A New Theropod Dinosaur (Theropoda, Dromaeosauridae) from the Late Cretaceous of Tajikistan

2021 ◽  
Vol 499 (1) ◽  
pp. 570-574
Author(s):  
A. O. Averianov ◽  
A. V. Lopatin
Keyword(s):  
Late Cretaceous ◽  
Theropod Dinosaur

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.

A new abelisauroid theropod from northwestern Patagonia

2006 ◽  
Vol 43 (9) ◽  
pp. 1283-1289 ◽  
Author(s):  
Rodolfo A Coria ◽  
Philip J Currie ◽  
Ariana Paulina Carabajal
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
First Record ◽  
South American ◽  
Middle Section ◽  
Theropod Dinosaur ◽  
Channel Deposits

The Argentinean record of abelisauroid theropods begins in the Early Cretaceous (Ligabueino) and spans most of the Late Cretaceous, from Cenomanian (Ilokelesia, Xenotarsosaurus, and Ekrixinatosaurus) to Campanian–Maastrichtian (Abelisaurus, Carnotaurus, Aucasaurus, and Noasaurus). A fragmentary specimen of a theropod dinosaur was collected in 2000 from the middle section of the Lisandro Formation (Turonian?) at Cerro Bayo Mesa, Neuquén Province, Argentina. The fossil-bearing level, which is part of the Lisandro Formation that also yielded the remains of the basal ornithopod Anabisetia saldiviai, corresponds to a reddish, massive mudstone linked with fluvial channel deposits. The theropod identified as MCF-PVPH-237 is an abelisauroid theropod that increases our knowledge about the evolution of South American Abelisauroidea and is the first record of this clade from the Lisandro Formation.

New theropod dinosaur from the late Cretaceous of Brazil improves abelisaurid diversity

2021 ◽  
pp. 103551
Author(s):  
Fabiano Vidoi Iori ◽  
Hermínio Ismael de Araújo-Júnior ◽  
Sandra A. Simionato Tavares ◽  
Thiago da Silva Marinho ◽  
Agustín G. Martinelli
Keyword(s):  
Late Cretaceous ◽  
Theropod Dinosaur

scholarly journals An Early Cretaceous theropod dinosaur from Brazil sheds light on the cranial evolution of the Abelisauridae

2020 ◽  
Author(s):  
Hussam ZAHER ◽  
Diego POL ◽  
Bruno A. NAVARRO ◽  
Rafael DELCOURT ◽  
Alberto B. CARVALHO
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Early Stage ◽  
Feeding Strategy ◽  
Occipital Region ◽  
Theropod Dinosaur

Abelisaurid theropods dominated the predator role across Gondwana during the Late Cretaceous. They are characterized by highly reduced forelimbs and one of the most specialized cranial morphologies among carnivorous dinosaurs, exemplified by a broad skull, short rostrum, high occipital region, and highly kinetic intramandibular joint, suggestive of a specialized feeding strategy. Late Cretaceous abelisaurids are known from some remarkably complete taxa with well-preserved skulls. However, little is known about the pattern of character transformation that led to their highly modified condition because there are no well-preserved abelisaurids before the Late Cretaceous. Here we report a basal abelisaurid from the Early Cretaceous of Brazil that preserves a complete skull and reveals an early stage in the cranial evolution of the group. It lacks the specialized temporal and mandibular features characteristic of derived abelisaurids, including the kinetic intramandibular joint and knob-like dorsal projection of the parietals.

Osteology and bone microstructure of new, small theropod dinosaur material from the early Late Cretaceous of Morocco

2015 ◽  
Vol 27 (3) ◽  
pp. 1034-1041 ◽  
Author(s):  
David C. Evans ◽  
Paul M. Barrett ◽  
Kirstin S. Brink ◽  
Matthew T. Carrano
Keyword(s):  
Late Cretaceous ◽  
Bone Microstructure ◽  
Theropod Dinosaur ◽  
Early Late

scholarly journals An aberrant island-dwelling theropod dinosaur from the Late Cretaceous of Romania

2010 ◽  
Vol 107 (35) ◽  
pp. 15357-15361 ◽  
Author(s):  
Z. Csiki ◽  
M. Vremir ◽  
S. L. Brusatte ◽  
M. A. Norell
Keyword(s):  
Late Cretaceous ◽  
Theropod Dinosaur

scholarly journals A new carcharodontosaurian theropod dinosaur occupies apex predator niche in the early Late Cretaceous of Uzbekistan

2021 ◽  
Vol 8 (9) ◽  
pp. 210923
Author(s):  
Kohei Tanaka ◽  
Otabek Ulugbek Ogli Anvarov ◽  
Darla K. Zelenitsky ◽  
Akhmadjon Shayakubovich Ahmedshaev ◽  
Yoshitsugu Kobayashi
Keyword(s):  
Late Cretaceous ◽  
First Record ◽  
New Taxon ◽  
Apex Predator ◽  
Apex Predators ◽  
Theropod Dinosaur ◽  
Rock Record ◽  
The Republic ◽  
Early Late ◽  
Kyzylkum Desert

Carcharodontosauria is a group of medium to large-sized predatory theropods, distributed worldwide during the Cretaceous. These theropods were probably the apex predators of Asiamerica in the early Late Cretaceous prior to the ascent of tyrannosaurids, although few Laurasian species are known from this time due to a poor rock record. Here, we describe Ulughbegsaurus uzbekistanensis gen. et sp. nov. from the early Late Cretaceous (Turonian) of Central Asia, which represents the first record of a Late Cretaceous carcharodontosaurian from the region. This new taxon is represented by a large, isolated maxilla from the Bissekty Formation of the Kyzylkum Desert, the Republic of Uzbekistan, a formation yielding a rich and diverse assemblage of dinosaurs and other vertebrates from fragmentary remains. Comparison of the maxilla with that of other allosauroids indicates Ulughbegsaurus was 7.5–8 m in body length and greater than 1000 kg in body mass, suggesting it was the previously unrecognized apex predator of the Bissekty ecosystem while smaller known tryannosauroids and dromaeosaurids were probable mesopredators. The discovery of Ulughbegsaurus records the geologically latest stratigraphic co-occurrence of carcharodontosaurid and tyrannosauroid dinosaurs from Laurasia, and evidence indicates carcharodontosaurians remained the dominant predators relative to tyrannosauroids, at least in Asia, as late as the Turonian.

scholarly journals The phylogenetic affinities and morphological peculiarities of the bird-like dinosaur Borogovia gracilicrus from the Upper Cretaceous of Mongolia

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12640
Author(s):  
Andrea Cau ◽  
Daniel Madzia
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Distal Part ◽  
The Other ◽  
Theropod Dinosaur ◽  
Distinctive Morphology ◽  
Valid Taxon ◽  
Phylogenetic Affinities ◽  
Second Toe

Borogovia gracilicrus is a small-bodied theropod dinosaur from the Maastrichtian (Upper Cretaceous) Nemegt Formation of southern Mongolia. The taxon is based on a single fragmentary specimen preserving only the distal part of the hindlimbs. The morphology of Borogovia shows a peculiar combination of features, some of which are traditionally considered troodontid synapomorphies and others which are unusual for Troodontidae but are shared with other maniraptoran clades. In particular, the second toe of B. gracilicrus differs from other troodontids in lacking some of the features which contribute to the specialized ‘sickle-clawed’ second toe, here termed the ‘falciphoran condition’, shared with dromaeosaurids and some other paravians, such as the strongly compressed and falciform ungual. Phylogeny reconstructions intended to explore the affinities of Borogovia consistently support its referral within a subclade of troodontids including all Late Cretaceous taxa. The placement of Borogovia is not significantly affected by its unusual combinations of hindlimb features or by the homoplasy of the elements forming the falciphoran condition. Borogovia is supported as a valid taxon and is distinct from the other Nemegt troodontids, Tochisaurus and Zanabazar. The lack of a falciform ungual, and the distinctive morphology of the second toe in B. gracilicrus are interpreted as a derived specialization among Troodontidae and not as retention of the plesiomorphic condition of non-paravian theropods.

Gut contents from a Cretaceous Tyrannosaurid: Implications for theropod dinosaur digestive tracts

2001 ◽  
Vol 75 (2) ◽  
pp. 401-406 ◽  
Author(s):  
David J. Varricchio
Keyword(s):  
Late Cretaceous ◽  
Digestive Enzymes ◽  
Food Source ◽  
Western Montana ◽  
Gut Contents ◽  
Theropod Dinosaur ◽  
Surface Corrosion ◽  
Limb Proportions ◽  
Partial Skeleton

A partial skeleton of Daspletosaurus sp. from the Late Cretaceous (Campanian) Two Medicine Formation of western Montana preserves the first gut contents reported for a tyrannosaurid. Associated remains found with this skeleton consist of acidetched vertebrae and a fragmentary dentary from juvenile hadrosaur dinosaurs. Hadrosaur bonebed data and comparisons of hadrosaur and tyrannosaurid limb proportions suggest that juvenile hadrosaurs represented both an abundant and accessible food source. The surface corrosion exhibited by the hadrosaur elements matches that produced by stomach acids and digestive enzymes in a wide variety of living vertebrates. Based upon these and other gut contents, and also upon tooth-marked bone studies, it appears that Daspletosaurus and most theropods ingested and digested prey in a manner similar to that of extant archosaurs (crocodilians and birds), employing a two-part stomach with an enzyme-producing proventriculus followed by a thick-walled muscular gizzard. This two-part stomach appears to be an archosaur synapomorphy.

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