Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-25T01:25:21.428Z Has data issue: false hasContentIssue false

The anatomy of the fossil varanid lizard Saniwa ensidens Leidy, 1870, based on a newly discovered complete skeleton

Published online by Cambridge University Press:  14 July 2015

Olivier Rieppel
Affiliation:
Department of Geology, the Field Museum, 1400 S Lake Shore Drive, Chicago, Illinois 60605-2496,
Lance Grande
Affiliation:
Department of Geology, the Field Museum, 1400 S Lake Shore Drive, Chicago, Illinois 60605-2496,

Abstract

The skeleton of a newly discovered, exceptionally preserved specimen of Saniwa ensidens is described in detail. the fossil consists of a complete articulated skeleton exposed in dorsal view. It adds important additional information to our knowledge of the anatomy of this fossil varanoid taxon, including a detailed description of the dermatocranium in dorsal view, complete vertebral counts, and a detailed account of the appendicular skeleton. Cartilage preservation allows the identification of treacheal rings, sternum, inscriptional ribs, epicoracoid and suprascapula. Patches of skin are preserved on dermal skull bones, and scattered scales surround the entire skeleton. Incomplete ossification of carpal and tarsal elements, as well as of epiphyses, indicate that the specimen is not fully mature.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ameghino, F. 1899. Sinopsis Geológico-paleontológica. Supplemento. Adiciones y Correcciónes. Obras Completas, 12:706.Google Scholar
Borsuk-Bialynicka, M. 1984. Anguimorphans and related lizards from the Late Cretaceous of the Gobi Desert, Mongolia. Palaeontologia Polonica, 46:5105.Google Scholar
Boulenger, A. G. 1891. On the osteology of Heloderma horridum and H. suspectum, with remarks on the systematic position of the Helodermatidae and on the vertebrae of the Lacertilia. Proceedings of the Zoological Society of London, 1891:109118.CrossRefGoogle Scholar
Boulenger, A.G. 1885. Catalogue of the Lizards in the British Museum, Volume 2, Trustees of the British Museum. London, xiii + 497 p.Google Scholar
Brattstrom, B. H. 1955. New snakes and lizards from the Eocene of California. Journal of Paleontology, 29:145149.Google Scholar
Bullet, P. 1941. Beiträge zur Kenntnis des Gebisses von Varanus salvator Laur. Vierteljahresschrift der Naturforschenden Gesellschaft Zürich, 87:139192.Google Scholar
Caldwell, M.W. 1996. Ontogeny and phylogeny of the mesopodial skeleton in mosasauroid reptiles. Zoological Journal of the Linnean Society, 116:407436.CrossRefGoogle Scholar
Caldwell, M. W. 2003. Holotype snout elements of Saniwa ensidens reassigned to cf. Restes sp. indet. (Xenosauridae). Journal of Paleontology, 77:393396.Google Scholar
Camp, C. L. 1923. Classification of the lizards. Bulletin of the American Museum of Natural History, 48:289481.Google Scholar
Cope, E. D. 1877. A contribution to the knowledge of the ichthyological fauna of the Green River shales. Bulletin of the United States Geological and Geographical Survey of the Territories, 3:807819.Google Scholar
Daudin, F. M. 1802. Histoire Naturelle, Générale et Particulière, des Reptiles, Volume 3, F. Dufart. Paris, 452 p.Google Scholar
Daudin, F. M. 1803. Histoire Naturelle, Générale et Particulière, des Reptiles, Volume 8, F. Dufart. Paris, 439 p.Google Scholar
Dollo, L. 1923. Saniwa orsmaelensis. Varanide nouveau du Landénien supérieur d'Orsmael (Brabant). Bulletin de la Société Belge de Géologie, Paléontologie, et Hydrologie, 33:7682.Google Scholar
Estes, R. 1983. Sauria Terrestria, Amphisbaenia. Encyclopedia of Paleoherpetology. Vol. 10A (Wellnhofer, P., ed.). Gustav Fischer, Stuttgart, 249 pp.Google Scholar
Estes, R., deQuieroz, K., and Gauthier, J. 1988. Phylogenetic relationships within Squamata, p. 119281. In Estes, R. and Pregill, G. (eds.), Phylogenetic Relationships of the Lizard Families. Stanford University Press, Stanford.Google Scholar
Fejérvary, G. J. de. 1918. Contributions to a monography on the fossil Varanidae and Megalanidae. Annales Historico-Naturales Musei Nationalis Hungarici, 16:341467.Google Scholar
Gao, K., and Norell, M. 1998. Taxonomic revision of Carusia (Reptilia: Squamata) from the Lare Cretaceous of the Gobi Desert and phylogenetic relationships of anguimorphan lizards. American Museum Novitates, 3230, 51p.Google Scholar
Gilmore, C. W. 1922. A new description of Saniwa ensidens Leidy, an extinct varanid lizard from Wyoming. Proceedings of the U.S. National Museum, 60:128.CrossRefGoogle Scholar
Gilmore, C. W. 1928. Fossil lizards of North America. Memoirs of the National Academy of Sciences, 22, 201 p.Google Scholar
Godinot, M., de Broin, F., Buffetaut, E., Rage, J.-C., and Russell, D. 1978. Dormaal: Une des plus anciennes faunes éocènes d'Europe. Comptes Rendus des Scéances de l'Académie des Sciences. Série D–Sciences Naturelles, 287:12731276.Google Scholar
Grande, L. 1984. Paleontology of the Green River Formation, with a review of the fish fauna. The Geological Survey of Wyoming Bulletin, 63, xviii + 333 p.Google Scholar
Grande, L. 1994. Studies of paleoenvironments and historical biogeography in the Fossil Butte and Laney members of the Green River Formation. Contributions to Geology, University of Wyoming, 300:1532.Google Scholar
Grande, L. 2001. An updated review of the fish faunas from the Green River Formation, the world's most productive freshwater Lagerstätten, p. 138. In Gunnell, G. F. (ed.), Eocene Biodiversity: Unusual Occurrences and Rarely Sampled Habitats. Kluwer Academic /Plenum Publishers, New York.Google Scholar
Grande, L., and Bemis, W. 1998. A comprehensive phylogenetic study of amiid fishes (Amiidae) based on comparative skeletal anatomy. An empirical search for interconnected patterns of natural history. Journal of Vertebrate Paleontology, 18, suppl. 1, x + 690 p.CrossRefGoogle Scholar
Grande, L., and Buchheim, P. 1994. Paleontological and sedimentological variation in Early Eocene Fossil Lake. Contributions to Geology, 30:3356.Google Scholar
Gray, J. E. 1831. A synopsis of the species of the class Reptilia, p. 1110. In Griffith, E. (ed.), The Animal Kingdom, Volume 9, Whittaker, Treacher and Co. London.Google Scholar
Gray, J. E. 1838. Catalogue of the slender-tongued saurians, with descriptions of many new genera and species. Annals of Natural History, 1:388394.CrossRefGoogle Scholar
Hecht, M. K., and Hoffstetter, R. 1962. Note préliminaire sur les amphibians et les squamates du Landénien Supérieur et du Tongrien de Belgique. Institut Royale des Sciences Naturelles de Belgique Bulletin, 38:130.Google Scholar
Hoffstetter, R. 1943. Varanidae et Necrosauridae fossiles. Bulletin du Muséum National d'Histoire Naturelle, 15:134141.Google Scholar
Hoffstetter, R. 1969. Présence de Varanidae (Reptilia, Sauria) dans le Miocène de Catalogne. Considérations sur l'histoire de la famille. Bulletin du Muséum National d'Histoire Naturelle, 40:10511064.Google Scholar
Hoffstetter, R., and Gasc, J.-P. 1967. Observations sur le squelette cervicale et spécialement sur les hypapophyses sauriens varanoides actuels et fossils. Bulletin du Muséum National d'Histoire Naturelle, 39:10281943.Google Scholar
Hoffstetter, R., and Gasc, J.-P. 1969. Vertebrae and ribs of modern reptiles, p. 201310. In Gans, C., Bellairs, A.d'A. and Parsons, T.S. (eds.), Biology of the Reptilia, Volume 1, Morphology A. Academic Press. London.Google Scholar
Jordan, D.S. 1907. The fossil fishes of California; with supplementary notes on other species of extinct fishes. Bulletin of the Department of Geology, University of California, 5:95145.Google Scholar
Koenigswald, W. v., Rose, K. D., Grande, L., and Martin, R. D. 2005a. First apatemyid skeleton from the Lower Eocene Fossil Butte Member, Wyoming (USA), compared to the European apatemyid from Messel, Germany. Palaeontographica, A, 272:149169.CrossRefGoogle Scholar
Koenigswald, W. v., Rose, K. D., Grande, L., and Martin, R. D. 2005b. Die Lebensweise eozäner Säugetiere (Pantolestidae und Apatemyidae) aus Messel (Europa) im Vergleich zu neuen Skeletttfunden aus dem Fossil Butte Member von Wyoming (Nordamerika). Geologisches Jahrbuch Hessen, 132:4354.Google Scholar
Laurenti, J. N. 1768. Specimen medicum, exhibens synopsin Reptilium emendatam cum experimentis circa venena et antidota Reptilium Austriacorum. De Trattnern, Vienna.CrossRefGoogle Scholar
Lécuru, S. 1968a. Étude des variations morphologiques du sternum, des clavicules, et de l'interclavicule des lacertiliens. Annales des Sciences Naturelles, Zoologie, (12) 10:511544.Google Scholar
Lécuru, S. 1968b. Remarques sur le scapulo-coracoïde des lacertiliens. Annales des Sciences Naturelles, Zoologie, (12) 10:475510.Google Scholar
Lécuru, S. 1969. Étude morphologique de l'humerus des lacertiliens. Annales des Sciences Naturelles, Zoologie, (12) 11:515558.Google Scholar
Lee, M. S. Y. 1997. The phylogeny of varanoid lizards and the affinities of snakes. Philosophical Transactions of the Royal Society of London, B, 352:5391.CrossRefGoogle Scholar
Lee, M. S. Y. 1998. Convergent evolution and character correlation in burrowing reptiles: Towards a resolution of squamate relationships. Biological Journal of the Linnean Society, 65:369453.CrossRefGoogle Scholar
Lee, M. S. Y. 2000. Soft anatomy, diffuse homoplasy, and the relationships of lizards and snakes. Zoologica Scripta, 29:101130.CrossRefGoogle Scholar
Leidy, J. 1870. (Descriptions of Emys jeanesi, E. haydeni, Baëna arenosa, and Saniwa ensidens). Proceedings of the Academy of Natural Science, Philadelphia, 1870:123124.Google Scholar
Leidy, J. 1872. On the fossil vertebrates of the Early Tertiary Formation of Wyoming. Reptiles. Report of the United States Geological Survey of the Territories, 1:14358.Google Scholar
Leidy, J. 1873. Contributions to the extinct vertebrate fauna of the western territories. Reptiles. Report of the United States Geological Survey of the Territories, 5:353372.Google Scholar
Lessman, M. H. 1952. Zur labialen Pleurodontie an Lacertilier-Gebissen. Anatomischer Anzeiger, 99:3567.Google Scholar
Linnaeus, C. 1758. Systema naturae, Editio decima, Reformata, Volume 1, Impensis Direct. Laurentii Salvii, Holmiae, ii + 824 p.Google Scholar
Maisano, J. A., Bell, C. J., Gauthier, J. A., and Rowe, T. 2002. The osteoderms and palpebral in Lanthanotus borneensis (Squamata, Anguimorpha). Journal of Herpetology, 36:678682.CrossRefGoogle Scholar
Marsh, O. C. 1872. Preliminary description of new Tertiary reptiles. American Journal of Science, 4:298309.CrossRefGoogle Scholar
McDowell, S. B., and Bogert, C. M. 1954. The systematic position of Lanthanotus, and the affinities of anguinomorphan lizards. Bulletin of the American Museum of Natural History, 105:1141.Google Scholar
Merrem, B. 1820. Versuch eines Systems der Amphibien. Tentamen systematis Amphibiorum. Krieger, Marburg, vi + 191 p.Google Scholar
Mertens, R. 1942a. Die Familie der Warane (Varanidae). Erster Teil: Allgemeines. Abhandlungen der senckenbergischen naturforschenden Gesellschaft, 462:1116.Google Scholar
Mertens, R. 1942b. Die Familie der Warane (Varanidae). Zweiter Teil: Der Schädel. Abhandlungen der senckenbergischen naturforschenden Gesellschaft, 465:117234.Google Scholar
Norell, M. A., and Gao, K. 1997. Braincase and phylogenetic relationships of Estesia mongoliensis from the Late Cretaceous of the Gobi Desert and the recognition of a new clade of lizards. American Museum Novitates, 3211, 25p.Google Scholar
Norell, M. A., McKenna, M. C., and Novacek, M. J. 1992. Estesia mongoliensis, a new fossil varanoid from the Late Cretaceous Barun Formation of Mongolia. American Museum Novitates, 3045, 24p.Google Scholar
Odermatt, C. 1940. Beiträge zur Kenntnis des Gebisses von Heloderma. Vierteljahresschrift der naturforschenden Gesellschaft in Zürich, 85:98141.Google Scholar
Oelrich, T. M. 1956. The anatomy of the head of Ctenosaura pectinata (Iguanidae). University of Michigan Museum of Zoology, Miscellaneous Publications, 94, 122p.Google Scholar
Ouwens, P.A. 1912. On a large Varanus species from the Island of Komodo. Bulletin du Jardin Botanique Buitenzorg, 6:13.Google Scholar
Pregill, G. K., Gauthier, J. A., and Greene, H. W. 1986. The evolution of helodermatid squamates, with description of a new taxon and an overview of Varanoidea. Transactions of the San Diego Society of Natural History, 21:167202.Google Scholar
Rieppel, O. 1979. A functional interpretation of the varanid dentition (Reptilia, Lacertilia, Varanidae). Gegenbaurs Morphologisches Jahrbuch, 125:797817.Google ScholarPubMed
Rieppel, O. 1980a. The phylogeny of anguinomorph lizards. Denkschriften der Schweizerischen Naturforschenden Gesellschaft, 94:186.Google Scholar
Rieppel, O. 1980b. The postcranial skeleton of Lanthanotus borneensis (Reptilia, Lacertilia). Amphibia-Reptilia, 1:95112.CrossRefGoogle Scholar
Rieppel, O. 1992. The skeleton of a juvenile Lanthanotus (Varanoidea). Amphibia – Reptilia 13:2734.CrossRefGoogle Scholar
Rieppel, O. 1993a. Studies on skeleton formation in reptiles. V. Patterns of ossification in the skeleton of Alligator mississippiensis Daudin (Reptilia, Crocodylia). Zoological Journal of the Linnean Society, 109:301325.CrossRefGoogle Scholar
Rieppel, O. 1993b. Studies on skeleton formation in reptiles. IV. The homology of the reptilian (amniote) astragalus revisited. Journal of Vertebrate Paleontology, 13:3147.CrossRefGoogle Scholar
Rieppel, O., and Zaher, H. 2000. The intramandibular joint in squamates, and the phylogenetic relationships of the fossil snake Pachyrhachis problematics. Fieldiana (Geology), n.s., 43:169.Google Scholar
Renous-Lécuru, S. 1973. Morphologie comparée du carpe chez les lépidosauriens actuels (Rhynchocéphales, Lacertiliens, Amphisbéniens). Gegenbaurs Morphologisches Jahrbuch, 119:727766.Google Scholar
Robinson, P. L. 1967. The evolution of the Lacertilia. Colloques Internationaux C.N.R.S., 163:395407.Google Scholar
Robinson, P. L. 1975. The functions of the hooked fifth metatarsal in lepidosaurian reptiles. Colloques Internationaux C.N.R.S., 218:461483.Google Scholar
Romer, A. S. 1956. The Osteology of the Reptiles. University of Chicago Press, Chicago, 772 p.Google Scholar
Schlegel, H. 1839. Abbildung neuer oder unvollständig bekannter Amphibien. Arnz, Düsseldorf, 141p., 50 pls.Google Scholar
Shaw, G. 1790. Lacerta varia, p. 253, pl. 38. In White, J. (ed.), Journal of a Voyage to New South Wales. J. Debrett, London[The page and plate number are those of the copy kept in The Field Museum Library].Google Scholar
Siebenrock, F. 1894. Das Skelet der Lacerta simony und der Lacertidenfamilie überhaupt. Sitzungsberichte der kaiserlichen Akademie der Wissenschaften, mathematisch-naturwissenschaftliche Klasse, 103:205292.Google Scholar
Steindachner, F. 1878. Über zwei neue Eidechsen-Arten aus Süd-Amerika und Borneo. Denkschriften der Akademie der Wissenschaften, mathematisch-naturwissenschaftliche Classe, Wien, 38:9396.Google Scholar
Tanner, W. W., and Avery, D. F. 1982. Buccal floor of reptiles, a summary. The Great Basin Naturalist, 42:273349.Google Scholar
Wiegmann, A.F.A. 1829. Berichtigung einiger Fehler in meinem Auffsatze Beiträge zur Amphibienkunde. Isis (Oken), 22:624,627.Google Scholar
Zaher, H., and Rieppel, O. 1999. Tooth implantation and replacement in squamates, with special reference to mosasaur lizards and snakes. American Museum Novitates, 3271, 19p.Google Scholar