DOCSLIB.ORG

The Braincase of Youngina Capensis (Reptilia, Diapsida): New Insights from High-Resolution Ct Scanning of the Holotype

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Braincase of Youngina Capensis (Reptilia, Diapsida): New Insights from High-Resolution Ct Scanning of the Holotype Marshall University Marshall Digital Scholar Biological Sciences Faculty Research Biological Sciences 11-2010 The rB aincase of Youngina Capensis (Reptilia, Diapsida): New Insights from High-Resolution CT Scanning of the Holotype Nicholas M. Gardner Marshall University Casey M. Holliday F. Robin O’Keefe Marshall University, [email protected] Follow this and additional works at: http://mds.marshall.edu/bio_sciences_faculty Part of the Animal Sciences Commons Recommended Citation Gardner, Nicholas M., Holliday, Casey M. , and O’Keefe, F. Robin, 2010. The rB aincase of Youngina capensis (Reptilia, Dipsida): New Insights from High-Resolution CT Scanning of the Holotype Palaeontologia Electronica Vol. 13, Issue 3; 19A:16p; http://palaeo- electronica.org/2010_3/217/index.html This Article is brought to you for free and open access by the Biological Sciences at Marshall Digital Scholar. It has been accepted for inclusion in Biological Sciences Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected], [email protected]. Palaeontologia Electronica http://palaeo-electronica.org THE BRAINCASE OF YOUNGINA CAPENSIS (REPTILIA, DIAPSIDA): NEW INSIGHTS FROM HIGH-RESOLUTION CT SCANNING OF THE HOLOTYPE Nicholas M. Gardner, Casey M. Holliday, and F. Robin O’Keefe Nicholas M. Gardner. Department of Biological Sciences, Marshall University, Huntington, West Virginia. [email protected] Casey M. Holliday. Department of Pathology & Anatomical Sciences, University of Missouri, Columbia, Missouri. [email protected] F. Robin O’Keefe. Department of Biological Sciences, Marshall University, Huntington, West Virginia. [email protected] ABSTRACT Detailed descriptions of braincase anatomy in early diapsid reptiles have been historically rare given the difficulty of accessing this deep portion of the skull, because of poor preservation of the fossils or the inability to remove the surrounding skull roof. Previous descriptions of the braincase of Youngina capensis, a derived stem-diapsid reptile from the Late Permian (250 MYA) of South Africa, have relied on only partially preserved fossils. High resolution X-ray computed tomography (HRXCT) scanning, a new advance in biomedical sciences, has allowed us to examine the reasonably com- plete braincase of the holotype specimen of Youngina capensis for the first time by dig- itally peering through the sandstone matrix that filled the skull postmortem. We present the first detailed 3D visualizations of the braincase and the vestibular system in a Permian diapsid reptile. This new anatomical description is of great comparative and phylogenetic relevance to the study of the structure, function and evolution of the reptil- ian head. KEY WORDS: Youngina capensis, diapsid reptiles, CT scanning, 3D models PE ERRATUM In the paper Gardner et al. (2010), we stated of the collections of the University of Chicago. This that UC 1528, the holotype specimen of Youngoi- was in error, as the specimen is housed at the Field des romeri Olson and Broom 1937, a junior syn- Museum of Natural History (Chicago, IL). Special onym of Youngina capensis Broom 1914, was part thanks to William F. Simpson (FMNH) for facilitat- PE Article Number: 13.3.19A Copyright: Palaeontological Association November 2010 Submission: 14 September 2009. Acceptance: 8 September 2010 Gardner, Nicholas M., Holliday, Casey M. , and O’Keefe, F. Robin, 2010. The Braincase of Youngina capensis (Reptilia, Dipsida): New Insights from High-Resolution CT Scanning of the Holotype Palaeontologia Electronica Vol. 13, Issue 3; 19A:16p; http://palaeo-electronica.org/2010_3/217/index.html GARDNER, HOLLIDAY, & O’KEEFE: BRAINCASE OF YOUNGINA ing the loan of FMNH UC 1528, thereby making Diapsida): New Insights from High-Resolution CT this research possible. *Nicholas M. Gardner, Scanning of the Holotype. Palaeontologica Elec- Casey M. Holliday, and F. Robin O'Keefe, 2010. tronica 13(3); 19A: 16p. The Braincase of Youngina capensis (Reptilia, NOTE IN PROOF Reisz et al. (2010) find a non-diapsid position ing topologies as new data are incorporated. How- for Apsisaurus as a varanopid synapsid, but unfor- ever, our tree was taken from Müller (2003) who tunately, their paper came too late for us to correct noted that the exclusion of Apsisaurus from his Figure 1 by removing it from our tree. We are data set does not affect the rest of the tree topol- aware that our placement in the tree for Apsisaurus ogy in the final analysis. is outdated, this is the unfortunate nature of shift- INTRODUCTION lution to this disputed portion of the amniote phy- logeny, and contribute to a new understanding of Reptiles first appeared in the fossil record dur- the evolutionary history of reptiles and the relation- ing the Late Carboniferous (320-310 MYA) and ships between extant diapsids (Modesto and Sues rapidly diversified into two different lineages, the 2002). parareptiles and the eureptiles (Müller 2003; Figure The Late Permian (250 MYA) diapsid reptile 1). The earliest known examples are Carboniferous Youngina capensis is often regarded as the ‘arche- eureptiles such as Hylonomus (Carroll 1988a) and typal’ basal diapsid (Smith and Evans 1996) and Petrolacosaurus (Reisz 1977; Reisz 1981). Para- recognized as an “ancestral morphotype” (Carroll reptiles and eureptiles further diversified into 1988b) between more primitive taxa such as para- numerous clades, of which only the diapsid eurep- reptiles and captorhinids and modern diapsids tiles survived past the Triassic and into modern (Müller 2003; Figure 1). Its relationships among times (archosaurs, lepidosaurs and turtles). The other diapsids have been disputed. Currie (1981, precise relationships among extant reptile clades 1982) posited that Youngina shared a closer rela- remain a problem for reptile biologists and paleon- tionship with Acerosodontosaurus (Currie 1980), tologists. For example, turtles have become con- Galesphyrus (Carroll 1976), Hovasaurus (Currie sensually accepted among reptile paleontologists 1981), Kenyasaurus (Harris and Carroll 1977), as being diapsids, but it is uncertain whether or not Tangasaurus (Currie 1982), and Thadeosaurus they are part of the crown-diapsid clade (Gregory (Carroll 1981). These taxa collectively were 1946; Ivachnenko 1987; Kordikova 2002; Laurin referred to as the Younginiformes, which were vari- and Reisz 1995; Lee 1997; Lee 2001; Lyson et al. ously allied to lepidosauromorphs (Benton 1985; 2010; Werneburg and Sánchez-Villagra 2009), or if Evans 1988) or as stem-diapsids (Gaffney 1980; they are crown-diapsids, whether or not they are Laurin 1991). Their monophyly was never explicitly closer to archosaurs (Bhullar and Bever 2009; tested and recently Bickelmann et al. (2009) pub- Evans 2009; Hedges and Poling 1999; Zardoya lished the results of their phylogenetic analysis that and Meyer 1998) or lepidosaurs (Bickelmann et al. suggested that these taxa do not form a monophyl- 2009; deBraga and Rieppel 1997; Li et al. 2008; etic relationship with each other to the exclusion of Müller 2003; Rieppel 2002; Rieppel and deBraga other diapsid reptiles, though the relationships 1996; Rieppel and Reisz 1999). Though conflicting between all stem-diapsids were highly unresolved data from molecular studies, soft-tissue morphol- in their topology. Youngina is the most derived ogy and bony morphology provide differing sup- known stem-diapsid to retain two complete fenes- ports for the position of turtles (Lee 2001; Rieppel trae in the temporal region, rather than having 2002), a more detailed understanding of the anat- evolved this condition secondarily (as in derived omy of early diapsids and other morphologically archosauromorphs and sphenodontids and possi- primitive reptiles would provide much-needed reso- bly as in sauropterygians and ichthyopterygians). 2 PALAEO-ELECTRONICA.ORG FIGURE 1. Cladogram demonstrating the evolutionary relationships between Youngina with other reptile taxa (modified from Müller 2003). Dagger denotes extinct taxa. Nodes: A, Amniota; B, Reptilia; C, Eurep- tilia; D, Diapsida; E, Neodiapsida; F, Sauria; G, Lepidosauromorpha; H, Lepidosauria; I, Archosauromor- pha. Thus it appears that the loss of the lower temporal superficial anatomy of the skull, and described it bar occurred in higher stem-diapsids more derived largely in palatal and occipital views. Gow (1975) than Youngina (Müller 2003). Youngina is well provided a preliminary discussion of the braincase known from numerous specimens that were previ- of TM 3603, which was given more attention later ously described as distinct “younginid” or by Evans (1987). Evans sawed this specimen in “younginiform” taxa (Gow 1975). Despite its obvi- half to gain access to the internal aspects of the ously critical position as a stem-diapsid and the neurocranial bones. Her description is currently the existence of multiple specimens, Youngina is in only published, detailed treatment of the braincase need of a thorough re-description. Formal descrip- of Youngina. tion of its anatomy is a crucial precursor to under- While all reptiles (and in fact, all amniotes) standing: 1) its phylogenetic relationships, 2) its ossify the caudoventral portion of the braincase relevance to the interrelationships between other cartilages, ossification patterns differ for the rostral diapsid reptiles and 3) the evolution of the skull in cartilages. Archosauriforms (birds, crocodiles and these reptiles (Bickelmann et al. 2009; Modesto their ancestors) have uniquely
Load more

Recommended publications
  • A New Xinjiangchelyid Turtle from the Middle Jurassic of Xinjiang, China and the Evolution of the Basipterygoid Process in Mesozoic Turtles Rabi Et Al
    A new xinjiangchelyid turtle from the Middle Jurassic of Xinjiang, China and the evolution of the basipterygoid process in Mesozoic turtles Rabi et al. Rabi et al. BMC Evolutionary Biology 2013, 13:203 http://www.biomedcentral.com/1471-2148/13/203 Rabi et al. BMC Evolutionary Biology 2013, 13:203 http://www.biomedcentral.com/1471-2148/13/203 RESEARCH ARTICLE Open Access A new xinjiangchelyid turtle from the Middle Jurassic of Xinjiang, China and the evolution of the basipterygoid process in Mesozoic turtles Márton Rabi1,2*, Chang-Fu Zhou3, Oliver Wings4, Sun Ge3 and Walter G Joyce1,5 Abstract Background: Most turtles from the Middle and Late Jurassic of Asia are referred to the newly defined clade Xinjiangchelyidae, a group of mostly shell-based, generalized, small to mid-sized aquatic froms that are widely considered to represent the stem lineage of Cryptodira. Xinjiangchelyids provide us with great insights into the plesiomorphic anatomy of crown-cryptodires, the most diverse group of living turtles, and they are particularly relevant for understanding the origin and early divergence of the primary clades of extant turtles. Results: Exceptionally complete new xinjiangchelyid material from the ?Qigu Formation of the Turpan Basin (Xinjiang Autonomous Province, China) provides new insights into the anatomy of this group and is assigned to Xinjiangchelys wusu n. sp. A phylogenetic analysis places Xinjiangchelys wusu n. sp. in a monophyletic polytomy with other xinjiangchelyids, including Xinjiangchelys junggarensis, X. radiplicatoides, X. levensis and X. latiens. However, the analysis supports the unorthodox, though tentative placement of xinjiangchelyids and sinemydids outside of crown-group Testudines. A particularly interesting new observation is that the skull of this xinjiangchelyid retains such primitive features as a reduced interpterygoid vacuity and basipterygoid processes.
    [Show full text]
  • A Phylogenomic Analysis of Turtles ⇑ Nicholas G
    Molecular Phylogenetics and Evolution 83 (2015) 250–257 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev A phylogenomic analysis of turtles ⇑ Nicholas G. Crawford a,b,1, James F. Parham c, ,1, Anna B. Sellas a, Brant C. Faircloth d, Travis C. Glenn e, Theodore J. Papenfuss f, James B. Henderson a, Madison H. Hansen a,g, W. Brian Simison a a Center for Comparative Genomics, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA b Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA c John D. Cooper Archaeological and Paleontological Center, Department of Geological Sciences, California State University, Fullerton, CA 92834, USA d Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA e Department of Environmental Health Science, University of Georgia, Athens, GA 30602, USA f Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA g Mathematical and Computational Biology Department, Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 9171, USA article info abstract Article history: Molecular analyses of turtle relationships have overturned prevailing morphological hypotheses and Received 11 July 2014 prompted the development of a new taxonomy. Here we provide the first genome-scale analysis of turtle Revised 16 October 2014 phylogeny. We sequenced 2381 ultraconserved element (UCE) loci representing a total of 1,718,154 bp of Accepted 28 October 2014 aligned sequence. Our sampling includes 32 turtle taxa representing all 14 recognized turtle families and Available online 4 November 2014 an additional six outgroups. Maximum likelihood, Bayesian, and species tree methods produce a single resolved phylogeny.
    [Show full text]
  • Reptile Family Tree
    Reptile Family Tree - Peters 2015 Distribution of Scales, Scutes, Hair and Feathers Fish scales 100 Ichthyostega Eldeceeon 1990.7.1 Pederpes 91 Eldeceeon holotype Gephyrostegus watsoni Eryops 67 Solenodonsaurus 87 Proterogyrinus 85 100 Chroniosaurus Eoherpeton 94 72 Chroniosaurus PIN3585/124 98 Seymouria Chroniosuchus Kotlassia 58 94 Westlothiana Casineria Utegenia 84 Brouffia 95 78 Amphibamus 71 93 77 Coelostegus Cacops Paleothyris Adelospondylus 91 78 82 99 Hylonomus 100 Brachydectes Protorothyris MCZ1532 Eocaecilia 95 91 Protorothyris CM 8617 77 95 Doleserpeton 98 Gerobatrachus Protorothyris MCZ 2149 Rana 86 52 Microbrachis 92 Elliotsmithia Pantylus 93 Apsisaurus 83 92 Anthracodromeus 84 85 Aerosaurus 95 85 Utaherpeton 82 Varanodon 95 Tuditanus 91 98 61 90 Eoserpeton Varanops Diplocaulus Varanosaurus FMNH PR 1760 88 100 Sauropleura Varanosaurus BSPHM 1901 XV20 78 Ptyonius 98 89 Archaeothyris Scincosaurus 77 84 Ophiacodon 95 Micraroter 79 98 Batropetes Rhynchonkos Cutleria 59 Nikkasaurus 95 54 Biarmosuchus Silvanerpeton 72 Titanophoneus Gephyrostegeus bohemicus 96 Procynosuchus 68 100 Megazostrodon Mammal 88 Homo sapiens 100 66 Stenocybus hair 91 94 IVPP V18117 69 Galechirus 69 97 62 Suminia Niaftasuchus 65 Microurania 98 Urumqia 91 Bruktererpeton 65 IVPP V 18120 85 Venjukovia 98 100 Thuringothyris MNG 7729 Thuringothyris MNG 10183 100 Eodicynodon Dicynodon 91 Cephalerpeton 54 Reiszorhinus Haptodus 62 Concordia KUVP 8702a 95 59 Ianthasaurus 87 87 Concordia KUVP 96/95 85 Edaphosaurus Romeria primus 87 Glaucosaurus Romeria texana Secodontosaurus
    [Show full text]
  • 14 August 2021 Aperto
    AperTO - Archivio Istituzionale Open Access dell'Università di Torino VINCOLI STRUTTURALI ED AMBIENTALI SULLA RIDUZIONE DELLE APPENDICI PARI NEI VERTEBRATI This is the author's manuscript Original Citation: Availability: This version is available http://hdl.handle.net/2318/1703200 since 2019-05-29T10:22:39Z Publisher: Rook, L., & Pandolfi, L. Terms of use: Open Access Anyone can freely access the full text of works made available as "Open Access". Works made available under a Creative Commons license can be used according to the terms and conditions of said license. Use of all other works requires consent of the right holder (author or publisher) if not exempted from copyright protection by the applicable law. (Article begins on next page) 09 October 2021 Paleodays 2019 La Società Paleontologica Italiana a Benevento e Pietraroja Parte 1: Volume dei riassunti XIX Riunione annuale SPI Ente GeoPaleontologico di Pietraroja (21)22-24(25) Maggio 2019 a cura di Rook L. & Pandolfi L. Paleodays 2019. La Società Paleontologica Italiana a Benevento e Pietraroja XIX Riunione annuale della Società Paleontologica Italiana Benevento/Pietraroja, (21)22-24(25) Maggio 2019 Comitato Organizzatore Ente GeoPaleontologico di Pietraroja: G. Santamaria, G. Festinese, P. Forte, G. Lioni, A.V. Maturo, R. Melillo, L. Prencipe, A. Torrillo, F.O. Amore, S. Foresta, C. Dal Sasso, V. Morra, L. Rook Comitato Scientifico F.O. Amore, L. Angiolini, A. Bartiromo, M. Bernardi, G. Carnevale, M. Cherin, M. Chiari, G. Crippa, C. Dal Sasso, A. Ferretti, E. Ghezzo, L. Jaselli,
    [Show full text]
  • Reptiles A. Cladistics 1. Many Groups of Organisms
    Reptiles A. Cladistics 1. Many groups of organisms are “polyphyletic” a. This means that the group combines 2 or more lineages - example=fish 2. Cladistics follows only pure lineages going back in time - example Osteichthys B. Reptile Classifiecation - looks like a polyphyletic group 1. Dry skin - no loss of water through skin like amphibians 2. Aminotic egg - an egg that can survive on dry land - in contrast with the amphibian egg C. Mammals and Birds are derived from different lineages of reptiles (We will see below) D. Stem Reptiles 1. Different lineages based on the temporal region of their skulls - number of holes (or bars) a. These holes are necessary to accommodate large jaw muscles b. Anapsid Skull - no holes in temporal - jaws can move fast, but with little force 1. Muscles that move the jaw are small 2. There is no good paleotological evidence for the transition between amphibians and reptiles - no fossil intermediates a. Fossil amphibians have lots of dermal bones in skull b. Amphibians have no temporal openings in skull 1. (Aside) both fossil amphibians and primitive reptiles have a parietal “eye” that senses light and dark (“third” eye in middle of head) c. Reptile skull is higher than amphibian to accomodate larger jaw muscles d. Of the modern reptiles only turtles are anapsids 2. Diapsid Skull - has holes in the temporal region a. Diapsid reptiles gave rise to lizards and snakes - they have a diapsid skull 1. Also Tuatara, crocodiles, dinosaurs and pterydactyls Reptiles b. One group of diapsids also had a pre-orbital hole in the skull in front of eye - this hole is still preserved in the birds - this anatomy suggests strongly that the birds are derived from the diapsid reptiles 3.
    [Show full text]
  • XIV Annual Meeting of the European Association of Vertebrate Palaeontologists
    XIV Annual Meeting of the European Association of Vertebrate Palaeontologists 6-10 July 2016, Haarlem, The Netherlands Programme and Abstract Book Edited by: EAVP 2016 Programme & Abstract Committee Femke Holwerda, Anneke Madern, Dennis Voeten, Anneke van Heteren, Hanneke Meijer, Natasja den Ouden EAVP 2016 Programme & Abstract Crew Stephan Spiekman, Tom Trapman, Feiko Miedema, Sifra Bijl, Mart Smeets, Pim Kaskes, Tim Rietbergen, Juliën Lubeek XIV EAVP Meeting, 6-10 July, 2016, Haarlem, The Netherlands THE HERPETOFAUNA FROM THE LATE TRIASSIC OF THE JAMESON LAND BASIN (EAST GREENLAND): REVIEW AND UPDATES M. Marzola1,2,3,4*, O. Mateus1,3, O. Wings5, N. Klein6, J. Mìlan7,8, and L.B. Clemmensen2 1Universidade Nova de Lisboa, GeoBioTec, Departamento de Ciências da Terra, Faculdade de Ciências e Tecnologia, Quinta da Torre, 2829-516 Caparica, Portugal 2University of Copenhagen, IGN, Department of Geosciences and Natural Resource Management, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark 3Museu da Lourinhã, Rua João Luís de Moura, 95, 2530-158 Lourinhã, Portugal 4Geocenter Møns Klint, Stengårdsvej 8, DK-4751 Borre, Denmark 5Landesmuseum Hannover, Willy-Brandt-Allee 5, 30169 Hannover, Germany 6State Museum of Natural History Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany 7Geomuseum Faxe/Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark 8University of Copenhagen,Natural History Museum of Denmark, Øster Voldgade 5-7, DK- 1350 Copenhagen K, Denmark *[email protected] The Norian-Rhaetian Fleming Fjord Formation (lacustrine and fluvial deposits) in the Jameson Land Basin (East Greenland) is rich in vertebrate fossils, recording all main groups of vertebrates known from the Late Triassic. Fishes, amphibians, a plethora of reptilians (including Testudines, Aetosauria, Phytosauria, Pterosauria, and Dinosauria), and early mammals compose the richness and completeness of the vertebrate record from this region of Greenland, explored with expeditions since the 1970’s.
    [Show full text]
  • HOVASAURUS BOULEI, an AQUATIC EOSUCHIAN from the UPPER PERMIAN of MADAGASCAR by P.J
    99 Palaeont. afr., 24 (1981) HOVASAURUS BOULEI, AN AQUATIC EOSUCHIAN FROM THE UPPER PERMIAN OF MADAGASCAR by P.J. Currie Provincial Museum ofAlberta, Edmonton, Alberta, T5N OM6, Canada ABSTRACT HovasauTUs is the most specialized of four known genera of tangasaurid eosuchians, and is the most common vertebrate recovered from the Lower Sakamena Formation (Upper Per­ mian, Dzulfia n Standard Stage) of Madagascar. The tail is more than double the snout-vent length, and would have been used as a powerful swimming appendage. Ribs are pachyostotic in large animals. The pectoral girdle is low, but massively developed ventrally. The front limb would have been used for swimming and for direction control when swimming. Copious amounts of pebbles were swallowed for ballast. The hind limbs would have been efficient for terrestrial locomotion at maturity. The presence of long growth series for Ho vasaurus and the more terrestrial tan~saurid ThadeosauTUs presents a unique opportunity to study differences in growth strategies in two closely related Permian genera. At birth, the limbs were relatively much shorter in Ho vasaurus, but because of differences in growth rates, the limbs of Thadeosau­ rus are relatively shorter at maturity. It is suggested that immature specimens of Ho vasauTUs spent most of their time in the water, whereas adults spent more time on land for mating, lay­ ing eggs and/or range dispersal. Specilizations in the vertebrae and carpus indicate close re­ lationship between Youngina and the tangasaurids, but eliminate tangasaurids from consider­ ation as ancestors of other aquatic eosuchians, archosaurs or sauropterygians. CONTENTS Page ABREVIATIONS . ..... ... ......... .......... ... ......... ..... ... ..... .. .... 101 INTRODUCTION .
    [Show full text]
  • Constraints on the Timescale of Animal Evolutionary History
    Palaeontologia Electronica palaeo-electronica.org Constraints on the timescale of animal evolutionary history Michael J. Benton, Philip C.J. Donoghue, Robert J. Asher, Matt Friedman, Thomas J. Near, and Jakob Vinther ABSTRACT Dating the tree of life is a core endeavor in evolutionary biology. Rates of evolution are fundamental to nearly every evolutionary model and process. Rates need dates. There is much debate on the most appropriate and reasonable ways in which to date the tree of life, and recent work has highlighted some confusions and complexities that can be avoided. Whether phylogenetic trees are dated after they have been estab- lished, or as part of the process of tree finding, practitioners need to know which cali- brations to use. We emphasize the importance of identifying crown (not stem) fossils, levels of confidence in their attribution to the crown, current chronostratigraphic preci- sion, the primacy of the host geological formation and asymmetric confidence intervals. Here we present calibrations for 88 key nodes across the phylogeny of animals, rang- ing from the root of Metazoa to the last common ancestor of Homo sapiens. Close attention to detail is constantly required: for example, the classic bird-mammal date (base of crown Amniota) has often been given as 310-315 Ma; the 2014 international time scale indicates a minimum age of 318 Ma. Michael J. Benton. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. [email protected] Philip C.J. Donoghue. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. [email protected] Robert J.
    [Show full text]
  • The Shoulder Girdle and Anterior Limb of Drepanosaurus Unguicaudatus
    <oological Journal of the Linnean Socieg (1994), Ill: 247-264. With 12 figures The shoulder girdle and anterior limb of Drepanosaurus unguicaudatus (Reptilia, Neodiapsida) from the upper Triassic (Norian) Downloaded from https://academic.oup.com/zoolinnean/article/111/3/247/2691415 by guest on 27 September 2021 of Northern Italy SILVIO RENESTO Dipartimento di Scienze della Terra, Universita degli Studi, Via Mangiagalli 34, I-20133 Milano, Italy Received January 1993, accepted for publication February 1994 A reinvestigation of the osteology of the holotype of Drepanosaurus unguicaudatus Pinna, 1980 suggests that in earlier descriptions some osteological features were misinterpreted, owing to the crushing of the bones and because taphonomic aspects were not considered. The pattern of the shoulder girdle and fore-limb was misunderstood: the supposed interclavicle is in fact the right scapula, and the bones previously identified as coracoid and scapula belong to the anterior limb. The new reconstruction of the shoulder girdle, along with the morphology of the phalanges and caudal vertebrae, leads to a new hypothesis about the mode oflife of this reptile. Drepanosaurus was probably an arboreal reptile which used its enormous claws to scrape the bark from trees, perhaps in search of insects, just as the modern pigmy anteater (Cyclopes) does. Available diagnostic characters place Drepanosaurus within the Neodiapsida Benton, but it is impossible to ascribe this genus to one or other of the two major neodiapsid lineages, the Archosauromorpha and the Lepidosauromorpha. ADDITIONAL KEY WORDS:-Functional morphology - taxonomy - taphonomy - palaeoecology . CONTENTS Introduction ................... 247 Taphonomy ..... .............. 249 Systematic palaeontology . .............. 251 Genus Drepanosaurus Pinna, 1980 .............. 252 Drepannsaurus unguicaudatus Pinna, 1980.
    [Show full text]
  • Evolution of the Iguanine Lizards (Sauria, Iguanidae) As Determined by Osteological and Myological Characters David F
    Brigham Young University Science Bulletin, Biological Series Volume 12 | Number 3 Article 1 1-1971 Evolution of the iguanine lizards (Sauria, Iguanidae) as determined by osteological and myological characters David F. Avery Department of Biology, Southern Connecticut State College, New Haven, Connecticut Wilmer W. Tanner Department of Zoology, Brigham Young University, Provo, Utah Follow this and additional works at: https://scholarsarchive.byu.edu/byuscib Part of the Anatomy Commons, Botany Commons, Physiology Commons, and the Zoology Commons Recommended Citation Avery, David F. and Tanner, Wilmer W. (1971) "Evolution of the iguanine lizards (Sauria, Iguanidae) as determined by osteological and myological characters," Brigham Young University Science Bulletin, Biological Series: Vol. 12 : No. 3 , Article 1. Available at: https://scholarsarchive.byu.edu/byuscib/vol12/iss3/1 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Brigham Young University Science Bulletin, Biological Series by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. S-^' Brigham Young University f?!AR12j97d Science Bulletin \ EVOLUTION OF THE IGUANINE LIZARDS (SAURIA, IGUANIDAE) AS DETERMINED BY OSTEOLOGICAL AND MYOLOGICAL CHARACTERS by David F. Avery and Wilmer W. Tanner BIOLOGICAL SERIES — VOLUME Xil, NUMBER 3 JANUARY 1971 Brigham Young University Science Bulletin
    [Show full text]
  • (Diapsida: Saurosphargidae), with Implications for the Morphological Diversity and Phylogeny of the Group
    Geol. Mag.: page 1 of 21. c Cambridge University Press 2013 1 doi:10.1017/S001675681300023X A new species of Largocephalosaurus (Diapsida: Saurosphargidae), with implications for the morphological diversity and phylogeny of the group ∗ CHUN LI †, DA-YONG JIANG‡, LONG CHENG§, XIAO-CHUN WU†¶ & OLIVIER RIEPPEL ∗ Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, China ‡Department of Geology and Geological Museum, Peking University, Beijing 100871, PR China §Wuhan Institute of Geology and Mineral Resources, Wuhan, 430223, PR China ¶Canadian Museum of Nature, PO Box 3443, STN ‘D’, Ottawa, ON K1P 6P4, Canada Department of Geology, The Field Museum, 1400 S. Lake Shore Drive, Chicago, IL 60605-2496, USA (Received 31 July 2012; accepted 25 February 2013) Abstract – Largocephalosaurus polycarpon Cheng et al. 2012a was erected after the study of the skull and some parts of a skeleton and considered to be an eosauropterygian. Here we describe a new species of the genus, Largocephalosaurus qianensis, based on three specimens. The new species provides many anatomical details which were described only briefly or not at all in the type species, and clearly indicates that Largocephalosaurus is a saurosphargid. It differs from the type species mainly in having three premaxillary teeth, a very short retroarticular process, a large pineal foramen, two sacral vertebrae, and elongated small granular osteoderms mixed with some large ones along the lateral most side of the body. With additional information from the new species, we revise the diagnosis and the phylogenetic relationships of Largocephalosaurus and clarify a set of diagnostic features for the Saurosphargidae Li et al.
    [Show full text]
  • A Small Lepidosauromorph Reptile from the Early Triassic of Poland
    A SMALL LEPIDOSAUROMORPH REPTILE FROM THE EARLY TRIASSIC OF POLAND SUSAN E. EVANS and MAGDALENA BORSUK−BIAŁYNICKA Evans, S.E. and Borsuk−Białynicka, M. 2009. A small lepidosauromorph reptile from the Early Triassic of Poland. Palaeontologia Polonica 65, 179–202. The Early Triassic karst deposits of Czatkowice quarry near Kraków, southern Poland, has yielded a diversity of fish, amphibians and small reptiles. Two of these reptiles are lepido− sauromorphs, a group otherwise very poorly represented in the Triassic record. The smaller of them, Sophineta cracoviensis gen. et sp. n., is described here. In Sophineta the unspecial− ised vertebral column is associated with the fairly derived skull structure, including the tall facial process of the maxilla, reduced lacrimal, and pleurodonty, that all resemble those of early crown−group lepidosaurs rather then stem−taxa. Cladistic analysis places this new ge− nus as the sister group of Lepidosauria, displacing the relictual Middle Jurassic genus Marmoretta and bringing the origins of Lepidosauria closer to a realistic time frame. Key words: Reptilia, Lepidosauria, Triassic, phylogeny, Czatkowice, Poland. Susan E. Evans [[email protected]], Department of Cell and Developmental Biology, Uni− versity College London, Gower Street, London, WC1E 6BT, UK. Magdalena Borsuk−Białynicka [[email protected]], Institut Paleobiologii PAN, Twarda 51/55, PL−00−818 Warszawa, Poland. Received 8 March 2006, accepted 9 January 2007 180 SUSAN E. EVANS and MAGDALENA BORSUK−BIAŁYNICKA INTRODUCTION Amongst living reptiles, lepidosaurs (snakes, lizards, amphisbaenians, and tuatara) form the largest and most successful group with more than 7 000 widely distributed species. The two main lepidosaurian clades are Rhynchocephalia (the living Sphenodon and its extinct relatives) and Squamata (lizards, snakes and amphisbaenians).
    [Show full text]