DOCSLIB.ORG

The Sutural Pattern of Skull-Roof Bones in Lower Permian Discosauriscus Austriacus from Moravia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Sutural Pattern of Skull-Roof Bones in Lower Permian Discosauriscus Austriacus from Moravia The sutural pattern of skull-roof bones in Lower Permian Discosauriscus austriacus from Moravia JOZEF KLEMBARA Klembara, J. 1994 06 15 The sutural pattern of skull-roofbones in Lower Permian DiKosauricN LETHAIA alcmiacuc &om Moravia. Lethaia, Vol. 27, pp. 85-95. Oslo. ISSN 0024-1 164. Sutures between ornamented bones of Discosaurixuc aumiacuc are mostly simple, but there are also more complicated, rarely serrated, sutures between some bones. In small individuals, the sutures are simple, but the same sutures also occur in the largest specimens. The character of the sutures and the incomplete ossification ofbones around the pineal foramen indicate the larva type of organization of DiKosauriKur The fenestra between premaxihies and nasals appears to be absent. In the majority of specimens, a squamosal-intertemporal sutural contact is present, altho~itissometimesredu~andinafewcasesintermptedbyapostorbitalandsupratemporal contact Therefore the character ‘intertmporal-squamosal suture present or absent’ cannot be used in this rigorous sense for testing the relationshipsof early tetrapods.The configuration of the suture between both parietals in osteolepiforms, Dixosaurixuc, and various early amphibians and reptiles indicates that the bones enclosing the pineal foramen in osteolepifonns are kontals. ODI~~RISCUS.Seymouriamorpha, Lower Permian mapod, skull woskLlcton, sutures. JoZqKlrmbara, Zoological Imthte, Faculty of Natural SCienceJ, Comeniuc University, Mlynskd dolina B-2,&42 15 Bratislava, Slovakia; 30th September, 1992; revised20th April, 1993. Two localities in the Boskovice Furrow in Moravia (Czech Material, methods and localities Republic) have produced a relatively large assemblage of more or less three-dimensional skeletal material of discosau- The localities and methods have been described by Klembara riscids (Klembara & MeszAroS 1992). Despite certain Mer- & MeszAroS (1992). ences in skull proportions, there are no reliable criteria for The following specimens (skull lengths 17-52 mm) were the determination of more than one species and genus used in this paper (D - locality DrvAlovice, K - locality (Klembara & Janiga 1993). In the following account, the new Kochov): D 18, D 47, D 52, D 69, D 70, D 87, D 208, K 1, K 13, collections of discosasuriscids from Moravia are interpreted K21,K3O,K41,K52,K72,KSO,K99,K 100,K 102,K 138, as one genus and species, Discosautisnrs ausrriacus (Makow- K 139, K 177, K 285, K 323, K 329, K 333, K 334, K 336. The sky 1876). specimens are deposited at Zoological Institute, Faculty of Discosauriscids are considered by most authors to be Natural Sciences, Comenius University, Bratislava. seymouriamorph tetrapods (e.g., Romer 1947; spinar 1952; Smithson 1985; Ivakhnenko 1987; Werneburg 1989), al- though an unambiguous assignment is not endorsed univer- Skull-roof bones sally (Heaton 1980; Holmes 1984). Detailed descriptions of the skull and the postcranial skel- In Discosaurixus, the dermal skull roof (Fig. 1) consists of all eton will be published in several papers, because this well- the bones normally present in seymouriamorph tetrapods preserved material deserves complete documentation.Many (e.g., Seymouria, White 1939, or Karpinskiosaurus, Ivakh- structures, in particular the sutures of the dermal skull roof, nenko 1987).There is a parietakabular contact, characteris- were previously undescribed. In some respects, this paper tic for Anthracosauria (sensu Save-Mderbergh 1934; 6. also complements the preceding paper (Klembara & Janiga Smithson 1985), one of the group of the reptiliomorph 1993) dealing with the proportional differences in Disco- evolutionary line of tetrapods (muSve-Merbergh 1934, SaUrisnrs. 1935; cf. Panchen & Smithson 1988). Unlike the embolo- The term ‘Anthracosauria’ will be used to include Embo- meres, but like Seymouria and Karpinskiosaurus and prob- lomeri, Gephyrostegidae and Eoherpetontidae (cf.‘Anthra- ablyalso Gqhyrostegus(Carrolll970) and Eoherpeton (Pan- cosauroideae’ sensu Smithson 1985). chen 1975), DiscosaurisncSpossesses a septomaxiUaxy. 86 Jozefk?embara LETHAL4 27 (1994) Fig 1. Discosauriscus aumiacus (Makowsky 18761, K 13. Skull in dorsal view. Abbreviations: FR - fiond, JU- jugal, IT - intertemporal,LA - lacrimal, MX - maxihy, NA - d,PA - paridPFR - prhond, PO - postorbid,POFR - postfrontal, PP - postparid, QJ- quadratojugal, SMX- septomaxihy, SQ - squamosal, ST - supratemporal,TA - tab*, tr.f. - transverse flange of pterygoid. Sutures position, or the orientation on a particular bone, is constant. An exception is the postparietal, in,which the median un- The sutures between the ornamented areas of the dermal ornamented area, which is overlapped by the other post- bones of the skull roof are almost always clearly visible. The parietal, is sometimes born by the left (e.g., K 177), and majority of the dermal skull-roof bones form squamose sometimes the right (e.g., D 47) postparietal. sutures, in which part of the edge of one bone overlaps the One of the simplest sutural patterns of the dermal skull unornamented part of the adjoining bone (e.g., parietals- roofofDiscosaurixusispresentinK13 (Fig. l).Theshapeof frontals, Fig. 1). In the region in front of the pineal foramen, the bone and its suture patterns are essentially bilaterally the nasals, hntals and parietals are closely attached at the symmetrical. The sutures between individual bones are midline, and the medial margin of one always fits to a certain simple. Such a ‘basic’ sutural pattern is relatively common degree into an elongated groove in the medial margin of the and does not depend on the size of the specimen. Diversity in other bone. In some skulls, however, these bones have rela- suture patterns is primarily the result ofvariations in size and tively broad unornamented areas (e.g., the left frontal of D shape of the ornamented surfaces, which is much more 87). Neither the lacrimal nor the maxillary form wider un- variable than the shape of individual bones. ornamented areas. The dorsal surface of the unornamented Because the detailed description of individual cranial areas is mostly markedly grooved (Fig. 1). Although the bones will be given in later papers, only the more pro- range of the unornamented areas can vary slightly, their nounced modifications of the relative positions of some LETHAIA 27 (1994) Skull-roof bones of DISCOSAURISCUS87 Fig. 2. Discosautiscusaustiacus (Makowdcy 1876). Skulls in dorsal view. ok K 138. OB. K 139. Abbreviations FR- frontal, IT - intertemporal,PA - parietal, PO - postorbital, POFR - postfrontal, ST - supratemporal. dermal bones and their ornamented surfaces regarding the bones is short (e.g., D 70 on the right) or fully interrupted condition in K 13 (Fig. 1) will be described here. (e.g., D 70 on the left); Fig. 4B. In some specimens (K 100, K 102, D 208), it is difficult to decide whether the contact was Region of the pineal foramen. - The size of the pineal fora- interrupted or not, because the distances involved are several men varies and does not depend on the size of the specimen. tenths of a millimetre. Moreover, the slight compression of In the majority of specimens, the pineal foramen is com- adjoining bones, often apparent at the junction of the skull pletely enclosed anteriorly by the parietal bones (Figs. 1,2A, table and cheek, may be of some importance. In K 333, 3B, 6). The length of the junction of the ornamented sur- however, a relatively long suture between the supratemporal faces of the parietals anterior to the pineal foramen varies. and postorbital (Fig. 5) completely precludes a squamosal- In some specimens this junction is relatively long (Fig. 2A), intertemporalcontact. This is due partly to a prolongation of but in others (e.g., D 18, K 139) the suture is not closed the posterior edge of the postorbital but mostly to the elon- anteriorly, and the frontal or fronds form part of its ante- gation of the anterolateral edge of the supratemporal (Figs. rior margin (Figs. 2B, 3A). Between the two extremes there 4B, 5). Although skulls show variability in relative width are many intermediate conditions (e.g., D 69, D 70, K 21, (Klembara & Janiga 1993), there is no correlation with the Figs. 3C, 4). This variation derives from the variable shape shorteningof the intertemporal-squamosal suture. A mini- of the anterior ends of the parietals and the posterior ends of mal junction ofthese bones, or its slight interruption, occurs the fiontals (on both right and left sides). As a result, differ- on ‘broad’, as well as ‘narrow’skulls (cf. specimen D 70, Fig. ent combinations of the character and length of the junc- 4B and Klembara & Janiga 1993, Fig. 1OC). It is also related tion of adjoining bones are produced, as well as variation in to the length of the postorbital bone, and/or its posterior the degree of participation of the frontal in the anterior process. It seems that individual variability is involved (cf. border of the pineal foramen. specimens D 69 and D 70, Figs. 4A and 4B). The position of the pineal foramen remains more or less constant; it varies only slightly relative to the anteroposterior Sutures beween the ornamented surfaces of bones. - The extent of the intertemporal. course of the sutures between the ornamented surfaces of individual skull-roof bones is rather variable, as is shown by Intertemporal-squamosul suture. - In the majority of skulls, theextentandshapeoftheseornamentedsurfaces.Thesecan the intertemporal has a lateral common suture with the besubstantidy different on the right and left side of the skull squamosal (Fig.
Load more

Recommended publications
  • Noise Annoys Not Mouriamorphs Filled a Niche THESE Days, Our Ears Are Too Sensitive for That Made Their Preserva­ Their Own Good
    NEWS AND VIEWS DAEDALUS--------~ An orthodox interpret­ ation might be that sey­ Noise annoys not mouriamorphs filled a niche THESE days, our ears are too sensitive for that made their preserva­ their own good. Primitive tribes, with only tion unlikely until the begin­ natural sounds to listen to, retain their ning of the acute hearing into late age. Modern Permian, at which point civilization, however, batters our ears into taphonomic circumstances early deafness. They have a natural changed and they were protection mechanism, but it badly needs suddenly abundantly pre­ upgrading. served, both in Euramerica It uses two tiny muscles, the tensor and in those plates newly tympani and the stapedius, which reduce accreting to Euramerica in the ear's sensitivity by stiffening the the Lower Permian. How­ joints of its transmission bones. They are ever, with tetrapods also tensed automatically by loud noise. They FIG. 2 Discosauriscus, a small, probably larval seymouri­ diversifying in East Gond­ worked well in prehistoric times, when amorph from the Lower Permian of the Czech Republic. Cal­ wana in the Early Carbonif­ most noises built up slowly. But they ibrated scale bar, 5 cm. (Science Museum of Minnesota; erous, it is equally possible photograph by A. M.) cannot react fast enough to modern that seymouriamorphs first bangs and crashes, and sustained uproar apparently centred on equatorial appeared there and, instead of spreading fatigues them. Daedalus wants to warn Euramerica, was largely a process of westwards, spread or hopped north across them of noise in advance. ecological niche-hopping within a s ingle the chain of North China, Tarim and A sound wave launched upwards into continent.
    [Show full text]
  • Early Tetrapod Relationships Revisited
    Biol. Rev. (2003), 78, pp. 251–345. f Cambridge Philosophical Society 251 DOI: 10.1017/S1464793102006103 Printed in the United Kingdom Early tetrapod relationships revisited MARCELLO RUTA1*, MICHAEL I. COATES1 and DONALD L. J. QUICKE2 1 The Department of Organismal Biology and Anatomy, The University of Chicago, 1027 East 57th Street, Chicago, IL 60637-1508, USA ([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
    [Show full text]
  • 3D Maps of Mineral Composition and Hydroxyapatite Orientation in Fossil Bone Samples Obtained by X-Ray Diffraction Computed Tomo
    www.nature.com/scientificreports OPEN 3D Maps of Mineral Composition and Hydroxyapatite Orientation in Fossil Bone Samples Obtained Received: 25 January 2018 Accepted: 20 June 2018 by X-ray Difraction Computed Published: xx xx xxxx Tomography Fredrik K. Mürer1, Sophie Sanchez2,3,4, Michelle Álvarez-Murga3, Marco Di Michiel3, Franz Pfeifer5,6, Martin Bech 7 & Dag W. Breiby1,8 Whether hydroxyapatite (HA) orientation in fossilised bone samples can be non-destructively retrieved and used to determine the arrangement of the bone matrix and the location of muscle attachments (entheses), is a question of high relevance to palaeontology, as it facilitates a detailed understanding of the (micro-)anatomy of extinct species with no damage to the precious fossil specimens. Here, we report studies of two fossil bone samples, specifcally the tibia of a 300-million-year-old tetrapod, Discosauriscus austriacus, and the humerus of a 370-million-year-old lobe-fnned fsh, Eusthenopteron foordi, using XRD-CT – a combination of X-ray difraction (XRD) and computed tomography (CT). Reconstructed 3D images showing the spatial mineral distributions and the local orientation of HA were obtained. For Discosauriscus austriacus, details of the muscle attachments could be discerned. For Eusthenopteron foordi, the gross details of the preferred orientation of HA were deduced using three tomographic datasets obtained with orthogonally oriented rotation axes. For both samples, the HA in the bone matrix exhibited preferred orientation, with the unit cell c-axis of the HA crystallites tending to be parallel with the bone surface. In summary, we have demonstrated that XRD-CT combined with an intuitive reconstruction procedure is becoming a powerful tool for studying palaeontological samples.
    [Show full text]
  • Curriculum Vitae
    CURRICULUM VITAE AMY C. HENRICI Collection Manager Section of Vertebrate Paleontology Carnegie Museum of Natural History 4400 Forbes Avenue Pittsburgh, Pennsylvania 15213-4080, USA Phone:(412)622-1915 Email: [email protected] BACKGROUND Birthdate: 24 September 1957. Birthplace: Pittsburgh. Citizenship: USA. EDUCATION B.A. 1979, Hiram College, Ohio (Biology) M.S. 1989, University of Pittsburgh, Pennsylvania (Geology) CAREER Carnegie Museum of Natural History (CMNH) Laboratory Technician, Section of Vertebrate Paleontology, 1979 Research Assistant, Section of Vertebrate Paleontology, 1980 Curatorial Assistant, Section of Vertebrate Paleontology, 1980-1984 Scientific Preparator, Section of Paleobotany, 1985-1986 Scientific Preparator, Section of Vertebrate Paleontology, 1985-2002 Acting Collection Manager/Scientific Preparator, 2003-2004 Collection Manager, 2005-present PALEONTOLOGICAL FIELD EXPERIENCE Late Pennsylvanian through Early Permian of Colorado, New Mexico and Utah (fish, amphibians and reptiles) Early Permian of Germany, Bromacker quarry (amphibians and reptiles) Triassic of New Mexico, Coelophysis quarry (Coelophysis and other reptiles) Upper Jurassic of Colorado (mammals and herps) Tertiary of Montana, Nevada, and Wyoming (mammals and herps) Pleistocene of West Virginia (mammals and herps) Lake sediment cores and lake sediment surface samples, Wyoming (pollen and seeds) PROFESSIONAL APPOINTMENTS Associate Editor, Society of Vertebrate Paleontology, 1998-2000. Research Associate in the Science Division, New Mexico Museum of Natural History and Science, 2007-present. PROFESSIONAL ASSOCIATIONS Society of Vertebrate Paleontology Paleontological Society LECTURES and TUTORIALS (Invited and public) 1994. Middle Eocene frogs from central Wyoming: ontogeny and taphonomy. California State University, San Bernardino 1994. Mechanical preparation of vertebrate fossils. California State University, San Bernardino 1994. Mechanical preparation of vertebrate fossils. University of Chicago 2001.
    [Show full text]
  • The Devonian Tetrapod Acanthostega Gunnari Jarvik: Postcranial Anatomy, Basal Tetrapod Interrelationships and Patterns of Skeletal Evolution M
    Transactions of the Royal Society of Edinburgh: Earth Sciences, 87, 363-421, 1996 The Devonian tetrapod Acanthostega gunnari Jarvik: postcranial anatomy, basal tetrapod interrelationships and patterns of skeletal evolution M. I. Coates ABSTRACT: The postcranial skeleton of Acanthostega gunnari from the Famennian of East Greenland displays a unique, transitional, mixture of features conventionally associated with fish- and tetrapod-like morphologies. The rhachitomous vertebral column has a primitive, barely differentiated atlas-axis complex, encloses an unconstricted notochordal canal, and the weakly ossified neural arches have poorly developed zygapophyses. More derived axial skeletal features include caudal vertebral proliferation and, transiently, neural radials supporting unbranched and unsegmented lepidotrichia. Sacral and post-sacral ribs reiterate uncinate cervical and anterior thoracic rib morphologies: a simple distal flange supplies a broad surface for iliac attachment. The octodactylous forelimb and hindlimb each articulate with an unsutured, foraminate endoskeletal girdle. A broad-bladed femoral shaft with extreme anterior torsion and associated flattened epipodials indicates a paddle-like hindlimb function. Phylogenetic analysis places Acanthostega as the sister- group of Ichthyostega plus all more advanced tetrapods. Tulerpeton appears to be a basal stem- amniote plesion, tying the amphibian-amniote split to the uppermost Devonian. Caerorhachis may represent a more derived stem-amniote plesion. Postcranial evolutionary trends spanning the taxa traditionally associated with the fish-tetrapod transition are discussed in detail. Comparison between axial skeletons of primitive tetrapods suggests that plesiomorphic fish-like morphologies were re-patterned in a cranio-caudal direction with the emergence of tetrapod vertebral regionalisation. The evolution of digited limbs lags behind the initial enlargement of endoskeletal girdles, whereas digit evolution precedes the elaboration of complex carpal and tarsal articulations.
    [Show full text]
  • Therocephalian (Therapsida) And
    第55卷 第1期 古 脊 椎 动 物 学 报 pp. 24-40 2017年1月 VERTEBRATA PALASIATICA figs. -1 7 Therocephalian (Therapsida) and chroniosuchian (Reptiliomorpha) from the Permo-Triassic transitional Guodikeng Formation of the Dalongkou Section, Jimsar, Xinjiang, China LIU Jun1,2 Fernando ABDALA3 (1 Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences Beijing 100044, China [email protected]) (2 University of Chinese Academy of Sciences Beijing 100039) (3 Evolutionary Studies Institute, University of the Witwatersrand Private Bag 3, WITS 2050, Johannesburg, South Africa) Abstract The Guodikeng Formation encompasses the terrestrial Permo-Triassic transition sequence in China. This formation crops out in the Dalongkou section, Jimsar, Xinjiang where remains of the dicynodonts Jimusaria and Lystrosaurus were found. We are describing here a therocephalian and a chroniosuchian from the Dalongkou section, which are the first records of these groups for the Guodikeng Formation. Diagnostic characters of the new therocephalian, Dalongkoua fuae gen. and sp. nov., include maxillary ventral margin strongly concave in lateral view; incisors spatulated and rounded; incisors and canines with faint serrations; coronoid process of the dentary with a marked external adductor fossa; triangular reflected lamina of the angular with two smooth concavities. Chroniosuchians are represented by several postcranial elements and the vertebral morphology is similar to Bystrowiana and Bystrowiella. These remains are interpreted as representing a Bystrowianidae indeterminate. The new findings increase the diversity of the Guodikeng Formation that is now represented by three or four dicynodonts, one therocephalian and one chroniosuchian. All these groups survived the massive P-T extinction but disappear from the fossil record in the Middle to Upper Triassic.
    [Show full text]
  • Investigating the Biomechanics of a Lizard Skull Using Advanced Computer Modelling Techniques with Experimental Validation
    INVESTIGATING THE BIOMECHANICS OF A LIZARD SKULL USING ADVANCED COMPUTER MODELLING TECHNIQUES WITH EXPERIMENTAL VALIDATION Being a Thesis submitted for the Degree of PhD In the University of Hull By Mehran Moazen, BSc (Hons) December 2008 Dedicated to my parents Table of contents Abstract Acknowledgements Contents…………………………………………………………………i Chapter 1: Introduction ......................................................................... 1 1.1 Overview............................................................................................................ 1 1.2 Model creation: geometry .................................................................................. 4 1.3 Biomechanical modelling .................................................................................. 5 1.3.1 Musculoskeletal modelling ......................................................................... 5 1.3.2 Finite element modelling ............................................................................ 7 1.4 Experimental validation study ........................................................................... 7 1.5 Methodology ...................................................................................................... 8 1.6 Goals of project.................................................................................................. 9 1.7 Chapter organization.......................................................................................... 9 Chapter 2: Lizard anatomy.................................................................
    [Show full text]
  • A New Discosauriscid Seymouriamorph Tetrapod from the Lower Permian of Moravia, Czech Republic
    A new discosauriscid seymouriamorph tetrapod from the Lower Permian of Moravia, Czech Republic JOZEF KLEMBARA Klembara, J. 2005. A new discosauriscid seymouriamorph tetrapod from the Lower Permian of Moravia, Czech Repub− lic. Acta Palaeontologica Polonica 50 (1): 25–48. A new genus and species, Makowskia laticephala gen. et sp. nov., of seymouriamorph tetrapod from the Lower Permian deposits of the Boskovice Furrow in Moravia (Czech Republic) is described in detail, and its cranial reconstruction is pre− sented. It is placed in the family Discosauriscidae (together with Discosauriscus and Ariekanerpeton) on the following character states: short preorbital region; rounded to oval orbits positioned mainly in anterior half of skull; otic notch dorsoventrally broad and anteroposteriorly deep; rounded to oval ventral scales. Makowskia is distinguished from other Discosauriscidae by the following characters: nasal bones equally long as broad; interorbital region broad; prefrontal− postfrontal contact lies in level of frontal mid−length (only from D. pulcherrimus); maxilla deepest at its mid−length; sub− orbital ramus of jugal short and dorsoventrally broad with long anterodorsal−posteroventral directed lacrimal−jugal su− ture; postorbital anteroposteriorly short and lacks elongated posterior process; ventral surface of basioccipital smooth; rows of small denticles placed on distinct ridges and intervening furrows radiate from place immediately laterally to artic− ular portion on ventral surface of palatal ramus of pterygoid (only from D. pulcherrimus);
    [Show full text]
  • New Chroniosuchian Materials from Xinjiang, China
    第58卷 第4期 古 脊 椎 动 物 学 报 pp. 283–292 figs. 1–4 2020年10月 VERTEBRATA PALASIATICA DOI: 10.19615/j.cnki.1000-3118.200415 New chroniosuchian materials from Xinjiang, China LIU Jun1,2,3 (1 Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences Beijing 100044) (2 CAS Center for Excellence in Life and Paleoenvironment Beijing 100044 [email protected]) (3 College of Earth and Planetary Sciences, University of Chinese Academy of Sciences Beijing 100049) Abstract Chroniosuchians have the earliest representatives in Gansu, China, but the Chinese records were scarcer compared to Russia, especially the Triassic one. In Xinjiang, there was only one specimen reported from the upper part of the Guodikeng Formation. Here three new chroniosuchian specimens are reported from three new stratigraphic horizons: the Quanzijie Formation (middle Permian), the base of the Guodikeng Formation (upper Permian), and the Jiucaiyuan Formation (Lower Triassic). The osteoderm from the Jiucaiyuan Formation represents the first definite Triassic chroniosuchian from China. The new findings increase the chroniosuchian diversity and their time range in China. The bystrowianid chroniosuchian specimens from the Guodikeng and Jiucaiyuan formations demonstrated that this group survived in the end-Permian mass extinction in Xinjiang, China. Key words Xinjiang, China; Permian, Triassic; Quanzijie Formation, Guodikeng Formation, Jiucaiyuan Formation; Bystrowianidae, chroniosuchians Citation Liu J, 2020. New chroniosuchian materials from Xinjiang, China. Vertebrata PalAsiatica, 58(4): 283–292 1 Introduction The chroniosuchians were an enigmatic clade of non-amniotic tetrapods with uncertain phylogenetic position (Clack and Klembara, 2009; Schoch et al., 2010; Buchwitz et al., 2012; Witzmann and Schoch, 2018; Marjanović and Laurin, 2019).
    [Show full text]
  • Meeting Program & Abstracts
    November 5 – 8, 2014 • Estrel Berlin • Berlin, Germany SOCIETY OF VERTEBRATE PALEONTOLOGY NOVEMBER 2014 ABSTRACTS OF PAPERS 74th ANNUAL MEETING Estrel Berlin Berlin, Germany November 5 – 8, 2014 HOST COMMITTEE Nadia Fröbisch; Jörg Fröbisch; Oliver Hampe; Heinrich Mallison; Johannes Müller; Juliane Röhner; Daniela Schwarz; Florian Witzmann EXECUTIVE COMMITTEE Cathy Forster, President; John Long, Vice President; Philip Currie, Past-President; Glenn Storrs, Secretary; Ted Vlamis, Treasurer; Elizabeth Hadly, Member-at-Large; Christian Sidor, Member-at-Large; Paul Barrett, Member-at-Large SYMPOSIUM CONVENORS David W. Bapst; Andreas Christian; Jussi T. Eronen; John R. Hutchinson; Martin Kundrat; Michelle Lawing; Graeme Lloyd; Nicholas J. Matzke; Andrew Milner; P. David Polly; Daniela Schwarz-Wings; Eric Snively; Jean Sébastien Steyer; Florian Witzmann; April Wright PROGRAM COMMITTEE Jonathan Bloch, Co-Chair; Anjali Goswami, Co-Chair; Heather Ahrens; Brian Beatty; Chris Brochu; Richard Butler; Ted Daeschler; David Evans; David Fox; Pat Holroyd; Marc Jones; Christian Kammerer; Matt Lamanna; Erin Maxwell; Josh Miller; Jessica Designed for palaeontology courses in biology and geology departments, this leading Miller-Camp;text will also be of interestKevin to enthusiasts Padian; who Lauren want to experience Sallan; the flavour William of how Sanders; Bruce Shockey; Mary the research is done. The book is strongly phylogenetic, and this makes it a source of currentSilcox; data on vertebrate Michelle evolution. Stocker; Rebecca Terry; Paul Upchurch;
    [Show full text]
  • Postcranial Anatomy and Histology of Seymouria, and the Terrestriality of Seymouriamorphs
    Postcranial anatomy and histology of Seymouria, and the terrestriality of seymouriamorphs Kayla D. Bazzana1,2, Bryan M. Gee1, Joseph J. Bevitt3 and Robert R. Reisz1,4 1 Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada 2 Department of Natural History, Royal Ontario Museum, Toronto, Ontario, Canada 3 Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Whales, Australia 4 International Center of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, Jilin Province, China ABSTRACT Seymouria is the best known of the seymouriamorphs, a group of Permo-Carboniferous reptiliomorphs with both terrestrial and aquatic taxa. The majority of research on Seymouria has focused on cranial anatomy, with few detailed descriptions or illustrations of the postcrania. We utilized neutron computed tomography (nCT) and histological sampling to provide updated, detailed figures that clarify details of the postcranial anatomy and to assess the development and histology of Seymouria through specimens from the early Permian Richards Spur locality. The correlation of morphological and histological data indicate rapid metamorphosis in this terrestrially capable stem amniote, with the youngest specimen being postmetamorphic despite being distinctly younger than premetamorphic individuals of Discosauriscus, the only other seymouriamorph to have been histologically sampled. The microanatomical data (e.g., semi-open medullary cavity) also
    [Show full text]
  • Early Vertebrate Evolution New Insights Into the Morphology of the Carboniferous Tetrapod Crassigyrinus Scoticus from Computed Tomography Eva C
    Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 109, 157–175, 2019 (for 2018) Early Vertebrate Evolution New insights into the morphology of the Carboniferous tetrapod Crassigyrinus scoticus from computed tomography Eva C. HERBST* and John R. HUTCHINSON Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire AL9 7TA, UK. Email: [email protected] *Corresponding author ABSTRACT: The Carboniferous tetrapod Crassigyrinus scoticus is an enigmatic animal in terms of its morphology and its phylogenetic position. Crassigyrinus had extremely reduced forelimbs, and was aquatic, perhaps secondarily. Recent phylogenetic analyses tentatively place Crassigyrinus close to the whatcheeriids. Many Carboniferous tetrapods exhibit several characteristics associated with terrestrial locomotion, and much research has focused on how this novel locomotor mode evolved. However, to estimate the selective pressures and constraints during this important time in vertebrate evolution, it is also important to study early tetrapods like Crassigyrinus that either remained aquatic or secondarily became aquatic. We used computed tomographic scanning to search for more data about the skeletal morphology of Crassigyrinus and discovered several elements previously hidden by the matrix. These elements include more ribs, another neural arch, potential evidence of an ossified pubis and maybe of pleurocentra. We also discovered several additional metatarsals with interesting asymmetrical morphology that may have functional implications. Finally, we reclassify what was previously thought to be a left sacral rib as a left fibula and show previously unknown aspects of the morphology of the radius. These discoveries are examined in functional and phylogenetic contexts. KEY WORDS: evolution, palaeontology, phylogeny, water-to-land transition.
    [Show full text]