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  • 1
    Publication Date: 2013-06-07
    Description: Reconstructing the earliest phases of primate evolution has been impeded by gaps in the fossil record, so that disagreements persist regarding the palaeobiology and phylogenetic relationships of the earliest primates. Here we report the discovery of a nearly complete and partly articulated skeleton of a primitive haplorhine primate from the early Eocene of China, about 55 million years ago, the oldest fossil primate of this quality ever recovered. Coupled with detailed morphological examination using propagation phase contrast X-ray synchrotron microtomography, our phylogenetic analysis based on total available evidence indicates that this fossil is the most basal known member of the tarsiiform clade. In addition to providing further support for an early dichotomy between the strepsirrhine and haplorhine clades, this new primate further constrains the age of divergence between tarsiiforms and anthropoids. It also strengthens the hypothesis that the earliest primates were probably diurnal, arboreal and primarily insectivorous mammals the size of modern pygmy mouse lemurs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ni, Xijun -- Gebo, Daniel L -- Dagosto, Marian -- Meng, Jin -- Tafforeau, Paul -- Flynn, John J -- Beard, K Christopher -- England -- Nature. 2013 Jun 6;498(7452):60-4. doi: 10.1038/nature12200.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Key Laboratory of Vertebrate Evolution and Human Origin, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi Zhi Men Wai Street, Beijing 100044, China. nixijun@ivpp.ac.cn〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23739424" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Cheirogaleidae/anatomy & histology ; China ; Dentition ; Foot Bones/anatomy & histology ; Forelimb/anatomy & histology ; *Fossils ; Hindlimb/anatomy & histology ; Phylogeny ; Primates/*anatomy & histology/classification ; *Skeleton ; Skull/anatomy & histology ; Tail/anatomy & histology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2013-01-22
    Description: The construction of the vertebral column has been used as a key anatomical character in defining and diagnosing early tetrapod groups. Rhachitomous vertebrae--in which there is a dorsally placed neural arch and spine, an anteroventrally placed intercentrum and paired, posterodorsally placed pleurocentra--have long been considered the ancestral morphology for tetrapods. Nonetheless, very little is known about vertebral anatomy in the earliest stem tetrapods, because most specimens remain trapped in surrounding matrix, obscuring important anatomical features. Here we describe the three-dimensional vertebral architecture of the Late Devonian stem tetrapod Ichthyostega using propagation phase-contrast X-ray synchrotron microtomography. Our scans reveal a diverse array of new morphological, and associated developmental and functional, characteristics, including a possible posterior-to-anterior vertebral ossification sequence and the first evolutionary appearance of ossified sternal elements. One of the most intriguing features relates to the positional relationships between the vertebral elements, with the pleurocentra being unexpectedly sutured or fused to the intercentra that directly succeed them, indicating a 'reverse' rhachitomous design. Comparison of Ichthyostega with two other stem tetrapods, Acanthostega and Pederpes, shows that reverse rhachitomous vertebrae may be the ancestral condition for limbed vertebrates. This study fundamentally revises our current understanding of vertebral column evolution in the earliest tetrapods and raises questions about the presumed vertebral architecture of tetrapodomorph fish and later, more crownward, tetrapods.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pierce, Stephanie E -- Ahlberg, Per E -- Hutchinson, John R -- Molnar, Julia L -- Sanchez, Sophie -- Tafforeau, Paul -- Clack, Jennifer A -- England -- Nature. 2013 Feb 14;494(7436):226-9. doi: 10.1038/nature11825. Epub 2013 Jan 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University Museum of Zoology, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. spierce@rvc.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23334417" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Extremities/*anatomy & histology ; *Fossils ; Phylogeny ; Spine/*anatomy & histology ; Synchrotrons ; Vertebrates/*anatomy & histology ; X-Ray Microtomography
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2014-04-18
    Description: The evolution of serially arranged, jointed endoskeletal supports internal to the gills--the visceral branchial arches--represents one of the key events in early jawed vertebrate (gnathostome) history, because it provided the morphological basis for the subsequent evolution of jaws. However, until now little was known about visceral arches in early gnathostomes, and theories about gill arch evolution were driven by information gleaned mostly from both modern cartilaginous (chondrichthyan) and bony (osteichthyan) fishes. New fossil discoveries can profoundly affect our understanding of evolutionary history, by revealing hitherto unseen combinations of primitive and derived characters. Here we describe a 325 million year (Myr)-old Palaeozoic shark-like fossil that represents, to our knowledge, the earliest identified chondrichthyan in which the complete gill skeleton is three-dimensionally preserved in its natural position. Its visceral arch arrangement is remarkably osteichthyan-like, suggesting that this may represent the common ancestral condition for crown gnathostomes. Our findings thus reinterpret the polarity of some arch features of the crown jawed vertebrates and invert the classic hypothesis, in which modern sharks retain the ancestral condition. This study underscores the importance of early chondrichthyans in resolving the evolutionary history of jawed vertebrates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pradel, Alan -- Maisey, John G -- Tafforeau, Paul -- Mapes, Royal H -- Mallatt, Jon -- England -- Nature. 2014 May 29;509(7502):608-11. doi: 10.1038/nature13195. Epub 2014 Apr 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Vertebrate Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA. ; European Synchrotron Radiation Facility, BP 220, 6 rue Jules Horowitz, 38043 Grenoble Cedex, France. ; Department of Geological Sciences, Ohio University, Athens, Ohio 45701, USA. ; School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24739974" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Branchial Region/anatomy & histology ; Cartilage/anatomy & histology ; *Fossils ; Gills/*anatomy & histology ; Phylogeny ; Sharks/*anatomy & histology/classification
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2014-02-14
    Description: Extant vertebrates form two clades, the jawless Cyclostomata (lampreys and hagfishes) and the jawed Gnathostomata (all other vertebrates), with contrasting facial architectures. These arise during development from just a few key differences in the growth patterns of the cranial primordia: notably, the nasal sacs and hypophysis originate from a single placode in cyclostomes but from separate placodes in gnathostomes, and infraoptic ectomesenchyme migrates forward either side of the single placode in cyclostomes but between the placodes in gnathostomes. Fossil stem gnathostomes preserve cranial anatomies rich in landmarks that provide proxies for developmental processes and allow the transition from jawless to jawed vertebrates to be broken down into evolutionary steps. Here we use propagation phase contrast synchrotron microtomography to image the cranial anatomy of the primitive placoderm (jawed stem gnathostome) Romundina, and show that it combines jawed vertebrate architecture with cranial and cerebral proportions resembling those of cyclostomes and the galeaspid (jawless stem gnathostome) Shuyu. This combination seems to be primitive for jawed vertebrates, and suggests a decoupling between ectomesenchymal growth trajectory, ectomesenchymal proliferation, and cerebral shape change during the origin of gnathostomes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dupret, Vincent -- Sanchez, Sophie -- Goujet, Daniel -- Tafforeau, Paul -- Ahlberg, Per E -- England -- Nature. 2014 Mar 27;507(7493):500-3. doi: 10.1038/nature12980. Epub 2014 Feb 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Uppsala University, Department of Organismal Biology, Subdepartment of Evolution and Development, Norbyvagen 18A, SE-752 36, Uppsala, Sweden. ; 1] Uppsala University, Department of Organismal Biology, Subdepartment of Evolution and Development, Norbyvagen 18A, SE-752 36, Uppsala, Sweden [2] European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex, France. ; Museum national d'Histoire naturelle, UMR 7207 CR2P CNRS/MNHN/UPMC, 8 rue Buffon, CP 38,75231 Paris Cedex 05, France. ; European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24522530" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Brain/anatomy & histology ; Face/anatomy & histology ; Fishes/*anatomy & histology/classification ; *Fossils ; *Jaw/anatomy & histology ; Lampreys/anatomy & histology ; Neural Crest/anatomy & histology ; Phylogeny
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2011-09-10
    Description: The virtual endocast of MH1 (Australopithecus sediba), obtained from high-quality synchrotron scanning, reveals generally australopith-like convolutional patterns on the frontal lobes but also some foreshadowing of features of the human frontal lobes, such as posterior repositioning of the olfactory bulbs. Principal component analysis of orbitofrontal dimensions on australopith endocasts (MH1, Sts 5, and Sts 60) indicates that among these, MH1 orbitofrontal shape and organization align most closely with human endocasts. These results are consistent with gradual neural reorganization of the orbitofrontal region in the transition from Australopithecus to Homo, but given the small volume of the MH1 endocast, they are not consistent with gradual brain enlargement before the transition.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carlson, Kristian J -- Stout, Dietrich -- Jashashvili, Tea -- de Ruiter, Darryl J -- Tafforeau, Paul -- Carlson, Keely -- Berger, Lee R -- New York, N.Y. -- Science. 2011 Sep 9;333(6048):1402-7. doi: 10.1126/science.1203922. Epub 2011 Sep 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Human Evolution, University of the Witwatersrand, Palaeosciences Centre, Private Bag 3, Wits 2050, South Africa. kristian.carlson@wits.ac.za〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21903804" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Brain/*anatomy & histology/growth & development ; *Fossils ; Frontal Lobe/*anatomy & histology/growth & development ; Hominidae/*anatomy & histology/growth & development ; Humans ; Imaging, Three-Dimensional ; Male ; Olfactory Bulb/anatomy & histology ; Organ Size ; Principal Component Analysis ; Skull/anatomy & histology/growth & development ; South Africa ; Synchrotrons ; Temporal Lobe/anatomy & histology ; Tomography, X-Ray Computed
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2011-01-08
    Description: Ammonites are prominent in macroevolutionary studies because of their abundance and diversity in the fossil record, but their paleobiology and position in the marine food web are not well understood due to the lack of preserved soft tissue. We present three-dimensional reconstructions of the buccal apparatus in the Mesozoic ammonite Baculites with the use of synchrotron x-ray microtomography. Buccal mass morphology, combined with the coexistence of food remains found in the buccal mass, suggests that these ammonites fed on plankton. This diet may have extended to all aptychophoran ammonites, which share the same buccal mass morphology. Understanding the role of these ammonites in the Mesozoic food web provides insights into their radiation in the Early Jurassic, as well as their extinction at the end of the Cretaceous/early Paleogene.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kruta, Isabelle -- Landman, Neil -- Rouget, Isabelle -- Cecca, Fabrizio -- Tafforeau, Paul -- New York, N.Y. -- Science. 2011 Jan 7;331(6013):70-2. doi: 10.1126/science.1198793.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉UMR-CNRS 7207, Departement Histoire de la Terre, Museum National d'Histoire Naturelle, 47 rue Cuvier, 75231 Paris Cedex 05, France. kruta@mnhn.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21212354" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Evolution ; Cephalopoda/*anatomy & histology/physiology ; Diet ; Digestive System ; Extinction, Biological ; Feeding Behavior ; *Food Chain ; *Fossils ; Gastropoda/anatomy & histology ; Isopoda/anatomy & histology ; Jaw/anatomy & histology ; Tooth/anatomy & histology ; X-Ray Microtomography ; *Zooplankton
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 2013-06-15
    Description: The transition from jawless to jawed vertebrates (gnathostomes) resulted in the reconfiguration of the muscles and skeleton of the head, including the creation of a separate shoulder girdle with distinct neck muscles. We describe here the only known examples of preserved musculature from placoderms (extinct armored fishes), the phylogenetically most basal jawed vertebrates. Placoderms possess a regionalized muscular anatomy that differs radically from the musculature of extant sharks, which is often viewed as primitive for gnathostomes. The placoderm data suggest that neck musculature evolved together with a dermal joint between skull and shoulder girdle, not as part of a broadly flexible neck as in sharks, and that transverse abdominal muscles are an innovation of gnathostomes rather than of tetrapods.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Trinajstic, Kate -- Sanchez, Sophie -- Dupret, Vincent -- Tafforeau, Paul -- Long, John -- Young, Gavin -- Senden, Tim -- Boisvert, Catherine -- Power, Nicola -- Ahlberg, Per Erik -- New York, N.Y. -- Science. 2013 Jul 12;341(6142):160-4. doi: 10.1126/science.1237275. Epub 2013 Jun 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Western Australian Organic and Isotope Geochemistry Centre, Department of Chemistry, Curtin University, Perth, Western Australia 6102, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23765280" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Fishes/*anatomy & histology/classification/*genetics ; *Fossils ; Maxillofacial Development/*genetics ; Neck Muscles/*anatomy & histology ; Phylogeny
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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