Late Cretaceous

A broken concretion with fossils inside; Late Cretaceous Pierre shale, near Ekalaka, Montana.

Sidersaura is a rebbachisaurid sauropod dinosaur from the Late Cretaceous of Argentina. Rebbachisaurids are the last known dipldocoids, and lived alongside the titanosaurs until fairly late in the Cretaceous before disappearing from the fossil record, presumably going extinct. They have long tails and relatively short necks, by sauropod standards. Sidersaura one of the most recent rebbachisaurids yet found, living in the Cenomanian–Turonian ages of the Late Cretaceous. It was large for a rebbachisaurid, growing to about 20 m in length.

Muzquizopteryx coahuilensis (Familyː Nyctosauridae) is a species of nyctosaurid pterodactyloid pterosaur from the Late Cretaceous period (early Coniacian stage) of what is now Coahuila, Mexico.

Alvarezsauroid theropod Linhenykus monodactylus Xu, Sullivan, Pittman, Choiniere, Hone, Upchurch, Tan, Xiao, Tan, and Han, 2011a, Bayan Mandahu (“Gate Locality”), Late Cretaceous (Campanian), holo−type (IVPP V17608). Skeletal silhouette showing preserved bones (missing portions shown in grey).

Diagram depicting the currently named Dinosauria from the Late Cretaceous Allen Formation of Argentina. Dinosaur taxa: Aeolosaurus sp. → Salitral Moreno locality, Río Negro Province.[1] Length = 15 meters.[2] Austroraptor cabazai → Santa Rosa Basin locality, Río Negro Province.[3][4] Length = 6 meters.[2] Bonapartenykus ultimus → Salitral Ojo de Agua locality, Río Negro Province.[5] Length = 2.5 meters.[5] Bonapartesaurus rionegrensis → Salitral Moreno locality, Río Negro Province.[6] Length = ∼6 meters.[1] Bonatitan reigi → Salitral de Santa Rosa locality, Río Negro Province.[7] Length = Extrapolated after relatives. Kelumapusaura machi → Cerro Matadero locality, Río Negro Province.[8] 9 meters.[8] Lamarqueavis australis → Cerro Tortugas locality, Río Negro Province.[9] Length = ∼House sparrow-sized.[9] Lapampasaurus cholinoi → Islas Malvinas locality, La Pampa Province.[10] Length = ∼7 meters.[2] Limenavis patagonica → Salitral Moreno locality, Río Negro Province.[11] Length = Extrapolated after relatives. Menucocelsior arriagadai → Salitral Ojo de Agua locality, Río Negro Province. Niebla antiqua → Cerro Matadero locality, Río Negro Province.[12] Length = 4.5 meters.[12] Panamericansaurus schroederi → Bodega Familia Schroeder locality, Neuquén Province.[13] Length = 11 meters.[2] Patagopelta cristata → Salitral Moreno locality, Río Negro Province. Quilmesaurus curriei → Salitral Ojo de Agua locality, Río Negro Province.[14] Length = 5.3 meters.[12] Rocasaurus muniozi → Salitral Moreno locality, Río Negro Province.[15] Length = Extrapolated after relatives. Excluded taxa: Willinakaqe salitralensis is considered a nomen dubium,[16] and its paratype has been reassigned to Bonapartesaurus rionegrensis.[6] Laplatasaurus araukanicus has been restricted to its lectotype which hails from the Anacleto Formation.[17] Abelisaurus comahuensis could either belong to the Allen or Anacleto formations.[12] Pellegrinisaurus powelli could either belong to the Allen or Anacleto formations.[18][19] References ↑ (2013). "The titanosaur sauropods from the late Campanian-early Maastrichtian Allen Formation of Salitral Moreno, Río Negro, Argentina". Acta Palaeontologica Polonica 58 (2): 269–284. DOI:10.4202/app.2011.0055. ↑ a b c (2007) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Random House ISBN: 9780375824197. Genus List for Holtz 2012 Weight Information ↑ (2008). "A bizarre Cretaceous theropod dinosaur from Patagonia and the evolution of Gondwanan dromaeosaurids". Proceedings of the Royal Society B: Biological Sciences 276 (1659): 1101–7. DOI:10.1098/rspb.2008.1554. ISSN 1471-2954. ↑ (2012). "A New Specimen of Austroraptor cabazai Novas, Pol, Canale, Porfiri and Calvo, 2008 (Dinosauria, Theropoda, Unenlagiidae) from the Latest Cretaceous (Maastrichtian) of Río Negro, Argentina". Ameghiniana 49 (4): 662–667. DOI:10.5710/AMGH.30.8.2012.574. ↑ a b Federico L. Agnolin (2012). "New alvarezsaurid (Dinosauria, Theropoda) from uppermost Cretaceous of north-western Patagonia with associated eggs". Cretaceous Research 35: 33–56. DOI:10.1016/j.cretres.2011.11.014. ↑ a b (2017). "Bonapartesaurus rionegrensis, a new hadrosaurine dinosaur from South America: implications for phylogenetic and biogeographic relations with North America". Journal of Vertebrate Paleontology 37 (2): 1–16. DOI:10.1080/02724634.2017.1289381. ↑ Salgado L., Gallina P.A. and Paulina Carabajal A. 2014. "Redescription of Bonatitan reigi (Sauropoda: Titanosauria), from the Campanian–Maastrichtian of the Río Negro Province (Argentina)". Historical Biology: An International Journal of Paleobiology 27(5): 525-548 ↑ a b (2022). "A new hadrosaurid (Dinosauria: Ornithischia) from the Late Cretaceous of northern Patagonia and the radiation of South American hadrosaurids". Journal of Systematic Palaeontology. DOI:10.1080/14772019.2021.2020917. ↑ a b (2010). "[https://pdfs.semanticscholar.org/f6f4/c6eb05d224719916c0b20634f54dfeb37d3f.pdf An avian coracoid from the Upper Cretaceous of Patagonia, Argentina]". Studia Geologica Salmanticensia 46 (2): 99-119. ISSN 0211-8327. ↑ Rodolfo A. Coria, Bernardo González Riga and Silvio Casadío (2012). "Un nuevo hadrosáurido (Dinosauria, Ornithopoda) de la Formación Allen, provincia de La Pampa, Argentina". Ameghiniana 49 (4): 552–572. ↑ Clarke and Chiappe, 2001. A new carinate bird from the Late Cretaceous of Patagonia (Argentina). American Museum Novitates. 3323, 1-23. ↑ a b c d (in English) Aranciaga Rolando, Mauro (2020). "A new medium-sized abelisaurid (Theropoda, Dinosauria) from the late cretaceous (Maastrichtian) Allen Formation of Northern Patagonia, Argentina". Journal of South American Earth Sciences: 102915. DOI:10.1016/j.jsames.2020.102915. ISSN 0895-9811. ↑ (2010). "Panamericansaurus schroederi gen. nov. sp. nov. Un nuevo Sauropoda (Titanosauridae-Aeolosaurini) de la Provincia del Neuquén, Cretácico Superior de Patagonia, Argentina". Brazilian Geographical Journal: Geosciences and Humanities research medium 1: 100–115. ↑ Coria, R.A. (2001) "A new theropod from the Late Cretaceous of Patagonia" in Tanke, Darren H., ed. Mesozoic Vertebrate Life, Life of the Past, Indiana University Press, pp. 3–9 ISBN: 978-0-253-33907-2. ↑ Salgado, L. and C. Azpilicueta. 2000. Un nuevo saltasaurino (Sauropoda, Titanosauridae) de la provincia de Río Negro (Formacíon Allen, Cretácico Superior), Patagonia, Argentina archive copy at the Wayback Machine. Ameghiniana 37 (3):259-264. ↑ (2016). "Revisiting the hadrosaurid diversity of the Allen Fm.: Re-evaluation of the taxonomic validity of Willinakaqe salitralensis (Ornithopoda, Hadrosauridae) from Salitral Moreno, Río Negro Province, Argentina". Ameghiniana 53 (2): 231–237. DOI:10.5710/AMGH.25.09.2015.2943. ↑ Pablo A. Gallina & Alejandro Otero (2015) Reassessment of Laplatasaurus araukanicus (SAUROPODA: TITANOSAURIA), from the Late Cretaceous of Patagonia, Argentina. Ameghiniana 52 (5):487–501. doi:10.5710/AMGH.08.06.2015.2911. ↑ (1996). "Pellegrinisaurus powelli nov. gen. et sp. (Sauropoda, Titanosauridae) from the Upper Cretaceous of Lago Pellegrini, Northwestern Patagonia, Argentina". Ameghiniana 33 (4): 355–365. ISSN 1851-8044. ↑ Heredia, S., & Salgado, L. (2014). Posición estratigráfica de los estratos supracretácicos portadores de dinosaurios en Lago Pellegrini, Patagonia septentrional, Argentina. Ameghiniana, 36(2), 229-234.

A restoration of Rinconsaurus compared to a human , • Based proportionally on fossil elements and skeletal reconstruction featured in the Rinconsaurus description,[1] with missing parts based on other titanosaur reconstructions. The remains of Rinconsaurus represent two adults and a juvenile all of which are incomplete; some of the proportions shown here, such as the neck, limb lengths, and skull shape are not certain. • Osteroderms are not yet known in Rinconsaurus. The osteoderms shown here are based loosely on Mendozasaurus.[2] Osteoderms are known from at least 10 titanosaur genera spread across the family tree but it's not clear if all titanosaurs had them.[3] Titanosaur osteoderms are rare and their layout and position on the body are not certain. [4] • The colours and patterns, as with the majority of reconstructions of prehistoric creatures, are speculative. • Human silhouette approximately 180 cm tall. NOTE: I often update my images. If you want to have any of my images on a website, please (if possible) don’t host/save it to the website server. I’d prefer it if the image's Wikimedia URL is used. This means that if I update an image, it will be updated on the site as well. Thanks. References ↑ Coria, Jorge; B.J.G. Riga (2003). "Rinconsaurus caudamirus gen. et sp nov., a new titanosaurid (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia, Argentina". Revista Geologica de Chile 30 (2): 333–353. ISSN 0716-0208. Retrieved on 2007-05-21. ↑ González Riga B (2003) A new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Mendoza, Argentina. Ameghiniana 40 (2) ↑ Carrano, M.T. and D’Emic, M.D. 2015 'Osteoderms of the titanosaur sauropod dinosaur Alamosaurus sanjuanensis Gilmore, 1922'. Journal of Vertebrate Paleontology. ↑ Vidal D, Ortega F, Sanz JL (2014) Titanosaur Osteoderms from the Upper Cretaceous of Lo Hueco (Spain) and Their Implications on the Armor of Laurasian Titanosaurs. PLoS ONE 9(8): e102488. doi:10.1371/journal.pone.0102488

Comparison of cranial features between closely related southern Laramidian taxa; (A), Akainacephalus johnsoni (UMNH VP 20202) from the Late Cretaceous Kaiparowits Formation of Utah; and (B), Nodocephalosaurus kirtlandensis (SMP VP-900) from the Late Cretaceous Kirtland Formation of New Mexico, in left lateral views. Various synapomorphies are shared with N. kirtlandensis (highlighted in black and white arrows) and includes “flaring nostrils”; enlarged, laterally projecting, loreal osteoderms that are situated directly dorsal to the external nares. Other synapomorphies include pyramid-shaped nasal and frontal osteoderms positioned on the dorsal regions of the skull. A number of significant differences have been observed between both specimens; in A. johnsoni, the anterior, and posterior supraorbital bosses form an enlarged element that is somewhat backswept, whereas in N. kirtlandensis, the posterior and anterior supraorbital bosses are clearly defined as individual osteoderms, and are much smaller in size. Additionally, the squamosal horn in Akainacephalus is very small but is prominent and tetrahedrally shaped in Nodocephalosaurus. The quadratojugal horn in Akainacephalus is massive, has a subtriangular morphology in lateral view and projects almost entirely ventral, whereas in Nodocephalosaurus, the quadratojugal horn is smaller and has a typical fin-shaped morphology. Study sites: asob, anterior supraorbital boss; ext naris, external naris; laca, lacrimal caputegulum; loca, loreal caputegulum; naca, nasal caputegulae; orb, orbit; psob, posterior supraorbital boss; qjh, quadratojugal horn; sqh, squamosal horn.

Digital illustration of the Sauropod Dinosaur Isisaurus colberti from the Late Cretaceous (Maastrichtian) of India (72.2-66 MYA). References include Jain & Bandyopadhyay (1997), several papers from Wilson et al. and skeletal reconstruction by Scott Hartman. Illustrated by Ansh Saxena. About Isisaurus– Isisaurus colberti (=Titanosaurus colberti) was a species of Titanosaurian Sauropod Dinosaur from the Late Cretaceous (Maastrichtian) age in the Indian Subcontinent. Isisaurus lived sympatrically with another Titanosaurian Sauropod Jainosaurus. It also lived alongside Theropods like Rajasaurus, Rahiolisaurus, Indosuchus etc. Remains of Isisaurus come from the Lameta formation of Central India.

Eonatator sternbergi, a mosasaur from the Late Cretaceous of Kansas. Digital.

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.

Reconstruction of Bissektipelta archibaldi an ankylosaurid dinosaur from the Late Cretaceous of Uzbekistan

Calvarius is a genus of styracosternan ornithopod from the Late Cretaceous of Spain. The name alludes to its chronostratigraphic proximity to the extinction event that wiped out the non-avian dinosaurs at the end of the Cretaceous. The highly modified metatarsal that is known from shows an example of convergent evolution, as it is more similar to non-iguanodontian ornithopods than to other styracosternans. It is thought that this is due to fulfilling a niche in its island habitat, resulting in Calvarius becoming a small-bodied animal, capable of rapid locomotion.

Astigmasaura is a medium-sized rebbachisaurid sauropod dinosaur from the Late Cretaceous period of what is now Argentina. Rebbachisaurids had highly pneumatized bones that helped them to hold their weight on their four pillar-like legs, and extremely long tails. Astigmasaura was likely a ground-level browsing herbivore.

Rebbachisaurids are the latest known sauropod dinosaurs outside the titanosaur lineage. Cienciargentina is a rebbachisaurid from the Late Cretaceous, making it among the most recent. It had many hollow bones, and likely had batteries of teeth used for chewing, a rebbachisaurid feature unique among sauropods.

Campananeyen is a rebbachisaurid sauropod that lived approximately 100 million years ago in the Late Cretaceous of what is now Argentina. Rebbachisaurids are the main group of diplodocoidea to have lived past the Jurassic, and had a more horizontal posture than contemporary sauropods, mainly the titanosaurs. They are unique among sauropods for having batteries of teeth used for chewing, rather than the typical peglike teeth sauropods used to strip leaves off branches.