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Early Sponge Evolution: a Review and Phylogenetic Framework
Available online at www.sciencedirect.com ScienceDirect Palaeoworld 27 (2018) 1–29 Review Early sponge evolution: A review and phylogenetic framework a,b,∗ a Joseph P. Botting , Lucy A. Muir a Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, China b Department of Natural Sciences, Amgueddfa Cymru — National Museum Wales, Cathays Park, Cardiff CF10 3LP, UK Received 27 January 2017; received in revised form 12 May 2017; accepted 5 July 2017 Available online 13 July 2017 Abstract Sponges are one of the critical groups in understanding the early evolution of animals. Traditional views of these relationships are currently being challenged by molecular data, but the debate has so far made little use of recent palaeontological advances that provide an independent perspective on deep sponge evolution. This review summarises the available information, particularly where the fossil record reveals extinct character combinations that directly impinge on our understanding of high-level relationships and evolutionary origins. An evolutionary outline is proposed that includes the major early fossil groups, combining the fossil record with molecular phylogenetics. The key points are as follows. (1) Crown-group sponge classes are difficult to recognise in the fossil record, with the exception of demosponges, the origins of which are now becoming clear. (2) Hexactine spicules were present in the stem lineages of Hexactinellida, Demospongiae, Silicea and probably also Calcarea and Porifera; this spicule type is not diagnostic of hexactinellids in the fossil record. (3) Reticulosans form the stem lineage of Silicea, and probably also Porifera. (4) At least some early-branching groups possessed biminerallic spicules of silica (with axial filament) combined with an outer layer of calcite secreted within an organic sheath. -
Fused and Vaulted Nasals of Tyrannosaurid Dinosaurs: Implications for Cranial Strength and Feeding Mechanics
Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics ERIC SNIVELY, DONALD M. HENDERSON, and DOUG S. PHILLIPS Snively, E., Henderson, D.M., and Phillips, D.S. 2006. Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics. Acta Palaeontologica Polonica 51 (3): 435–454. Tyrannosaurid theropods display several unusual adaptations of the skulls and teeth. Their nasals are fused and vaulted, suggesting that these elements braced the cranium against high feeding forces. Exceptionally high strengths of maxillary teeth in Tyrannosaurus rex indicate that it could exert relatively greater feeding forces than other tyrannosaurids. Areas and second moments of area of the nasals, calculated from CT cross−sections, show higher nasal strengths for large tyrannosaurids than for Allosaurus fragilis. Cross−sectional geometry of theropod crania reveals high second moments of area in tyrannosaurids, with resulting high strengths in bending and torsion, when compared with the crania of similarly sized theropods. In tyrannosaurids trends of strength increase are positively allomeric and have similar allometric expo− nents, indicating correlated progression towards unusually high strengths of the feeding apparatus. Fused, arched nasals and broad crania of tyrannosaurids are consistent with deep bites that impacted bone and powerful lateral movements of the head for dismembering prey. Key words: Theropoda, Carnosauria, Tyrannosauridae, biomechanics, feeding mechanics, computer modeling, com− puted tomography. Eric Snively [[email protected]], Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada; Donald M. Henderson [[email protected]], Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, Alberta T0J 0Y0, Canada; Doug S. -
Die Microsauria Des Mitteleuropäischen Rotliegend
Die Microsauria des mitteleuropäischen Rotliegend Dissertation zur Erlangung des Grades „Doktor der Naturwissenschaften" im Promotionsfach Geologie/Paläontologie am Fachbereich Chemie, Pharmazie und Geowissenschaften der Johannes Gutenberg-Universität in Mainz Sabine Glienke geb. in Worms Mainz, 2011 http://d-nb.info/1058187503 Inhalt Inhalt 1. Einleitung 6 1.1. Allgemeine Merkmale und Bearbeitungsgeschichte 6 1.2. Fundorte und Erhaltung 9 2. Methoden, Abkürzungen und Material 16 2.1. Methoden 16 2.1.1. Bearbeitung der Skelette 16 2.1.2. Gewinnung und Bearbeitung der Einzelknochen 16 2.1.3. Kladogramme 17 2.2. Abkürzungen 17 2.2.1. Sammlungen 17 2.2.2. In den Zeichnungen verwendete Abkürzungen 17 2.3. Übersicht über die untersuchten Skelette 19 3. Beschreibungen 21 3.1. Die Familie Brachystelechidae CARROLL& GASKILL, 1978 21 3.1.1. Systematische Stellung 21 3.1.2. Diagnose 21 3.2. Die Gattung Batropetes CARROLL & GASKILL, 1971 21 3.2.1. Systematische Stellung 21 3.2.2. Diagnose 22 3.2.3. Die vier Spezies der Gattung Batropetes 22 3.3. Batropetes niederkirchensis n. sp 26 3.3.1. Diagnose 26 3.3.2. Beschreibung 28 3.3.2.1. Schädel 28 3.3.2.1.1. Schädeldach 28 3.3.2.1.2. Gaumen 38 3.3.2.1.3. Hirnkapsel 43 3.3.2.1.4. Unterkiefer 46 3.3.2.2. Postcraniales Skelett 48 Inhalt 3.4. Batropetes palatinus n. sp 62 3.4.1. Diagnose 62 3.4.2. Beschreibung 63 3.4.2.1. Schädel 74 3.4.2.1.1. Schädeldach 74 3.4.2.1.2. -
A Critique of Phanerozoic Climatic Models Involving Changes in The
Earth-Science Reviews 56Ž. 2001 1–159 www.elsevier.comrlocaterearscirev A critique of Phanerozoic climatic models involving changes in the CO2 content of the atmosphere A.J. Boucot a,), Jane Gray b,1 a Department of Zoology, Oregon State UniÕersity, CorÕallis, OR 97331, USA b Department of Biology, UniÕersity of Oregon, Eugene, OR 97403, USA Received 28 April 1998; accepted 19 April 2001 Abstract Critical consideration of varied Phanerozoic climatic models, and comparison of them against Phanerozoic global climatic gradients revealed by a compilation of Cambrian through Miocene climatically sensitive sedimentsŽ evaporites, coals, tillites, lateritic soils, bauxites, calcretes, etc.. suggests that the previously postulated climatic models do not satisfactorily account for the geological information. Nor do many climatic conclusions based on botanical data stand up very well when examined critically. Although this account does not deal directly with global biogeographic information, another powerful source of climatic information, we have tried to incorporate such data into our thinking wherever possible, particularly in the earlier Paleozoic. In view of the excellent correlation between CO2 present in Antarctic ice cores, going back some hundreds of thousands of years, and global climatic gradient, one wonders whether or not the commonly postulated Phanerozoic connection between atmospheric CO2 and global climatic gradient is more coincidence than cause and effect. Many models have been proposed that attempt to determine atmospheric composition and global temperature through geological time, particularly for the Phanerozoic or significant portions of it. Many models assume a positive correlation between atmospheric CO2 and surface temperature, thus viewing changes in atmospheric CO2 as playing the critical role in r regulating climate temperature, but none agree on the levels of atmospheric CO2 through time. -
Chitinozoan Dynamics and Biostratigraphy in the Väo Formation (Darriwilian) of the Uuga Cliff, Pakri Peninsula, NW Estonia
Estonian Journal of Earth Sciences, 2010, 59, 1, 25–36 doi: 10.3176/earth.2010.1.02 Chitinozoan dynamics and biostratigraphy in the Väo Formation (Darriwilian) of the Uuga Cliff, Pakri Peninsula, NW Estonia Mairy Tammekänd, Olle Hints, and Jaak Nõlvak Institute of Geology at Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; [email protected], [email protected], [email protected] Received 3 August 2009, accepted 27 October 2009 Abstract. The distribution of chitinozoans in the Väo Formation (Lasnamägi and Uhaku regional stages, Darriwilian) of the Uuga Cliff, Pakri Peninsula, NW Estonia, was investigated from 62 samples. Chitinozoans are very common and assemblages are diverse, with a total of 36 species and up to 170 specimens per gram of rock. The assemblage is dominated by Belonechitina, Desmochitina, Cyathochitina, and Euconochitina. The relative and absolute frequency of particular taxa displays regular and possibly cyclic patterns, which are not directly reflected in lithology or geochemistry. Abrupt changes in chitinozoan abundance, coinciding with some of the discontinuity surfaces, suggest the presence of stratigraphical gaps. The diversity of chitinozoans is the highest in the lower part of the Väo Formation (Rebala Member), where up to 20 species were identified in one sample and the standing species diversity exceeded 25. Within the studied interval at least 11 biostratigraphical horizons can be distinguished, including the subzonal boundaries within the Laufeldochitina striata Zone. The disappearance of abundant Belonechitina pellifera can be used for tracing the lower boundary of the Uhaku Stage. Key words: chitinozoans, frequency patterns, diversity, biostratigraphy, Ordovician, Estonia. INTRODUCTION Although the largest chitinozoan collections in the world come from the Baltic area (Paris et al. -
Skeletonized Microfossils from the Lower–Middle Cambrian Transition of the Cantabrian Mountains, Northern Spain
Skeletonized microfossils from the Lower–Middle Cambrian transition of the Cantabrian Mountains, northern Spain SÉBASTIEN CLAUSEN and J. JAVIER ÁLVARO Clausen, S. and Álvaro, J.J. 2006. Skeletonized microfossils from the Lower–Middle Cambrian transition of the Cantabrian Mountains, northern Spain. Acta Palaeontologica Polonica 51 (2): 223–238. Two different assemblages of skeletonized microfossils are recorded in bioclastic shoals that cross the Lower–Middle Cambrian boundary in the Esla nappe, Cantabrian Mountains. The uppermost Lower Cambrian sedimentary rocks repre− sent a ramp with ooid−bioclastic shoals that allowed development of protected archaeocyathan−microbial reefs. The shoals yield abundant debris of tube−shelled microfossils, such as hyoliths and hyolithelminths (Torellella), and trilobites. The overlying erosive unconformity marks the disappearance of archaeocyaths and the Iberian Lower–Middle Cambrian boundary. A different assemblage occurs in the overlying glauconitic limestone associated with development of widespread low−relief bioclastic shoals. Their lowermost part is rich in hyoliths, hexactinellid, and heteractinid sponge spicules (Eiffelia), chancelloriid sclerites (at least six form species of Allonnia, Archiasterella, and Chancelloria), cambroclaves (Parazhijinites), probable eoconchariids (Cantabria labyrinthica gen. et sp. nov.), sclerites of uncertain af− finity (Holoplicatella margarita gen. et sp. nov.), echinoderm ossicles and trilobites. Although both bioclastic shoal com− plexes represent similar high−energy conditions, the unconformity at the Lower–Middle Cambrian boundary marks a drastic replacement of microfossil assemblages. This change may represent a real community replacement from hyolithelminth−phosphatic tubular shells to CES (chancelloriid−echinoderm−sponge) meadows. This replacement coin− cides with the immigration event based on trilobites previously reported across the boundary, although the partial infor− mation available from originally carbonate skeletons is also affected by taphonomic bias. -
Shell Microstructures in Early Cambrian Molluscs
Shell microstructures in Early Cambrian molluscs ARTEM KOUCHINSKY Kouchinsky, A. 2000. Shell microstructures in Early Cambrian molluscs. - Acta Palaeontologica Polonica 45,2, 119-150. The affinities of a considerable part of the earliest skeletal fossils are problematical, but investigation of their microstructures may be useful for understanding biomineralization mechanisms in early metazoans and helpful for their taxonomy. The skeletons of Early Cambrian mollusc-like organisms increased by marginal secretion of new growth lamel- lae or sclerites, the recognized basal elements of which were fibers of apparently aragon- ite. The juvenile part of some composite shells consisted of needle-like sclerites; the adult part was built of hollow leaf-like sclerites. A layer of mineralized prism-like units (low aragonitic prisms or flattened spherulites) surrounded by an organic matrix possibly existed in most of the shells with continuous walls. The distribution of initial points of the prism-like units on a periostracurn-like sheet and their growth rate were mostly regular. The units may be replicated on the surface of internal molds as shallow concave poly- gons, which may contain a more or less well-expressed tubercle in their center. Tubercles are often not enclosed in concave polygons and may co-occur with other types of tex- tures. Convex polygons seem to have resulted from decalcification of prism-like units. They do not co-occur with tubercles. The latter are interpreted as casts of pore channels in the wall possibly playing a role in biomineralization or pits serving as attachment sites of groups of mantle cells. Casts of fibers and/or lamellar units may overlap a polygonal tex- ture or occur without it. -
Um Éon De História Dos Bivalvia: Ideias Sobre a Sua Origem, Filogenia E Importância Paleontológica E Educativa
Um Éon de história dos Bivalvia: ideias sobre a sua origem, filogenia e importância paleontológica e educativa Ricardo J. Pimentel1, Pedro M. Callapez2 & Paulo Legoinha3 1 Agrupamento de Escolas de Guia, P-3105 075 Guia, Pombal, Portugal. E-mail: [email protected] 2 Universidade de Coimbra, CITEUC - Centro de Investigação da Terra e do Espaço da Universidade de Coimbra, Faculdade de Ciências e Tecnologia, Departamento de Ciências da Terra, Polo II, Rua Sílvio Lima, P-3030 790 Coimbra, Portugal. E-mail: [email protected] 3 Universidade NOVA de Lisboa, GEOBIOTEC - GeoBiociências, Geotecnologias e Geoengenharias, Faculdade de Ciências e Tecnologia, Departamento de Ciências da Terra, Quinta da Torre, P-2829 516 Caparica, Portugal. E-mail: [email protected] Resumo: A Classe Bivalvia, cuja monofilia se encontra bem suportada por estudos recentes, destaca-se como o segundo taxon, em termos de biodiversidade, do Filo Mollusca. O registo da sua história evolutiva remonta ao Fortuniano (Câmbrico). Diversos dados paleontológicos fundamentados no registo fóssil sugerem que os bivalves atuais são, sobretudo, herdeiros de carateres morfológicos e requisitos ecológicos transmitidos por linhagens da transição devónico-carbonífera. Estes invertebrados habitam a maioria dos ambientes aquáticos atuais e constituem um dos principais grupos de animais invertebrados da biosfera atual, são herdeiros de uma longa história evolutiva e ecológica que é intrínseca à própria história biótica dos oceanos durante o Fanerozoico. São um exemplo de sucesso entre as comunidades bióticas e a sua abundância, diversidade e acessibilidade propiciam a sua utilização como recursos educativos em Ciências Naturais. Palavras-chave: Bivalvia, Educação científica, Filogenia, Mollusca, Registo fóssil. -
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. -
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 ([email protected]; [email protected]) 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 ([email protected]) (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 -
Palynology of the Middle Ordovician Hawaz Formation in the Murzuq Basin, South-West Libya
This is a repository copy of Palynology of the Middle Ordovician Hawaz Formation in the Murzuq Basin, south-west Libya. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/125997/ Version: Accepted Version Article: Abuhmida, F.H. and Wellman, C.H. (2017) Palynology of the Middle Ordovician Hawaz Formation in the Murzuq Basin, south-west Libya. Palynology, 41. pp. 31-56. ISSN 0191-6122 https://doi.org/10.1080/01916122.2017.1356393 Reuse Items deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ Palynology of the Middle Ordovician Hawaz Formation in the Murzuq Basin, southwest Libya Faisal H. Abuhmidaa*, Charles H. Wellmanb aLibyan Petroleum Institute, Tripoli, Libya P.O. Box 6431, bUniversity of Sheffield, Department of Animal and Plant Sciences, Alfred Denny Building, Western Bank, Sheffield, S10 2TN, UK Twenty nine core and seven cuttings samples were collected from two boreholes penetrating the Middle Ordovician Hawaz Formation in the Murzuq Basin, southwest Libya. -
The Evolution of Trilobite Body Patterning
ANRV309-EA35-14 ARI 20 March 2007 15:54 The Evolution of Trilobite Body Patterning Nigel C. Hughes Department of Earth Sciences, University of California, Riverside, California 92521; email: [email protected] Annu. Rev. Earth Planet. Sci. 2007. 35:401–34 Key Words First published online as a Review in Advance on Trilobita, trilobitomorph, segmentation, Cambrian, Ordovician, January 29, 2007 diversification, body plan The Annual Review of Earth and Planetary Sciences is online at earth.annualreviews.org Abstract This article’s doi: The good fossil record of trilobite exoskeletal anatomy and on- 10.1146/annurev.earth.35.031306.140258 togeny, coupled with information on their nonbiomineralized tis- Copyright c 2007 by Annual Reviews. sues, permits analysis of how the trilobite body was organized and All rights reserved developed, and the various evolutionary modifications of such pat- 0084-6597/07/0530-0401$20.00 terning within the group. In several respects trilobite development and form appears comparable with that which may have charac- terized the ancestor of most or all euarthropods, giving studies of trilobite body organization special relevance in the light of recent advances in the understanding of arthropod evolution and devel- opment. The Cambrian diversification of trilobites displayed mod- Annu. Rev. Earth Planet. Sci. 2007.35:401-434. Downloaded from arjournals.annualreviews.org ifications in the patterning of the trunk region comparable with by UNIVERSITY OF CALIFORNIA - RIVERSIDE LIBRARY on 05/02/07. For personal use only. those seen among the closest relatives of Trilobita. In contrast, the Ordovician diversification of trilobites, although contributing greatly to the overall diversity within the clade, did so within a nar- rower range of trunk conditions.