DOCSLIB.ORG

Fossil Diversity from the Ediacaran and Cambrian

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fossil Diversity from the Ediacaran and Cambrian Lab 10 – Fossils OEB 51 Lab 10: Fossil diversity from the Ediacaran and Cambrian 20 April 2016 We are extremely lucky to have access to a large assortment of historically important fossils, including many Cambrian specimens from the famous Burgess Shale site. Please handle these fossils with extreme care. Feel free to place them under the dissecting scope to see any details. Draw and label your figures with suggested structures. Consider the following questions: What is a fossil? What needs to happen for fossils to form? Can we know all animals that ever lived by looking at the fossil record? Why or why not? While you go through the material, think about the following aspects of the animal’s life and take notes. What can you infer about the biology of that animal based on its remains? • Life style (benthic vs. pelagic; sessile vs. mobile etc.) • Feeding habits • Symmetry Do you think it belonged to any of the modern phyla? If yes, what are the reasons? You can make your own reconstruction of how you think these animals were like when alive. 1 Lab 10 – Fossils OEB 51 Ediacaran (Late Neoproterozoic) When was the Ediacaran period? CHOOSE These fossils represent some of the earliest evidence of macroscopic life. Using both the specimens ONE and figures from the available books, try to understand the organization of the organisms. • Charnia masoni • Dickinsonia elongata It is tempting to try to assign fossils of the Ediacaran to modern groups of animals. You probably have already done this to a certain degree in your head. What does Charnia resemble? Is this line of reasoning fruitful, or are there reasons to avoid it? 2 Lab 10 – Fossils OEB 51 • Stromatolites are even older and were abundant during the Proterozoic. Although there are modern stromatolites, they are rare. What organisms build these structures? What could have caused the decline of stromatolites in the end of the Precambrian/Cambrian? Cambrian (Early Phanerozoic) Trace fossils (Ichnofossils) Ichnofossils are impressions left on the substrates by organisms. They are indirect evidence of ancient life and provide us with a record of the activity of an organism. Ichnofossils include trails, burrows and can also mean the remains of other organic/chemical material produced. CHOOSE ONE • Treptichnus pedum The first 3-dimensional animal traces, piercing through bedding planes of sediment, and also the definition of the lower Cambrian. What kind of organism might have left these traces? What behavior do they record? • Ruscophycus trilobatum Any guesses as to what type of animal may have left these marks? What anatomical innovations might have been needed? • Arenicolites woodi (Upper Cambrian) What kind of organism do you think made these burrows? 3 Lab 10 – Fossils OEB 51 Cambrian (continued) • Archaeocyatha CHOOSE Archaeocyathus profundus • Cambrocyathus profundus ONE These are characteristic members of the early Cambrian fauna, and the whole group was extinct by the end of the Cambrian. They lived in shallow water and are considered to be the first ‘reef- building’ animals. What kind of animals do you think they were and why? What might have been their life style and feeding mode? • Hyolithida Haplophrentis reesei Does this fossil resemble any extant group? Which and why? • Trilobita Paradoxides harlani (Middle Cambrian) • Isotelus gigas (Middle Ordovician) Draw and label one. Compare the Cambrian and post-Cambrian trilobite fossils. Do you see any major differences? Identify the invertebrate clade in which you would place these animals. 4 Lab 10 – Fossils OEB 51 Burgess Shale (Cambrian) The Burgess Shale fossil bed provides a unique glimpse into animal life shortly after the Cambrian Explosion. It shows exceptional preservation (Lagerstätten) – what geological event must have CHOOSE happened to allow this? Consider the rock matrix in which these fossils occur – how large are the TWO sediment grains? Are animals preserved 3-dimensionally? • Anomalocaris canadensis Are these the entire animal? If not, what part of the body are they? What was the life style of the animal? Look at illustrations in the textbooks. • Burgessochaeta setigera Can you see any characteristics that make it similar to the extant polychaete annelids? You might need a dissecting microscope to observe in more details. • Marrella splendens Marrella is the most abundant genus in the Burgess Shale. In which phylum can we place it? • Vauxia gracilenta This fossil is thought to be a branching sponge (Porifera). Can you see oscula? 5 Lab 10 – Fossils OEB 51 Burgess Shale (continued) Look up at the geological time scale to visualize where each of the organisms and moments we studied today are placed in time. 6 Lab 10 – Fossils OEB 51 More recent Phanerozoic invertebrate fossils Some of the following fossils are more similar to their modern counter-parts. Identify the phylum to which they belong. What were the main characters that you used to make this placement? Saccocoma pectinata Upper Jurassic period Phylloceras heterophyllum Lower Jurassic Worm trails Devonian Eurypterus (sea scorpion) Silurian period (New York) Lithified block – Upper Ordovician period Examine this fossil assemblage from the Ordovician, well after the Cambrian Explosion. What phyla do you recognize? 7 .
Load more

Recommended publications
  • Sedimentology, Taphonomy, and Palaeoecology of a Laminated
    Palaeogeography, Palaeoclimatology, Palaeoecology 243 (2007) 92–117 www.elsevier.com/locate/palaeo Sedimentology, taphonomy, and palaeoecology of a laminated plattenkalk from the Kimmeridgian of the northern Franconian Alb (southern Germany) ⁎ Franz Theodor Fürsich a, , Winfried Werner b, Simon Schneider b, Matthias Mäuser c a Institut für Paläontologie, Universität Würzburg, Pleicherwall 1, 97070 Würzburg, Germany LMU b Bayerische Staatssammlung für Paläontologie und Geologie and GeoBio-Center , Richard-Wagner-Str. 10, D-80333 München, Germany c Naturkunde-Museum Bamberg, Fleischstr. 2, D-96047 Bamberg, Germany Received 8 February 2006; received in revised form 3 July 2006; accepted 7 July 2006 Abstract At Wattendorf in the northern Franconian Alb, southern Germany, centimetre- to decimetre-thick packages of finely laminated limestones (plattenkalk) occur intercalated between well bedded graded grainstones and rudstones that blanket a relief produced by now dolomitized microbialite-sponge reefs. These beds reach their greatest thickness in depressions between topographic highs and thin towards, and finally disappear on, the crests. The early Late Kimmeridgian graded packstone–bindstone alternations represent the earliest plattenkalk occurrence in southern Germany. The undisturbed lamination of the sediment strongly points to oxygen-free conditions on the seafloor and within the sediment, inimical to higher forms of life. The plattenkalk contains a diverse biota of benthic and nektonic organisms. Excavation of a 13 cm thick plattenkalk unit across an area of 80 m2 produced 3500 fossils, which, with the exception of the bivalve Aulacomyella, exhibit a random stratigraphic distribution. Two-thirds of the individuals had a benthic mode of life attached to hard substrate. This seems to contradict the evidence of oxygen-free conditions on the sea floor, such as undisturbed lamination, presence of articulated skeletons, and preservation of soft parts.
    [Show full text]
  • ALBIAN AMMONITES of POLAND (Plates 1—25)
    PALAEONTOLOGIA POLQNICA mm ■'Ъ-Ь POL T S H ACADEMY OF SCIENCES INSTITUTE OF PALEOBIOLOGY PALAEONTOLOGIA POLONICA—No. 50, 1990 t h e a l b ia w AMMONITES OF POLAND (AMQNITY ALBU POLS К I) BY RYSZARD MARCINOWSKI AND JOST WIEDMANN (WITH 27 TEXT-FIGURES, 7 TABLES AND 25 PLATES) WARSZAWA —KRAKÔW 1990 PANSTWOWE WYDAWNICTWO NAUKOWE KEDAKTOR — EDITOR JOZEP KA2MIERCZAK 2ASTEPCA HEDAKTOHA _ ASSISTANT EDITOR m AôDAlenA BÛRSUK-BIALYNICKA Adres Redakcjl — Address of the Editorial Office Zaklad Paleobiologij Polska Akademia Nauk 02-089 Warszawa, AI. 2w irki i Wigury 93 KOREKTA Zespol © Copyright by Panstwowe Wydawnictwo Naukowe Warszawa — Krakôw 1990 ISBN 83-01-09176-2 ISSN 0078-8562 Panstwowe Wydawnielwo Naukowe — Oddzial w Krakowie Wydanie 1, Naklad 670 + 65 cgz. Ark. wyd. 15. Ark. druk. 6 + 25 wkladek + 5 wklejek. Papier offset, sat. Ill kl. 120 g. Oddano do skiadania w sierpniu 1988 r. Podpisano do druku w pazdzierniku 1990 r. Druk ukoriczono w listopadzie 1990 r. Zara. 475/87 Drukarnia Uniwersytetu Jagielloriskiego w Krakowie In Memory of Professor Edward Passendorfer (1894— 1984) RYSZARD MARCINOWSKI and JOST WIEDMANN THE ALBIAN AMMONITES OF POLAND (Plates 1—25) MARCINOWSKI, R. and WIEDMANN, J.: The Albian ammonites of Poland. Palaeonlologia Polonica, 50, 3—94, 1990. Taxonomic and ecological analysis of the ammonite assemblages, as well as their general paleogeographical setting, indicate that the Albian deposits in the Polish part of the Central European Basin accumulated under shallow or extremely shallow marine conditions, while those of the High-Tatra Swell were deposited in an open sea environment. The Boreal character of the ammonite faunas in the epicontinental area of Poland and the Tethyan character of those in the Tatra Mountains are evident in the composition of the analyzed assemblages.
    [Show full text]
  • Review of the Mineralogy of Calcifying Sponges
    Dickinson College Dickinson Scholar Faculty and Staff Publications By Year Faculty and Staff Publications 12-2013 Not All Sponges Will Thrive in a High-CO2 Ocean: Review of the Mineralogy of Calcifying Sponges Abigail M. Smith Jade Berman Marcus M. Key, Jr. Dickinson College David J. Winter Follow this and additional works at: https://scholar.dickinson.edu/faculty_publications Part of the Paleontology Commons Recommended Citation Smith, Abigail M.; Berman, Jade; Key,, Marcus M. Jr.; and Winter, David J., "Not All Sponges Will Thrive in a High-CO2 Ocean: Review of the Mineralogy of Calcifying Sponges" (2013). Dickinson College Faculty Publications. Paper 338. https://scholar.dickinson.edu/faculty_publications/338 This article is brought to you for free and open access by Dickinson Scholar. It has been accepted for inclusion by an authorized administrator. For more information, please contact [email protected]. © 2013. Licensed under the Creative Commons http://creativecommons.org/licenses/by- nc-nd/4.0/ Elsevier Editorial System(tm) for Palaeogeography, Palaeoclimatology, Palaeoecology Manuscript Draft Manuscript Number: PALAEO7348R1 Title: Not all sponges will thrive in a high-CO2 ocean: Review of the mineralogy of calcifying sponges Article Type: Research Paper Keywords: sponges; Porifera; ocean acidification; calcite; aragonite; skeletal biomineralogy Corresponding Author: Dr. Abigail M Smith, PhD Corresponding Author's Institution: University of Otago First Author: Abigail M Smith, PhD Order of Authors: Abigail M Smith, PhD; Jade Berman, PhD; Marcus M Key Jr, PhD; David J Winter, PhD Abstract: Most marine sponges precipitate silicate skeletal elements, and it has been predicted that they would be among the few "winners" in an acidifying, high-CO2 ocean.
    [Show full text]
  • Phylloceratina (Ammonoidea) Del Pliensbachiano Italiano
    00 o Riv. Ital. Paleont. > n . 2 pp. 193-250 tav. 19-20 Milano 1974 PHYLLOCERATINA (AMMONOIDEA) DEL PLIENSBACHIANO ITALIANO N e r in a F a n t i n i S e s t i n i Abstract. This paper concerns thè conclusive researchs on Pliensbachian Phyllo- ceratina from Italy, among which thè genera Geyeroceras Hyatt, 1900 and Partschiceras Fucini, 1923 were already investigated (Fantini Sestini, 1969, 1971). The fossils were collected in stratigraphic sections from Selva di Zandobbio and Alpe Turati in Lombar- dy and from thè M. Nerone area in thè centrai Apennines. They consist of internai moulds and complete shells. The family Juraphyllitidae is present with genera: Jura- phyllites Miiller, Meneghiniceras Hyatt, Harpophylloceras Spath e Galaticeras Spath. Only four genera of Pliensbachian age can be attributed to thè fam. Phylloceratidae; they are as follows: Phylloceras Suess, 1865 with thè two subgenera Phylloceras s.s. e Zetoceras Kovacs, 1939. Test with ornaments visible at low magnification; internai mould smooth, section elliptical, ovai or sublanceolate; E/L and L/U with or without phylloids (minor subdivisions of folioles). Partschiceras Fucini, 1923 ( = Procliviceras Fucini, 1923; Phyllopachyceras Spath, 1925). Test with well distinct riblets, sometimes with ribs and periumbilical ridges; inter­ nai mould with weak constrictions in thè inner whorls and with very weakly outlined ornaments on thè venter; E/L with phylloids; Hantkeniceras Kovacs, 1939 (= Calaiceras Kovacs, 1939). Test smooth; internai mould smooth with rare weak nearly straight constrictions; L/U with 2/3 folioles jointed at their base. Calliphylloceras Spath, 1927. Test with very well developed riblets along with strong rounded ribs; internai mould smooth with 4 to 8 deep arcuate constrictions; L/U with 2 folioles jointed at their base.
    [Show full text]
  • Functional Anatomy and Mode of Life of the Latest Jurassic Crinoid Saccocoma
    Functional anatomy and mode of life of the latest Jurassic crinoid Saccocoma MICHAŁ BRODACKI Brodacki, M. 2006. Functional anatomy and mode of life of the latest Jurassic crinoid Saccocoma. Acta Palaeontologica Polonica 51 (2): 261–270. Loose elements of the roveacrinid Saccocoma from the Tithonian red Rogoża Coquina, Rogoźnik, Pieniny Klippen Belt, Poland, are used to test the contradictory opinions on the mode of life of Saccocoma. The investigated elements belong to three morphological groups, which represent at least two separate species: S. tenella, S. vernioryi, and a third form, whose brachials resemble those of S. vernioryi but are equipped with wings of different shape. The geometry of brachials’ articu− lar surfaces reveals that the arms of Saccocoma were relatively inflexible in their proximal part and left the cup at an angle of no more than 45°, then spread gradually to the sides. There is no evidence that the wings were permanently oriented in either horizontal or vertical position, as proposed by two different benthic life−style hypotheses. The first secundibrachial was probably more similar to the first primibrachial than to the third secundibrachial, in contrast to the traditional assump− tion. The winged parts of the arms were too close to the cup and presumably too stiff to propel the animal in the water effi− ciently. Swimming was probably achieved by movements of the distal, finely branched parts of the arms. The non− horizontal attitude of the winged parts of the arms is also not entirely consistent with the assumption that they functioned as a parachute. Moreover, the wings added some weight and thus increased the energy costs associated with swimming.
    [Show full text]
  • PROGRAMME ABSTRACTS AGM Papers
    The Palaeontological Association 63rd Annual Meeting 15th–21st December 2019 University of Valencia, Spain PROGRAMME ABSTRACTS AGM papers Palaeontological Association 6 ANNUAL MEETING ANNUAL MEETING Palaeontological Association 1 The Palaeontological Association 63rd Annual Meeting 15th–21st December 2019 University of Valencia The programme and abstracts for the 63rd Annual Meeting of the Palaeontological Association are provided after the following information and summary of the meeting. An easy-to-navigate pocket guide to the Meeting is also available to delegates. Venue The Annual Meeting will take place in the faculties of Philosophy and Philology on the Blasco Ibañez Campus of the University of Valencia. The Symposium will take place in the Salon Actos Manuel Sanchis Guarner in the Faculty of Philology. The main meeting will take place in this and a nearby lecture theatre (Salon Actos, Faculty of Philosophy). There is a Metro stop just a few metres from the campus that connects with the centre of the city in 5-10 minutes (Line 3-Facultats). Alternatively, the campus is a 20-25 minute walk from the ‘old town’. Registration Registration will be possible before and during the Symposium at the entrance to the Salon Actos in the Faculty of Philosophy. During the main meeting the registration desk will continue to be available in the Faculty of Philosophy. Oral Presentations All speakers (apart from the symposium speakers) have been allocated 15 minutes. It is therefore expected that you prepare to speak for no more than 12 minutes to allow time for questions and switching between presenters. We have a number of parallel sessions in nearby lecture theatres so timing will be especially important.
    [Show full text]
  • Lower Cambrian Bioherms: Pioneer Reefs of the Phanerozoic
    ACT A PAL A EON T 0 L 0 .6 ICA POL 0 N I CA ---------_.._._------------------- Vol. 25 1980 No. 3-3 NOEL P. JAMES and FRANCOISE DEBRENNE LOWER CAMBRIAN BIOHERMS: PIONEER REEFS OF THE PHANEROZOIC JAMES, N. P. and DEBRENNE, F.: Lower Cambrian bioherms: pioneer reefs of the Phanerozoic. Acta Palaeont. Polonica, 25, 3/4, 655-668, January 1981. Synthesis of information presently available on the makeup of Lower Cambrian bioherms indicates a gradual transition in their composition through time. The oldest bioherms (Lower Tommotian of the Siberian Platform) are mounds composed of lime mud and calcareous algae (Epiphyton and Rena!cis) with archaeocyaths most common in the surrounding sediments. This trend con­ tinues throughout most of early Lower Cambrlan time. In the middle part of the Lower Cambrian, archaeocyaths become an important part of the bioherm biota. By late Lower Cambrian time, as much as 50'10 of the limestone in bio­ herms is composed of archaeocyath skeletons and the structures illustrate the same sedimentological and ecological attributes as skeletal metazoan reefs later in the Phanerozoic. Key w 0 r d s: Archaeocyatha, algae, bioherms, reefs, Lower Cambrian. Noel P. Ja.mes, Department of Geo!ogy,. Memorial University, St' JOhn's, New­ founland, Canada, AIC 3X5. Fran<;oise Debrenne, Instttut de Paleonto!ogie, ER 154, C. N. R. S., 8 rue de Bu//on, 75005 Paris, France. Received: September 1979. INTRODUCTION Bioherms in the stratigraphic record can generally be separated into one of two types: (1) algal mounds, composed of sediment-trapping and binding, or calcareous algae, which are most common in Precambrian and Lower Paleozoic time, and (2) reefs and reef mounds, structures composed primarily of skeletal metazoa and calcareous algae, which occur throughout the Phanerozoic.
    [Show full text]
  • Contributions in BIOLOGY and GEOLOGY
    MILWAUKEE PUBLIC MUSEUM Contributions In BIOLOGY and GEOLOGY Number 51 November 29, 1982 A Compendium of Fossil Marine Families J. John Sepkoski, Jr. MILWAUKEE PUBLIC MUSEUM Contributions in BIOLOGY and GEOLOGY Number 51 November 29, 1982 A COMPENDIUM OF FOSSIL MARINE FAMILIES J. JOHN SEPKOSKI, JR. Department of the Geophysical Sciences University of Chicago REVIEWERS FOR THIS PUBLICATION: Robert Gernant, University of Wisconsin-Milwaukee David M. Raup, Field Museum of Natural History Frederick R. Schram, San Diego Natural History Museum Peter M. Sheehan, Milwaukee Public Museum ISBN 0-893260-081-9 Milwaukee Public Museum Press Published by the Order of the Board of Trustees CONTENTS Abstract ---- ---------- -- - ----------------------- 2 Introduction -- --- -- ------ - - - ------- - ----------- - - - 2 Compendium ----------------------------- -- ------ 6 Protozoa ----- - ------- - - - -- -- - -------- - ------ - 6 Porifera------------- --- ---------------------- 9 Archaeocyatha -- - ------ - ------ - - -- ---------- - - - - 14 Coelenterata -- - -- --- -- - - -- - - - - -- - -- - -- - - -- -- - -- 17 Platyhelminthes - - -- - - - -- - - -- - -- - -- - -- -- --- - - - - - - 24 Rhynchocoela - ---- - - - - ---- --- ---- - - ----------- - 24 Priapulida ------ ---- - - - - -- - - -- - ------ - -- ------ 24 Nematoda - -- - --- --- -- - -- --- - -- --- ---- -- - - -- -- 24 Mollusca ------------- --- --------------- ------ 24 Sipunculida ---------- --- ------------ ---- -- --- - 46 Echiurida ------ - --- - - - - - --- --- - -- --- - -- - - ---
    [Show full text]
  • Lee-Riding-2018.Pdf
    Earth-Science Reviews 181 (2018) 98–121 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Marine oxygenation, lithistid sponges, and the early history of Paleozoic T skeletal reefs ⁎ Jeong-Hyun Leea, , Robert Ridingb a Department of Geology and Earth Environmental Sciences, Chungnam National University, Daejeon 34134, Republic of Korea b Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996, USA ARTICLE INFO ABSTRACT Keywords: Microbial carbonates were major components of early Paleozoic reefs until coral-stromatoporoid-bryozoan reefs Cambrian appeared in the mid-Ordovician. Microbial reefs were augmented by archaeocyath sponges for ~15 Myr in the Reef gap early Cambrian, by lithistid sponges for the remaining ~25 Myr of the Cambrian, and then by lithistid, calathiid Dysoxia and pulchrilaminid sponges for the first ~25 Myr of the Ordovician. The factors responsible for mid–late Hypoxia Cambrian microbial-lithistid sponge reef dominance remain unclear. Although oxygen increase appears to have Lithistid sponge-microbial reef significantly contributed to the early Cambrian ‘Explosion’ of marine animal life, it was followed by a prolonged period dominated by ‘greenhouse’ conditions, as sea-level rose and CO2 increased. The mid–late Cambrian was unusually warm, and these elevated temperatures can be expected to have lowered oxygen solubility, and to have promoted widespread thermal stratification resulting in marine dysoxia and hypoxia. Greenhouse condi- tions would also have stimulated carbonate platform development, locally further limiting shallow-water cir- culation. Low marine oxygenation has been linked to episodic extinctions of phytoplankton, trilobites and other metazoans during the mid–late Cambrian.
    [Show full text]
  • Late Jurassic Ammonites from Alaska
    Late Jurassic Ammonites From Alaska GEOLOGICAL SURVEY PROFESSIONAL PAPER 1190 Late Jurassic Ammonites From Alaska By RALPH W. IMLAY GEOLOGICAL SURVEY PROFESSIONAL PAPER 1190 Studies of the Late jurassic ammonites of Alaska enables fairly close age determinations and correlations to be made with Upper Jurassic ammonite and stratigraphic sequences elsewhere in the world UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1981 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress catalog-card No. 81-600164 For sale by the Distribution Branch, U.S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 CONTENTS Page Page Abstract ----------------------------------------- 1 Ages and correlations -----------------------------­ 19 19 Introduction -------------------------------------- 2 Early to early middle Oxfordian --------------­ Biologic analysis _________________________________ _ 14 Late middle Oxfordian to early late Kimmeridgian 20 Latest Kimmeridgian and early Tithonian _____ _ 21 Biostratigraphic summary ------------------------- 14 Late Tithonian ______________________________ _ 21 ~ortheastern Alaska -------------------------­ 14 Ammonite faunal setting --------------------------­ 22 Wrangell Mountains -------------------------- 15 Geographic distribution ---------------------------- 23 Talkeetna Mountains -------------------------­ 17 Systematic descriptions ___________________________ _ 28 Tuxedni Bay-Iniskin Bay area ----------------- 17 References
    [Show full text]
  • Characteristic Jurassic Mollusks from Northern Alaska
    Characteristic Jurassic Mollusks From Northern Alaska GEOLOGICAL SURVEY PROFESSIONAL PAPER 274-D Characteristic Jurassic Mollusks From Northern Alaska By RALPH W. IMLAY A SHORTER CONTRIBUTION TO GENERAL GEOLOGY GEOLOGICAL SURVEY PROFESSIONAL PAPER 274-D A study showing that the northern Alaskan faunal succession agrees with that elsewhere in the Boreal region and in other parts of North America and in northwest Europe UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1955 UNITED STATES DEPARTMENT OF THE INTERIOR Douglas McKay, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - BMMH§ts (paper cover) Price $1.00 CONTENTS Page Abstract_________________ 69 Introduction _________________ 69 Biologic analysis____________ 69 Stratigraphic summary. _______ 70 Ages of fossils________________ 73 Comparisons with other faunas. 75 Ecological considerations___ _ 75 Geographic distribution____. 78 Summary of results ___________ 81 Systematic descriptions__ _. 82 Literature cited____________ 92 Index_____________________ 95 ILLUSTRATIONS [Plates &-13 follow Index] PLATE 8. Inoceramus and Gryphaea 9. Aucella 10. Amaltheus, Dactylioceras, "Arietites," Phylloceras, and Posidonia 11. Ludwigella, Dactylioceras, and Harpoceras. 12. Pseudocadoceras, Arcticoceras, Amoeboceras, Tmetoceras, Coeloceras, and Pseudolioceras 13. Reineckeia, Erycites, and Cylindroteuthis. Page FIGXTKE 20. Index map showing Jurassic fossil collection localities in northern Alaska.
    [Show full text]
  • Life and Death of Saccocoma Tenella (GOLDFUSS)
    Swiss J Geosci (2011) 104 (Suppl 1):S99–S106 DOI 10.1007/s00015-011-0059-z Life and death of Saccocoma tenella (GOLDFUSS) Hans Hess • Walter Etter Received: 15 September 2009 / Accepted: 25 June 2010 / Published online: 19 April 2011 Ó Swiss Geological Society 2011 Abstract The morphology of the small stalkless Sacco- Das Skelett ist a¨ußerst leicht gebaut; die proximalen coma tenella is unique among crinoids. It is characterized Armglieder tragen seitlich abstehende ‘‘Schwimmplatten’’ by an extremely light skeleton with dish-like lateral wings oder Flu¨gel, die distalen gepaarte vertikale Fortsa¨tze wel- on the proximal brachials and peculiar paired vertical che die Nahrungsfurche flankieren. Die Arme sind reich processes flanking the food grooves of more distal verzweigt. Die Flu¨gel dienten offensichtlich zur vertikalen brachials. The arms are heavily branched. The lateral wings Bewegung. Die vertikalen Fortsa¨tze wurden als Fu¨hrung obviously were involved in vertical movement. For the fu¨r das Einrollen der Arme zu einem ‘‘Schnapp-Schwim- vertical processes a ‘‘baffle rail’’ function for arm curling men’’ gedeutet. Dabei wa¨ren sie durch Muskeln verbunden and ‘‘snap swimming’’ has been postulated, with muscles gewesen. Da Indizien fu¨r Muskeln zwischen den vertikalen between the processes. However, there is no evidence that Fortsa¨tzen fehlen, wird zur Nahrungsaufnahme das Modell the processes were connected by muscles. For food col- eines in der Wassersa¨ule ‘‘pulsierenden Trichters’’ vor- lection a ‘‘pulsating funnel’’ model in the water column is geschlagen, mit Fang von Plankton zwischen den Fortsa¨tzen advocated, with the processes serving to collect plankton wa¨hrend der Aufwa¨rtsbewegung der Arme.
    [Show full text]