DOCSLIB.ORG

Ciencias Das Origens Nº 7.Indd

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ciencias Das Origens Nº 7.Indd Uma publicação do Geoscience Research Institute (Instituto de Pesquisas em Geociências) Estuda a Terra e a Vida: Sua origem, suas mudanças, sua preservação. Edição em língua portuguesa patrocinada pela DSA da IASD com colaboração da SCB. APRESENTAÇÃO DO SÉTIMO NÚMERO DE CIÊNCIAS DAS ORIGENS TRADUZIDO PARA A LÍNGUA PORTUGUESA A Sociedade Criacionista Brasileira, Standish, que aponta para um interessante Renovam-se aqui os agradecimentos dentro de sua programação editorial, tem a campo de pesquisas – as aves. especiais à Divisão Sul-Americana da satisfação de apresentar o sétimo número Como sempre, ficam expressos os Igreja Adventista do Sétimo Dia, na pessoa deste periódico (primeiro número anual agradecimentos da Sociedade Criacionista do seu Presidente, Pastor Ruy Nagel, de 2004), versão brasileira de “Ciencia Brasileira a todos os que colaboraram para pela continuidade do apoio à publicação de los Orígenes”, editado originalmente possibilitar esta publicação em Português, periódica desta revista. pelo “Geoscience Research Institute” nos particularmente a nossa associada Marly E.U.A. Barreto Vieira pela primorosa tradução e Ruy Carlos de Camargo Vieira Ressaltamos o artigo de fundo “Aves a Roosevelt S. de Castro pelo excelente Diretor-Presidente da Fósseis”, de autoria do Dr. Timothy trabalho de editoração gráfica. Sociedade Criacionista Brasileira AVES FÓSSEIS Timothy Standish, Geoscience Research Institute Quando o livro “A Origem das Espécies” um elo perdido. Além disso, o foi publicado pela primeira vez, o registro aparecimento do Archaeopteryx fóssil constituia uma grande objeção às numa formação geológica do idéias de Charles Darwin: no registro Jurássico Superior o coloca não constavam as formas intermediárias no lugar onde seria esperado, preditas por sua teoria. Darwin explicava depois do aparecimento isto invocando “a extrema imperfeição do dos dinossauros e antes do registro fóssil” 1 . Rapidamente depois da aparecimento das aves fósseis. publicação do livro, os fósseis intermediários Desde o seu descobrimento, a – “elos perdidos” - começaram a aparecer. teoria de que as aves evoluíram Alguns desses elos perdidos não superaram a partir de dinossauros tem sido a prova do tempo: o Homem de Piltdown, muito popular, e controvertida. um suposto elo perdido na cadeia de símios O Archaeopteryx era perfeito a seres humanos, acabou mostrando- demais como evidência a se uma fraude. Em tempos recentes o favor da teoria da evolução Archaeoraptor 2, um suposto intermediário darwinista, e a autenticidade entre dinossauros e aves, mostrou-se dos espécimes que mostravam também uma vergonhosa falsificação.3 vestígios de penas, permanece Pelo menos um dos primeiros “elos controvertida.4 perdidos” encontrados passou pela prova Por mais de um século, do tempo: O Archaeopteryx (Figura 1), o Archaeopteryx se manteve um impressionante fóssil das jazidas de como o elo perdido entre calcáreo de Solnhofen na Alemanha, dinossauros e aves, porém pareceu à primeira vista ser um dinossauro numerosos pássaros fósseis com penas. Como as penas são encontradas foram descobertos nos últimos somente nas aves, e não eram conhecidas vinte anos nos estratos Figura 1 nos dinossauros, o Archaeopteryx foi aceito geológicos próximos de onde Reprodução do fóssil Archaeopteryx. As penas podem como uma forma intermediária entre as foi descoberto o Archaeopteryx. ser vistas vagamente na cauda e em uma asa. Foto- aves e os dinossauros, e portanto como Estes novos fósseis põem em grafia: cortesia de Tim Standish. cheque a colocação do Archaeopteryx classificação junto com os pássaros não experts. Os dados proporcionados pelos na linha direta que teria produzido as parecem controvertidas. Além disso, dinossauros “com penas” e as aves aves. O Archaeopteryx agora, pelo foram descobertos muitos fósseis que fósseis, as quais são bastante diferentes contrário, é visto como um ramo lateral têm sido classificados como dinossauros das aves modernas, poderiam servir de da evolução que eventualmente se e que têm estruturas identificadas como evidência favorável da teoria de que as extingüiu.5 Ao contrário do Archaeopteryx, penas. A autenticidade destas “penas” aves evoluíram a partir de dinossauros, tanto a autenticidade destes fósseis tem sido posta em dúvida e continua mesmo que seja difícil decidir o que seria recentemente descobertos, como sua como questão aberta aos olhos de muitos um elo perdido. TABELA 1 Aves Fósseis do Jurássico Superior e do Cretáceo Inferior Gênero Espécie Idade Formação - Local Confuciusornis sanctus Jurássico Superior Yixian Basal - Liaoning, China Confuciusornis chuonzhous Jurássico Superior Yixian Basal - Liaoning, China Confuciusornis suniae Jurássico Superior Yixian Basal - Liaoning, China Jibeinia luanhera Jurássico Superior Yixian - Liaoning, China Liaoningornis longidigitus Jurássico Superior Yixian Basal - Liaoning, China Archaeopteryx recurva* Jurássico Superior Solnhofen – Alemanha Archaeopteryx lithographica Jurássico Superior Solnhofen – Alemanha Archaeopteryx siemensii Jurássico Superior Solnhofen – Alemanha Liaoxiornis delicatus Cretáceo Inferior Yixian - Liaoning, China Sinornis santensis Cretáceo Inferior Jiufotang - Liaoning, China Boluochia zhengi Cretáceo Inferior Loufotang - Liaoning, China Cathayornis yandica Cretáceo Inferior Jiufotang - Liaoning, China Cathayornis caudatus Cretáceo Inferior Jiufotang - Liaoning, China Longchengornis sanyanensis Cretáceo Inferior Jiufotang - Liaoning, China Otogornis genghisi Cretáceo Inferior Yijinhuoluo - Yike Zhaomeng, Mongólia Interior Cuspirostrisornis houi Cretáceo Inferior Jiufotang - Liaoning, China Largirostrornis sexdentoris Cretáceo Inferior Jiufotang - Liaoning, China Gansus yumenensis Cretácep Inferior Xiagou Medio - Gansu, China Chaoyangia beishanensis Cretáceo Inferior Jiufotang - Liaoning, China Songlingornis linghensis Cretáceo Inferior Jiufotang - Liaoning, China Jeholornis prima Cretáceo Inferior Jiufotang - Liaoning, China Yanornis martini Cretáceo Inferior Jiufotang - Liaoning, China Yixianornis grabaui Cretáceo Inferior Jiufotang - Liaoning, China Protopteryx fengningensis Cretáceo Inferior Yixian - Liaoning, China Sapeornis chaoyangensis Cretáceo Inferior Jiufotang - Liaoning, China Concornis Lacustris Cretáceo Inferior Las Hoyas, Espanha Nanantius eos Cretáceo Inferior Toolebuc - Queensland, Austrália Ambiortus dementjevi Cretáceo Inferior Mongólia Enaliornis barretti Cretáceo Inferior Cambridge, Inglaterra Noguerornis gonzalezi Cretáceo Inferior Espanha Iberomesornis romerali Cretáceo Inferior Las Hoyas – Espanha Eoalulavis hoyasi Cretáceo Inferior Las Hoyas – Espanha *Taxa particularmente duvidosos ou controvertidos. Entretanto, como parece ser possíveis fragmentos de Nanantius porém designação de três espécies com base freqüentemente o caso, a imagem a evidência a favor da existência deste nos espécimes fósseis disponíveis. 8 que estes novos e fascinantes fósseis pássaro fóssil continua sendo mínima. 7 Mesmo admitindo algumas apresentam é significativamente mais Dentro da lista dos pássaros do designações duvidosas, a lista das interessante e, quem sabe, confusa, do Jurássico Superior e do Cretáceo Inferior aves fósseis conhecidas do Jurássico que um exame superficial possa sugerir. estão também algumas espécies que Superior e Cretáceo Inferior é substancial, A Tabela 1 contém 27 fósseis do Jurássico podem ter sido o resultado da divisão particularmente dada a escassez de aves Superior e do Cretáceo Inferior. Algumas de opiniões dentro da comunidade fósseis em geral e a relativamente grande das espécies da lista se baseiam em paleontológica. Por exemplo, o gênero proporção deles recolhidos em algumas evidências muito fragmentárias. Por Archaeopteryx aparece como tendo três poucas localidades da China. Entretanto, exemplo, Nanantius eos parece ter sido espécies. Mesmo embora possam ter vale a pena mencionar que as aves fósseis descrito a partir de um fragmento de 3 existido várias espécies de Archaeopteryx do Jurássico Superior e Cretáceo Inferior cm de tibiotarso (osso da parte inferior da (supondo em primeiro lugar que tenham não aparecem somente na China. Além perna). 6 Foram encontrados alguns outros sido reais), alguns questionam a do exemplar australiano de Nanantius e 2 Nº 6 Ciências das Origens o exemplar alemão de Archaeopteryx, o que tem sido chamado de “evolução Um interessante aspecto das aves mencionados anteriormente, outros em mosaico”. Em outras palavras, uma fósseis encontradas até agora é que alguns espécimes de diversas qualidades foram espécie pode apresentar dois ou três dos traços considerados como primitivos encontrados na Espanha e na Inglaterra. traços encontrados nas aves modernas e nos pássaros fósseis são evidentes em Se fossem incluídas todas as aves outra espécie pode apresentar um conjunto algumas aves modernas. Por exemplo, o fósseis do Cretáceo, existiriam numerosos de traços “derivados”. Deste modo, por professor Hao Lianhai destaca a “ausência excelentes espécimes procedentes de exemplo, Confuciusornis sanctus carece de processos uncinados nas costelas” como todos os continentes, com a possível de dentes e parece ter um bico moderno um traço primitivo, 10 porém a ema australiana exceção da Antártida, com o que as aves e cauda de comprimento médio. Por outro moderna (Dromaius novaehollandiae) fósseis se manifestam em uma escala lado, Jibeinia luanhera tem muitos dentes, carece de processos uncinados nas global nos estratos do Jurássico Superior porém uma cauda de aparência moderna costelas. 11 Outros traços “primitivos” e Cretáceo
Load more

Recommended publications
  • A Second Cretaceous Ornithuromorph Bird from the Changma Basin, Gansu Province, Northwestern China Author(S): Hai-Lu You , Jessie Atterholt , Jingmai K
    A Second Cretaceous Ornithuromorph Bird from the Changma Basin, Gansu Province, Northwestern China Author(s): Hai-Lu You , Jessie Atterholt , Jingmai K. O'Connor , Jerald D. Harris , Matthew C. Lamanna and Da-Qing Li Source: Acta Palaeontologica Polonica, 55(4):617-625. 2010. Published By: Institute of Paleobiology, Polish Academy of Sciences DOI: http://dx.doi.org/10.4202/app.2009.0095 URL: http://www.bioone.org/doi/full/10.4202/app.2009.0095 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. A second Cretaceous ornithuromorph bird from the Changma Basin, Gansu Province, northwestern China HAI−LU YOU, JESSIE ATTERHOLT, JINGMAI K. O’CONNOR, JERALD D. HARRIS, MATTHEW C. LAMANNA, and DA−QING LI You, H.−L., Atterholt, J., O’Connor, J.K., Harris, J.D., Lamanna, M.C., and Li, D.−Q. 2010. A second Cretaceous ornithuromorph bird from the Changma Basin, Gansu Province, northwestern China.
    [Show full text]
  • A Diapsid Skull in a New Species of the Primitive Bird Confuciusornis
    letters to nature 8. Hemley, J. J., Cygan, G. L., Fein, J. B., Robinson, G. R. & D’Angelo, W. M. Hydrothermal ore-forming remarkably well preserved skeleton with feathers and, for the first processes in the light of studies in rock-buffered systems: I. Iron-copper-zinc-lead sulfide solubility relations. Econ. Geol. 87, 1–22 (1992). time in the Mesozoic record, direct evidence of the shape of a 9. Seward, T. M. & Barnes, H. L. in Geochemistry of Hydrothermal Ore Deposits 3rd edn (ed. Barnes, H. L.) horny beak. It has a complete and large preserved postorbital that 435–486 (Wiley, New York, 1997). has a broad contact with the jugal bone. This character is 10. Taylor, S. R. & McLennan, S. M. The Continental Crust: its Composition and Evolution (Blackwell Scientific, Oxford, 1985). presently only known in Confuciusornis, and may confirm pre- 11. McDonald, G. D. & Arnold, L. C. Geological and geochemical zoning of the Grasberg igneous vious suggestions of a postorbital in Archaeopteryx5. The squamosal complex, Irian Jaya, Indonesia. J. Geochem. Explor. 50, 143–178 (1994). 12. Ulrich, T. in Actas X Congreso Latinoamericano de Geologia and VI Congreso Nacional de Geologia is in tight contact with the postorbital. These two bones form an Economica 239 (Universidad de Buenos Aires, 1998). arch dividing the upper and lower temporal fenestrae, as in other 13. Gu¨nther, D., Frischknecht, R., Heinrich, C. A. & Kahlert, H.-J. Capabilities of an argon fluoride 193nm 6 excimer laser for laser ablation inductively coupled plasma mass spectrometry microanalysis of diapsid reptiles . The presence of a typical diapsid cheek region geological materials.
    [Show full text]
  • The Remarkable Fossils from the Early Cretaceous Jehol Biota of China and How They Have Changed Our Knowledge of Mesozoic Life
    The remarkable fossils from the Early Cretaceous Jehol Biota of China and how they have changed our knowledge of Mesozoic life Presidential Address, delivered 2nd May 2008 Michael J. Benton1, Zhou Zhonghe2, Patrick J. Orr3, Zhang Fucheng2 & Stuart L. Kearns1 BENTON, M. J., ZHOU Z., ORR, P. J., ZHANG, F. & KEARNS, S. L. 2008. The remarkable fossils from the Early Cretaceous Jehol Biota of China and how they have changed our knowledge. Proceedings of the Geologists’ Association, 119, 209–228. Palaeontologists and others have been repeatedly amazed by reports of spectacularly well-preserved fossils from China, and one of the key sources has been the Jehol Biota of Liaoning, Hebei and Inner Mongolia in NE China. The Jehol Biota consists of three main horizons, the Dabeigou, Yixian and Jiufotang formations, spanning the late Hauterivian to early Aptian (131–120 Ma) of the Early Cretaceous and, collectively, these have produced thousands of essentially complete specimens of plants, insects, aquatic invertebrates, fishes, frogs, salamanders, turtles, lizards, choristoderes, pterosaurs, dinosaurs, birds and mammals. Most of the specimens show some aspect of exceptional preservation, ranging from clear impressions of the body outlines to traces of soft tissues (liver, teleost air sac, eye spots) and external body coverings (scales, feathers, hair). The claim was made that these discoveries have revolutionized our understanding of evolution through this critical part of the Cretaceous Terrestrial Revolution. Key insights have come from the numerous specimens of dinosaurs with feathers, but numerical study shows that only the finds of birds and mammals have substantially changed our views about global diversity and patterns of evolution through the Early Cretaceous.
    [Show full text]
  • Supporting Information from “Time for a Rethink: Time Sub-Sampling Methods in Disparity-Through-Time Analyses”
    Title Time for a rethink: time sub-sampling methods in disparity- through-time analyses Authors Guillerme, T; Cooper, N Date Submitted 2018-04-24 Supporting Information: S1 Guillerme & Cooper 2018 Supporting Information from “Time for a rethink: time sub-sampling methods in disparity-through-time analyses” APPENDIX S1: ADDITIONAL DETAILS OF DATASETS Beck2014 (Figure A1) The following taxa were removed because they were in the phylogeny but not the character matrix or vice versa: Montanalestes, Lainodon, Kharmerun- gulatum, Alymlestes. Brusatte2014 (Figure A2) We used one randomly selected time-scaled tree from Brusatte et al. (2014). Zero-length branches were replaced with the minimum branch length in the phylogeny. The following taxa were removed because they were in the phylogeny but not the character matrix or vice versa: Sinraptor dongi, Hesperonychus elizabethae, Pyroraptor olympius, Limenavis patagonica, Lithornis, Crypturellus undulatus, Gallus gallus, Crax pauxi, Anas platyrhynchus, Chauna torquata, Epidendrosaurus and Kinnareemimus. The following taxa were removed because they shared no characters in the morphological matrix: Shanag ashile, Atrociraptor marshalli, Proceratosaurus bradleyi, Incisivosaurus gauthieri, Enigmosaurus, Nanshiungosaurus brevispi- nus, Xixiasaurus, Tsaagan mangas, Mirischia, Pedopenna, Suzhousaurus, Ju- ratyrant, Vorona, Bonapartenykus, Teratophoneus, Gobipteryx, Songlingornis, Liaoningornis longidigitu and Achillesaurus. Bapst2016 (Figure A3) We used the maximum clade credibility tree from Bapst et al.
    [Show full text]
  • A Second Cretaceous Ornithuromorph Bird from the Changma Basin, Gansu Province, Northwestern China Hai-Lu You,Jessie Atterholt
    1 http://app.pan.pl/acta55/app55-You_etal_SOM.pdf SUPPLEMENTARY ONLINE MATERIAL FOR A second Cretaceous ornithuromorph bird from the Changma Basin, Gansu Province, northwestern China Hai-Lu You, Jessie Atterholt, Jingmai K. O’Connor, Jerald D. Harris, Matthew C. Lamanna and Da-Qing Li Published in Acta Palaeontologica Polonica 2010 55 (4): 617-625. doi: 10.4202/app.2009.0095 SOM_1 Hypothesized phylogenetic position of Ornithuromorpha gen. et sp. indet. (FRDC-05-CM-021 [05-CM-021, indicated by sternum]) from the Early Cretaceous of the Changma Basin, northwestern Gansu Province, China. Two most parsimonious trees (A, B) of 592 steps (CI = 47; RCI = 47; RI = 67) recovered by cladistic analysis. Other specimen numbers correspond to undescribed enantiornithine fossils in the FRDC collection. http://app.pan.pl/SOM/app55-You_etal_SOM/SOM_1.bmp SOM_2 Apomorphies supporting nodes (with absolute/relative [0-100] Bremer support values in parentheses) from one of the two most parsimonious trees recovered by the present phylogenetic analysis (depicted in SOM_1:A). Confuciusornithidae (3/45): char 62: 0 --> 2 char 128: 1 --> 2 char 172: 0 --> 1 char 173: 0 --> 1 char 231: 0 --> 2 2 Zhongornis + Confuciusornithidae (1/4): char 35: 0 --> 1 char 103: 1 --> 0 char 143: 1 --> 0 char 175: 1 --> 0 Shanweiniao + Longirostravis (2/8): char 171: 0 --> 1 char 209: 0 --> 1 Longipterygidae (2/38): char 5: 0 --> 1 char 79: 0 --> 1 char 196: 0 --> 1 Eoalulavis + Liaoningornis (1/8): char 117: 2 --> 3 Gobipteryx + Vescornis (1/8): char 77: 1 --> 0 char 238: 0 -->
    [Show full text]
  • Mesozoic Birds of China
    Mesozoic Birds of China by Lianhai Hou Institute of Vertebrate Paleontology and Paleoanthropology Published by the Phoenix Valley Provincial Aviary of Taiwan Translated By Will Downs Bilby Research Center Northern Arizona University January, 2001 III Table of Contents Abvreviations for figures ..................................................................V Foreword by Delongjiang..................................................................X Foreword by Guangmei Zheng ..........................................................XI Foreword by Alan Feduccia............................................................XIII Foreword by Larry D. Martin..........................................................XIV Preface .....................................................................................XV Chapter 1. Synopsis of research Historical and geographic synopsis........................................................1 History of research ..........................................................................7 Chapter 2. Taxonomic descriptions...............................................................10 Sauriurae.............................................................................................11 Confuciusornithiformes Confuciusornithidae Confuciusornis Confuciusornis sanctus ........................................11 Confuciusornis chuonzhous sp. nov.........................33 Confuciusornis suniae sp. nov................................37 Jibeinia luanhera .........................................................50
    [Show full text]
  • Chapter 4 the Biogeography of Coelurosaurian Theropods and Its Impact on Their Evolutionary History
    Chapter 4 The Biogeography of Coelurosaurian Theropods and Its Impact on Their Evolutionary History ANYANG DING,1 MICHAEL PITTMAN,1 PAUL UPCHURCH,2 JINGMAI O’CONNOR,3 DANIEL J. FIELD,4 AND XING XU3 ABSTRACT The Coelurosauria are a group of mostly feathered theropods that gave rise to birds, the only dinosaurians that survived the Cretaceous-Paleogene extinction event and are still found today. Between their first appearance in the Middle Jurassic up to the end Cretaceous, coelurosaurians were party to dramatic geographic changes on the Earth’s surface, including the breakup of the supercon- tinent Pangaea, and the formation of the Atlantic Ocean. These plate tectonic events are thought to have caused vicariance or dispersal of coelurosaurian faunas, influencing their evolution. Unfortu- nately, few coelurosaurian biogeographic hypotheses have been supported by quantitative evidence. Here, we report the first, broadly sampled quantitative analysis of coelurosaurian biogeography using the likelihood-based package BioGeoBEARS. Mesozoic geographic configurations and changes are reconstructed and employed as constraints in this analysis, including their associated uncertainties. We use a comprehensive time-calibrated coelurosaurian evolutionary tree produced from the The- ropod Working Group phylogenetic data matrix. Six biogeographic models in the BioGeoBEARS package with different assumptions about the evolution of spatial distributions are tested against geographic constraints. Our results statistically favor the DIVALIKE+J and DEC+J models, which allow vicariance and founder events, supporting continental vicariance as an important factor in coelurosaurian evolution. Ancestral range estimation indicates frequent dispersal events via the Apu- lian route (connecting Europe and Africa during the Early Cretaceous) and the Bering land bridge (connecting North America and Asia during the Late Cretaceous).
    [Show full text]
  • Ciencia De Los Orígenes
    Ciencia de los Or ígenes Una publicaci\n del Geoscience Research Institute Mayo 2004 Loma Linda, California Ndmero 67 AVES FÓSILES Timothy Standish, Geoscience Research Institute Cuando se publicó por primera vez el Origen de las Desde su descubrimiento, la teoría de que las aves han Especies, el registro fósil presentaba una gran objeción a evolucionado a partir de los dinosaurios ha sido muy popu- las ideas de Charles Darwin: no había producido las formas lar y debatida. Archaeopteryx era casi demasiado perfecto intermedias predichos por su teoría. Darwin explicaba esto como evidencia para la evolución darwinista y la autenti- invocando “la extrema imperfección del registro fósil.”1 cidad de los especimenes mostrando restos de plumas Muy pronto después de la publicación de El Origen, los permanece controvertida.4 fósiles intermedios – “eslabones perdidos” comenzaron a Durante más de un siglo, Archaeopteryx se mantuvo aparecer. Algunos de esos eslabones perdidos no han super- como el eslabón perdido entre dinosaurios y aves, pero ado la prueba del tiempo: el numerosos pájaros fósiles Hombre de Piltdown, un han sido descubiertos en los supuesto eslabón perdido en la últimos veinte años en los cadena de simios a humanos, estratos geológicos cerca- resultó ser un engaño. En tiem- nos a donde había sido de- pos recientes el Archaeorap- scubierto Archaeopteryx. tor, 2 un supuesto intermedio Estos nuevos fósiles ponen entre dinosaurios y aves, re- en entredicho la colocación sultó ser una vergonzosa falsi- de Archaeopteryx en la lí- ficación.3 nea directa que produjo las Al menos uno de los pri- aves. Al contrario, Archae- meros “eslabones perdidos” opteryx es ahora visto como en ser encontrado ha pasado una rama lateral de la evo- la prueba del tiempo; Archae- lución que eventualmente opteryx (Figura 1), un asom- se extinguió.5 A diferencia broso fósil de las calizas de de Archaeopteryx, tanto la Solnhofen en Alemania, pare- autenticidad de estos fósiles ció, a primera vista, ser un recientemente descubiertos dinosaurio con plumas.
    [Show full text]
  • A New Paravian Dinosaur from the Late Jurassic of North America Supports a Late Acquisition of Avian flight
    A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight Scott Hartman1, Mickey Mortimer2, William R. Wahl3, Dean R. Lomax4, Jessica Lippincott3 and David M. Lovelace5 1 Department of Geoscience, University of Wisconsin-Madison, Madison, WI, USA 2 Independent, Maple Valley, WA, USA 3 Wyoming Dinosaur Center, Thermopolis, WY, USA 4 School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK 5 University of Wisconsin Geology Museum, University of Wisconsin-Madison, Madison, WI, USA ABSTRACT The last two decades have seen a remarkable increase in the known diversity of basal avialans and their paravian relatives. The lack of resolution in the relationships of these groups combined with attributing the behavior of specialized taxa to the base of Paraves has clouded interpretations of the origin of avialan flight. Here, we describe Hesperornithoides miessleri gen. et sp. nov., a new paravian theropod from the Morrison Formation (Late Jurassic) of Wyoming, USA, represented by a single adult or subadult specimen comprising a partial, well-preserved skull and postcranial skeleton. Limb proportions firmly establish Hesperornithoides as occupying a terrestrial, non-volant lifestyle. Our phylogenetic analysis emphasizes extensive taxonomic sampling and robust character construction, recovering the new taxon most parsimoniously as a troodontid close to Daliansaurus, Xixiasaurus, and Sinusonasus. Multiple alternative paravian topologies have similar degrees of support, but proposals of basal paravian archaeopterygids, avialan microraptorians, and Rahonavis being closer to Pygostylia than archaeopterygids or unenlagiines are strongly rejected. All parsimonious results support the hypothesis that each early paravian clade was plesiomorphically flightless, raising the possibility that avian Submitted 10 September 2018 flight originated as late as the Late Jurassic or Early Cretaceous.
    [Show full text]
  • Evolution and Ecological Associations in Herbivorous Theropods Albert Chen 4/25/2016 Advisor: Dr
    Evolution and Ecological Associations in Herbivorous Theropods Albert Chen 4/25/2016 Advisor: Dr. Thomas Holtz GEOL 394 1 Abstract Theropod dinosaurs are inferred to have been ancestrally carnivorous and include numerous lineages specialized for hypercarnivory. However, evidence from fossil gut contents, anatomical characteristics, and phylogenetic bracketing suggests that several theropod clades convergently transitioned away from a carnivorous lifestyle to become herbivores or omnivores. The evolutionary drivers of these trophic shifts are unknown. Methods involving the use of the Paleobiology Database (PBDB) were used to test for the potential impact of ecological factors that may have affected the diversification of non-hypercarnivorous theropods, such as the diversity of other herbivorous vertebrates, the diversity of plants, and change in global sea level. After demonstrating feasibility of the proposed methods by using restricted parameters (solely considering oviraptorosaurian theropods from the Cretaceous of Asia and contemporaneous herbivores), said methods were applied to an expanded dataset including more than 500 taxa from 51 geologic formations. No statistically significant correlations were found between non- hypercarnivorous theropod diversity and that of plants, but overall diversity of non- hypercarnivorous theropods was found to positively correlate through space and time with the diversity of other herbivores. These results suggest that non-hypercarnivorous theropods did not strongly compete with contemporaneous herbivores.
    [Show full text]
  • A Mid-Cretaceous Enantiornithine Foot and Tail Feather Preserved in Burmese Amber Lida Xing 1,2,3*, Ryan C
    www.nature.com/scientificreports OPEN A mid-Cretaceous enantiornithine foot and tail feather preserved in Burmese amber Lida Xing 1,2,3*, Ryan C. McKellar4,5,6*, Jingmai K. O’Connor 7, Kecheng Niu3 & Huijuan Mai8,9 Since the frst skeletal remains of avians preserved in amber were described in 2016, new avian remains trapped in Cretaceous-age Burmese amber continue to be uncovered, revealing a diversity of skeletal and feather morphologies observed nowhere else in the Mesozoic fossil record. Here we describe a foot with digital proportions unlike any previously described enantiornithine or Mesozoic bird. No bones are preserved in the new specimen but the outline of the foot is recorded in a detailed skin surface, which is surrounded by feather inclusions including a partial rachis-dominated feather. Pedal proportions and plumage support identifcation as an enantiornithine, but unlike previous discoveries the toes are stout with transversely elongated digital pads, and the outer toe appears strongly thickened relative to the inner two digits. The new specimen increases the known diversity and morphological disparity among the Enantiornithes, hinting at a wider range of habitats and behaviours. It also suggests that the Burmese amber avifauna was distinct from other Mesozoic assemblages, with amber entrapment including representatives from unusual small forms. Te discovery of skeletal remains preserved in Cretaceous-age amber is one of the most intriguing developments in 21st century palaeontology, with current research barely scratching the surface of the potential of these dis- coveries to shed light on the biology of long extinct organisms. To date, all diagnostic avian remains recovered from Burmese amber are referable to the Enantiornithes, the dominant clade of land birds in the Cretaceous.
    [Show full text]
  • Section 1. Systematics, Fossil Record, and Biogeography
    SECTION 1. SYSTEMATICS, FOSSIL RECORD, AND BIOGEOGRAPHY Chapter 1 Pennaraptoran Systematics MICHAEL PITTMAN,1 JINGMAI O’CONNOR,2 DANIEL J. FIELD,3 ALAN H. TURNER,4 WAISUM MA,5 PETER MAKOVICKY,6 AND XING XU2 ABSTRACT New and important pennaraptoran specimens continue to be discovered on a regular basis. Yet, with these discoveries the number of viable phylogenetic hypotheses has increased, including ones that challenge the traditional grouping of dromaeosaurids and troodontids within a monophy- letic Deinonychosauria. This chapter will cover recent efforts to address prevailing phylogenetic uncertainties and controversies, both between and within key clades, including deinonychosaurian monophyly, the phylogenetic position of anchiornithines and scansoriopterygids, and the inter- relationships of enantiornithines. While recent discoveries mainly from Asia have created much of the latest uncertainty and controversy, new material, particularly from Asia, promises to rather fittingly address these issues. Further curatorship of long-standing phylogenetic datasets and more prevalent use of extended analytical protocols will be essential to meeting this challenge, especially for groups whose boundaries have been blurred. As it becomes increasingly difficult to study all fossil materials, owing to their growing numbers and ever disparate locations, broader use of digital fossils and online character databases for character coding is acutely needed to ensure that errors arising from remote, rather than firsthand, scoring are reduced as far as possible, particu- larly at this time of rapid data accumulation. 1 Vertebrate Palaeontology Laboratory, Division of Earth and Planetary Science, the University of Hong Kong, Hong Kong. 2 Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology & Paleoanthropology, Beijing; CAS Center for Excellence in Life and Paleoenvironment, Beijing.
    [Show full text]