Upper Cretaceous ◽  
Temporal Window ◽  
Track Record ◽  
Important Addition ◽  
Additional Support ◽  
Upper Campanian

Abstract Late Cretaceous tracks attributable to deinonychosaurs in North America are rare, with only one occurrence of Menglongipus from Alaska and two possible, but indeterminate, occurrences reported from Mexico. Here we describe the first probable deinonychosaur tracks from Canada: a possible trackway and one isolated track on a single horizon from the Upper Cretaceous Wapiti Formation (upper Campanian) near Grande Prairie in Alberta. The presence of a relatively short digit IV differentiates these from argued dromaeosaurid tracks, suggesting the trackmaker was more likely a troodontid. Other noted characteristics of the Wapiti specimens include a rounded heel margin, the absence of a digit II proximal pad impression, and a broad, elliptical digit III. Monodactyl tracks occur in association with the didactyl tracks, mirroring similar discoveries from the Early Cretaceous Epoch of China, providing additional support for their interpretation as deinonychosaurian traces. Although we refrain from assigning the new Wapiti specimens to any ichnotaxon because of their relatively poor undertrack preservation, this discovery is an important addition to the deinonychosaur track record; it helps to fill a poorly represented geographic and temporal window in their known distribution, and demonstrates the presence of a greater North American deinonychosaur ichnodiversity than has previously been recognized.

scholarly journals The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA)

2017 ◽  
Author(s):  
Andrew A. Farke ◽  
George E. Phillips
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Depositional Environment ◽  
Upper Cretaceous ◽  
Eastern North America ◽  
Western North America ◽  
Western Interior Seaway ◽  
Double Root ◽  
Union County ◽  
Dentary Tooth

Ceratopsids (“horned dinosaurs”) are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

scholarly journals The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3342 ◽  
Author(s):  
Andrew A. Farke ◽  
George E. Phillips
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Depositional Environment ◽  
Upper Cretaceous ◽  
Eastern North America ◽  
Western North America ◽  
Western Interior Seaway ◽  
Double Root ◽  
Union County ◽  
Dentary Tooth

Ceratopsids (“horned dinosaurs”) are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

The first records of Elmisaurus (Saurischia, Theropoda) from North America

1989 ◽  
Vol 26 (6) ◽  
pp. 1319-1324 ◽  
Author(s):  
Philip J. Currie
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Genetic Similarity ◽  
Upper Cretaceous ◽  
Type Specimen ◽  
Longitudinal Ridge ◽  
Provincial Park

The discovery of a fused tarsometatarsus in the Upper Cretaceous (Campanian) strata of Dinosaur Provincial Park shows that Elmisaurus, previously known only from Mongolia, also lived in North America. Reexamination of the type specimen of "Ornithomimus" elegans (Parks 1933) confirms the identification and provides a species name. Elmisaurus elegans is more gracile than Elmisaurus rarus, has a weaker longitudinal ridge on the fourth metatarsal, and has a pair of distal processes on metatarsals II and IV. Although six theropod families had representatives in both North America and Asia during Cretaceous times, the degree of genetic similarity is poorly understood. Analysis of the Elmisaurus material suggests that faunal interchange was still underway during the Late Cretaceous.

scholarly journals The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA)

2017 ◽  
Author(s):  
Andrew A. Farke ◽  
George E. Phillips
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Depositional Environment ◽  
Upper Cretaceous ◽  
Eastern North America ◽  
Western North America ◽  
Western Interior Seaway ◽  
Double Root ◽  
Union County ◽  
Dentary Tooth

Ceratopsids (“horned dinosaurs”) are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

Mammals from the Upper Cretaceous Oldman Formation, Alberta. V. Eodelphis Matthew, and the evolution of the Stagodontidae (Marsupialia)

1981 ◽  
Vol 18 (2) ◽  
pp. 350-365 ◽  
Author(s):  
Richard C. Fox
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Related Species ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Time Development ◽  
Special Relationship ◽  
Subsequent Increase ◽  
Closely Related Species ◽  
Primitive Species

The Judithian (Late Cretaceous) stagodontid marsupial Eodelphis Matthew is known from two closely related species, E. cutleri and E. browni, which differ in size and proportions of P3 and robustness of the molars. P1 is shown to be two-rooted in both species and not only in E. cutleri, as previously believed. Known upper molars of Eodelphis lack a stylar cusp D, indicating that neither E. cutleri nor E. browni can be a part of the direct (species) ancestry of the later Cretaceous stagodontid Didelphodon. Evolution of the Stagodontidae probably included derivation of an E. cutleri-like radicle having robust premolars and molars from E. browni-like ancestors, present in North America by Aquilan time; development by the Edmontonian of specialized crushing premolars in primitive species of Didelphodon, descended from ancestors that were similar to E. cutleri in size but had a prominent stylar cusp D on the upper molars; and subsequent increase in size leading to Lancian D. vorax and D. padanicus. Contrary to recent speculation, the Stagodontidae have no special relationship to the Lower Cretaceous Pappotheriidae, which are Eutheria.

Frontal bones of non-avian theropod dinosaurs from the Upper Cretaceous (Santonian–?Campanian) Bostobe Formation of the northeastern Aral Sea region, Kazakhstan

2016 ◽  
Vol 53 (2) ◽  
pp. 168-175 ◽  
Author(s):  
Alexander Averianov
Keyword(s):  
North America ◽  
Cerebral Hemisphere ◽  
Upper Cretaceous ◽  
Aral Sea ◽  
Dome A ◽  
Anterior Process ◽  
Theropod Dinosaurs ◽  
Orbital Rim

Three theropod taxa have been identified based on isolated frontal bones from the Santonian–?Campanian Bostobe Formation at the Shakh-Shakh locality, in the northeastern Aral Sea region of Kazakhstan. A frontal referable to Ornithomimosauria indet. is distinct in having a slightly pronounced cerebral dome. A frontal of an unidentified therizinosaur resembles the element in Erlikosaurus (Cenomanian—Turonian of Mongolia) in most features, but it differs in having an anterolateral prong along the orbital rim, a less-developed facet for contact with the prefrontal, and a larger depression for the cerebral hemisphere. A frontal identifiable as Troodontidae indet. differs from that of Troodon (Campanian—Maastrichtian of North America) and resembles that of the Mongolian Campanian Gobivenator in having a larger supratemporal fossa and the anterior process of the parietals wedged between the frontals. This specimen is the first reliable record for Troodontidae from the Bostobe Formation.

A large pteranodontid pterosaur from the Late Cretaceous of Eastern Europe

2020 ◽  
pp. 1-13
Author(s):  
Alexander O Averianov ◽  
Maxim S Arkhangelsky
Keyword(s):  
North America ◽  
Eastern Europe ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
The Other

Abstract The Campanian Beloe Ozero locality within the Rybushka Formation in Saratov Province, Russia, is one of the richest and most diverse Upper Cretaceous pterosaur localities in Europe. It produces identifiable remains of Pteranodontidae indet. and Azhdarchidae indet., as well as bones which can be attributed to either of these groups. The pteranodontid specimens from the Beloe Ozero locality described in this paper include a cervical III, distal scapula, humerus deltopectoral crest, proximal syncarpal, preaxial carpal and complete femur. Based on the femur and proximal syncarpal, the wingspan estimate for the Beloe Ozero pteranodontid varies from 5.2 to 6.5 m. Volgadraco bogolubovi, known from the neighbouring Shyrokii Karamysh locality of the same formation and attributed previously to the Azhdarchidae, is more likely pteranodontid than azhdarchid. The other putative records of the Pteranodontidae in the Late Cretaceous of North America, Europe and Asia are discussed. Pteranodontid pterosaurs had a much wider distribution on the northern continents in the Late Cretaceous than previously thought.

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