Late Paleozoic Life & Extinctions

Total Page:16

File Type:pdf, Size:1020Kb

Late Paleozoic Life & Extinctions Late Paleozoic World, Life & Extinctions Norman MacLeod School of Earth Sciences & Engineering, Nanjing University Late Paleozoic World, Life & Extinctions Objectives Understand the structure of the Late Paleozoic (Carbon- iferous - Permian world in terms of timescales, geo- graphy, environments, and organisms. Understand the structure of Late Paleozoic extinction events. Understand the major Late Paleozoic extinction drivers. Understand the degree to which these putative drivers correlate with Late Paleozoic extinction events. Late Paleozoic World, Life & Extinctions Presentation Topics Stratigraphy - chronostrati- graphy & geochronology Geography - tectonics & distribution Climate - circulation, temp- erature, weather Biota - protists, inverte- brates, vertebrates, plants Evolution - evolutionary faunas, adaptive radiations, major innovations Significant Events - sea-level changes, volcanic eruptions, marine anoxia events, bolide impacts, extinctions Carboniferous Carboniferous Paleozoic System Durations 75 60 45 30 Duration(myr) 15 0 Camb. Ord. Sil. Dev. Carbon. Perm. Data from ICS (2020) Carboniferous Timescale System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 ± 0.15 Gzhelian Upper 303.7 ± 0.1 Kasimovian 307.0 ± 0.1 Middle Moscovian 315.2 ± 0.2 Pennsylvanian Lower Bashkirian 315.2 ± 0.2 Upper Serpukhovian 323.2 ± 0.4 Carboniferous Middle Visean 346.7 ± 0.4 Tournasian Mississippian Lower 358.9 ± 0.4 ICS International Chronostrat. Chart 2020/03 Carboniferous Tectonic Configuration Pangea becomes unified and occupies southern polar region with Euramerica (= Laurentia + Avalonia + Baltica) & Siberia forming satellite continents separated from (former) Gondwana by a broad seaway in the Early Carboniferous the former joined to Gondwana (to form Pangea by the Late Carboniferous. Northern seaway referred to as Iapetus Ocean Southern seaway referred to as the Rheic Ocean Both Iapetus and Rhetic Oceans close during the Interval … … leaving the Paleo- Tethys, Panthalassic Ocean (= Proto-Pacific). Map from Scotese PaleoMap Project (2001) Carboniferous Tectonic Configuration Pangea becomes unified and occupies southern polar region with Euramerica (= Laurentia + Avalonia + Baltica) & Siberia forming satellite continents separated from (former) Gondwana by a broad seaway in the Early Carboniferous the former joined to Gondwana (to form Pangea by the Late Carboniferous. Northern seaway referred to as Iapetus Ocean Southern seaway referred to as the Rheic Ocean Both Iapetus and Rhetic Oceans close during the Interval … … leaving the Paleo- Tethys, Panthalassic Ocean (= Proto-Pacific). Map from Scotese PaleoMap Project (2001) Carboniferous Marine Circulation Simplified, but hemispherically heterogeneous circulation patterns. Strong circum-Arctic cold current Disrupted circum-equatorial current Northern & southern Paleo- Tethys gyres Broken circum-Antarctic cold current Upwelling zone off western Euamerica & northern Gondwana Map from Scotese PaleoMap Project (2001) Carboniferous Paleoenvironment Atmospheric O Atmospheric CO 2 2 35 5000 28 4000 21 3000 14 2000 Percent byVol. 7 PerMillionParts 1000 0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Mean Surface Temperature Sea Level 25 250 20 200 15 150 10 Present 100 Meters Above Meters Degrees Celsius 5 50 0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Carboniferous Climate Zones Comparative Criteria Silurian O2 Content of 32.3% vol. % Atmosphere (+162%) CO2 Content of 800 ppm Atmosphere (x3) Mean Surface 14°C Temperature (0°C) Sea Level +120m - 0m - +20m Characterized by high sea-levels and a marked greenhouse effect resulting from high atmospheric CO2 concentrations Greatly expanded tropical, arid & temperate belts Clear southern ice cap early, melting as interval proceeds Falling sea levels through Moscovian, then rising sea levels Draining, the refolding of continental platforms Map from Scotese PaleoMap Project (2000) Carboniferous Cambrian Evolutionary Fauna Trilobite Graptolite Inarticulata Monoplacophora Hyolith Carboniferous Paleozoic Evolutionary Fauna Articulata Crinoid Tabulate Coral Bryozoan Ammonite Ruose Coral Carboniferous Modern Evolutionary Fauna Bivalve Gastropod Echinoid Bony Fish Carboniferous Reefs Carboniferous Reef Widespread reef formation in epicontinental seas, becoming progressively more restricted geographically as the tropical Iapetus and Rhetic seas close. Laurentia / Euamerica Baltica Siberia Northern Gondwana Map from Scotese PaleoMap Project (2000) Carboniferous Reefs Carboniferous deep-water reefs were typically characterized as mud mounds. Core of reef-forming organisms (e.g., bryozoans, crinoids) created topological reef by baffling lime mud around themselves Carboniferous mud reefs had no apparent framework Began in deeper water, but could grow into shallower depths Microbial reef organisms important elements of reef composition/construction Reef structure attracted a host of marine benthos & nekton Diagram from Wood (1998) Carboniferous Fish Platystomus Rhizodus Latimeria Acrolepis Carboniferous Fish Carboniferous Elasmobranchs Akmonistion Diploselache Hybodontid Damocles serrates Carboniferous Elasmobranchs Carboniferous Terrestrial Environment Adjacent to the low and mid-latitude shallow seas were dense tropical forests that form the basis for thick and laterally extensive coal deposits. Temperate forests and steppes were present at higher latitudes Plants Arthropods (incl. insects) Amphibians The first reptiles Carboniferous Terrestrial Scene Carboniferous Terrestrial Environment Equisetales Sphenophyllales Lycopodiales Lepidodendrales Filicales (Horse Tails) (Scramblers) (Club Mosses) (Scale Trees) (Ferns) Cordaitales Cycadophyta (Early Conifers) (Cycads) Carboniferous Terrestrial Environment Carboniferous Forest Carboniferous Terrestrial Arthropods Terrestrial arthropods were able to grow to such enormous sizes because of the high concentration of O2 in the Carboniferous atmosphere (32.3% vol. %, or +162% present day concentrations) Arthropleura (Largest known land arthropod: Length 2.5 m) Pulmonoscorpius Carboniferous Terrestrial Insects Dictyoptera (Cockroach Ancestor) Meganeura Protorthoptera (Largest known insects: wingspan c. 75 cm) (Earliest known Winged Insect) Palaeodictyoptera (Superorder: 50% of all known insects) Carboniferous Quadrupeds (Amphibians) Eyrops Pederpes (Labyrinthodont: Temnospondyl) (Labyrinthodont) Hyloplesion (Lepospondyl: Microsauria) Dioplocaulus (Lepospondyl: Lissamphibian) Ophiderpeton (Lepospondyl: Aïstopod) Carboniferous Quadrupeds (Amphibians) Chart from Roelants et al. (2005) Carboniferous Amphibian - Reptile Transition Reptiles appear in the fossil record in the Late Carboniferous Reptile Characteristics Strong skeletal Advanced lung & leg Development of hard- structure designs shelled eggs (and Protective coating for Loss of gills possibly paternal egg- incubation behaviors) skin (scales) Dominantly carnivorous Increased brain size Carboniferous Reptile Cranium Types Anapsid Synapsid Parapsid Euryapsid Diapsid Carboniferous Quadrupeds (Reptiles) Protoclepsydrops Gephyrostegus Hylonomus (Earliest Reptile) Petrolacosaurus (Early Diapsid) Archaeothyris (Early Synapsid) Carboniferous Biodiversity 800 600 Carboniferous Extinction 400 Modern Fauna 200 Paleozoic Fauna NumberFamilies of Cambrian Fauna 0 Cambrian Ordovician Sil. Devonian Carbon. Permian Tri. Jurassic Cretaceous Tertiary 500 400 300 200 100 0 Geological Time Data from Sepkoski (1981) Carboniferous Biodiversity Figure from Fan et al. (2020) Carboniferous Extinctions End-Ordovician End-Devonian End-Permian End-Triassic End-Cretaceous 80 Palaeozoic Mesozoic Cenozoic Carbonif. 60 40 PercentExtinction 20 0 Cambrian Ord. Sil. Dev. Carb. Perm. Trias. Jurassic Cretaceous Paleoc. Neo. Paleozoic Mesozoic Cenozoic Data from Sepkoski (1998) Carboniferous Extinctions System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Gzhelian Upper 303.7 Kasimovian Mid-Carboniferous 307.0 Extinction event Middle Moscovian Ammonites Pennsylvanian 315.2 Conodonts Lower Bashkirian 315.2 Crinoids Upper Serpukhovian Brachiopods 323.2 Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 No. Of Genera ICS International Chronostrat. Chart 2020/03 Carboniferous Sea-Level Changes System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Gzhelian Upper 303.7 Kasimovian 307.0 Middle Moscovian Pennsylvanian 315.2 Lower Bashkirian 315.2 Upper Serpukhovian 323.2 Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 0.5 0.0 200 100 0 No. Of Genera Onlap Sea Level ICS International Chronostrat. Chart 2020/03 Carboniferous Ocean Anoxia Events System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Gzhelian Upper 303.7 Kasimovian 307.0 Middle Moscovian Pennsylvanian 315.2 Lower Bashkirian 315.2 Upper Serpukhovian 323.2 Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 No. Of Genera ICS International Chronostrat. Chart 2020/03 Carboniferous LIP Eruptions System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Skagerrak (150 Kkm2) Gzhelian Upper 303.7 Kasimovian 307.0 Middle Moscovian Pennsylvanian 315.2 Lower Bashkirian 315.2 Kennedy-Conors- Upper Serpukhovian Auburn (500 Kkm2) 323.2 Tianshan (250 Kkm2) Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 No. Of Genera ICS International Chronostrat. Chart 2020/03 Carboniferous LIP Eruptions Kennedy-Conors-Auburn Large Igneous Province
Recommended publications
  • The Engineering of the Giant Dragonflies of the Permian: Revised Body Mass, Power, Air Supply, Thermoregulation and the Role of Air Density Alan E
    © 2018. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2018) 221, jeb185405. doi:10.1242/jeb.185405 COMMENTARY The engineering of the giant dragonflies of the Permian: revised body mass, power, air supply, thermoregulation and the role of air density Alan E. R. Cannell ABSTRACT abdomen as well as spiny and surprisingly robust legs. Illustrations An engineering examination of allometric and analogical data on the of M. monyi and a female Meganeurula selysii (Shear and flight of giant Permian insects (Protodonata, Meganeura or griffinflies) Kukalova-Peck, 1990) also indicate creatures with strong mouth indicates that previous estimates of the body mass of these insects parts, well-developed pincers and strong long thick legs. In both are too low and that the largest of these insects (wingspan of 70 cm or drawings, the abdomen is similar in diameter to the thorax, unlike more) would have had a mass of 100–150 g, several times greater the structure of most modern dragonflies, which have much more – – than previously thought. Here, the power needed to generate lift and slender abdomens. This large size and consequently high mass fly at the speeds typical of modern large dragonflies is examined has attracted attention for over a hundred years as there are no extant together with the metabolic rate and subsequent heat generated by insects of this size and their physiology in terms of power generation the thoracic muscles. This evaluation agrees with previous work and thermoregulation is not understood. This Commentary suggesting that the larger specimens would rapidly overheat in the examines the questions of mass, power generation to fly and high ambient temperatures assumed in the Permian.
    [Show full text]
  • Novtautesamerican MUSEUM PUBLISHED by the AMERICAN MUSEUM of NATURAL HISTORY CENTRAL PARK WEST at 79TH STREET, NEW YORK, N.Y
    NovtautesAMERICAN MUSEUM PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2722, pp. 1-24, figs. 1-1I1 January 29, 1982 Studies on the Paleozoic Selachian Genus Ctenacanthus Agassiz: No. 2. Bythiacanthus St. John and Worthen, Amelacanthus, New Genus, Eunemacanthus St. John and Worthen, Sphenacanthus Agassiz, and Wodnika Miunster JOHN G. MAISEY1 ABSTRACT Some of the finspines originally referred to Eunemacanthus St. John and Worthen is revised Ctenacanthus are reassigned to other taxa. Sev- to include some European and North American eral characteristically tuberculate lower Carbon- species. Sphenacanthus Agassiz is shown to be iferous finspines are referred to Bythiacanthus St. a distinct taxon from Ctenacanthus Agassiz, on John and Worthen, including one of Agassiz's the basis of finspine morphology, and its wide- original species, Ctenacanthus brevis. Finspines spread occurrence in the Carboniferous of North referable to Bythiacanthus are known from west- America is demonstrated. Similarities are noted ern Europe, the U.S.S.R., and North America. between the finspines of Sphenacanthus and Amelacanthus, new genus, is described on the Wodnika, and both taxa are placed provisionally basis of finspines from the United Kingdom. Four in the family Sphenacanthidae. A new species of species are recognized, two of which were origi- Wodnika, W. borealis, is recognized on the basis nally assigned to Onchus by Agassiz, and all four of a finspine from the Permian of Alaska. of which were referred to Ctenacanthus by Davis. INTRODUCTION The present paper is the second in a series Ctenacanthus in an attempt to restrict this of reviews of the Paleozoic chondrichthyan taxon to sharks with finspines that closely Ctenacanthus.
    [Show full text]
  • Early Tetrapod Relationships Revisited
    Biol. Rev. (2003), 78, pp. 251–345. f Cambridge Philosophical Society 251 DOI: 10.1017/S1464793102006103 Printed in the United Kingdom Early tetrapod relationships revisited MARCELLO RUTA1*, MICHAEL I. COATES1 and DONALD L. J. QUICKE2 1 The Department of Organismal Biology and Anatomy, The University of Chicago, 1027 East 57th Street, Chicago, IL 60637-1508, USA (mruta@midway.uchicago.edu; mcoates@midway.uchicago.edu) 2 Department of Biology, Imperial College at Silwood Park, Ascot, Berkshire SL57PY, UK and Department of Entomology, The Natural History Museum, Cromwell Road, London SW75BD, UK (d.quicke@ic.ac.uk) (Received 29 November 2001; revised 28 August 2002; accepted 2 September 2002) ABSTRACT In an attempt to investigate differences between the most widely discussed hypotheses of early tetrapod relation- ships, we assembled a new data matrix including 90 taxa coded for 319 cranial and postcranial characters. We have incorporated, where possible, original observations of numerous taxa spread throughout the major tetrapod clades. A stem-based (total-group) definition of Tetrapoda is preferred over apomorphy- and node-based (crown-group) definitions. This definition is operational, since it is based on a formal character analysis. A PAUP* search using a recently implemented version of the parsimony ratchet method yields 64 shortest trees. Differ- ences between these trees concern: (1) the internal relationships of aı¨stopods, the three selected species of which form a trichotomy; (2) the internal relationships of embolomeres, with Archeria
    [Show full text]
  • For the Love of Insects
    For the Love of Insects “In terms of biomass and their interactions with other terrestrial organisms, insects are the most important group of terrestrial animals.” --Grimaldi and Engel, 2005 Outline • The Most Successful Animals on Earth: a Brief (Entomological) Journey through Time • Insect Physiology and Development • Common Insects and their Identification Whence and Whither: Insect Origins and Evolution Before diversity, there was evolution… A ~500 million year journey… Silurian • Insect Flight: 400 mya • Modern insect orders: 250 mya • Primitive mammals: 120 mya • Modern mammals: 60 mya The Jointed Animals Phylum: Arthropoda • 75% of all species on earth are arthropods • Internal/External specialization of body parts = tagmosis • Hardened exoskeleton • Articulated body plates • Paired, jointed appendages sciencenewsjournal.com Tagmosis: highly specialized body segments found in all arthropods; insects: head, thorax, abdomen; spiders: cephalothorax and opisthosoma Epiclass HEXAPODA: Late Silurian/Early Devonian Class Entognatha Order Diplura Ellipura Order Protura Order Collembola Class Insecta (= Ectognatha) Hexapoda • 6 legs; 11 abdominal segments (or fewer) taxondiversity.fieldofscience.com • Entognatha: Protura, Diplura, and Collembola • Ectognatha: Insects The First Insects: Apterygota Archaeognatha: The Jumping Bristletails • ~500 spp. worldwide; wide range of habitats; • 4 Families (2 extinct) which occur mostly in rocky habitats • Mostly detritovores, but scavenge dead arthropods or eat exuviae; • Indirect mating behavior;
    [Show full text]
  • The Devonian Tetrapod Acanthostega Gunnari Jarvik: Postcranial Anatomy, Basal Tetrapod Interrelationships and Patterns of Skeletal Evolution M
    Transactions of the Royal Society of Edinburgh: Earth Sciences, 87, 363-421, 1996 The Devonian tetrapod Acanthostega gunnari Jarvik: postcranial anatomy, basal tetrapod interrelationships and patterns of skeletal evolution M. I. Coates ABSTRACT: The postcranial skeleton of Acanthostega gunnari from the Famennian of East Greenland displays a unique, transitional, mixture of features conventionally associated with fish- and tetrapod-like morphologies. The rhachitomous vertebral column has a primitive, barely differentiated atlas-axis complex, encloses an unconstricted notochordal canal, and the weakly ossified neural arches have poorly developed zygapophyses. More derived axial skeletal features include caudal vertebral proliferation and, transiently, neural radials supporting unbranched and unsegmented lepidotrichia. Sacral and post-sacral ribs reiterate uncinate cervical and anterior thoracic rib morphologies: a simple distal flange supplies a broad surface for iliac attachment. The octodactylous forelimb and hindlimb each articulate with an unsutured, foraminate endoskeletal girdle. A broad-bladed femoral shaft with extreme anterior torsion and associated flattened epipodials indicates a paddle-like hindlimb function. Phylogenetic analysis places Acanthostega as the sister- group of Ichthyostega plus all more advanced tetrapods. Tulerpeton appears to be a basal stem- amniote plesion, tying the amphibian-amniote split to the uppermost Devonian. Caerorhachis may represent a more derived stem-amniote plesion. Postcranial evolutionary trends spanning the taxa traditionally associated with the fish-tetrapod transition are discussed in detail. Comparison between axial skeletons of primitive tetrapods suggests that plesiomorphic fish-like morphologies were re-patterned in a cranio-caudal direction with the emergence of tetrapod vertebral regionalisation. The evolution of digited limbs lags behind the initial enlargement of endoskeletal girdles, whereas digit evolution precedes the elaboration of complex carpal and tarsal articulations.
    [Show full text]
  • Arthropod Adventure *Location of Activity Provided by Staff*
    Arthropod Adventure *Location of activity provided by staff* Grades: (suggested) 4-8 ​ ​ Subject: Arthropods and Anatomy ​ ​ Activity Objective: ​ To have students review arthropods...including anatomy, types of arthropods, and types of metamorphosis. Students take a short walk in the desert discovering arthropods and evidence of arthropods and discuss their findings. Materials & Preparation: ​ PROVIDED: ● Velcro board and illustrations ● Arthropod models ● 2 Trilobites ● Specimen of arthropod ● Meal game ● 10 cartoons ● 7 magnifying glasses PREP: Check out the materials, leader may wish to do additional research on arthropods. If time allows (before first group) walk along the trail to familiarize yourself with the area. Key Vocabulary Terms: arthropods, anatomy, specimens ​ ​ Arthropod Adventure Cooper CEL-TUSD page 1 NOTE: Some students will be familiar with Arthropods because of studies in earlier grades. ​ Others will not be familiar with them. A quick review of the phylum of Arthropods will help students identify arthropods or evidence of arthropods on the nature walk. Intro Discussion: (5-10 mins) ​ Explain to the students that they are going to learn about desert arthropods and go on a discovery walk to see if they can find any live specimens or evidence of arthropod life. Arthropod is the scientific name for the group of animals that includes insects, spiders, scorpions, centipedes, millipedes, lobsters, crabs, etc. The prefix arthro is from the Greek ​ ​ language and it means joint. Think of arthritis, which is an inflammation of the joints. ​ ​ ​ ​ Please do not make the common mistake of calling these animals "aNthropods". Pod ​ ​ ​ ​ means "foot". Thus, the animals in this phylum are the "joint-footed".
    [Show full text]
  • Lopingian, Permian) of North China
    Foss. Rec., 23, 205–213, 2020 https://doi.org/10.5194/fr-23-205-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. The youngest occurrence of embolomeres (Tetrapoda: Anthracosauria) from the Sunjiagou Formation (Lopingian, Permian) of North China Jianye Chen1 and Jun Liu1,2,3 1Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China 2Chinese Academy of Sciences Center for Excellence in Life and Paleoenvironment, Beijing 100044, China 3College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China Correspondence: Jianye Chen (chenjianye@ivpp.ac.cn) Received: 7 August 2020 – Revised: 2 November 2020 – Accepted: 16 November 2020 – Published: 1 December 2020 Abstract. Embolomeri were semiaquatic predators preva- 1 Introduction lent in the Carboniferous, with only two species from the early Permian (Cisuralian). A new embolomere, Seroher- Embolomeri are a monophyletic group of large crocodile- peton yangquanensis gen. et sp. nov. (Zoobank Registration like, semiaquatic predators, prevalent in the Carboniferous number: urn:lsid:zoobank.org:act:790BEB94-C2CC-4EA4- and early Permian (Cisuralian) (Panchen, 1970; Smithson, BE96-2A1BC4AED748, registration: 23 November 2020), is 2000; Carroll, 2009; Clack, 2012). The clade is generally named based on a partial right upper jaw and palate from the considered to be a stem member of the Reptiliomorpha, taxa Sunjiagou Formation of Yangquan, Shanxi, China, and is late that are more closely related to amniotes than to lissamphib- Wuchiapingian (late Permian) in age. It is the youngest em- ians (Ruta et al., 2003; Vallin and Laurin, 2004; Ruta and bolomere known to date and the only embolomere reported Coates, 2007; Clack and Klembara, 2009; Klembara et al., from North China Block.
    [Show full text]
  • Carboniferous Protodonatoid Dragonfly Nymphs and the Synapo- Morphies of Odonatoptera and Ephemeroptera (Insecta: Palaeoptera)
    Palaeodiversity 2: 169–198; Stuttgart, 30.12.2009. 169 Carboniferous protodonatoid dragonfly nymphs and the synapo- morphies of Odonatoptera and Ephemeroptera (Insecta: Palaeoptera) JARMILA KUKALOVÁ-PECK Abstract Three extremely rare fossil protodonatoid dragonfly nymphs are described from the middle Pennsylvanian (Moscovian) of Mazon Creek, Illinois: Dragonympha srokai n. gen., n. sp. (Meganisoptera), a large, nearly com- plete young nymph with an extended labial mask and uplifted wing pads; Alanympha richardsoni n. gen., n. sp. (Meganisoptera), a nymphal forewing with two articular plates attached to it; and Carbonympha herdinai n. gen., n. sp. (Eomeganisoptera), a detached nymphal forewing. Plesiomorphic states in Dragonympha n. gen. indicate ho- mologies unresolved in modern Odonata. The segmented head bears 3rd tergum ventrally invaginated. The extended labial mask still shows limb segments. The prothorax bears a pair of winglets. The short wing pads are fully articu- lated, twisted, uplifted and streamlined with body. The mesothoracic anepisternum is placed between acrotergite and prescutum. The abdominal leglets form long, segmented, serial gill filaments. In the ontogenesis of modern dragonflies, the wing and articulation disc occurs just above subcoxal pleuron and far from tergum. Wing sclerites are arranged in eight rows protecting eight blood pathways running towards eight wing veins. The sistergroup of Odonatoptera has not yet been convincingly resolved with computer cladistic approaches. Reasons are examined and discussed. More accurate, evolution-based character evaluations are shown with examples. The role of a correct model of the pan-arthropod limb and the origin of insect wings is discussed. Groundplan characters in dragonflies and mayflies are compared in their Paleozoic and modern states, their obscurity is clarified and complex synapo- morphies are proposed.
    [Show full text]
  • Bones, Molecules, and Crown- Tetrapod Origins
    TTEC11 05/06/2003 11:47 AM Page 224 Chapter 11 Bones, molecules, and crown- tetrapod origins Marcello Ruta and Michael I. Coates ABSTRACT The timing of major events in the evolutionary history of early tetrapods is discussed in the light of a new cladistic analysis. The phylogenetic implications of this are com- pared with those of the most widely discussed, recent hypotheses of basal tetrapod interrelationships. Regardless of the sequence of cladogenetic events and positions of various Early Carboniferous taxa, these fossil-based analyses imply that the tetrapod crown-group had originated by the mid- to late Viséan. However, such estimates of the lissamphibian–amniote divergence fall short of the date implied by molecular studies. Uneven rates of molecular substitutions might be held responsible for the mismatch between molecular and morphological approaches, but the patchy quality of the fossil record also plays an important role. Morphology-based estimates of evolutionary chronology are highly sensitive to new fossil discoveries, the interpreta- tion and dating of such material, and the impact on tree topologies. Furthermore, the earliest and most primitive taxa are almost always known from very few fossil localities, with the result that these are likely to exert a disproportionate influence. Fossils and molecules should be treated as complementary approaches, rather than as conflicting and irreconcilable methods. Introduction Modern tetrapods have a long evolutionary history dating back to the Late Devonian. Their origins are rooted into a diverse, paraphyletic assemblage of lobe-finned bony fishes known as the ‘osteolepiforms’ (Cloutier and Ahlberg 1996; Janvier 1996; Ahlberg and Johanson 1998; Jeffery 2001; Johanson and Ahlberg 2001; Zhu and Schultze 2001).
    [Show full text]
  • A New Discosauriscid Seymouriamorph Tetrapod from the Lower Permian of Moravia, Czech Republic
    A new discosauriscid seymouriamorph tetrapod from the Lower Permian of Moravia, Czech Republic JOZEF KLEMBARA Klembara, J. 2005. A new discosauriscid seymouriamorph tetrapod from the Lower Permian of Moravia, Czech Repub− lic. Acta Palaeontologica Polonica 50 (1): 25–48. A new genus and species, Makowskia laticephala gen. et sp. nov., of seymouriamorph tetrapod from the Lower Permian deposits of the Boskovice Furrow in Moravia (Czech Republic) is described in detail, and its cranial reconstruction is pre− sented. It is placed in the family Discosauriscidae (together with Discosauriscus and Ariekanerpeton) on the following character states: short preorbital region; rounded to oval orbits positioned mainly in anterior half of skull; otic notch dorsoventrally broad and anteroposteriorly deep; rounded to oval ventral scales. Makowskia is distinguished from other Discosauriscidae by the following characters: nasal bones equally long as broad; interorbital region broad; prefrontal− postfrontal contact lies in level of frontal mid−length (only from D. pulcherrimus); maxilla deepest at its mid−length; sub− orbital ramus of jugal short and dorsoventrally broad with long anterodorsal−posteroventral directed lacrimal−jugal su− ture; postorbital anteroposteriorly short and lacks elongated posterior process; ventral surface of basioccipital smooth; rows of small denticles placed on distinct ridges and intervening furrows radiate from place immediately laterally to artic− ular portion on ventral surface of palatal ramus of pterygoid (only from D. pulcherrimus);
    [Show full text]
  • Fossils Provide Better Estimates of Ancestral Body Size Than Do Extant
    Acta Zoologica (Stockholm) 90 (Suppl. 1): 357–384 (January 2009) doi: 10.1111/j.1463-6395.2008.00364.x FossilsBlackwell Publishing Ltd provide better estimates of ancestral body size than do extant taxa in fishes James S. Albert,1 Derek M. Johnson1 and Jason H. Knouft2 Abstract 1Department of Biology, University of Albert, J.S., Johnson, D.M. and Knouft, J.H. 2009. Fossils provide better Louisiana at Lafayette, Lafayette, LA estimates of ancestral body size than do extant taxa in fishes. — Acta Zoologica 2 70504-2451, USA; Department of (Stockholm) 90 (Suppl. 1): 357–384 Biology, Saint Louis University, St. Louis, MO, USA The use of fossils in studies of character evolution is an active area of research. Characters from fossils have been viewed as less informative or more subjective Keywords: than comparable information from extant taxa. However, fossils are often the continuous trait evolution, character state only known representatives of many higher taxa, including some of the earliest optimization, morphological diversification, forms, and have been important in determining character polarity and filling vertebrate taphonomy morphological gaps. Here we evaluate the influence of fossils on the interpretation of character evolution by comparing estimates of ancestral body Accepted for publication: 22 July 2008 size in fishes (non-tetrapod craniates) from two large and previously unpublished datasets; a palaeontological dataset representing all principal clades from throughout the Phanerozoic, and a macroecological dataset for all 515 families of living (Recent) fishes. Ancestral size was estimated from phylogenetically based (i.e. parsimony) optimization methods. Ancestral size estimates obtained from analysis of extant fish families are five to eight times larger than estimates using fossil members of the same higher taxa.
    [Show full text]
  • Insects Took Off When They Evolved Wings 23 January 2018, by Ker Than
    Insects took off when they evolved wings 23 January 2018, by Ker Than author Sandra Schachat, a graduate student at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth). Many ideas have been proposed to explain this curious lacuna in the insect fossil record, which scientists have dubbed the Hexapod Gap. According to one popular hypothesis, insect size and abundance were limited by the amount of oxygen available in Earth's atmosphere during the late Devonian period. When insects such as this Meganeura monyi, which had a wingspan of about 27 inches, developed wings roughly The strongest evidence for this theory is a model of 325 million years ago, the insect population exploded, atmospheric oxygen during the past 570 million Stanford researchers found. Credit: Alexandre Albore, years that the late Yale geologist Robert Berner Wikimedia Commons developed by comparing ratios of oxygen and carbon in ancient rocks and fossils. According to Berner's model, the atmospheric The evolution of wings not only allowed ancient oxygen level about 385 million years ago during the insects to become the first creatures on Earth to start of the Hexapod Gap was below 15 percent, so take to the skies, but also propelled their rise to low that wildfires would have been unsustainable. become one of nature's great success stories, (For comparison, today's atmospheric oxygen according to a new study. concentration is about 21 percent.) Comprising up to 10 million living species, insects Another possibility is that insects were abundant today can be found on all seven continents and before 323 million years ago, but don't show up in inhabit every terrestrial niche imaginable.
    [Show full text]