Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-23T05:54:28.419Z Has data issue: false hasContentIssue false
  • English
  • Français

Postcranium of the paradigm elasmosaurid plesiosaurian Libonectes morgani (Welles, 1949)

Published online by Cambridge University Press:  20 November 2014

SVEN SACHS  and
BENJAMIN P. KEAR
SVEN SACHS*
Affiliation:
Im Hof 9, 51766 Engelskirchen, Germany
BENJAMIN P. KEAR
Affiliation:
Palaeobiology Programme, Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala, Sweden
*
†Author for correspondence: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Elasmosauridae constitutes one of the most immediately recognizable plesiosaurian radiations. Their distinctive body plan represents the popular model for Plesiosauria, and is typified by an osteological morphology especially adapted for hyper-elongation of the neck. Nevertheless, many archetypal elasmosaurids are known only from incomplete and/or inadequately documented material, a problem that has contributed to their uncertain intra-clade relationships. A prime example of this is Libonectes morgani from the Upper Cretaceous of Texas, USA, which is frequently presented as an elasmosaurid structural proxy because of its three-dimensionally preserved holotype skull. Perplexingly though, both the taxonomic diagnosis and phylogenetic placement of L. morgani rely primarily upon the cervical vertebrae, together with the pectoral girdle and forelimb, yet most of these elements are now lost and figured only as line drawings. We therefore reviewed the remnant postcranial skeleton of L. morgani first-hand with the objective of clarifying its defining character states. Our observations showed that the existing diagnosis of L. morgani is indeed inadequate. Moreover, the only identifiable autapomorphies occurred within the axial skeleton. This concurred with an examination of character scores used in published plesiosaurian phylogenies, and highlights the persistent significance of postcranial elements for discriminating elasmosaurid taxa.

Keywords

Plesiosauriaaxial skeletonatlas-axis complexsystematics
Type
Original Articles
Information
Geological Magazine , Volume 152 , Issue 4 , July 2015 , pp. 694 - 710
Copyright
Copyright © Cambridge University Press 2014 

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

Andrews, C. W. 1910. A Descriptive Catalogue of the Marine Reptiles of the Oxford Clay, Part I. London, England: British Museum (Natural History), 202 pp.Google Scholar
Andrews, C. W. 1922. Description of a new plesiosaur from the Weald Clay of Berwick (Sussex). Quarterly Journal of the Geological Society of London 78, 285–95.Google Scholar
Araújo, R. & Polcyn, M. J. 2013. A biomechanical analysis of the skull and adductor chamber muscles in the Late Cretaceous plesiosaur Libonectes. Palaeontologia Electronica 16, 1–25.Google Scholar
Bardet, N. P., Godefroit, P. & Sciau, J. 1999. A new elasmosaurid plesiosaur from the Lower Jurassic of Southern France. Palaeontology 42, 927–52.Google Scholar
Benson, R. B. J. & Druckenmiller, P. S. 2014. Faunal turnover of marine tetrapods during the Jurassic–Cretaceous transition. Biological Reviews 89, 1–23.Google Scholar
Benson, R. B. J., Evans, M. & Druckenmiller, P. S. 2012. High diversity, low disparity and small body size in plesiosaurs (Reptilia, Sauropterygia) from the Triassic–Jurassic boundary. PLoS ONE 7, e31838.Google Scholar
Benson, R. B. J., Ketchum, H. F., Naish, D. & Turner, L. E. 2013. A new leptocleidid (Sauropterygia, Plesiosauria) from the Vectis Formation (Early Barremian–early Aptian; Early Cretaceous) of the Isle of Wight and the evolution of Leptocleididae, a controversial clade. Journal of Systematic Palaeontology 11, 233–50.Google Scholar
Berezin, Y. A. 2011. A new plesiosaur of the family Aristonectidae from the Early Cretaceous of the center of the Russian Platform. Paleontological Journal 45, 648–60.Google Scholar
de Blainville, H. D. 1835. Description de quelques espèces de reptiles de la Californie, précédée de l’analyse d’un système général d’Erpétologie et d’Amphibiologie. Nouvelles Annales du Muséum (national) d’Histoire Naturelle de Paris 4, 233–96.Google Scholar
Brown, D. S. 1981. The English Upper Jurassic Plesiosauroidea (Reptilia) and a review of the phylogeny and classification of the Plesiosauria. Bulletin of the British Museum (Natural History), Geology Series 35, 253–347.Google Scholar
Brown, D. S. 1993. A taxonomic reappraisal of the families Elasmosauridae and Cryptoclididae. Revue de Paléobiologie 7, 9–16.Google Scholar
Brown, D. S., Vincent, P. & Bardet, N. 2013. Osteological redescription of the skull of Microcleidus homalospondylus (Sauropterygia, Plesiosauria) from the Lower Jurassic of England. Journal of Paleontology 87, 537–49.Google Scholar
Buchy, M.-C. 2006. An elasmosaur (Reptilia: Sauropterygia) from the Turonian (Upper Cretaceous) of Morocco. Carolinea 63, 5–28.Google Scholar
Cabrera, A. 1941. Un plesiosaurio nuevo del Cretáceo del Chubut. Revista del Museo de La Plata 2, 113–30.Google Scholar
Carpenter, K. 1997. Comparative cranial anatomy of two North American plesiosaurs. In Ancient Marine Reptiles (eds Callaway, J. M. & Nicholls, E. L.), pp. 191–216. San Diego: Academic Press.Google Scholar
Carpenter, K. 1999. Revision of North American elasmosaurs from the Cretaceous of the Western Interior. Paludicola 2, 148–73.Google Scholar
Chatterjee, S. & Small, B. J. 1989. New plesiosaurs from the Upper Cretaceous of Antarctica. In Origins and Evolution of the Antarctic Biota (ed. Crame, J. A.), pp. 197–215. Geological Society of London, Special Publication no. 47.Google Scholar
Cobban, W. A. 1984. Mid-Cretaceous ammonite zones, Western Interior, United States. Bulletin of the Geological Society of Denmark 33, 71–89.Google Scholar
Cope, E. D. 1868. [Remarks on a new large enaliosaur]. Proceedings of the Academy of Natural Sciences of Philadelphia 20, 92–3.Google Scholar
Cope, E. D. 1869. Synopsis of the extinct Batrachia and Reptilia of North America. Part 1. Transactions of the American Philosophical Society 14, 1–235.Google Scholar
Cope, E. D. 1877. Report on the geology of the region of the Judith River, Montana, and on the vertebrate fossils obtained on or near the Missouri River. Bulletin of the United States Geological and Geographical Survey of the Territories 3, 565–97.Google Scholar
Cruickshank, A. R. I. & Fordyce, R. E. 2002. A new marine reptile (Sauropterygia) from New Zealand: further evidence for a Late Cretaceous austral radiation of cryptoclidid plesiosaurs. Palaeontology 45, 557–75.Google Scholar
Dames, W. 1895. Die Plesiosaurier der süddeutschen Liasformation. Abhandlungen der Königlich Preussischen Akademie der Wissenschaften zu Berlin 1895, 1–81.Google Scholar
Dawson, W. C. 2000. Shale microfacies: Eagle Ford Group (Cenomanian-Turonian) north-central Texas outcrops and subsurface equivalents. Gulf Coast Association of Geological Societies Transactions 50, 607–21.Google Scholar
Druckenmiller, P. S. 2002. Osteology of a new plesiosaur from the Lower Cretaceous (Albian) Thermopolis Shale of Montana. Journal of Vertebrate Paleontology 22, 29–42.Google Scholar
Druckenmiller, P. S. & Russell, A. P. 2006. A new elasmosaurid plesiosaur (Reptilia: Sauropterygia) from the Lower Cretaceous Clearwater Formation, northeastern Alberta, Canada. Paludicola 5,184–99.Google Scholar
Druckenmiller, P. S. & Russell, A. P. 2008 a. A phylogeny of Plesiosauria (Sauropterygia) and its bearing on the systematic status of Leptocleidus Andrews, 1922. Zootaxa 1863, 1–120.Google Scholar
Druckenmiller, P. S. & Russell, A. P. 2008 b. Skeletal anatomy of an exceptionally complete specimen of a new genus of plesiosaur from the Early Cretaceous (Early Albian) of northeastern Alberta, Canada. Palaeontographica A283, 1–33.Google Scholar
Everhart, M. 2006. The occurrence of elasmosaurids (Reptilia: Plesiosauria) in the Niobrara Chalk of western Kansas. Paludicola 5, 170–83.Google Scholar
Fraas, E. 1910. Plesiosaurier aus dem oberen Lias von Holzmaden. Palaeontographica 57, 105–40.Google Scholar
Gasparini, Z., Bardet, N. & Iturralde-Vinent, M. 2002. A new cryptoclidid plesiosaur from the Oxfordian (Late Jurassic) of Cuba. Geobios 35, 201–11.CrossRefGoogle Scholar
Gasparini, Z., Bardet, N., Martin, J. E. & Fernandez, M. 2003. The elasmosaurid plesiosaur Aristonectes Cabrera from the latest Cretaceous of South America and Antarctica. Journal of Vertebrate Paleontology 23, 104–15.Google Scholar
Gradstein, F. J., Ogg, J. G., Schmitz, M. D. & Ogg, G. M. 2012. The Geologic Time Scale 2012. Volume 2. Amsterdam: Elsevier, 1176 pp.Google Scholar
Großmann, F. 2007. The taxonomic and phylogenetic position of the Plesiosauroidea from the Lower Jurassic Posidonia Shale of south-west Germany. Palaeontology 50, 545–64.Google Scholar
Hampe, O. 2013. The forgotten remains of a leptocleidid plesiosaur (Sauropterygia: Plesiosauroidea) from the Early Cretaceous of Gronau (Münsterland, Westphalia, Germany). Paläontologische Zeitschrift 87, 473–91.Google Scholar
Hector, J. 1874. On the fossil reptiles of New Zealand. Transactions of the New Zealand Institute 6, 333–58.Google Scholar
Hiller, N. & Mannering, A. A. 2005. An unusual new elasmosaurid plesiosaur (Sauropterygia) from the Upper Haumurian (Maastrichtian) of the South Island, New Zealand. Memoirs of the Queensland Museum 51, 27–37.Google Scholar
Hiller, N., Mannering, A. A., Jones, C. M. & Cruickshank, A. R. I. 2005. The nature of Mauisaurus haasti Hector, 1874 (Reptilia: Plesiosauria). Journal of Vertebrate Paleontology 25, 588–601.Google Scholar
Hiller, N., O’Gorman, J. P. & Otero, R. A. 2014. A new elasmosaurid plesiosaur from the lower Maastrichtian of North Canterbury, New Zealand. Cretaceous Research 50, 27–37.Google Scholar
Huene, F. von. 1923. Ein neuer Plesiosaurier aus dem oberen Lias Württembergs. Jahreshefte des Vereins für Vaterländische Naturkunde in Württemberg 79, 3–23.Google Scholar
Jacobs, L. L., Polcyn, M. J., Winkler, D. A., Myers, T. S., Kennedy, J. G. & Wagner, J. B. 2013. Late Cretaceous strata and vertebrate fossils of North Texas In Late Cretaceous to Quaternary Strata and Fossils of Texas, Field Excursions Celebrating 125 Years of GSA and Texas Geology, GSA South-Central Section Meeting, Austin, Texas, April 2013 (eds Hunt, B. B. & Catlos, E. J.), pp. 1–13. Geological Society of America Field Guide no. 30.Google Scholar
Kear, B. P. 2002. Reassessment of the Early Cretaceous plesiosaur Cimoliasaurus maccoyi Etheridge, 1904 (Reptilia, Sauropterygia) from White Cliffs, New South Wales. Australian Journal of Zoology 50, 671–85.Google Scholar
Kear, B. P. 2005 a. A new elasmosaurid plesiosaur from the Lower Cretaceous of Queensland, Australia. Journal of Vertebrate Paleontology 25, 792–805.CrossRefGoogle Scholar
Kear, B. P. 2005 b. Marine reptiles from the Lower Cretaceous (Aptian) deposits of White Cliffs, southeastern Australia: implications of a high-latitude cold-water assemblage. Cretaceous Research 26, 769–82.Google Scholar
Kear, B. P. 2006. Marine reptiles from the Lower Cretaceous of South Australia: elements of a high-latitude cold-water assemblage. Palaeontology 49, 837–56.Google Scholar
Kear, B. P. & Barrett, P. M. 2011. Reassessment of the Early Cretaceous (Barremian) pliosauroid Leptocleidus superstes Andrews, 1922 and other plesiosaur remains from the nonmarine Wealden succession of southern England. Zoological Journal of the Linnean Society 161, 663–91.Google Scholar
Kennedy, W. J. 1988. Late Cenomanian and Turonian ammonite faunas from northeast and central Texas. Special Papers in Palaeontology 39, 1–131.Google Scholar
Kennedy, W. J. & Cobban, W. A. 1991. Stratigraphy and interregional correlation of the Cenomanian-Turonian transition in the Western Interior of the United States near Pueblo, Colorado, a potential boundary stratotype for the base of the Turonian stage. Newsletters on Stratigraphy 24, 1–33.CrossRefGoogle Scholar
Kennedy, W. J., Walaszczyk, I. & Cobban, W. A. 2005. The global boundary stratotype section and point for the base of the Turonian Stage of the Cretaceous; Pueblo, Colorado, USA. Episodes 28, 93–104.Google Scholar
Ketchum, H. F. & Benson, R. B. J. 2010. Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses. Biological Reviews 85, 361–92.Google Scholar
Ketchum, H. F. & Smith, A. S. 2010. The anatomy and taxonomy of Macroplata tenuiceps (Sauropterygia, Plesiosauria) from the Hettangian (Lower Jurassic) of Warwickshire, United Kingdom. Journal of Vertebrate Paleontology 30, 1069–81.Google Scholar
Knutsen, E. M., Druckenmiller, P. S. & Hurum, J. H. 2012. Two new species of long-necked plesiosaurians (Reptilia: Sauropterygia) from the Upper Jurassic (Middle Volgian) Agardhfjellet Formation of central Spitsbergen. Norwegian Journal of Geology 92, 187–212.Google Scholar
Kubo, T., Mitchell, M. T. & Henderson, D. M. 2012. Albertonectes vanderveldei, a new elasmosaur (Reptilia, Sauropterygia) from the Upper Cretaceous of Alberta. Journal of Vertebrate Paleontology 32, 557–72.Google Scholar
Lomax, D. R. & Wahl, W. R. 2013. A new specimen of the elasmosaurid plesiosaur Zarafasaura oceanis from the Upper Cretaceous (Maastrichtian) of Morocco. Paludicola 9, 97–109.Google Scholar
McGowen, J. H., Proctor, C. V., Haenggi, W. T., Reaser, D. F. & Barnes, V. E. 1987. Geologic atlas of Texas, Dallas sheet (Gayle Scott Memorial Edition). Geologic Atlas of Texas. Bureau of Economic Geology, University of Texas at Austin, Austin 1, no. 250,000.Google Scholar
Nixon, K. C. 1999. The parsimony ratchet, a new method for rapid parsimony analysis. Cladistics 15, 407–14.Google Scholar
O’Gorman, J. P., Gasparini, Z. B. & Salgado, L. 2013. Postcranial morphology of Aristonectes (Plesiosauria, Elasmosauridae) from the Upper Cretaceous of Patagonia and Antarctica. Antarctic Science 25, 71–82.Google Scholar
O’Keefe, F. R. 2001. A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia, Sauropterygia). Acta Zoologica Fennica 213, 1–63.Google Scholar
O’Keefe, F. R. 2002. The evolution of plesiosaur and pliosaur morphotypes in the Plesiosauria (Reptilia: Sauropterygia). Paleobiology 28, 101–12.Google Scholar
O’Keefe, F. R. 2004. Preliminary description and phylogenetic position of a new plesiosaur (Reptilia, Sauropterygia) from the Toarcian of Holzmaden, Germany. Journal of Paleontology 78, 973–88.Google Scholar
O’Keefe, F. R. & Hiller, N. 2006. Morphologic and ontogenetic patterns in elasmosaur neck length, with comments on the taxonomic utility of neck length variables. Paludicola 5, 206–29.Google Scholar
Otero, R. A., Soto-Acuña, S. & Rubilar-Rogers, D. 2012. A postcranial skeleton of an elasmosaurid plesiosaur from the Maastrichtian of central Chile, with comments on the affinities of Late Cretaceous plesiosauroids from the Weddellian Biogeographic Province. Cretaceous Research 37, 89–99.Google Scholar
Otero, R. A., Soto-Acuña, S., O’Keefe, F. R., O’Gorman, J. P., Stinnesbeck, W., Suárez, M. E., Rubilar-Rogers, D., Salazar, C. & Quinzio-Sinn, L. A. 2014. Aristonectes quiriquinensis, sp. nov., a new highly derived elasmosaurid from the upper Maastrichtian of central Chile. Journal of Vertebrate Paleontology 34, 100–25.Google Scholar
Owen, R. 1860. On the orders of fossil and recent Reptilia, and their distribution in time. Reports of the British Association for the Advancement of Science, London 29, 153–66.Google Scholar
Owen, R. 1865. Monograph on the Fossil Reptilia of the Liassic Formations. Part I: Sauropterygia. London: The Palaeontographical Society, 40 pp.Google Scholar
Persson, P. O. 1963. A revision of the classification of the Plesiosauria with a synopsis of the stratigraphical and geographical distribution of the group. Lunds Universitets Årsskrift 59, 1–59.Google Scholar
Phillips, J. 1871. Geology of Oxford and the Valley of the Thames. Oxford: Clarendon Press, 523 pp.Google Scholar
Sachs, S. 2004. Redescription of Woolungasaurus glendowerensis (Plesiosauria: Elasmosauridae) from the Lower Cretaceous of Northeast Queensland. Memoirs of the Queensland Museum 49, 713–31.Google Scholar
Sachs, S. 2005 a. Redescription of Elasmosaurus platyurus Cope 1868 (Plesiosauria: Elasmosauridae) from the Upper Cretaceous (lower Campanian) of Kansas, USA. Paludicola 5, 92–106.Google Scholar
Sachs, S. 2005 b. Tuarangisaurus australis sp. nov. (Plesiosauria: Elasmosauridae) from the Lower Cretaceous of Northeastern Queensland, with additional notes on the phylogeny of the Elasmosauridae. Memoirs of the Queensland Museum 50, 425–40.Google Scholar
Sachs, S, Kear, B. P. & Everhart, M. J. 2013. Revised vertebral count in the “longest-necked vertebrate” Elasmosaurus platyurus Cope 1868, and clarification of the cervical-dorsal transition in Plesiosauria. PLoS ONE 8, e70877.CrossRefGoogle ScholarPubMed
Sato, T. 2003. Terminonatator ponteixensis, a new elasmosaur (Reptilia; Sauropterygia) from the Upper Cretaceous of Saskatchewan. Journal of Vertebrate Paleontology 23, 89–103.Google Scholar
Sato, T., Hasegawa, Y. & Manabe, M. 2006. A new elasmosaurid plesiosaur from the Upper Cretaceous of Fukushima, Japan. Palaeontology 49, 467–84.CrossRefGoogle Scholar
Seeley, H. G. 1874. On Muraenosaurus leedsii, a plesiosaurian from the Oxford Clay. Part I. Quarterly Journal of the Geological Society of London 30, 197–208.Google Scholar
Sennikov, A. G. & Arkhangelsky, M. S. 2010. On a typical Jurassic sauropterygian from the Upper Triassic of Wilczek Land (Franz Josef Land, Arctic Russia). Paleontological Journal 44, 567–72.Google Scholar
Shuler, E. W. 1950. A new elasmosaur from the Eagle Ford Shale of Texas. Part II. The elasmosaur and its environment. The Fondren Science Series 1, 1–32.Google Scholar
Shumard, B. F. 1860. Descriptions of new Cretaceous fossils from Texas. Academy of Science St Louis Transactions 1, 590–610.Google Scholar
Sikes, D. S. & Lewis, P. O. 2001. PAUPRat: PAUP* Implementation of the Parsimony Ratchet. Storrs: University of Connecticut, Department of Ecology and Evolutionary Biology.Google Scholar
Smith, A. S, Araújo, R. & Mateus, O. 2012. A new plesiosauroid from the Toarcian (Lower Jurassic) of Alhadas, Portugal. Acta Palaeontologica Polonica 57, 257–66.Google Scholar
Sollas, W. J. 1881. On a new species of Plesiosaurus (P. conybeari) from the Lower Lias of Charmouth; with observations on P. megacephalus, Stutchbury, and P. brachycephalus, Owen. Quarterly Journal of the Geological Society of London 37, 440–81.Google Scholar
Storrs, G. W. 1991. Anatomy and relationships of Corosaurus alcovensis (Diapsida: Sauropterygia) and the Triassic Alcova Limestone of Wyoming. Bulletin of the Peabody Museum of Natural History 44, 1–163.Google Scholar
Storrs, G. W. 1999. An examination of Plesiosauria (Diapsida Sauropterygia) from the Niobrara Chalk (Upper Cretaceous) of Central North America. The University of Kansas Paleontological Contributions 11, 1–15.Google Scholar
Swofford, D. 2002. Phylogenetic Analysis using Parsimony *4.0b10. Sunderland, MA: Sinauer Associates, Inc.Google Scholar
Thiele, K. 1993. The holy grail of the perfect character: the cladistic treatment of morphometric data. Cladistics 9, 275–304.Google Scholar
Vincent, P., Bardet, N., Pereda Suberbiola, X., Bouya, B., Amaghzaz, M. & Meslouh, S. 2011. Zarafasaura oceanis, a new elasmosaurid (Reptilia: Sauropterygia) from the Maastrichtian Phosphates of Morocco and the palaeobiogeography of latest Cretaceous plesiosaurs. Gondwana Research 19, 1062–73.Google Scholar
Vincent, P., Bardet, N., Houssaye, A., Amaghzaz, M. & Meslouh, S. 2013. New plesiosaur specimens from the Maastrichtian Phosphates of Morocco and their implications for the ecology of the latest Cretaceous marine apex predators. Gondwana Research 24, 796–805.Google Scholar
Wegner, T. H. 1914. Brancasaurus brancai n. g. n. sp., ein Elasmosauride aus dem Wealden Westfalens. In Festschrift für Wilhelm Branca zum 70. Geburtstage 1914, pp. 235–305. Leipzig: Borntraeger.Google Scholar
Welles, S. P. 1943. Elasmosaurid plesiosaurs with a description of new material from California and Colorado. University of California Publications in Geological Sciences 13, 125–215.Google Scholar
Welles, S. P. 1949. A new elasmosaur from the Eagle Ford Shale of Texas. Part I. Systematic description. Fondren Science Series 1, 1–28.Google Scholar
Welles, S. P. 1952. A review of the North American Cretaceous elasmosaurs. University of California Publications in Geological Sciences 29, 47–143.Google Scholar
Welles, S. P. 1962. A new species of elasmosaur from the Aptian of Colombia, and a review of the Cretaceous plesiosaurs. University of California Publications in Geological Sciences 44, 1–96.Google Scholar
Welles, S. P. & Bump, J. 1949. Alzadasaurus pembertoni, a new elasmosaur from the Upper Cretaceous of South Dakota. Journal of Paleontology 23, 521–35.Google Scholar
Williston, S. W. 1890. A new plesiosaur from the Niobrara Cretaceous of Kansas. Transactions of the Kansas Academy of Science 12, 174–8.Google Scholar
Wiffen, J. & Moisley, W. L. 1986. Late Cretaceous reptiles (families Elasmosauridae and Pliosauridae) from the Mangahouanga Stream, North Island, New Zealand. New Zealand Journal of Geology and Geophysics 29, 205–52.Google Scholar