Crétacé

Size of Austroraptor cabazai compared to a human, a species of Dromaeosaurid Unenlagiinae who lived during the Cretaceous period in Argentina, more precisely in the Allen Formation.

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.

Left dentary of rebbachisaurid sauropod Demandasaurus darwini gen. et sp. nov. from Late Barremian–Early Aptian, Early Cretaceous of Tenadas de los Vallejos II, Spain, MDS−RVII,443, in lateral (A) and dorsal (B) views. The arrow indicates a depressed area in a dorsolateral position.

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.

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.

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.

Life restoration of Cearadactylus atrox. Based on figure 2 of "On the systematic relationships of Cearadactylus atrox, an enigmatic Early Cretaceous pterosaur from the Santana Formation of Brazil" by D. M. Unwin Mitteilungen Museum für Naturkunde Berlin, Geowissenschaftlichen Reihe 5: 239-263

Figure 1: Geographic distribution of Early Cretaceous iguanodontians in North America. Taxa found at each locality are as follows: (A) Dakotadon lakotaensis; (B) Osmakasaurus depressus; (C) Tenontosaurus tilletti, Tenontosaurus dossi; (D) Tenontosaurus tilletti; (E) Theiophytalia kerri; (F) Cedrorestes crichtoni, Planicoxa venenica; (G) Hippodraco scutodens; (H) Iguanacolossus fortis; (I) Tenontosaurus sp; (J) Tenontosaurus tilletti.

Figure 1: Geographic distribution of Early Cretaceous iguanodontians in North America. Taxa found at each locality are as follows: (A) Dakotadon lakotaensis; (B) Osmakasaurus depressus; (C) Tenontosaurus tilletti, Tenontosaurus dossi; (D) Tenontosaurus tilletti; (E) Theiophytalia kerri; (F) Cedrorestes crichtoni, Planicoxa venenica; (G) Hippodraco scutodens; (H) Iguanacolossus fortis; (I) Tenontosaurus sp; (J) Tenontosaurus tilletti.

Reconstruction of Mochlodon suessi from the Late Cretaceous of Austria. Based on Zalmoxes by Scott Hartman

Life restoration of the mosasaurine mosasaurid Eremiasaurus, with unknown portions and soft tissues based primarily on Prognathodon and supplemented with Mosasaurus where needed. References Leblanc, A.R.H.; Caldwell, M.W.; Bardet, N. (2012). "A new mosasaurine from the Maastrichtian (Upper Cretaceous) phosphates of Morocco and its implications for mosasaurine systematics". Journal of Vertebrate Paleontology 32 (1): 82–104. Lindgren, J.; Kaddumi, H.; Polcyn, M. (2013). "Soft tissue preservation in a fossil marine lizard with a bilobed tail fin". Nature Communications 4: 2423. DOI:10.1038/ncomms3423. Konishi, T.; Brinkman, D.; Massare, J.A.; Caldwell, M.W. (2011). "New exceptional specimens of Prognathodon overtoni (Squamata, Mosasauridae) from the upper Campanian of Alberta, Canada, and the systematics and ecology of the genus". Journal of Vertebrate Paleontology 31 (5): 1026–1046. Russell, D.A. (1967). "Systematics and morphology of American mosasaurs". Bulletin of the Peabody Museum of Natural History 23: 1–241.

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.

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.