[en] Ichthyosaurs rapidly diversified and colonised a wide range of ecological niches during the Early and Middle Triassic period, but experienced a major decline in diversity near the end of the Triassic. Timing and causes of this demise and the subsequent rapid radiation of the diverse, but less disparate, parvipelvian ichthyosaurs are still unknown, notably because of inadequate sampling in strata of latest Triassic age. Here, we describe an exceptionally large radius from Lower Jurassic deposits at Penarth near Cardiff, South Wales (UK) the morphology of which places it within the giant Triassic shastasaurids. A tentative total body size estimate, based on a regression analysis of various complete ichthyosaur skeletons, yields a value of 12-15 m. The specimen is substantially younger than any previously reported last known occurrences of shastasaurids and implies a Lazarus range in the lowermost Jurassic for this ichthyosaur morphotype.
Disciplines :
Earth sciences & physical geography Zoology
Author, co-author :
Martin, Jeremy E
Vincent, Peggy
Suan, Guillaume
Sharpe, Tom
Hodges, Peter
Williams, Matt
Howells, Cindy
Fischer, Valentin ; Université de Liège - ULiège > Département de géologie > Paléontologie animale et humaine
Language :
English
Title :
A mysterious giant ichthyosaur from the lowermost Jurassic of Wales
Bardet, N. 1994. Extinction events among Mesozoic marine reptiles. Historical Biology 7: 313-324.
Bardet, N. 1995. Evolution et extinction des reptiles marins au cours du Méso zoïque. Paleovertebrata 24: 177-283.
Bardet, N., Cuny, G., Lachkar, G., Pereda Suberbiola, X., Mazin, J.M., Thomel, G., Barbieri, L., Vasse, D., Parot, B., Emily, A. 1999. A new marine vertebrate fauna from the uppermost Triassic of Eastern Provence (France). In: J.W.M. Jagt, P.H. Lambers, E.W.A. Mulder, and A.S. Schulp (eds.), Proceedings of the Third European Workshop on Vertebrate Palaeontology, Maastricht, 6-9 May, 1998. Geologie en Mijnbouw 78 (3-4): 12.
Benson, R.B., 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.
Benton, M.J. 1986a. More than one event in the late Triassic mass extinction. Nature 321: 857-861.
Benton, M.J. 1986b. The Late Triassic tetrapod extinction events. In: K. Padian (ed.), The Beginning of the Age of Dinosaurs; Faunal change across the Triassic-Jurassic Boundary, 303-320. Cambridge University Press, Cambridge.
Benton, M.J., Cook, E., Turner, P. 2002. Permian and Triassic Red Beds and the Penarth Group of Great Britain. Geological Conservation Review Series 24: 1-337.
Blainville, H.M.D. 1835. Description de quelques espèces de reptiles de la Californie, précédeé de l'analyse d'un système général d'erpétologie et d'amphibiologie. Nouvelles Annales du Museúm d'Histoire Naturelle, Paris 4: 233-296.
Callaway, J.M., Massare, J.A. 1989. Shastasaurus altispinus (Ichthyosauria, Shastasauridae) from the Upper Triassic of the El Antimonio district, northwestern Sonora, Mexico. Journal of Paleontology 63: 930-939.
Dal Sasso, C., Pinna, G. 1996. Besanosaurus leptorhynchus n. gen. n. sp., a new shastasaurid ichthyosaur from the Middle Triassic of Besano (Lombardy, N. Italy). Paleontologia Lombardia 4: 3-23.
Fischer V., Appleby, R.M., Naish, D., Liston, J., Riding, J.B., Brindley, S., Godefroit, P., 2013. A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs. Biology Letters 9, 20130021.
Fischer V., Cappetta, H., Vincent, P., Garcia, G., Goolaerts, S., Martin, J.E., Roggero, D., Valentin, X., 2014. Ichthyosaurs from the French Rhaetian indicate a severe turnover across the Triassic-Jurassic boundary. Naturwissenschaften 101, 1027-1040.
Fröbisch, N.B., Fröbisch, J., Sander, P.M., Schmitz, L., Rieppel, O. 2013. Macro-predatory ichthyosaur from the Middle Triassic and the origin of modern trophic networks. Proceedings of the National Academy of Sciences 110: 1393-1397.
Fröbisch, N.B., Sander, P.M., Rieppel, O. 2006. A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and a re-evaluation of the skull osteology of the genus. Zoological Journal of the Linnean Society 147: 515-538.
Godefroit, P. 1992. Présence de Leptopterygius tenuirostris (Reptilia, Ichthyosauria) dans le Lias moyen de Lorraine belge. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre 62: 163-170.
Hesselbo, S.P., Robinson, S.A., Surlyk, F., Piasecki, S. 2002 Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbation: A link to initiation of massive volcanism Geology 30: 251-254.
Hillebrandt, A. von and Krystyn, L. 2009. On the oldest Jurassic ammonites of Europe (Northern Calcareous Alps, Austria) and their global significance. Neues Jahrbuch für Geologie und Palaöntologie, Abhandlungen 253: 163-195.
Hodges, P. 1994. The base of the Jurassic system: new data on the first appearance of Psiloceras planorbis in southwest England. Geological Magazine 131: 841-844.
Hounslow, M.W., Posen, P.E., Warrington, G. 2004. Magnetostratigraphy and bio-stratigraphy of the upper Triassic and lowermost Jurassic succession, St. Audrie's Bay, UK. Palaeogeography, Palaeoclimatology, Palaeoecology 213: 331-358.
Ji, C., Jiang, D.-Y., Motani, R., Hao, W.-C., Sun, Z.-Y., Cai, T. 2013. A new juvenile specimen of Guanlingsaurus (Ichthyosauria, Shastasauridae) from the Upper Triassic of southwestern China. Journal of Vertebrate Paleontology 33: 340-348.
Jiang, D.A., Hao, W.-C., Maisch, M.W., Matzke, A.T., Sun., Y.-L. 2005., A basal mixosaurid ichthyosaur from the middle Triassic of China. Palaeontology 48: 869-882.
Jiang, D.-Y., Schmitz, L., Hao, W.-C., Sun, Y.-L. 2006. A new mixo saurid ichthyosaur from the middle Triassic of China. Journal of Vertebrate Paleontology 26: 60-69.
Kosch, B.F. 1990. A revision of the skeletal reconstruction of Shonisaurus popularis (Reptilia: Ichthyosauria). Journal of Vertebrate Paleontology 10: 512-514.
Korte, C., Hesselbo, S.P., Jenkyns, H.C., Rickaby, R.E.M., Spötl, C. 2009. Palaeo-environmental significance of carbon-and oxygen-isotope stratigraphy of marine Triassic-Jurassic boundary sections in SW Britain. Journal of the Geological Society of London 166: 431-445.
Lawrence, D.J.D., Waters, R.A. 1989. Geological notes and local details for 1:10 000 sheet ST17NE (Penarth). British Geological Survey Technical Report WA/89/72, Nottingham.
Liu, J., Motani, R., Jiang, D.-Y., Hu, S.-X., Aitchison, J.C., Rieppel, O., Benton, M.J., Zhang, Q.-Y., Zhou, C.-Y. 2013. The first specimen of the middle Triassic Phalarodon atavus (Ichthyosauria: mixosauridae) from south-China, showing postcranial anatomy and peri-Tethyan distribution. Palaeontology 56: 849-866.
Maisch, M.W., Matzke, A.T. 2000. The Ichthyosauria. Stuttgarter Beiträge zur Naturkunde Serie B Geologie und Palaöntologie 298: 1-159.
Mander, L., Twitchett, R.J. 2008 Quality of the Triassic-Jurassic bivalve fossil record in northwest Europe. Palaeontology 51: 1213-1223.
Mander, L., Twitchett, R.J., Benton, M.J. 2008 Palaeoecology of the Late Triassic extinction event in the SW UK. Journal of the Geological Society of London 165: 319-332.
Martin, J.E., Fischer, V., Vincent, P., Suan, G. 2012. A longirostrine Temnodontosaurus (Ichthyosauria) with comments on early Jurassic niche partitioning and disparity. Palaeontology 55: 995-1005.
Massare, J.A. 1987. Tooth morphology and prey preference of Mesozoic marine reptiles. Journal of Vertebrate Paleontology 7: 121-137.
Massare, J.A. 1997. Faunas, behavior, and evolution. In: J.M. Callaway and E.L. Nicholls (eds.), Ancient Marine Reptiles, 401-421. Academic Press, San Diego.
Massare, J.A., Callaway, J.M. 1990. The affinities and ecology of Triassic ichthyosaurs. Geological Society of America Bulletin 102: 409-416.
Mazin, J.M. 1988. Paleóbiogeógraphie des reptiles marins du Trias: phylogénie, systématique, écologie et implications paleóbiogeógra phiques. Mémoires des Sciences de la Terre de l'Université Pierre et Marie Curie, Paris: 8/88: 1-312.
McGowan, C. 1991. An ichthyosaur forefin from the Triassic of British Columbia exemplifying Jurassic features. Canadian Journal of Earth Sciences 28: 1553-1560.
McGowan, C. 1993. A new species of large, long-snouted ichthyosaur from the English lower Lias. Canadian Journal of Earth Sciences 30: 1197-1204.
McGowan, C. 1994. A new species of Shastasaurus (Reptilia: Ichthyosauria) from the Triassic of British Columbia: the most complete exemplar of the genus. Journal of Vertebrate Paleontology 14: 168-179.
McGowan, C. 1995. A remarkable small ichthyosaur from the Upper Triassic of British Columbia, representing a new genus and species. Canadian Journal of Earth Sciences 32: 292-303.
McGowan, C. 1996. Giant ichthyosaurs of the Early Jurassic. Canadian Journal of Earth Sciences 33: 1011-1021.
McGowan, C. 1997. A transitional ichthyosaur fauna. In: J.M. Callaway and E.L. Nicholls (eds.), Ancient Marine Reptiles, 61-80. Academic Press, San Diego.
McGowan, C., Motani, R. 1999. A reinterpretation of the Upper Triassic ichthyosaur Shonisaurus. Journal of Vertebrate Paleontology 19: 42-49.
McGowan, C., Motani, R. 2003. Part 8 Ichthyopterygia. 175 pp. Verlag Dr. Friedrich Pfeil, München.
Merriam, J.C. 1902. Triassic Ichthyopterygia from California and Nevada. University of California Publications. Bulletin of the Department of Geology 3: 63-108.
Merriam, J.C. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1-155.
Motani, R. 1998. First complete forefin of the ichthyosaur Grippia longirostris from the Triassic of Spitsbergen. Palaeontology 41: 591-599.
Motani, R. 2005. Evolution of fish-shaped reptiles (Reptilia: Ichthyopterygia) in their physical environments and constraints. Annual Reviews of Earth and Planetary Science 33: 395-420.
Motani, R., Ji, C., Tomita, T., Kelley, N., Maxwell, E., Jiang, D., Sander, P.M. 2013. Absence of suction feeding ichthyosaurs and its implications for Triassic mesopelagic paleoecology. PLoS ONE 8: e66075.
Motani, R., Manabe, M., Dong, Z.-M. 1999. The status of Himalayasaurus tibetensis (Ichthyopterygia). Paludicola 2: 174-181.
Nicholls, E.L., Manabe, M. 2004. Giant ichthyosaurs of the Triassic-a new species of Shonisaurus from the Pardonet Formation (Norian: Late Triassic) of British Columbia. Journal of Vertebrate Paleontology 24: 838-849.
Ruhl, M., Deenen, M.H.L., Abels, H.A., Bonis, N.R., Krijgsman, W., Kürschner, W.M. 2010. Astronomical constraints on the duration of the early Jurassic Hettangian stage and recovery rates following the end-Triassic mass extinction (St Audrie's Bay/East Quantoxhead, UK). Earth and Planetary Science Letter 295: 262-276.
Ruhl, M., Kürschner, W.M., Krystyn, L. 2009. Triassic-Jurassic organic carbon isotope stratigraphy of key sections in the western Tethys realm (Austria). Earth and Planetary Science Letters 281: 169-187.
Sander, P.M. 1989. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163-173.
Sander, P.M. 2000. The Ichthyosauria: their diversity, distribution, and phylogeny. Palaöntologische Zeitschrift 74: 1-35.
Sander, P.M., Chen, X., Cheng, L., Wang, X. 2011. Short-snouted toothless ichthyosaur from China suggests Late Triassic diversification of suction feeding ichthyosaurs. PLoS ONE 6: e19480.
Scheyer, T.M., Romano, C., Jenks, J., Bucher, H. 2014. Early Triassic marine biotic recovery: the predators' perspective. PLoS ONE 9: e88987.
Suan, G., Föllmi, K.B., Adatte, T., Bomou, B., Spangenberg, J.E., Schoot B. V. 2012. Major environmental change and bonebed genesis prior to the Triassic-Jurassic mass extinction. Journal of the Geological Society of London 169: 191-200.
Thorne, P.M., Ruta, M., Benton, M.J. 2011. Resetting the evolution of marine reptiles at the Triassic-Jurassic boundary. Proceedings of the National Academy of Sciences 108: 8339-8344.
Waters, R.A., Lawrence, D.J.D. 1987. Geology of the South Wales Coalfield, Part III, the Country Around Cardiff. Memoir for the 1:50 000 geological sheet 263 (England and Wales). Third edition. HMSO, London.
Warrington, G., Ivimey-Cook, H.C. 1995. The late Triassic and early Jurassic of coastal sections in west Somerset and South and Mid-Glamorgan. In: P.D. Taylor (ed.), Field Geology of the British Jurassic, 9-30. Geological Society, London.
