DOCSLIB.ORG

Maquetación 1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Maquetación 1 See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/335794209 New Proterochampsid Specimens Expand the Morphological Diversity of the Rhadinosuchines of the Chañares Formation (Lower Carnian, Northwestern Argentina) Article in AMEGHINIANA · June 2019 DOI: 10.5710/AMGH.25.05.2019.3230 CITATIONS READS 6 309 4 authors: Martin Ezcurra M. Belen von Baczko Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" 174 PUBLICATIONS 3,780 CITATIONS 34 PUBLICATIONS 330 CITATIONS SEE PROFILE SEE PROFILE maría jimena Trotteyn Julia B Desojo National Scientific and Technical Research Council Universidad Nacional de La Plata 36 PUBLICATIONS 399 CITATIONS 116 PUBLICATIONS 1,968 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Geochronologic constraints on early dinosaur evolution View project Paleoneurology of the paracrocodylomorph archosaur Postosuchus kirkpatricki View project All content following this page was uploaded by M. Belen von Baczko on 13 September 2019. The user has requested enhancement of the downloaded file. NEW PROTEROCHAMPSID SPECIMENS EXPAND THE MORPHOLOGICAL DIVERSITY OF THE RHADINOSUCHINES OF THE CHAÑARES FORMATION (LOWER CARNIAN, NORTHWESTERN ARGENTINA) MARTÍN D. EZCURRA 1,2 M. BELÉN VON BACZKO 2,3 M. JIMENA TROTTEYN 2,4 JULIA B. DESOJO 2,3 1Sección Paleontología de Vertebrados, CONICET–Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Avenida Ángel Gallardo 470, C1405DJR CABA, Argentina. 2Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Rivadavia 1917, C1033AAJ CABA, Argentina. 3División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Paseo del Bosque s/n, B1900FWA La Plata, Argentina. 4Instituto de Geología Emiliano P. Aparicio, INGEO-CIGEOBIO, Universidad Nacional de San Juan, Av. Ignacio de la Rosa 590 (oeste), J5402DCS San Juan, Argentina. Submitted: September 25 th , 2018 - Accepted: April 25 th , 2019 - Published online: June 9 th , 2019 To cite this article: Martín D. Ezcurra, M. Belén Von Baczko, M. Jimena Trotteyn, and Julia B. Desojo (2019). New proterochampsid specimens expand the morphological diversity of the rhadinosuchines of the Chañares Formation (Lower Carnian, northwestern Argentina). Ameghiniana 56: 79–115. To link to this article: http://dx.doi.org/ 10.5710/AMGH.25.05.2019.3230 PLEASE SCROLL DOWN FOR ARTICLE Also appearing in this issue: New early Carnian rhadinosuchines Assemblages generated by owls New species of gastropods from Argentina show high record 14 species of rodents and reveal the presence of fauna morphological diversity and reveal quantitative differences with tropical affinities in intraspecific variation. with extant fauna. Central Argentina. AMEGHINIANA - 2019 - Volume 56 (2): 79–115 ARTICLES ISSN 0002-7014 NEW PROTEROCHAMPSID SPECIMENS EXPAND THE MOR - PHOLOGICAL DIVERSITY OF THE RHADINOSUCHINES OF THE CHAÑARES FORMATION (LOWER CARNIAN, NORTHWESTERN ARGENTINA) MARTÍN D. EZCURRA 1,2 , M. BELÉN VON BACZKO 2,3 , M. JIMENA TROTTEYN 2,4 , AND JULIA B. DESOJO 2,3 1Sección Paleontología de Vertebrados, CONICET–Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Avenida Ángel Gallardo 470, C1405DJR CABA, Argentina. [email protected] 2Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Rivadavia 1917, C1033AAJ CABA, Argentina. 3División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Paseo del Bosque s/n, B1900FWA La Plata, Argentina. be [email protected] ; [email protected] 4Instituto de Geología Emiliano P. Aparicio, INGEO-CIGEOBIO, Universidad Nacional de San Juan, Av. Ignacio de la Rosa 590 (oeste), J5402DCS San Juan, Ar gentina. Abstract . The proterochampsids are crocodile-like, small- to medium-sized, quadrupedal and predatory stem-archosaurs. The rhadinosuchines are a clade of deeply nested proterochampsids that are the most abundant diapsids of the Massetognathus -Chanaresuchus Assemblage Zone of the Chañares Formation (lower Carnian) of north-western Argentina. Here, we describe two new rhadinosuchine proterochampsid specimens recently collected from the Massetognathus -Chanaresuchus Assemblage Zone of the Chañares Formation. These specimens are represented by an articulated partial skeleton and disarticulated cranial and postcranial bones, respectively. One of them is less complete, but its well-preserved disarticulated bones considerably expand the anatomical knowledge of certain regions of the rhadinosuchine skeleton. The combination of character-states present in both specimens and shared with other known rhadinosuchine species ( e.g. , Chanaresuchus bonapartei , Gualosuchus reigi , Rhadinosuchus gracilis ) results in an unexpected increase of the morphological diversity of the group ( e.g. , antorbital fossa on the horizon - tal process of maxilla, well-exposed antorbital fossa on lacrimal, X-shaped osteoderms). We conclude that the taxonomy of the currently known rhadinosuchine specimens should be revisited, including a careful reappraisal of the intraspecific variation and the post-mortem deformation that affected the specimens in different ways . Key words. Archosauriformes. Proterochampsidae. Ischigualasto-Villa Unión Basin. Triassic. South America. Resumen. NUEVOS ESPECÍMENES DE PROTEROCHÁMPSIDOS EXPANDEN LA DIVERSIDAD MORFOLÓGICA DE LOS RHADINOSUQUINOS DE LA FORMACIÓN CHAÑARES (CARNIANO INFERIOR, NOROESTE DE ARGENTINA). Los proterochámpsidos son arcosauriformes no arcosauria - nos de tamaño mediano a pequeño, predadores y cuadrúpedos, parecidos a los cocodrilos. Los rhadinosuquinos son un clado profundamente anidado dentro de los proterochámpsidos y son los diápsidos más abundantes de la Zona de Asociación de Massetognathus -Chanaresuchus de la Formación Chañares (Carniano inferior) del noroeste de Argentina. Aquí describimos dos nuevos especímenes de proterochámspidos rhadi - nosuquinos recientemente colectados de la Zona de Asociación de Massetognathus-Chanaresuchus de la Formación Chañares. Estos especí - menes están representados por un esqueleto parcial articulado y huesos craneanos y poscraneanos desarticulados, respectivamente. Uno de ellos es menos completo, pero sus huesos desarticulados bien preservados incrementan considerablemente el conocimiento anatómico de ciertas regiones del esqueleto de los rhadinosuquinos. La combinación de estados de caracter presentes en ambos especímenes y com - partidos con otras especies conocidas de rhadinosuquinos ( e.g. , Chanaresuchus bonapartei , Gualosuchus reigi , Rhadinosuchus gracilis ) resulta en un incremento inesperado de la diversidad morfológica del grupo ( e.g. , fosa antorbital sobre el proceso horizontal del maxilar, fosa antorbital expuesta ampliamente sobre el lacrimal, oste odermos con forma de X). Concluimos que la taxonomía de los ejemplares de rhadinosuquinos actualmente conocidos debería ser revisada, in cluyendo una cuidadosa reevaluación de la variación intraespecífica y de la deformación post- mortem que afectó a los especímenes de diferentes maneras. Palabras clave. Archosauriformes. Proterochampsidae. Cuenca de Ischigualasto-Villa Unión. Triásico. América del Sur. PROTEROCHAMPSIDAE is a clade of small- to medium-sized fos sil record restricted to the lower Upper Triassic rocks of quadrupedal, predatory, crocodile-like diapsids, with a South America (Trotteyn et al. , 2013). There is a general con - AMGHB2-0002-7014/12$00.00+.50 79 AMEGHINIANA - 2019 - Volume 56 (2): 79–115 sensus that this group is one of the closest sister-taxa to les, Universidad Nacional de La Rioja, La Rioja, Argentina; crown group Archosauria ( e.g. , Benton and Clark, 1988; PVL, Paleontología de Vertebrados, Instituto Miguel Lillo, Sereno and Arcucci, 1990; Sereno, 1991; Parrish, 1993; Juul, San Salvador de Tucumán, Argentina; PVSJ, Paleontología 1994; Dilkes and Sues, 2009; Nesbitt, 2011; Ezcurra, 2016), de Vertebrados, Museo de Ciencias Naturales, Universidad but their phylogenetic proximity to the latter clade is still Nacional de San Juan, San Juan, Argentina; SAM-PK, Iziko under debate (Nesbitt, 2011; Ezcurra, 2016). A total of eight South African Museum, Cape Town, South Africa; SMNS, nominal species are currently known from the Ischigua - Staatliches Museum für Naturkunde, Stuttgart, Germany; lasto -Villa Unión Basin of north-western Argentina and the SNSB-BSPG, Staatliche Na tur wissenschaftliche Samm - Paraná Basin of southern Brazil (Huene, 1938; Price, 1946; lungen Bayerns-Bayerische Staatssammlung für Paläonto - Reig, 1959; Romer, 1971; Barberena, 1982; Arcucci, 1990; logie und Geologie, Munich, Germany; UFRGS, Universidade Trotteyn et al. , 2012). The proterochampsids are the most Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. abundant diapsids of the Massetognathus -Chanaresuchus Assemblage Zone ( AZ ) ( sensu Ezcurra et al. , 2017) of the SYSTEMATIC PALEONTOLOGY Chañares Formation (Ischigualasto-Villa Unión Basin; north - western Argentina), and the species Chanaresuchus bona - DIAPSIDA Osborn, 1903 sensu Laurin (1991) partei is the most abundant (Mancuso et al. , 2014). Although ARCHOSAUROMORPHA Huene, 1946 sensu Dilkes (1998) more than ten specimens from Argentina and Brazil have ARCHOSAURIFORMES Gauthier, Kluge, and Rowe, 1988 sensu been referred to Chanaresuchus bonapartei in the last 50 Gauthier, Kluge, and Rowe (1988) years, some of
Load more

Recommended publications
  • Ischigualasto Formation. the Second Is a Sile- Diversity Or Abundance, but This Result Was Based on Only 19 of Saurid, Ignotosaurus Fragilis (Fig
    This article was downloaded by: [University of Chicago Library] On: 10 October 2013, At: 10:52 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Journal of Vertebrate Paleontology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ujvp20 Vertebrate succession in the Ischigualasto Formation Ricardo N. Martínez a , Cecilia Apaldetti a b , Oscar A. Alcober a , Carina E. Colombi a b , Paul C. Sereno c , Eliana Fernandez a b , Paula Santi Malnis a b , Gustavo A. Correa a b & Diego Abelin a a Instituto y Museo de Ciencias Naturales, Universidad Nacional de San Juan , España 400 (norte), San Juan , Argentina , CP5400 b Consejo Nacional de Investigaciones Científicas y Técnicas , Buenos Aires , Argentina c Department of Organismal Biology and Anatomy, and Committee on Evolutionary Biology , University of Chicago , 1027 East 57th Street, Chicago , Illinois , 60637 , U.S.A. Published online: 08 Oct 2013. To cite this article: Ricardo N. Martínez , Cecilia Apaldetti , Oscar A. Alcober , Carina E. Colombi , Paul C. Sereno , Eliana Fernandez , Paula Santi Malnis , Gustavo A. Correa & Diego Abelin (2012) Vertebrate succession in the Ischigualasto Formation, Journal of Vertebrate Paleontology, 32:sup1, 10-30, DOI: 10.1080/02724634.2013.818546 To link to this article: http://dx.doi.org/10.1080/02724634.2013.818546 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content.
    [Show full text]
  • Crocodylomorpha, Neosuchia), and a Discussion on the Genus Theriosuchus
    bs_bs_banner Zoological Journal of the Linnean Society, 2015. With 5 figures The first definitive Middle Jurassic atoposaurid (Crocodylomorpha, Neosuchia), and a discussion on the genus Theriosuchus MARK T. YOUNG1,2, JONATHAN P. TENNANT3*, STEPHEN L. BRUSATTE1,4, THOMAS J. CHALLANDS1, NICHOLAS C. FRASER1,4, NEIL D. L. CLARK5 and DUGALD A. ROSS6 1School of GeoSciences, Grant Institute, The King’s Buildings, University of Edinburgh, James Hutton Road, Edinburgh EH9 3FE, UK 2School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, UK 3Department of Earth Science and Engineering, Imperial College London, London SW6 2AZ, UK 4National Museums Scotland, Chambers Street, Edinburgh EH1 1JF, UK 5The Hunterian, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK 6Staffin Museum, 6 Ellishadder, Staffin, Isle of Skye IV51 9JE, UK Received 1 December 2014; revised 23 June 2015; accepted for publication 24 June 2015 Atoposaurids were a clade of semiaquatic crocodyliforms known from the Late Jurassic to the latest Cretaceous. Tentative remains from Europe, Morocco, and Madagascar may extend their range into the Middle Jurassic. Here we report the first unambiguous Middle Jurassic (late Bajocian–Bathonian) atoposaurid: an anterior dentary from the Isle of Skye, Scotland, UK. A comprehensive review of atoposaurid specimens demonstrates that this dentary can be referred to Theriosuchus based on several derived characters, and differs from the five previously recog- nized species within this genus. Despite several diagnostic features, we conservatively refer it to Theriosuchus sp., pending the discovery of more complete material. As the oldest known definitively diagnostic atoposaurid, this discovery indicates that the oldest members of this group were small-bodied, had heterodont dentition, and were most likely widespread components of European faunas.
    [Show full text]
  • 8. Archosaur Phylogeny and the Relationships of the Crocodylia
    8. Archosaur phylogeny and the relationships of the Crocodylia MICHAEL J. BENTON Department of Geology, The Queen's University of Belfast, Belfast, UK JAMES M. CLARK* Department of Anatomy, University of Chicago, Chicago, Illinois, USA Abstract The Archosauria include the living crocodilians and birds, as well as the fossil dinosaurs, pterosaurs, and basal 'thecodontians'. Cladograms of the basal archosaurs and of the crocodylomorphs are given in this paper. There are three primitive archosaur groups, the Proterosuchidae, the Erythrosuchidae, and the Proterochampsidae, which fall outside the crown-group (crocodilian line plus bird line), and these have been defined as plesions to a restricted Archosauria by Gauthier. The Early Triassic Euparkeria may also fall outside this crown-group, or it may lie on the bird line. The crown-group of archosaurs divides into the Ornithosuchia (the 'bird line': Orn- ithosuchidae, Lagosuchidae, Pterosauria, Dinosauria) and the Croco- dylotarsi nov. (the 'crocodilian line': Phytosauridae, Crocodylo- morpha, Stagonolepididae, Rauisuchidae, and Poposauridae). The latter three families may form a clade (Pseudosuchia s.str.), or the Poposauridae may pair off with Crocodylomorpha. The Crocodylomorpha includes all crocodilians, as well as crocodi- lian-like Triassic and Jurassic terrestrial forms. The Crocodyliformes include the traditional 'Protosuchia', 'Mesosuchia', and Eusuchia, and they are defined by a large number of synapomorphies, particularly of the braincase and occipital regions. The 'protosuchians' (mainly Early *Present address: Department of Zoology, Storer Hall, University of California, Davis, Cali- fornia, USA. The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds (ed. M.J. Benton), Systematics Association Special Volume 35A . pp. 295-338. Clarendon Press, Oxford, 1988.
    [Show full text]
  • From the Terrestrial Upper Triassic of China
    第 39 卷 第 4 期 古 脊 椎 动 物 学 报 pp. 251～265 2001 年 10 月 V ERTEBRATA PALASIATICA figs. 1～4 ,pl. I 中国陆相上三叠统第一个初龙形类动物1) 吴肖春1 刘 俊2 李锦玲2 (1 加拿大自然博物馆 渥太华 K1P 6P4) (2 中国科学院古脊椎动物与古人类研究所 北京 100044) 摘要 初步研究了山西省永和县桑壁镇铜川组二段产出的两件初龙形类化石标本 ( IVPP V 12378 ,V 12379) ,在此基础上建立了一新属新种 ———桑壁永和鳄 ( Yonghesuchus sangbiensis gen. et sp. nov. ) 。 它以下列共存的衍生特征区别于其他初龙形类 (archosauriforms) :1) 吻部前端尖削 ;2) 眶前窝前部具一凹陷 ;3) 眶前窝与外鼻孔间宽 ;4) 眶后骨下降突的后 2/ 3 宽且深凹 ;5) 基蝶 骨腹面有两个凹陷 ;6) 齿骨后背突相当长 ;7) 关节骨的反关节区有明显的背脊 ,有穿孔的翼 状的内侧突 ,以及指向前内侧向和背向的十分显著的后内侧突。 由于缺乏跗骨的形态信息 ,目前很难通过支序分析建立永和鳄的系统发育关系。但可以 通过头骨形态来推测永和鳄在初龙形类中的系统位置。永和鳄有翼骨齿 ,这表明它不属于狭 义的初龙类 (archosaurians) 。其通过内颈动脉脑支的孔位于基蝶骨的前侧面而不是腹面 ,在 这点上永和鳄比原鳄龙科 ( Proterochampsidae) 更进步 ,这表明与后者相比永和鳄和狭义的初 龙类的关系可能更近。在中国早期的初龙形类中 ,达坂吐鲁番鳄 ( Turf anosuchus dabanensis) 与桑壁永和鳄最接近 ,但前者由于内颈动脉脑支的孔腹位而比后者更为原始。 根据以上头骨特征以及枢后椎椎体之间间椎体的存在与否 ,推测派克鳄 ( Euparkeria) 、 达坂吐鲁番鳄 (如果存在间椎体) 、原鳄龙科和永和鳄与初龙类的关系逐渐接近 。而且这与这 些初龙形类的生存时代基本一致。 永和鳄比产于上三叠统下部的原鳄龙 ( Proterocham psa) 进步 ,它的发现支持含化石的铜 川组时代为晚三叠世的观点。 关键词 山西永和 ,晚三叠世 ,铜川组 ,初龙形类 ,解剖学 中图法分类号 Q915. 864 1) 中国科学院古生物学与古人类学科基础研究特别支持基金项目(编号 :9809) 资助。 收稿日期 :2001- 03- 23 252 古 脊 椎 动 物 学 报 39 卷 THE ANATOMY OF THE FIRST ARCHOSAURIFORM ( DIAPSIDA) FROM THE TERRESTRIAL UPPER TRIASSIC OF CHINA WU Xiao2Chun1 L IU J un2 L I Jin2Ling2 (1 Paleobiology , Research Division , Canadian M useum of Nat ure P.O.Box 3443 Station D, Ottawa, ON K1P 6P4 , Canada) (2 Instit ute of Vertebrate Paleontology and Paleoanthropology , Chinese Academy of Sciences Beijing 100044) Abstract Yonghesuchus sangbiensis , a new genus and species of the Archosauriformes , is erected on the basis of its peculiar cranial features. This taxon represents the first record of tetrapods from the Late Triassic terrestrial deposits of China. Its discovery is significant not only to our study on the phylogeny of the Archosauriformes but also to our understanding of the evolution of the Triassic terrestrial vertebrate faunae in China.
    [Show full text]
  • Osteology of Pseudochampsa Ischigualastensis Gen. Et Comb. Nov
    RESEARCH ARTICLE Osteology of Pseudochampsa ischigualastensis gen. et comb. nov. (Archosauriformes: Proterochampsidae) from the Early Late Triassic Ischigualasto Formation of Northwestern Argentina M. Jimena Trotteyn1,2*, Martı´n D. Ezcurra3 1. CONICET, Consejo Nacional de Investigaciones Cientı´ficas y Te´cnicas, Ciudad Auto´noma de Buenos Aires, Buenos Aires, Argentina, 2. INGEO, Instituto de Geologı´a, Facultad de Ciencias Exactas, Fı´sicas y Naturales, Universidad Nacional de San Juan, San Juan, San Juan, Argentina, 3. School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, West Midlands, United Kingdom *[email protected] Abstract OPEN ACCESS Proterochampsids are crocodile-like, probably semi-aquatic, quadrupedal Citation: Trotteyn MJ, Ezcurra MD (2014) Osteology archosauriforms characterized by an elongated and dorsoventrally low skull. The of Pseudochampsa ischigualastensis gen. et comb. nov. (Archosauriformes: Proterochampsidae) from the group is endemic from the Middle-Late Triassic of South America. The most Early Late Triassic Ischigualasto Formation of recently erected proterochampsid species is ‘‘Chanaresuchus ischigualastensis’’, Northwestern Argentina. PLoS ONE 9(11): e111388. doi:10.1371/journal.pone.0111388 based on a single, fairly complete skeleton from the early Late Triassic Editor: Peter Dodson, University of Pennsylvania, Ischigualasto Formation of northwestern Argentina. We describe here in detail the United States of America non-braincase cranial and postcranial anatomy
    [Show full text]
  • Comparative Bone Microstructure of Three Archosauromorphs from the Carnian, Late Triassic Chañares Formation of Argentina
    Comparative bone microstructure of three archosauromorphs from the Carnian, Late Triassic Chañares Formation of Argentina JORDI ALEXIS GARCIA MARSÀ, FEDERICO L. AGNOLÍN, and FERNANDO E. NOVAS Marsà, J.A.G., Agnolín, F.L., and Novas, F.E. 2020. Comparative bone microstructure of three archosauromorphs from the Carnian, Late Triassic Chañares Formation of Argentina. Acta Palaeontologica Polonica 65 (2): 387–398. The Chañares Formation exhibits one of the most important archosauriform records of early Carnian ecosystems. Here we present new data on the palaeohistology of Chañares archosauriforms and provide new insights into their paleobiology, as well as possible phylogenetically informative traits. Bone microstructure of Lagerpeton chanarensis and Tropidosuchus romeri is dominated by fibro-lamellar tissue and dense vascularization. On the other hand, Chanaresuchus bonapartei is more densely vascularized, but with cyclical growth characterized by alternate fibro-lamellar, parallel-fibered and lamellar-zonal tissues. Dense vascularization and fibro-lamellar tissue imply fast growth and high metabolic rates for all these taxa. These histological traits may be tentatively interpreted as a possible adaptative advantage in front of Chañares Formation environmental conditions. Key words: Archosauromorpha, Lagerpeton, Tropidosuchus, paleobiology, paleohistology, Mesozoic, South America. Jordi Alexis Garcia Marsà [[email protected]] and Fernando E. Novas [[email protected]], Labora- torio de Anatomía Comparada y Evolución de los Vertebrados,
    [Show full text]
  • The Osteoderm Microstructure in Doswelliids and Proterochampsids and Its Implications for Palaeobiology of Stem Archosaurs
    The osteoderm microstructure in doswelliids and proterochampsids and its implications for palaeobiology of stem archosaurs DENIS A. PONCE, IGNACIO A. CERDA, JULIA B. DESOJO, and STERLING J. NESBITT Ponce, D.A., Cerda, I.A., Desojo, J.B., and Nesbitt, S.J. 2017. The osteoderm microstructure in doswelliids and proter- ochampsids and its implications for palaeobiology of stem archosaurs. Acta Palaeontologica Polonica 62 (4): 819–831. Osteoderms are common in most archosauriform lineages, including basal forms, such as doswelliids and proterochamp- sids. In this survey, osteoderms of the doswelliids Doswellia kaltenbachi and Vancleavea campi, and proterochampsid Chanaresuchus bonapartei are examined to infer their palaeobiology, such as histogenesis, age estimation at death, development of external sculpturing, and palaeoecology. Doswelliid osteoderms have a trilaminar structure: two corti- ces of compact bone (external and basal) that enclose an internal core of cancellous bone. In contrast, Chanaresuchus bonapartei osteoderms are composed of entirely compact bone. The external ornamentation of Doswellia kaltenbachi is primarily formed and maintained by preferential bone growth. Conversely, a complex pattern of resorption and redepo- sition process is inferred in Archeopelta arborensis and Tarjadia ruthae. Vancleavea campi exhibits the highest degree of variation among doswelliids in its histogenesis (metaplasia), density and arrangement of vascularization and lack of sculpturing. The relatively high degree of compactness in the osteoderms of all the examined taxa is congruent with an aquatic or semi-aquatic lifestyle. In general, the osteoderm histology of doswelliids more closely resembles that of phytosaurs and pseudosuchians than that of proterochampsids. Key words: Archosauria, Doswelliidae, Protero champ sidae, palaeoecology, microanatomy, histology, Triassic, USA.
    [Show full text]
  • Ministerio De Cultura Y Educacion Fundacion Miguel Lillo
    MINISTERIO DE CULTURA Y EDUCACION FUNDACION MIGUEL LILLO NEW MATERIALS OF LAGOSUCHUS TALAMPAYENSIS ROMER (THECODONTIA - PSEUDOSUCHIA) AND ITS SIGNIFICANCE ON THE ORIGIN J. F. BONAPARTE OF THE SAURISCHIA. LOWER CHANARIAN, MIDDLE TRIASSIC OF ARGENTINA ACTA GEOLOGICA LILLOANA 13, 1: 5-90, 10 figs., 4 pl. TUCUMÁN REPUBLICA ARGENTINA 1975 NEW MATERIALS OF LAGOSUCHUS TALAMPAYENSIS ROMER (THECODONTIA - PSEUDOSUCHIA) AND ITS SIGNIFICANCE ON THE ORIGIN OF THE SAURISCHIA LOWER CHANARIAN, MIDDLE TRIASSIC OF ARGENTINA* by JOSÉ F. BONAPARTE Fundación Miguel Lillo - Career Investigator Member of CONICET ABSTRACT On the basis of new remains of Lagosuchus that are thoroughly described, including most of the skeleton except the manus, it is assumed that Lagosuchus is a form intermediate between Pseudosuchia and Saurischia. The presacral vertebrae show three morphological zones that may be related to bipedality: 1) the anterior cervicals; 2) short cervico-dorsals; and 3) the posterior dorsals. The pelvis as a whole is advanced, in particular the pubis and acetabular area of the ischium, but the ilium is rather primitive. The hind limb has a longer tibia than femur, and the symmetrical foot is as long as the tibia. The tarsus is of the mesotarsal type. The morphology of the distal area of the tibia and fibula, and the proximal area of the tarsus, suggest a stage transitional between the crurotarsal and mesotarsal conditions. The forelimb is proportionally short, 48% of the hind limb. The humerus is slender, with advanced features in the position of the deltoid crest. The radius and ulna are also slender, the latter with a pronounced olecranon process. A new family of Pseudosuchia is proposed for this form: Lagosuchidae.
    [Show full text]
  • New Transitional Fossil from Late Jurassic of Chile Sheds Light on the Origin of Modern Crocodiles Fernando E
    www.nature.com/scientificreports OPEN New transitional fossil from late Jurassic of Chile sheds light on the origin of modern crocodiles Fernando E. Novas1,2, Federico L. Agnolin1,2,3*, Gabriel L. Lio1, Sebastián Rozadilla1,2, Manuel Suárez4, Rita de la Cruz5, Ismar de Souza Carvalho6,8, David Rubilar‑Rogers7 & Marcelo P. Isasi1,2 We describe the basal mesoeucrocodylian Burkesuchus mallingrandensis nov. gen. et sp., from the Upper Jurassic (Tithonian) Toqui Formation of southern Chile. The new taxon constitutes one of the few records of non‑pelagic Jurassic crocodyliforms for the entire South American continent. Burkesuchus was found on the same levels that yielded titanosauriform and diplodocoid sauropods and the herbivore theropod Chilesaurus diegosuarezi, thus expanding the taxonomic composition of currently poorly known Jurassic reptilian faunas from Patagonia. Burkesuchus was a small‑sized crocodyliform (estimated length 70 cm), with a cranium that is dorsoventrally depressed and transversely wide posteriorly and distinguished by a posteroventrally fexed wing‑like squamosal. A well‑defned longitudinal groove runs along the lateral edge of the postorbital and squamosal, indicative of a anteroposteriorly extensive upper earlid. Phylogenetic analysis supports Burkesuchus as a basal member of Mesoeucrocodylia. This new discovery expands the meagre record of non‑pelagic representatives of this clade for the Jurassic Period, and together with Batrachomimus, from Upper Jurassic beds of Brazil, supports the idea that South America represented a cradle for the evolution of derived crocodyliforms during the Late Jurassic. In contrast to the Cretaceous Period and Cenozoic Era, crocodyliforms from the Jurassic Period are predomi- nantly known from marine forms (e.g., thalattosuchians)1.
    [Show full text]
  • CROCODYLIFORMES, MESOEUCROCODYLIA) from the EARLY CRETACEOUS of NORTH-EAST BRAZIL by DANIEL C
    [Palaeontology, Vol. 52, Part 5, 2009, pp. 991–1007] A NEW NEOSUCHIAN CROCODYLOMORPH (CROCODYLIFORMES, MESOEUCROCODYLIA) FROM THE EARLY CRETACEOUS OF NORTH-EAST BRAZIL by DANIEL C. FORTIER and CESAR L. SCHULTZ Departamento de Paleontologia e Estratigrafia, UFRGS, Avenida Bento Gonc¸alves 9500, 91501-970 Porto Alegre, C.P. 15001 RS, Brazil; e-mails: [email protected]; [email protected] Typescript received 27 March 2008; accepted in revised form 3 November 2008 Abstract: A new neosuchian crocodylomorph, Susisuchus we recovered the family name Susisuchidae, but with a new jaguaribensis sp. nov., is described based on fragmentary but definition, being node-based group including the last com- diagnostic material. It was found in fluvial-braided sedi- mon ancestor of Susisuchus anatoceps and Susisuchus jagua- ments of the Lima Campos Basin, north-eastern Brazil, ribensis and all of its descendents. This new species 115 km from where Susisuchus anatoceps was found, in corroborates the idea that the origin of eusuchians was a rocks of the Crato Formation, Araripe Basin. S. jaguaribensis complex evolutionary event and that the fossil record is still and S. anatoceps share a squamosal–parietal contact in the very incomplete. posterior wall of the supratemporal fenestra. A phylogenetic analysis places the genus Susisuchus as the sister group to Key words: Crocodyliformes, Mesoeucrocodylia, Neosuchia, Eusuchia, confirming earlier studies. Because of its position, Susisuchus, new species, Early Cretaceous, north-east Brazil. B razilian crocodylomorphs form a very expressive Turonian–Maastrichtian of Bauru basin: Adamantinasu- record of Mesozoic vertebrates, with more than twenty chus navae (Nobre and Carvalho, 2006), Baurusuchus species described up to now.
    [Show full text]
  • A New Longirostrine Dyrosaurid
    [Palaeontology, Vol. 54, Part 5, 2011, pp. 1095–1116] A NEW LONGIROSTRINE DYROSAURID (CROCODYLOMORPHA, MESOEUCROCODYLIA) FROM THE PALEOCENE OF NORTH-EASTERN COLOMBIA: BIOGEOGRAPHIC AND BEHAVIOURAL IMPLICATIONS FOR NEW-WORLD DYROSAURIDAE by ALEXANDER K. HASTINGS1, JONATHAN I. BLOCH1 and CARLOS A. JARAMILLO2 1Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA; e-mails: akh@ufl.edu, jbloch@flmnh.ufl.edu 2Smithsonian Tropical Research Institute, Box 0843-03092 and #8232, Balboa-Ancon, Panama; e-mail: [email protected] Typescript received 19 March 2010; accepted in revised form 21 December 2010 Abstract: Fossils of dyrosaurid crocodyliforms are limited rosaurids. Results from a cladistic analysis of Dyrosauridae, in South America, with only three previously diagnosed taxa using 82 primarily cranial and mandibular characters, sup- including the short-snouted Cerrejonisuchus improcerus from port an unresolved relationship between A. guajiraensis and a the Paleocene Cerrejo´n Formation of north-eastern Colom- combination of New- and Old-World dyrosaurids including bia. Here we describe a second dyrosaurid from the Cerrejo´n Hyposaurus rogersii, Congosaurus bequaerti, Atlantosuchus Formation, Acherontisuchus guajiraensis gen. et sp. nov., coupatezi, Guarinisuchus munizi, Rhabdognathus keiniensis based on three partial mandibles, maxillary fragments, teeth, and Rhabdognathus aslerensis. Our results are consistent with and referred postcrania. The mandible has a reduced seventh an African origin for Dyrosauridae with multiple dispersals alveolus and laterally depressed retroarticular process, both into the New World during the Late Cretaceous and a transi- diagnostic characteristics of Dyrosauridae. Acherontisuchus tion from marine habitats in ancestral taxa to more fluvial guajiraensis is distinct among known dyrosaurids in having a habitats in more derived taxa.
    [Show full text]
  • Extant Taxa Stem Frogs Stem Turtles Stem Lepidosaurs Stem Squamates
    Stem Taxa - Peters 2016 851 taxa, 228 characters 100 Eldeceeon 1990.7.1 91 Eldeceeon holotype 100 Romeriscus Ichthyostega Gephyrostegus watsoni Pederpes 85 Eryops 67 Solenodonsaurus 87 Proterogyrinus 100 Chroniosaurus Eoherpeton 94 72 Chroniosaurus PIN3585/124 98 Seymouria Chroniosuchus Kotlassia Stem 58 94 Westlothiana Utegenia Casineria 84 81 Amphibamus Brouffia 95 72 Cacops 93 77 Coelostegus Paleothyris 98 Doleserpeton 84 91 78 100 Gerobatrachus Hylonomus Rana Archosauromorphs Protorothyris MCZ1532 95 66 98 Adelospondylus 85 Protorothyris CM 8617 89 Brachydectes Protorothyris MCZ 2149 Eocaecilia 87 86 Microbrachis Vaughnictis Pantylus 80 89 75 94 Anthracodromeus Elliotsmithia 90 Utaherpeton 51 Apsisaurus Kirktonecta 95 90 86 Aerosaurus 96 Tuditanus 67 90 Varanops Stem Frogs 59 94 Eoserpeton Varanodon Diplocaulus Varanosaurus FMNH PR 1760 100 Sauropleura 62 84 Varanosaurus BSPHM 1901 XV20 88 Ptyonius 89 Archaeothyris 70 Scincosaurus Euryodus primus Ophiacodon 74 82 84 Micraroter Haptodus 91 Rhynchonkos 97 82 Secodontosaurus Batropetes 85 76 100 Dimetrodon 97 Sphenacodon Silvanerpeton Ianthodon 85 Edaphosaurus Gephyrostegeus bohemicus 99 Stem100 Reptiles 80 82 Ianthasaurus Glaucosaurus 94 Cutleria 100 Urumqia Bruktererpeton Stenocybus Stem Mammals 63 97 Thuringothyris MNG 7729 62 IVPP V18117 82 Thuringothyris MNG 10183 87 62 71 Kenyasaurus 82 Galechirus 52 Suminia Saurorictus Venjukovia 99 99 97 83 70 Cephalerpeton Opisthodontosaurus 94 Eodicynodon 80 98 Reiszorhinus 100 Dicynodon 75 Concordia KUVP 8702a Hipposaurus 100 98 96 Concordia
    [Show full text]