Crétacé

Phylogenetic relationships, chronostratigraphic, and paleoecological implications of M. intrepidus. a Graphic illustrating temporal range of North American tyrannosauroids including species-level range prior to the discovery of M. intrepidus, extension of current range, and hypothesized range based on isolated teeth12. The current gap in the North American tyrannosauroid record spans from the Tithonian to the Aptian. Faunal composition of Late Cretaceous ecosystems was established between the Albian and Turonian, as recognized by the stratigraphic appearance of major clades (see refs. 7,12 and references therein). b generalized phylogenetic relationships of Tyrannosauroidea, showing the appearance of select traits related to cursoriality in tyrannosaurs that are newly optimized as a result of the discovery of M. intrepidus. Tree topology follows this study using the modified dataset of Carr and colleagues27. Coelurus and Tanycolagreus are grafted as basal tyrannosauroids following Brusatte and colleagues5. c Stratigraphic distribution of Allosauria in North America (incl. Megaraptora but see ref. 70 for alternative hypotheses regarding this clade) documents overlap with M. intrepidus in early Late Cretaceous ecosystems leading to (d) refined calibration on the origin of late diverging tyrannosauroids and clade-level faunal turnover within apex predator roles throughout the Late Jurassic–Late Cretaceous of North America. Colored polygons are stylized call-outs and are not intended to reflect two-dimensional data. Temporal data corresponding to this figure are available in Supplementary Table 5

Clidastes propython, a mosasaur from the Late Cretaceous of Kansas, digital.

A map showing the distribution of paraves in Late Cretaceous with the respective paleogeographic setting.

A map showing the distribution of paraves in Early Cretaceous with respective paleogeographic setting.

Diuqin is an unenlagiine dinosaur from the Late Cretaceous of what is now Argentina. Unenlagiines, known exclusively from South America, are usually classified as dromaeosaurs though this is sometimes debated. Like dromaeosaurs, they were covered in feathers, carnivorous, and had the large sickle-like claw on the inner toe of each foot. Unique to unenlagiines is their elongated snout, suggesting a piscivorous diet. Diuqin was a medium-sized unenlagiine, at about 4 m in length.

Figure 1. Evolution of macroecological traits in Dinosauria. Large scale event in dinosaur evolution (a); the origin of dinosaurs (star), hyperthermals (volcano), the earliest fossil Avialae (bird), the earliest fossil angiosperm (flower), the Cretaceous/Palaeogene mass extinction (asteroid). Phylogeny of dinosaurs (b) redrawn from Sereno and adapted to the current consensus and upon which an ancestral state reconstruction of temperature niche (mean annual temperature) after Chiarenza et al. is plotted; Mesozoic palaeogeographies (c) for Triassic (T), Jurassic (J) and Cretaceous (K). Silhouette colours symbolize body mass for each of the taxa represented; information on dietary habits are plotted after Barrett and Zanno & Makovicky; numbers represent clades discussed through this study: 1, Ornithischia; 2, Thyreophora; 3, Ornithopoda; 4, Hadrosauroidea; 5, Marginocephalia; 6, Ceratopsia; 7, Saurischia; 8, Sauropodomorpha; 9, Sauropoda; 10, Theropoda; 11, Ceratosauria; 12, Tetanurae; 13, Coelurosauria; 14, Maniraptoriformes; 15, Maniraptora; 16, Deinonychosauria; 17, Avialae; 18, Ornithothoraces. Palaeogeographies modified from original plots via R package ‘mapast’ using plate models by Scotese.

A photograph of partial specimen American Museum of Natural History (AMNH) 22555, skull without mandible, of Anhanguera sp. (formerly often assigned to Anhanguera santanae),[1] from the Early Cretaceous Romualdo Formation (former Romualdo Member of the Santana Formation) of NE Brazil in right lateral view.

A photograph of partial specimen American Museum of Natural History (AMNH) 22555, anterior dorsal vertebrae, dorsal ribs and partial shoulder girdle (at least right scapula) of Anhanguera sp. (formerly often assigned to Anhanguera santanae),[1] from the Early Cretaceous Romualdo Formation (former Romualdo Member of the Santana Formation) of NE Brazil in dorsal view.

A photograph of partial specimen American Museum of Natural History (AMNH) 22555, posterior dorsal vertebrae, and the sacrum and pelvis (both iliae, and right ischium and pubis) of Anhanguera sp. (formerly often assigned to Anhanguera santanae),[1] from the Early Cretaceous Romualdo Formation (former Romualdo Member of the Santana Formation) of NE Brazil in dorsal view.

Reconstitution d'un Tylosaurus rex dans la voie maritime intérieure occidentale de l'Amérique du Nord, datant de l'époque du Crétacé.

Elasmosaurus platyurus, plesiosaurian from Late Cretaceous (Campanian) of North America

Elasmosaurus platyurus, plesiosaurian from Late Cretaceous (Campanian) of North America

Dorsal vertebra of platecarpus, a cretaceous. Mosasaur from the Niobrara Chalk of Kansas etc. General Collections Keywords: prehistoric archaeology; Paleopathology; Moodie, Roy Lee

Holotype of Alcione elainus. Fig. 6 of: Longrich, N. R., Martill, D. M., & Andres, B. (2018). Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary. PLoS biology, 16(3), e2001663. --- Original figure legend: A. elainus FSAC-OB 2, holotype partial skeleton and FSAC-OB 217, metacarpal IV. (A) Holotype right humerus in anterior view, (B) holotype right ulna and radius in anterior view, respectively, (C) holotype sternum in left lateral view, (D) referred metacarpal IV, (E) holotype, distal end of left metacarpal IV and left scapulocoracoid, and (F) holotype right femur in posterior view. Abbreviations: co, coracoid; cr, cristospine; dc, distal condyle; dpc, deltopectoral crest; ect, ectepicondyle; fh, femoral head; gl, glenoid; gt, greater trochanter; hh, humeral head; hum, humerus; mcIV, metacarpal IV, pc, proximal cotyle; pf, pneumatic foramen; rad, radius; scpr, supracondylar process; ste, sternum; uln, ulna.

Holotype of Alcione elainus. Fig. 6 of: Longrich, N. R., Martill, D. M., & Andres, B. (2018). Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary. PLoS biology, 16(3), e2001663. --- Original figure legend: A. elainus FSAC-OB 2, holotype partial skeleton and FSAC-OB 217, metacarpal IV. (A) Holotype right humerus in anterior view, (B) holotype right ulna and radius in anterior view, respectively, (C) holotype sternum in left lateral view, (D) referred metacarpal IV, (E) holotype, distal end of left metacarpal IV and left scapulocoracoid, and (F) holotype right femur in posterior view. Abbreviations: co, coracoid; cr, cristospine; dc, distal condyle; dpc, deltopectoral crest; ect, ectepicondyle; fh, femoral head; gl, glenoid; gt, greater trochanter; hh, humeral head; hum, humerus; mcIV, metacarpal IV, pc, proximal cotyle; pf, pneumatic foramen; rad, radius; scpr, supracondylar process; ste, sternum; uln, ulna.

Illustration of a juvenile Tyrannosaurus rex. Most of this restoration is mostly inspired from the models of 1-year old Tyrannosaurus from the exhibition "T.rex: The Ultimate Predator" at American Museum of Natural History, New York (2019-2021).[1] [2] and the juvenile Tarbosaurus MPC-D 107/7 (2-3 years old at death).[3] References ↑ [1] ↑ [2] ↑ Tsuihiji T et.al (2011). "Cranial osteology of a juvenile specimen of Tarbosaurus bataar (Theropoda, Tyrannosauridae) from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia". Journal of Vertebrate Paleontology 31(3): p. 497-517