Abstract
The predatory pliosaurs were among the largest creatures ever to inhabit the oceans, some reaching gigantic proportions greater than 15 m in length. Fossils of this subclade of plesiosaurs are known from sediments all over the world, ranging in age from the Hettangian (approximately 198 Myr) to the Turonian (approximately 92 Myr). However, due to a lack of detailed studies and because only incomplete specimens are usually reported, pliosaur evolution remains poorly understood. In this paper, we describe the three dimensionally preserved skull of the giant Jurassic pliosaur Rhomaleosaurus cramptoni. The first phylogenetic analysis dedicated to in-group relationships of pliosaurs allows us to hypothesise a number of well-supported lineages that correlate with marine biogeography and the palaeoecology of these reptiles. Rhomaleosaurids comprised a short-lived and early diverging lineage within pliosaurs, whose open-water top-predator niche was filled by other pliosaur taxa by the mid-late Jurassic.
References
Brown DS (1981) The English Upper Jurassic Plesiosauroidea (Reptilia) and a review of the phylogeny and classification of the Plesiosauria. Bull Br Mus Nat Hist Geol 35:253–347
Buchy M-C, Frey E, Stinnesbeck W, López-Oliva JG (2003) First occurrence of a gigantic pliosaurid plesiosaur in the Late Jurassic (Kimmeridgian) of Mexico. Bull Soc Géol Fr 174:271–278
Carte A, Bailey WH (1863) Description of a new species of Plesiosaurus, from the Lias, near Whitby, Yorkshire. J R Dublin Soc 4:160–170
Cruickshank ARI (1994) Cranial anatomy of the Lower Jurassic pliosaur Rhomaleosaurus megacephalus (Stutchbury) (Reptilia: Plesiosauria). Philos Trans R Soc Lond Ser B 343:247–260
De Blainville HD (1835) Description de quelques espèces de reptiles de la Californie, précédée de l’analyse d’un system general d’Erpetologie et d’Amphibiologie. Nouv Ann Mus Hist Nat Paris 4:233–296
Druckenmiller PS (2006) A phylogeny of Plesiosauria (Sauropterygia) with emphasis on the systematic status of Leptocleidus, Andrews 1922. J Vertebr Palaeontol 26:57A
Fraas E (1910) Plesiosaurier aus dem oberen Lias von Holzmaden. Palaeontographica 57:105–140
Kear BJ, Schroeder NI, Lee MSY (2006) An archaic crested plesiosaur in opal from the Lower Cretaceous high-latitude deposits of Australia. Biol Lett 2:615–619
Noè LF, Smith DTJ, Walton DI (2004) A new species of Kimmeridgian pliosaur (Reptilia; Sauropterygia) and its bearing on the nomenclature of Liopleurodon macromerus. Proc Geol Assoc 115:13–24
Nopsca F (1928) The genera of reptiles. Palaeobiologica 1:163–188
O’Keefe FR (2001) A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia). Acta Zool Fenn 213:1–63
O’Keefe FR (2002) The evolution of plesiosaur and pliosaur morphotypes in the Plesiosauria (Reptilia: Sauropterygia). Palaeobiology 28:101–112
Persson PO (1963) A revision of the classification of the Plesiosauria with a synopsis of the stratigraphical and geographical distribution of the group. Lunds Univ Årsskr NF Avd 59:1–59
Rieppel O (2000) Sauropterygia I: Placodontia, Pachypleurosauria, Nothosauria, Pistosauroidea. In: Wellnhofer P (ed) Encyclopedia of palaeoherpetology, vol 12A. Pfeil, Munich, pp 1–134
Seeley HG (1874) Note on some of the generic modifications of the plesiosaurian pectoral arch. Q J Geol Soc Lond 30:436–449
Seeley HG (1892) The nature of the shoulder girdle and clavicular arch in Sauropterygia. Proc R Soc Lond 51:119–151
Smith AS (2007) Anatomy and systematics of the Rhomaleosauridae (Sauropterygia, Plesiosauria). Ph.D. thesis, University College Dublin
Swofford DL (2000) PAUP*: Phylogenetic analysis using parsimony, version 4.0. Sinauer, Sunderland, Massachusetts
Tarlo LB (1959) Stretosaurus gen. nov., a giant pliosaur from the Kimmeridge Clay. Palaeontology 2:39–55
Taylor MA (1992) Functional anatomy of the head of the large aquatic predator Rhomaleosaurus zetlandicus (Plesiosauria: Reptilia) from the Toarcian (Lower Jurassic) of Yorkshire, England. Philos Trans R Soc Lond Ser B 335:247–280
Acknowledgements
We thank N. Monaghan, M. Parkes and J. Sigwart (NMI) for supporting this project, S. Moore-Fay and C. Collins for the preparation, K. Grimes for photographs and R. O’Keefe, R. Schouten, R. Forrest and M. Taylor for the assistance. G. Mayr, M. Caldwell and three referees provided comments in review.
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Smith, A.S., Dyke, G.J. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics. Naturwissenschaften 95, 975–980 (2008). https://doi.org/10.1007/s00114-008-0402-z
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DOI: https://doi.org/10.1007/s00114-008-0402-z