DOCSLIB.ORG

Molecules, Morphology, and the Monophyly of Diapsid Reptiles

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Molecules, Morphology, and the Monophyly of Diapsid Reptiles Contributions to Zoology, 70 (I) 1-22 (2001) SPB Academic Publishing bv, The Hague Molecules, morphology, and the monophyly of diapsid reptiles Michael+S.Y. Lee Department of Zoology, University of Queensland Brisbane, QLD 4072, Australia, e-mail: [email protected] Keywords: Reptilia, testudines, cladistics, osteology, fossils, molecular phylogenetics Abstract Contents The morphological and molecular evidence forhigher-level reptile Introduction 1 relationships is reassessed, A combined analysis of 176 osteo- Morphological and molecular data sets 4 logical, 40 soft anatomical, and 2903 (1783 aligned) molecular Data analyses 6 characters in 28 amniote taxa yields the traditional reptile tree. Phylogenetic results 7 Synapsids the sister taxon to all other 7 (including mammals) are Separate analyses ' amniotes, all Turtles with 8 including extant reptiles. group anapsid Homogeneity tests parareptiles and fall outside a monophyletic Diapsida. Within Combined analyses 9 diapsids, squamates and Sphenodon form a monophyletic Molecules, morphology and the importance of fossils 11 Lepidosauria, and crocodiles plus birds form a monophyletic Acknowledgements 16 Archosauria. This tree is identical to the tree strongly supported References 16 by the data included. 18 osteological alone when fossils are In a Appendix combined analysis the strong osteological signal linking turtles with is anapsids sufficient to override a soft anatomical signal placing turtles next to a heterodox archosaur-mammal clade, Introduction and a weaker molecular signal linking turtles with archosaurs. However, the turtle-archosaur clade cannot be statistically rejected. When fossils of the are ignored, the signal in the osteological Despite over a century research, relationships data set disappears and, in a combined analysis of morphology of amniotes between the major groups living (mam- and molecules, the molecular (turtle-archosaur) signal prevails. mals, turtles, squamates, Sphenodon and archosaurs) These results highlight the importance of fossils, not just in remain contentious. There is now a consensus that osteological studies, but even in “combined” analyses where all form i.e. that turtles they cannot be living reptiles a clade, are scored for the majority ofcharacters (soft anatomy and molecules). Although the total number of molecular traits more closely related to other living reptiles than is much (2903) than the total number of greater morphological to mammals. This arrangement has now been sup- taits (216), when only characters informative at the relevant ported compelling evidence from both morphol- levels by are considered, the two data sets are approximatelyequal (Gauthier et ah, 1988;Laurin and Reisz, 1995; size. The ogy in partition homogeneity test yields unreliable results de and unless uninformative Lee, 1997; Braga Rieppel, 1997) and mol- (invariant and autapomorphic) characters are excluded. ecules Eernisse and Analyses ofthe mitochondrial data suggest that (Marshall, 1992; Kluge, 1993; recent evidence from nuclear for heterodox turtle- genes a Van de Peeret ah, 1993; Caspers et ah, 1996; Zar- crocodile clade be artefact of inade- (excluding birds) might an doya and Meyer, 1998). However, relationships quate of sampling a diverse outgroup (mammals) and thus, within the clade remain controversial, due problems with reptile rooting the reptile tree. mainly to disagreement over the affinities of turtles with the remaining reptiles, which are all conven- termed the basis of their tionally “diapsids” on pos- session oftwo temporal fenestrae(Williston, 1917; Romer, 1966; Carroll, 1988; Benton, 1996). There Downloaded from Brill.com10/08/2021 07:17:21AM via free access 2 M.S. Y. Lee - Phylogenetics of diapsid reptiles archosaurs are two major clades of living diapsids, (crocodiles and birds) and lepidosaurs (Sphenodon and and squamates). The monophyly of archosaurs, of lepidosaurs, is extremely strongly corroborated (e.g. Gauthier, 1984; Benton, 1984,, 1985; Evans, 1984, 1988; Gauthier et ah, 1988; Kemp, 1988; but Rieppel and de Braga, 1996; Dilkes, 1998; see Hedges and Poling, 1999 and comments below). If these two diapsid clades are provisionally ac- in which turtles cepted, there are three ways might outside be related to diapsids: they might fall a monophyletic Diapsida, or might render diapsids (as currently construed) paraphyletic by being the Fig. I. The three proposed positions for turtles with respect to sister to either or archosaurs. group lepidosaurs living diapsids. 1 is the “anapsid”hypothesis, 2 is the “lepidosaur” These three possibilities are here called the “anap- hypothesis, and 3 is the “archosaur” hypothesis. sid”, “lepidosaur” and “archosaur” hypotheses re- of diapsid mono- spectively (Fig. I). Each has some recent charac- The widespread assumption and or was challenged by Rieppel ter support from either morphology molecules. phyly recently and 1997), who The anapsid hypothesis is the traditional arrange- deBraga (1996; deBraga Rieppel, the of detailed of ment. It implies that turtles retain primitively on basis a analysis osteological the second - that turtles unfenestrated (anapsid) skulls, and that the presence traits suggested arrangement nested within as the sister to of two temporal openings is one of the diagnostic are diapsids group and con- derived characters uniting archosaurs and lepido- extant lepidosaurs. DeBraga Rieppel’s clusions were based on the first saurs as a monophyletic Diapsida (e.g. Williston, comprehensive of basal amniotes (including 1917; Gaffney, 1980; Reisz, 1981; Gauthier, 1984; phylogenetic analysis assumed to be Benton, 1985, 1996; Gaffney and Meylan, 1988; turtles) where diapsids were not The results when Carroll, 1988). Under the most recent interpreta- monophyletic. were unexpected: into all its lin- tions of this hypothesis, the nearest relatives to the Diapsida was split component these lineages did not form a clade. Rather, turtles are primitive anapsid reptiles, in particular, eages, the cluster of procolophonoids (Laurin and Reisz, 1995) or turtles nested within diapsid lineages, marine as the sister to sauropterygians, a pareiasaurs (Gregory, 1946; Ivachnenko, 1987; group of and Lee, 1997). The hypothesis of diapsid monophyly radiation consisting placodonts, plesiosaurs, relatives. were the nearest has been supported largely by morphological, and their Lepidosaurs extant the clade. This in particular skeletal, traits. However, even the relatives of sauropterygian-turtle also that turtles have skeletal traits are relatively few, and some are implies secondarily correlated with temporal fenestration (e.g. Reisz, closed their temporal fenestra. However, a reanalysis 1981; Gauthier, 1984; Benton, 1985; Evans, 1988; of deBraga and RieppeTs data showed that, even ifall their character Laurin and Reisz, 1995). Furthermore, soft ana- codings were accepted as cor- tomical for their over traits support a radically different arrange- rect, support preferred phylogeny not ment of amniotes (Gauthier et ah, 1988; Gardiner, the traditional phylogeny was significant the Further where 1982, 1993; see below). Thus, morphological (Wilkinson et ah, 1997). reanalysis, evidence for diapsid monophyly is not strong. Nev- some miscoded characters in the data set were with turtles ertheless, (his arrangement was widely accepted, rescored, yielded the traditional tree, and outside and analyses of basal amniote relationships con- grouping with anapsid reptiles falling However, as tinued to assume diapsids were monophyletic, and a monophyletic Diapsida. relatively thus were to cause this represented them using only one or two pre- few characters changed topo- tree not sumably basal forms (e.g. Laurin and Reisz, 1995; logical shift, the revised (traditional) was Lee, 1995). strongly supported over the heterodox topology Downloaded from Brill.com10/08/2021 07:17:21AM via free access Contributions to Zoology, 70 (1) - 2001 3 (Lee, 1997). Thus, although deBraga and Rieppel’s sizeable portions of the mitochondrialand nuclear analysis did not demonstrate that turtles were molecular data support the archosaur hypothesis, modified diapsids, it certainly highlighted that the the results are not yet conclusive. traditional anapsid hypothesis is far weaker than Given the disagreement over reptile relationships generally assumed, and that the lepidosaur hypo- and the observation that both the morphological thesis deserves serious consideration.A more recent and molecular evidence is ambiguous, it was de- combined study (Rieppel and Reisz, 1999) has again argued cided to integrate these datainto a phylo- for a turtle-sauropterygian clade, and discussed a genetic analysis. This study thus revisits an impor- scenario for an aquatic origin of turtles. tant earlier study of amniote relationships (Eernisse It was suggested that molecular sequences would and Kluge, 1993) that included an earlier version provide independent data to resolve the issue (Wil- of the osteological data (Gauthier et ah, 1988) and kinson et the molecular data the short and ah, 1997). However, only relatively poorly sampled gene have then surprisingly supported neither of the two sequences that were available. That analysis included arrangements proposed on the basis ofmorphology. also only two “anapsid” groups (turtles molecular results seemed and thus could the Instead, early most consis- captorhinids), and not test mono- tent - with the third possibility that turtles are most phyly of diapsids with respect to other anapsids, closely related
Load more

Recommended publications
  • 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]
  • A New Archosauriform Reptile with Distinctive Teeth from the Middle Triassic (Ladinian) of Germany
    Journal of Vertebrate Paleontology ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/ujvp20 A new archosauriform reptile with distinctive teeth from the Middle Triassic (Ladinian) of Germany Hans-Dieter Sues , Rainer R. Schoch , Gabriela Sobral & Randall B. Irmis To cite this article: Hans-Dieter Sues , Rainer R. Schoch , Gabriela Sobral & Randall B. Irmis (2020) A new archosauriform reptile with distinctive teeth from the Middle Triassic (Ladinian) of Germany, Journal of Vertebrate Paleontology, 40:1, e1764968, DOI: 10.1080/02724634.2020.1764968 To link to this article: https://doi.org/10.1080/02724634.2020.1764968 View supplementary material Published online: 23 Jun 2020. Submit your article to this journal Article views: 200 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ujvp20 Journal of Vertebrate Paleontology e1764968 (14 pages) The work of Hans–Dieter Sues was authored as part of his official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 USC. 105, no copyright protection is available for such works under US Law. Rainer R. Schoch, Gabriela Sobral and Randall B. Irmis hereby waive their right to assert copyright, but not their right to be named as co–authors in the article. DOI: 10.1080/02724634.2020.1764968 ARTICLE A NEW ARCHOSAURIFORM REPTILE WITH DISTINCTIVE TEETH FROM THE MIDDLE TRIASSIC (LADINIAN) OF GERMANY HANS-DIETER SUES, *,1 RAINER R. SCHOCH, 2 GABRIELA SOBRAL, 2 and RANDALL B. IRMIS3 1Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, MRC 121, P.O.
    [Show full text]
  • Studies on Continental Late Triassic Tetrapod Biochronology. I. the Type Locality of Saturnalia Tupiniquim and the Faunal Succession in South Brazil
    Journal of South American Earth Sciences 19 (2005) 205–218 www.elsevier.com/locate/jsames Studies on continental Late Triassic tetrapod biochronology. I. The type locality of Saturnalia tupiniquim and the faunal succession in south Brazil Max Cardoso Langer* Departamento de Biologia, FFCLRP, Universidade de Sa˜o Paulo (USP), Av. Bandeirantes 3900, 14040-901 Ribeira˜o Preto, SP, Brazil Received 1 November 2003; accepted 1 January 2005 Abstract Late Triassic deposits of the Parana´ Basin, Rio Grande do Sul, Brazil, encompass a single third-order, tetrapod-bearing sedimentary sequence that includes parts of the Alemoa Member (Santa Maria Formation) and the Caturrita Formation. A rich, diverse succession of terrestrial tetrapod communities is recorded in these sediments, which can be divided into at least three faunal associations. The stem- sauropodomorph Saturnalia tupiniquim was collected in the locality known as ‘Waldsanga’ near the city of Santa Maria. In that area, the deposits of the Alemoa Member yield the ‘Alemoa local fauna,’ which typifies the first association; includes the rhynchosaur Hyperodapedon, aetosaurs, and basal dinosaurs; and is coeval with the lower fauna of the Ischigualasto Formation, Bermejo Basin, NW Argentina. The second association is recorded in deposits of both the Alemoa Member and the Caturrita Formation, characterized by the rhynchosaur ‘Scaphonyx’ sulcognathus and the cynodont Exaeretodon, and correlated with the upper fauna of the Ischigualasto Formation. Various isolated outcrops of the Caturrita Formation yield tetrapod fossils that correspond to post-Ischigualastian faunas but might not belong to a single faunal association. The record of the dicynodont Jachaleria suggests correlations with the lower part of the Los Colorados Formation, NW Argentina, whereas remains of derived tritheledontid cynodonts indicate younger ages.
    [Show full text]
  • Controle Cardiovascular Autonômico E Metabolismo Em Embriões De Lagartos (Reptilia; Lepidosauria)
    UNIVERSIDADE ESTADUAL PAULISTA “JÚLIO DE MESQUITA FILHO” unesp INSTITUTO DE BIOCIÊNCIAS – RIO CLARO PROGRAMA DE PÓS-GRADUAÇÃO EM CIÊNCIAS BIOLÓGICAS ÁREA DE ZOOLOGIA (DOUTORADO) Controle cardiovascular autonômico e metabolismo em embriões de lagartos (Reptilia; Lepidosauria) MARINA RINCON SARTORI Tese apresentada ao Instituto de Biociências do Câmpus de Rio Claro, Universidade Estadual Paulista, como parte dos requisitos para obtenção do título de Doutora em Ciências Biológicas (Área de Zoologia). Setembro - 2016 Controle cardiovascular autonômico e metabolismo em embriões de lagartos (Reptilia; Lepidosauria) MARINA RINCON SARTORI Tese apresentada ao Instituto de Biociências do Câmpus de Rio Claro, Universidade Estadual Paulista, como parte dos requisitos para obtenção do título de Doutora em Ciências Biológicas (Área de Zoologia). Orientador: Augusto Shinya Abe Setembro - 2016 598.1 Sartori, Marina Rincon S251c Controle cardiovascular autonômico e metabolismo em embriões de lagartos (Reptilia; Lepidosauria) / Marina Rincon Sartori. - Rio Claro, 2016 141 f. : il., figs., gráfs., tabs., fots. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro Orientador: Augusto Shinya Abe 1. Réptil. 2. Regulação cardiovascular. 3. Desenvolvimento embrionário. 4. Iguana. 5. Squamata. 6. Frequência cardíaca. I. Título. Ficha Catalográfica elaborada pela STATI - Biblioteca da UNESP Campus de Rio Claro/SP Agradecimentos Um doutorado se resume a anos de dedicação e aprendizado. Nesse período há um grande amadurecimento, pessoal e profissional. E não é possível chegar até o fim sem o apoio e suporte de diversas pessoas, tanto as diretamente quanto as indiretamente envolvidas. Muitas não serão citadas nesta breve seção de agradecimentos mas a todos os que compartilharam comigo muitos desses momentos gostaria de deixar o meu sentimento de gratidão.
    [Show full text]
  • The Conservation Biology of Tortoises
    The Conservation Biology of Tortoises Edited by Ian R. Swingland and Michael W. Klemens IUCN/SSC Tortoise and Freshwater Turtle Specialist Group and The Durrell Institute of Conservation and Ecology Occasional Papers of the IUCN Species Survival Commission (SSC) No. 5 IUCN—The World Conservation Union IUCN Species Survival Commission Role of the SSC 3. To cooperate with the World Conservation Monitoring Centre (WCMC) The Species Survival Commission (SSC) is IUCN's primary source of the in developing and evaluating a data base on the status of and trade in wild scientific and technical information required for the maintenance of biological flora and fauna, and to provide policy guidance to WCMC. diversity through the conservation of endangered and vulnerable species of 4. To provide advice, information, and expertise to the Secretariat of the fauna and flora, whilst recommending and promoting measures for their con- Convention on International Trade in Endangered Species of Wild Fauna servation, and for the management of other species of conservation concern. and Flora (CITES) and other international agreements affecting conser- Its objective is to mobilize action to prevent the extinction of species, sub- vation of species or biological diversity. species, and discrete populations of fauna and flora, thereby not only maintain- 5. To carry out specific tasks on behalf of the Union, including: ing biological diversity but improving the status of endangered and vulnerable species. • coordination of a programme of activities for the conservation of biological diversity within the framework of the IUCN Conserva- tion Programme. Objectives of the SSC • promotion of the maintenance of biological diversity by monitor- 1.
    [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]
  • 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]
  • 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]
  • The First Possible Choristoderan Trackway from the Lower
    www.nature.com/scientificreports OPEN The frst possible choristoderan trackway from the Lower Cretaceous Daegu Formation of South Korea and its implications on choristoderan locomotion Yuong‑Nam Lee1*, Dal‑Yong Kong2 & Seung‑Ho Jung2 Here we report a new quadrupedal trackway found in the Lower Cretaceous Daegu Formation (Albian) in the vicinity of Ulsan Metropolitan City, South Korea, in 2018. A total of nine manus‑pes imprints show a strong heteropodous quadrupedal trackway (length ratio is 1:3.36). Both manus and pes tracks are pentadactyl with claw marks. The manus prints rotate distinctly outward while the pes prints are nearly parallel to the direction of travel. The functional axis in manus and pes imprints suggests that the trackmaker moved along the medial side during the stroke progressions (entaxonic), indicating weight support on the inner side of the limbs. There is an indication of webbing between the pedal digits. These new tracks are assigned to Novapes ulsanensis, n. ichnogen., n. ichnosp., which are well‑matched not only with foot skeletons and body size of Monjurosuchus but also the fossil record of choristoderes in East Asia, thereby N. ulsanensis could be made by a monjurosuchid‑like choristoderan and represent the frst possible choristoderan trackway from Asia. N. ulsanensis also suggests that semi‑aquatic choristoderans were capable of walking semi‑erect when moving on the ground with a similar locomotion pattern to that of crocodilians on land. South Korea has become globally famous for various tetrapod footprints from Cretaceous strata1, among which some clades such as frogs2, birds3 and mammals4 have been proved for their existences only with ichnological evidence.
    [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]
  • Evolution of Limblessness
    Evolution of Limblessness Evolution of Limblessness Early on in life, many people learn that lizards have four limbs whereas snakes have none. This dichotomy not only is inaccurate but also hides an exciting story of repeated evolution that is only now beginning to be understood. In fact, snakes represent only one of many natural evolutionary experiments in lizard limblessness. A similar story is also played out, though to a much smaller extent, in amphibians. The repeated evolution of snakelike tetrapods is one of the most striking examples of parallel evolution in animals. This entry discusses the evolution of limblessness in both reptiles and amphibians, with an emphasis on the living reptiles. Reptiles Based on current evidence (Wiens, Brandley, and Reeder 2006), an elongate, limb-reduced, snakelike morphology has evolved at least twenty-five times in squamates (the group containing lizards and snakes), with snakes representing only one such origin. These origins are scattered across the evolutionary tree of squamates, but they seem especially frequent in certain families. In particular, the skinks (Scincidae) contain at least half of all known origins of snakelike squamates. But many more origins within the skink family will likely be revealed as the branches of their evolutionary tree are fully resolved, given that many genera contain a range of body forms (from fully limbed to limbless) and may include multiple origins of snakelike morphology as yet unknown. These multiple origins of snakelike morphology are superficially similar in having reduced limbs and an elongate body form, but many are surprisingly different in their ecology and morphology. This multitude of snakelike lineages can be divided into two ecomorphs (a are surprisingly different in their ecology and morphology.
    [Show full text]