DOCSLIB.ORG

The Cretaceous World - 144 - 65 MY: a Period of Dramatic Changes and a Transition Towards the Modern World

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Cretaceous World - 144 - 65 MY: a Period of Dramatic Changes and a Transition Towards the Modern World The Cretaceous World - 144 - 65 MY: a period of dramatic changes and a transition towards the modern world - Jarðsaga 1 - Saga Lífs og Lands – Ólafur Ingólfsson Late Jurassic-Early Cretaceous: Pangea is ripping apart, creating new landscapes and habitats and changing evolutionary conditions Continental drift and Ocean spreading causes transgressions in N America and Europe Turonian Stage Texas (93.5-88.5 million years ago) Large scale trans- gression from both north and south connects Arctic to Gulf region, dividing North America into two landmasses. Europe undergoes a series of transgression- regression events Climate and landscapes during the early Cretaceous No major mountain- building episode for 100 MY. Erosion and deposition prevailed. Widespread plains and lowlands, deltas, swamps and warm, shallow seas. There were no glaciers anywhere on Earth, and global sea level was 60m + Early Cretaceous: A world steaming under near-tropical conditions... (cool temperate climates at very high latitudes, >70oN and S) ... with incredible diversity of both fauna and flora, as well as optimal conditions for evolution and occupation of new evolutionary niches... Oceanic circulation The fossil story reflecting warm conditions Finds of Cretaceous fossil tree-trunks The fossil story reflecting warm conditions Cretaceous vs modern temperatures http://www.clas.ufl.edu/users/emartin/GLY3074S01/figures/cretgradient.htm Laterite and Laterite Bauxite Bauxite Thick, red, greatly The chief ore of Residual deposits formed weathered and aluminium, under tropical climate altered strata of consisting of conditions, where sili- tropical ground. hydrous aluminium cate-rich rocks are Laterites are red oxides and leched during a wet because silicates aluminous laterite. season and subject to have been leached It is a claylike strong evaporation during out, and iron and amorphous dry season... aluminium salts now material formed predominate. by the weathering Horizons are unclear of silicate rocks and the nutrient under tropical status of the soil is conditions. The low. Laterite is soft chief producers but hardens rapidly are Australia, when to the air until Guinea, Jamaica, it has a brick-like Russia, Brazil, and hardness. Surinam. Deltas and swamps... Crocodile-like animals appeared in the Late Triassic, and true croc´s in Jurassic times. Some Cretaceous crocodiles were awesome: the giant Deionsuchus ('terrible crocodile') was 12-14 m long and had a skull 1.8 m long Sarcosuchus The crocodile is believed to have reached 14 m in length. The animal lived about 110 million years ago in what is now the windswept Ténéré Desert in central Niger. The snout and > 100 teeth were designed for grabbing prey–fish, turtles and dinosaurs that strayed too close. This enormous reptile would have made Africa’s ancient riverbanks a dangerous place, even for a Fossil remains of one of the largest crocodilian species dinosaur. The fossils belong to an ever to live have been extinct creature named found in the Sahara by a Sarcosuchus imperator ("flesh team led by Paul Sereno (University of Chicago). crocodile emperor") Metriorhynchus – purely aquatic crocodile Metriorhynchus was ca. 3 m long. It was a highly modi- fied aquatic predator which had evolved from its cousins, the land living crocodiles. Apart from its long snout,it bears little resemblance to Metriorhyncus probably moved the conventional crocodile by sideways beatings of its tail shape. Metriorhynchus was and it had evolved to be more flexible and mobile than its land- specially adapted to an living relatives, making it faster aquatic way of life with in water. Its skin was also less flippers to replace the legs scaly and more flexible than that of the land-crocodiles, reducing and a vertical fin at the end its resistance through the water. of its tail to help it swim. Snakes and lizzards Snakes are uncommon as fossils: They have lightly constructed skeletons and skulls comprised of separate moveable sections and so are generally too fragile to preserve well. The more They were the last major group of specialised reptiles to appear in the fossil record. poisonous snakes One of the earliest known forms was are not thought Dinilysia, meaning 'terrible destroyer', to have evolved which lived in the Early Cretaceous until the middle period. It seems likely that snakes of the Tertiary evolved from aquatic lizards, although period, perhaps most have now returned to life on land. 30 MY ago. And then there were the dinosaurs... Cretaceous dinosaurs lived on all Gondwana-Laurentia continents, except Antarctica Development towards heavier herbivorae armour and more vicious predators The break-up of Pangea affected dinosaur evolution Dinosaurian paleobiogeography: Temporally calibrated areagram showing the breakup of Pangaea into 10 major land areas by the end of the Cretaceous. Checkered bars indicate high-latitude con- nections that may have persisted into the Late Cretaceous. Five paleogeographic reconstructions divide continental areas into dry land (black) and shallow (epieric) seas (unshaded). Different lines of evolution among the allosaurs Dinosaurian paleobiogeography. Acrocanthosaurus, Giganotosaurus, and Carcharodontosaurus, living on N America, S America, and Africa, respectively, approximately 90-110 MY. Dino´s walked across existing land bridges... The geographic distribution of ceratops and some other groups during Late Cretaceous can only be explained by dispersal across Beringia. The Dino´s... The dinosaurs came in all varieties including carnivores (meat-eaters), herbivores (plant eaters) and omnivores (all-eaters). Some were small as a chicken and others as big as a house, some of them flew like birds. They occupied almost every nisch... Within the last decaded there has been a transformation in our under- standing of dinosaur paleobiology. They now are regarded as active, agile, and adaptable, as opposed to huge, awkward, lumbering versions of large reptiles. HERBIVORES: Plant-eating dinosaurs were the most common large animals in the Cretaceous ecosystems A group of Omeisaurus, medium-sized sauropods, are reconstructed browsing in a conifer forest. Their physology is poorly understood, and some aspects are widely debated: • Biomechanical problems. Some paleobiologists argue that the mechanics of muscle and tendon attachment would not permit these animals to raise their long necks that far above the horizontal. • Blood pressure. It is difficult to imagine how sufficient blood could have been provided to the head at extreme elevation to avoid unconsciousness when the head was held up for any extended period. The huge sauropods, so typical for Late Jurassic dinosaurs, continued to live in Gondwana, but died out in Laurassia Paralititan stromeri, a Titanosauria, Madagaskar new, giant sauropod dinosaur from Upper Cretaceous mangrove deposits in Egypt. Laurassic herbivores relatively small and heavily armed Ankylosaurs: They were relatively small, heavily armored Cretaceous herbivores. Their ecology is poorly understood, but their build suggests that they fed primarily on vegetation at ground level. Hadrosaurs: A small group of Telmatosaurus, hadrosaurs from the Upper Cretaceous of central Europe. Hadrosaurs were a very diverse group of bipedal herbivores and were the most important herbivore group during the Cretaceous. Ceratopsians The most widely recognized ceratopsian dinosaur is Triceratops, but this was a very diverse group of Creta- ceous herbivores and the only group that may have been adaptively radiating near the end of the period. No armour, quick and agile: an alternative strategy... Curiously, the most abundant and diverse of the Cretaceous herbivores were the unarmoured ornithopod dinosaurs, specifically the hypsilophodontids and iguanodontian lines, all of which achieved cosmopolitan distribution. Dinosaur Carnivores Given the relatively large size of most dinosaur carnivores, they would have required significant numbers of large prey animals to sustain their populations. Carnivores would thus be much less numerous than herbivores in any Mesozoic ecosystem. An Ornithomimus, Cretaceous, USA. These animals were probably very quick and agile and may have preyed largely on the eggs of other dinosaurs. The Therapods The theropod (meaning "beast-footed") dinosaurs are a diverse group of bipedal saurischian dinosaurs. They include the largest terrestrial carnivores ever. Birds are the descendants of small nonflying theropods. http://www.ucmp.berkeley.edu/diapsids/saurischia/theropoda.html T-Rex and friends... Tyrannosaurus rex was a huge (12 m long, about 6 m tall, 5-7 tons) meat-eating dinosaur that lived during the late Cretaceous, 85-65 MY ago. T. rex lived in a humid, semi-tropical environment, in open forests with nearby rivers and in coastal forested swamps. Until recently, Tyrannosaurus rex was the biggest known carnivorous dinosaur; Gigan- otosaurus and Carcharodontosaurus were slightly bigger. How fast did the dinosaurs move: There is a general relationship between speed and stride length in living animals. This can be used to estimate how fast the dinosaurs were: • Sauropods and ankylosaurs were slowest, ~ 3-5 km/hr • Most ornithopods were faster, ~ 5-7 km/hr • Theropod predators were fastest, ~ 10 km/hr, bursts up to 40-50 km/hr Velociraptor ("Speedy Thief“) Velociraptor was a fast- running, two-legged dinosaur. This meat-eater had about 80 very sharp, curved teeth in a long, flat snout; some of the teeth were over 2.5 cm long. This predator had an s-shaped neck, arms with three-fingered
Load more

Recommended publications
  • Early Cretaceous (Albian) Decapods from the Glen Rose and Walnut Formations of Texas, USA
    Bulletin of the Mizunami Fossil Museum, no. 42 (2016), p. 1–22, 11 fi gs., 3 tables. © 2016, Mizunami Fossil Museum Early Cretaceous (Albian) decapods from the Glen Rose and Walnut formations of Texas, USA Carrie E. Schweitzer*, Rodney M. Feldmann**, William L. Rader***, and Ovidiu Fran㶥escu**** *Department of Geology, Kent State University at Stark, 6000 Frank Ave. NW, North Canton, OH 44720 USA <[email protected]> **Department of Geology, Kent State University, Kent, OH 44242 USA ***8210 Bent Tree Road, #219, Austin, TX 78759 USA ****Division of Physical and Computational Sciences, University of Pittsburgh Bradford, Bradford, PA 16701 USA Abstract Early Cretaceous (Albian) decapod crustaceans from the Glen Rose Limestone and the Walnut Formation include the new taxa Palaeodromites xestos new species, Rosadromites texensis new genus, new species, Karyosia apicava new genus new species, Aetocarcinus new genus, Aetocarcinus muricatus new species, and the new combinations Aetocarcinus roddai (Bishop, 1983), Necrocarcinus pawpawensis (Rathbun, 1935) and Necrocarcinus hodgesi (Bishop, 1983). These two formations have yielded a much less diverse decapod fauna than the nearly coeval and proximally deposited Pawpaw Formation. Paleoenvironment is suggested as a controlling factor in the decapod diversity of these units. Key words: Brachyura, Nephropidae, Dromiacea, Raninoida, Etyioidea, North America Introduction deposited in the shallow waters of a broad carbonate platform. Deposition occurred on the southeastern flank of Late Early Cretaceous decapod faunas from the Gulf the Llano Uplift and, on the seaward margin to the Coastal Plain of North America have been well reported northwest, behind the Stuart City Reef Trend. Coral and and described since the early part of the twentieth century rudist reefs, algal beds, extensive ripple marks, evaporites, (Rathbun, 1935; Stenzel, 1945).
    [Show full text]
  • 71St Annual Meeting Society of Vertebrate Paleontology Paris Las Vegas Las Vegas, Nevada, USA November 2 – 5, 2011 SESSION CONCURRENT SESSION CONCURRENT
    ISSN 1937-2809 online Journal of Supplement to the November 2011 Vertebrate Paleontology Vertebrate Society of Vertebrate Paleontology Society of Vertebrate 71st Annual Meeting Paleontology Society of Vertebrate Las Vegas Paris Nevada, USA Las Vegas, November 2 – 5, 2011 Program and Abstracts Society of Vertebrate Paleontology 71st Annual Meeting Program and Abstracts COMMITTEE MEETING ROOM POSTER SESSION/ CONCURRENT CONCURRENT SESSION EXHIBITS SESSION COMMITTEE MEETING ROOMS AUCTION EVENT REGISTRATION, CONCURRENT MERCHANDISE SESSION LOUNGE, EDUCATION & OUTREACH SPEAKER READY COMMITTEE MEETING POSTER SESSION ROOM ROOM SOCIETY OF VERTEBRATE PALEONTOLOGY ABSTRACTS OF PAPERS SEVENTY-FIRST ANNUAL MEETING PARIS LAS VEGAS HOTEL LAS VEGAS, NV, USA NOVEMBER 2–5, 2011 HOST COMMITTEE Stephen Rowland, Co-Chair; Aubrey Bonde, Co-Chair; Joshua Bonde; David Elliott; Lee Hall; Jerry Harris; Andrew Milner; Eric Roberts EXECUTIVE COMMITTEE Philip Currie, President; Blaire Van Valkenburgh, Past President; Catherine Forster, Vice President; Christopher Bell, Secretary; Ted Vlamis, Treasurer; Julia Clarke, Member at Large; Kristina Curry Rogers, Member at Large; Lars Werdelin, Member at Large SYMPOSIUM CONVENORS Roger B.J. Benson, Richard J. Butler, Nadia B. Fröbisch, Hans C.E. Larsson, Mark A. Loewen, Philip D. Mannion, Jim I. Mead, Eric M. Roberts, Scott D. Sampson, Eric D. Scott, Kathleen Springer PROGRAM COMMITTEE Jonathan Bloch, Co-Chair; Anjali Goswami, Co-Chair; Jason Anderson; Paul Barrett; Brian Beatty; Kerin Claeson; Kristina Curry Rogers; Ted Daeschler; David Evans; David Fox; Nadia B. Fröbisch; Christian Kammerer; Johannes Müller; Emily Rayfield; William Sanders; Bruce Shockey; Mary Silcox; Michelle Stocker; Rebecca Terry November 2011—PROGRAM AND ABSTRACTS 1 Members and Friends of the Society of Vertebrate Paleontology, The Host Committee cordially welcomes you to the 71st Annual Meeting of the Society of Vertebrate Paleontology in Las Vegas.
    [Show full text]
  • The Late Jurassic Tithonian, a Greenhouse Phase in the Middle Jurassic–Early Cretaceous ‘Cool’ Mode: Evidence from the Cyclic Adriatic Platform, Croatia
    Sedimentology (2007) 54, 317–337 doi: 10.1111/j.1365-3091.2006.00837.x The Late Jurassic Tithonian, a greenhouse phase in the Middle Jurassic–Early Cretaceous ‘cool’ mode: evidence from the cyclic Adriatic Platform, Croatia ANTUN HUSINEC* and J. FRED READ *Croatian Geological Survey, Sachsova 2, HR-10000 Zagreb, Croatia Department of Geosciences, Virginia Tech, 4044 Derring Hall, Blacksburg, VA 24061, USA (E-mail: [email protected]) ABSTRACT Well-exposed Mesozoic sections of the Bahama-like Adriatic Platform along the Dalmatian coast (southern Croatia) reveal the detailed stacking patterns of cyclic facies within the rapidly subsiding Late Jurassic (Tithonian) shallow platform-interior (over 750 m thick, ca 5–6 Myr duration). Facies within parasequences include dasyclad-oncoid mudstone-wackestone-floatstone and skeletal-peloid wackestone-packstone (shallow lagoon), intraclast-peloid packstone and grainstone (shoal), radial-ooid grainstone (hypersaline shallow subtidal/intertidal shoals and ponds), lime mudstone (restricted lagoon), fenestral carbonates and microbial laminites (tidal flat). Parasequences in the overall transgressive Lower Tithonian sections are 1– 4Æ5 m thick, and dominated by subtidal facies, some of which are capped by very shallow-water grainstone-packstone or restricted lime mudstone; laminated tidal caps become common only towards the interior of the platform. Parasequences in the regressive Upper Tithonian are dominated by peritidal facies with distinctive basal oolite units and well-developed laminate caps. Maximum water depths of facies within parasequences (estimated from stratigraphic distance of the facies to the base of the tidal flat units capping parasequences) were generally <4 m, and facies show strongly overlapping depth ranges suggesting facies mosaics. Parasequences were formed by precessional (20 kyr) orbital forcing and form parasequence sets of 100 and 400 kyr eccentricity bundles.
    [Show full text]
  • And Early Jurassic Sediments, and Patterns of the Triassic-Jurassic
    and Early Jurassic sediments, and patterns of the Triassic-Jurassic PAUL E. OLSEN AND tetrapod transition HANS-DIETER SUES Introduction parent answer was that the supposed mass extinc- The Late Triassic-Early Jurassic boundary is fre- tions in the tetrapod record were largely an artifact quently cited as one of the thirteen or so episodes of incorrect or questionable biostratigraphic corre- of major extinctions that punctuate Phanerozoic his- lations. On reexamining the problem, we have come tory (Colbert 1958; Newell 1967; Hallam 1981; Raup to realize that the kinds of patterns revealed by look- and Sepkoski 1982, 1984). These times of apparent ing at the change in taxonomic composition through decimation stand out as one class of the great events time also profoundly depend on the taxonomic levels in the history of life. and the sampling intervals examined. We address Renewed interest in the pattern of mass ex- those problems in this chapter. We have now found tinctions through time has stimulated novel and com- that there does indeed appear to be some sort of prehensive attempts to relate these patterns to other extinction event, but it cannot be examined at the terrestrial and extraterrestrial phenomena (see usual coarse levels of resolution. It requires new fine- Chapter 24). The Triassic-Jurassic boundary takes scaled documentation of specific faunal and floral on special significance in this light. First, the faunal transitions. transitions have been cited as even greater in mag- Stratigraphic correlation of geographically dis- nitude than those of the Cretaceous or the Permian junct rocks and assemblages predetermines our per- (Colbert 1958; Hallam 1981; see also Chapter 24).
    [Show full text]
  • Reconstructions of the Continents Around the North Atlantic at About the 60Th Parallel
    CORE Metadata, citation and similar papers at core.ac.uk Provided by RERO DOC Digital Library 1 Published in Earth and Planetary Science Letters 187: 55-69, 2001 Reconstructions of the continents around the North Atlantic at about the 60th parallel Trond H. Torsvik a;d, Rob Van der Voo b;*, Joseph G. Meert a;e, Jon Mosar a, Harald J. Walderhaug c a VISTA, c/o Geological Survey of Norway, Leiv Eiriksonsvei 39, N-7491 Trondheim, Norway b Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1063, USA c University of Bergen, Institute of Solid Earth Physics, Allegt. 41, N-5007Bergen, Norway d Institute for Petroleum Technology and Applied Geophysics, S.P. Andersens v. 15a, N-7491 Trondheim, NTNU, Norway e Department of Geography and Geology, Indiana State University, Terre Haute, IN 47809, USA Received 12 September 2000; received in revised form 16 February 2001; accepted 21 February 2001 Abstract Late Carboniferous^Early Tertiary apparent polar wander (APW) paths (300^40 Ma) for North America and Europe have been tested in various reconstructions. These paths demonstrate that the 500 fathom Bullard et al. fit is excellent from Late Carboniferous to Late Triassic times, but the continental configuration in northern Pangea changed systematically between the Late Triassic (ca. 214 Ma) and the Mid-Jurassic (ca. 170 Ma) due to pre-drift extension. Best fit North Atlantic reconstructions minimize differences in the Late Carboniferous^Early Jurassic and Late Cretaceous^ Tertiary segments of the APW paths, but an enigmatic difference exists in the paths for most of the Jurassic, whereas for the Early Cretaceous the data from Europe are nearly non-existent.
    [Show full text]
  • Archaeorhynchus Preserving Significant Soft Tissue Including Probable Fossilized Lungs
    Archaeorhynchus preserving significant soft tissue including probable fossilized lungs Xiaoli Wanga,b,1, Jingmai K. O’Connorc,d,1,2, John N. Mainae, Yanhong Panf, Min Wangc,d, Yan Wanga,b, Xiaoting Zhenga,b, and Zhonghe Zhouc,d,2 aInstitute of Geology and Paleontology, Linyi University, Linyi, 276000 Shandong, China; bShandong Tianyu Museum of Nature, Pingyi, 273300 Shandong, China; cKey Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 10010 Beijing, China; dCAS Center for Excellence in Life and Paleoenvironment, 10010 Beijing, China; eDepartment of Zoology, University of Johannesburg, 2006 Johannesburg, South Africa; and fKey Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 21008 Nanjing, China Contributed by Zhonghe Zhou, September 13, 2018 (sent for review April 10, 2018; reviewed by C. G. Farmer and Mark A. Norell) We describe a specimen of the basal ornithuromorph Archaeor- of preserved traces of lung tissue in a stem bird, occurring in a hynchus spathula from the Lower Cretaceous Jiufotang Formation specimen of the basalmost ornithuromorph Archaeorhynchus with extensive soft tissue preservation. Although it is the fifth spathula (STM7-11; Shandong Tianyu Museum of Nature, Pingyi, specimen to be described, unlike the others it preserves signifi- China; Fig. 1) from the Early Cretaceous Jehol Lagerstätte in cant traces of the plumage, revealing a pintail morphology pre- northeastern China. This Lagerstätte has produced more ex- viously unrecognized among Mesozoic birds, but common in ceptional specimens of early birds and dinosaurs preserving extant neornithines. In addition, this specimen preserves the prob- soft tissue than any other (1, 6, 7), a taphonomic phenomenon able remnants of the paired lungs, an identification supported by likely exaggerated by the enormous volume of collected spec- topographical and macro- and microscopic anatomical observa- imens.
    [Show full text]
  • The Fragile Legacy of Amphicoelias Fragillimus (Dinosauria: Sauropoda; Morrison Formation – Latest Jurassic)
    Volumina Jurassica, 2014, Xii (2): 211–220 DOI: 10.5604/17313708 .1130144 The fragile legacy of Amphicoelias fragillimus (Dinosauria: Sauropoda; Morrison Formation – latest Jurassic) D. Cary WOODRUFF1,2, John R. FOSTER3 Key words: Amphicoelias fragillimus, E.D. Cope, sauropod, gigantism. Abstract. In the summer of 1878, American paleontologist Edward Drinker Cope published the discovery of a sauropod dinosaur that he named Amphicoelias fragillimus. What distinguishes A. fragillimus in the annals of paleontology is the immense magnitude of the skeletal material. The single incomplete dorsal vertebra as reported by Cope was a meter and a half in height, which when fully reconstructed, would make A. fragillimus the largest vertebrate ever. After this initial description Cope never mentioned A. fragillimus in any of his sci- entific works for the remainder of his life. More than four decades after its description, a scientific survey at the American Museum of Natural History dedicated to the sauropods collected by Cope failed to locate the remains or whereabouts of A. fragillimus. For nearly a cen- tury the remains have yet to resurface. The enormous size of the specimen has generally been accepted despite being well beyond the size of even the largest sauropods known from verifiable fossil material (e.g. Argentinosaurus). By deciphering the ontogenetic change of Diplodocoidea vertebrae, the science of gigantism, and Cope’s own mannerisms, we conclude that the reported size of A. fragillimus is most likely an extreme over-estimation. INTRODUCTION saurs pale in comparative size; thus A. fragillimus could be the largest dinosaur, and largest vertebrate in Earth’s history Described by Edward Drinker Cope in 1878, the holo- (the Blue Whale being approximately 29 meters long [Reilly type (and only) specimen of A.
    [Show full text]
  • PRRUCS Paper S4-3 Peter Dodson Oct 2016.Pub
    On Fossils and Faith Peter Dodson Program for Research on Religion and Urban Civil Society, University of Pennsylvania, Philadelphia, PA 19104, USA October 14, 2016 I am a geologist, paleontologist, veterinary anat- that time I have spent my entire professional omist, evolutionary biologist, and a lifelong career teaching gross anatomy to veterinary Christian. I am extraordinarily privileged to students at the University of Pennsylvania in teach in a superb research university, and I have Philadelphia, while also supervising undergradu- been blessed with a succession of excellent stu- ate and graduate students in the Department of dents with whom I have traveled the world. I Earth and Environmental Sciences. have been even more greatly blessed with the companionship of my wife of 48 years, Dawn, In the first two decades of my scientific ca- with whom I have two children and three grand- reer, I confined my research to Canada and the children. These are the three great priorities of United States. My first new discovery was a my life: family, faith and fossils. small horned dinosaur from south central Mon- tana, which in 1986 I named Avaceratops lam- As a child, dinosaurs fascinated me. While mersi. A skeleton of the dinosaur is on display most children grow out of this fascination, I at the Academy of Natural Sciences of Philadel- simply never did. I lived in northern Indiana phia (now the Academy of Natural Sciences of until I was 11. My older brother, Steve, was an Drexel University). This animal is named not amateur naturalist and astronomer. He taught after my wife, but after Ava Cole, the wife of me to love collecting fossils.
    [Show full text]
  • Report 2015–1087
    Chronostratigraphic Cross Section of Cretaceous Formations in Western Montana, Western Wyoming, Eastern Utah, Northeastern Arizona, and Northwestern New Mexico, U.S.A. Pamphlet to accompany Open-File Report 2015–1087 U.S. Department of the Interior U.S. Geological Survey Chronostratigraphic Cross Section of Cretaceous Formations in Western Montana, Western Wyoming, Eastern Utah, Northeastern Arizona, and Northwestern New Mexico, U.S.A. By E.A. Merewether and K.C. McKinney Pamphlet to accompany Open-File Report 2015–1087 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2015 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Merewether, E.A., and McKinney, K.C., 2015, Chronostratigraphic cross section of Cretaceous formations in western Montana, western Wyoming, eastern Utah, northeastern Arizona, and northwestern New Mexico, U.S.A.: U.S. Geological Survey Open-File Report 2015–1087, 10 p.
    [Show full text]
  • A Fast-Growing Basal Troodontid (Dinosauria: Theropoda) from The
    www.nature.com/scientificreports OPEN A fast‑growing basal troodontid (Dinosauria: Theropoda) from the latest Cretaceous of Europe Albert G. Sellés1,2*, Bernat Vila1,2, Stephen L. Brusatte3, Philip J. Currie4 & Àngel Galobart1,2 A characteristic fauna of dinosaurs and other vertebrates inhabited the end‑Cretaceous European archipelago, some of which were dwarves or had other unusual features likely related to their insular habitats. Little is known, however, about the contemporary theropod dinosaurs, as they are represented mostly by teeth or other fragmentary fossils. A new isolated theropod metatarsal II, from the latest Maastrichtian of Spain (within 200,000 years of the mass extinction) may represent a jinfengopterygine troodontid, the frst reported from Europe. Comparisons with other theropods and phylogenetic analyses reveal an autapomorphic foramen that distinguishes it from all other troodontids, supporting its identifcation as a new genus and species, Tamarro insperatus. Bone histology shows that it was an actively growing subadult when it died but may have had a growth pattern in which it grew rapidly in early ontogeny and attained a subadult size quickly. We hypothesize that it could have migrated from Asia to reach the Ibero‑Armorican island no later than Cenomanian or during the Maastrichtian dispersal events. During the latest Cretaceous (ca. 77–66 million years ago) in the run-up to the end-Cretaceous mass extinc- tion, Europe was a series of islands populated by diverse and distinctive communities of dinosaurs and other vertebrates. Many of these animals exhibited peculiar features that may have been generated by lack of space and resources in their insular habitats.
    [Show full text]
  • Anatomy of the Early Cretaceous Enantiornithine Bird Rapaxavis Pani
    Anatomy of the Early Cretaceous enantiornithine bird Rapaxavis pani JINGMAI K. O’CONNOR, LUIS M. CHIAPPE, CHUNLING GAO, and BO ZHAO O’Connor, J.K., Chiappe, L.M., Gao, C., and Zhao, B. 2011. Anatomy of the Early Cretaceous enantiornithine bird Rapaxavis pani. Acta Palaeontologica Polonica 56 (3): 463–475. The exquisitely preserved longipterygid enantiornithine Rapaxavis pani is redescribed here after more extensive prepara− tion. A complete review of its morphology is presented based on information gathered before and after preparation. Among other features, Rapaxavis pani is characterized by having an elongate rostrum (close to 60% of the skull length), rostrally restricted dentition, and schizorhinal external nares. Yet, the most puzzling feature of this bird is the presence of a pair of pectoral bones (here termed paracoracoidal ossifications) that, with the exception of the enantiornithine Concornis lacustris, are unknown within Aves. Particularly notable is the presence of a distal tarsal cap, formed by the fu− sion of distal tarsal elements, a feature that is controversial in non−ornithuromorph birds. The holotype and only known specimen of Rapaxavis pani thus reveals important information for better understanding the anatomy and phylogenetic relationships of longipterygids, in particular, as well as basal birds as a whole. Key words: Aves, Enantiornithes, Longipterygidae, Rapaxavis, Jiufotang Formation, Early Cretaceous, China. Jingmai K. O’Connor [[email protected]], Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, 142 Xizhimenwaidajie, Beijing, China, 100044; The Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007 USA; Luis M. Chiappe [[email protected]], The Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Ex− position Boulevard, Los Angeles, CA 90007 USA; Chunling Gao [[email protected]] and Bo Zhao [[email protected]], Dalian Natural History Museum, No.
    [Show full text]
  • Dinosaur Morphological Diversity and the End-Cretaceous Extinction
    ARTICLE Received 24 Feb 2012 | Accepted 30 Mar 2012 | Published 1 May 2012 DOI: 10.1038/ncomms1815 Dinosaur morphological diversity and the end-Cretaceous extinction Stephen L. Brusatte1,2, Richard J. Butler3,4, Albert Prieto-Márquez4 & Mark A. Norell1 The extinction of non-avian dinosaurs 65 million years ago is a perpetual topic of fascination, and lasting debate has focused on whether dinosaur biodiversity was in decline before end- Cretaceous volcanism and bolide impact. Here we calculate the morphological disparity (anatomical variability) exhibited by seven major dinosaur subgroups during the latest Cretaceous, at both global and regional scales. Our results demonstrate both geographic and clade-specific heterogeneity. Large-bodied bulk-feeding herbivores (ceratopsids and hadrosauroids) and some North American taxa declined in disparity during the final two stages of the Cretaceous, whereas carnivorous dinosaurs, mid-sized herbivores, and some Asian taxa did not. Late Cretaceous dinosaur evolution, therefore, was complex: there was no universal biodiversity trend and the intensively studied North American record may reveal primarily local patterns. At least some dinosaur groups, however, did endure long-term declines in morphological variability before their extinction. 1 Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024 USA. 2 Department of Earth and Environmental Sciences, Columbia University, New York, New York 10025 USA. 3 GeoBio-Center, Ludwig-Maximilians-Universität München, Richard- Wagner-Straße 10, Munich D-80333, Germany. 4 Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, Munich D- 80333, Germany. Correspondence and requests for materials should be addressed to S.L.B.
    [Show full text]