Skip to main content Accessibility help
×
Home

Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of Texas and comments on the phylogeny of Mosasauridae (Squamata)

  • G.L. Bell (a1) and M.J. Polcyn (a2)

Abstract

A new genus and species of primitive-limbed mosasauroid, Dallasaurus turneri, from the Middle Turonian (∼92 Ma) of north-central Texas, is described on the basis of two incomplete skeletons. The new taxon retains plesiomorphic characters such as facultatively terrestrial limbs (plesiopedal) but also exhibits certain characters shared with derived mosasaurs of the subfamily Mosasaurinae. In phylogenetic analysis, the new taxon reconstructs as the basal member of that clade. Other plesiopedal taxa previously included in the family Aigialosauridae reconstruct in basal positions within three different, major clades that include members that achieved the derived (hydropedal) fin-like limb condition. In addition, Opetiosaurus and Aigialosaurus reconstruct as successive outgroup taxa to all other mosasauroids, thereby demonstrating the paraphyletic nature of the current concept of Aigialosauridae. Interpretation of our phylogenetic analysis suggests that three different lineages of mosasauroids independently achieved the derived mosasaur body plan, including fully marine limb modifications culminating in the development of flippers or paddle-like appendages. The inclusion of plesiopedal forms within lineages of well-established hydropedal clades requires a reorganisation of our concepts of Mosasauridae to include these basal forms. In order to avoid continued use of the paraphyletic taxon ‘Aigialosauridae’ as currently defined, we recommend ‘Aigialosauridae’ as a formal taxonomic name be used only for inclusion of Aigialosaurus dalmaticus and potential members of its own independent lineage. This also avoids the implicit polyphyletic use of ‘Mosasauridae’. Additionally, the diagnosis of Mosasauridae should be modified to exclude limb characters that discriminate between more terrestrial versus more aquatic adaptations.

    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of Texas and comments on the phylogeny of Mosasauridae (Squamata)
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of Texas and comments on the phylogeny of Mosasauridae (Squamata)
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of Texas and comments on the phylogeny of Mosasauridae (Squamata)
      Available formats
      ×

Copyright

Corresponding author

* Corresponding author. Email: gbell@dellcity.com

References

Hide All
Adkins, W.S., 1928. Handbook of Texas Cretaceous fossils. University of Texas Bulletin 1838: 1–303.
Bardet, N., Pereda Suberbiola, X. & Jalil, N.-E., 2003. A new mosasauroid (Squamata) from the Late Cretaceous (Turonian) of Morocco. Comptes Rendus Palevol 2: 607–616.
Bell, G.L. Jr., 1993. A phylogenetic analysis of Mosasauroidea (Squamata). University of Texas at Austin, Texas: 293 pp. (unpubl. PhD thesis).
Bell, G.L. Jr., 1995. Middle Turonian (Cretaceous) mosasauroids from Big Bends National Park, Texas, In: Santucci, V.L. & McClelland, L. (eds): National Park Service Paleontological Research, Technical Report NPS/NRP01NRTR-95/16, U.S. Department of the Interior, National Park Service (Denver, Colorado): 118 pp.
Bell, G.L. Jr., 1997. A phylogenetic revision of North American and Adriatic Mosasauroidea. In: Callaway, J.M. & Nicholls, E.L. (eds): Ancient marine reptiles. Academic Press (San Diego): 293–332.
Bell, G.L. Jr. & Polcyn, M.J., 1995. A new basal mosasauroid from the Arcadia Park Member of the Eagle Ford Shale (Late Middle Turonian) near Dallas, Texas. Journal of Vertebrate Paleontology 15 (Suppl. to 3): 18A.
Bell, G.L. Jr. & VonLoh, J.P., 1998. New records of Turonian mosasauroids from the western United States. In: Martin, J.E., Hogenson, J.W. & Benton, R.C. (eds): Partners preserving our past, planning our future. Dakoterra 5: 15–28.
Caldwell, M.W., Carroll, R.L. & Kaiser, H., 1995. The pectoral girdle and forelimb of Carsosaurus marchesetti (Aigialosauridae), with a preliminary phylogenetic analysis of mosasauroids and varanoids. Journal of Vertebrate Paleontology 15: 516–531.
Calligaris, R., 1988. I rettili fossili degli ‘Strati calcariei ittilitici di comeno’ e dell’isola di Lesina. Atti del Museo civico di Storia naturale Trieste 41: 85–125.
Carroll, R.L. & DeBraga, M., 1992. Aigialosaurs: mid-Cretaceous varanoid lizards. Journal of Vertebrate Paleontology 12: 66–86.
DeBraga, M. & Carroll, R.L., 1993. The origin of mosasaurs as a model of macroevolutionary patterns and processes. Evolutionary Biology 27: 245–322.
Hattin, D.E., 1962. Stratigraphy of the Carlile Shale (Upper Cretaceous) in Kansas. Kansas Geological Survey, Bulletin 156: 1–155.
Hill, R.T., 1901. Geography and geology of the Black and Grand Prairies, Texas. United States Geological Survey, Report 21(7): 1–666.
Jacobs, L.L., Ferguson, K., Polcyn, M.J. & Rennison, C., 2005a. Cretaceous δ13C stratigraphy and the age of dolichosaurs and early mosasaurs. In: Schulp, A.S. & Jagt, J.W.M., (eds): Proceedings of the First Mosasaur Meeting.Netherlands Journal of Geosciences 84: 257–268.
Jacobs, L.L., Polcyn, K.J., Taylor, L.H. & Ferguson, K., 2005b. Sea-surface temperatures and palaeoenvironments of dolichosaurs and early mosasaurs. In: Schulp, A.S. & Jagt, J.W.M., (eds): Proceedings of the First Mosasaur Meeting. Netherlands Journal of Geosciences 84: 269–281.
Kornhuber, A.G., 1873. Über einen neuen fossilen Saurier aus Lesina. Abhandlungen der kaiserlich-königlichen geologischen Reichsanstalt zu Wien 5: 75–90.
Kornhuber, A.G., 1893. Carsosaurus marchesetti, ein neuer fossiler Lacertilier aus den Kreideschichten des Karstes bei Komen. Abhandlungen der geologischen Reichsanstalt zu Wien 17: 1–15.
Kornhuber, A.G., 1901. Opetiosaurus bucchichi, eine neue fossile Eidechse aus der unteren Kreide von Lesina in Dalmatien. Abhandlungen der geologischen Reichsanstalt zu Wien 17: 1–24.
Kramberger, K.G., 1892. Aigiaiosaurus, eine neue Eidechse aus den Kreideschiefern der Insel Lesina mit Rücksicht auf die bereits beschriebenen Lacertiden von Comen und Lesina. Glasnik huvatskoga naravolosovnoga derstva (Societas historico-matulis croatica) u Zagrebu 7: 74–106.
Lingham-Soliar, T., 1992. The tylosaurine mosasaurs (Reptilia, Mosasauridae) from the Upper Cretaceous of Europe and Africa. Bulletin de l’Institut royal des Sciences naturelles de Belgique, Sciences de la Terre 62: 171–194.
Lingham-Soliar, T., 1994. The mosasaur ‘Angolasaurus’ bocagei (Reptilia: Mosasauridae) from the Turonian of Angola re-interpreted as the earliest member of the genus Platecarpus. Paläontologische Zeitschrift 68(1/2): 287–282.
Lingham-Soliar, T., 1995. Anatomy and functional morphology of the largest marine reptile known, Mosasaurus hoffmani (Mosasauridae, Reptilia) from the Upper Cretaceous, Upper Maastrichtian of the Netherlands. Philosophical Transactions of the Royal Society London B347: 155–180.
Lydekker, R.A., 1888. Catalogue of the fossil Reptilia and Amphibia in the British Museum (Natural History), Part 1. Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia and Proterosauria. British Museum (NH) (London): xxviii + 309 pp.
Martin, L.D. & Stewart, J.D., 1977. The oldest (Turonian) mosasaurs from Kansas. Journal of Paleontology 51: 973–975.
Mulder, E.W.A. & Mai, H., 2003. Pre-Maastrichtian tetrapods from the Maastrichtian area: the oldest tylosaurine mosasaur (Reptilia: Squamata) from the late Cretaceous of Belgium; Hermann von Meyer (1860) revisited. In: Mulder, E.W.A. On the latest Cretaceous tetrapods from the Maastrichtian type area. Publicaties van het Natuurhistorisch Genootschap in Limburg 44: 19–22.
Owen, R., 1851. A monograph on the Reptilia of the Cretaceous formations. Palaeontographical Society, London. 5: 1–118.
Páramo, M.E., 1994. Posición sistemática de un reptil marino con base en los restos fósiles encontrados en capas del Cretácico superior en Yaguara (Huila). Revista de la Academia Colombiana de Ciencias exactas, físicas y naturales 19: 63–80.
Páramo, M.E., 2000. Yaguarasaurus columbianus (Reptilia, Mosasauridae), a primitive mosasaur from the Turonian (Upper Cretaceous) of Columbia. Historical Biology 14: 121–131.
Polcyn, M.J. & Bell, G.L. Jr., 1996. A complete skull of a new mosasauroid from the Arcadia Park Member of the Eagle Ford Shale (Late Middle Turonian) near Dallas, Texas. Journal of Vertebrate Paleontology 16 (Supplement to 3): 58A.
Polcyn, M.J. & Bell, G.L., 2005. Russellosamus coheni n. gen., n. sp., a 92 million-year-old mosasaur from Texas (USA), and the definition of the parafamily Russellosaurina. In: Schulp, A.S. & Jagt, J.W.M., (eds): Proceedings of the First Mosasaur Meeting. Netherlands Journal of Geosciences 84: 321–333.
Polcyn, M.J., Tchernov, E. & Jacobs, L.L., 1999. The Cretaceous biogeography of the eastern Mediterranean with a description of a new basal mosasauroid from ‘Ein Yabrud, Israel. In: Tomida, T., Rich, T. & Vickers-Rich, P. (eds): Proceedings of the Second Gondwanan Dinosaur Symposium. National Science Museum Tokyo, Monographs 15: 259–290.
Polcyn, M.J., Tchernov, E. & Jacobs, L.L., 2003. Haasiasaurus gen. nov., a new generic name for the basal mosasauroid Haasia Polcyn et al., 1999. Journal of Vertebrate Paleontology 23: 476.
Russell, D.A., 1967. Systematics and morphology of American mosasaurs. Bulletin of the Peabody Museum of Natural History, Yale University 23: 1–241.
Stewart, J.D. & Bell, G.L. Jr., 1994. North America’s oldest mosasaurs are teleosts. Natural History Museum of Los Angeles County, Contributions in Science 441: 1–9.
Swofford, D.L., 2002. PAUP*. Phylogenetic Analysis Using Parsimony (*and Other Methods). Sinauer Associates (Sunderland, Massachusetts).
Telles Antunes, M., 1964. 0 Neocretácico e o Cenozóico do litoral de Angola. Junta de Investigaçõ do Ultramar (Lisboa): 255 pp.
VonLoh, J.P. & Bell, G.L. Jr., 1998. Fossil reptiles from the Late Cretaceous Greenhorn Formation (Late Cenomanian-Middle Turonian) of the Black Hills region, South Dakota. In: Martin, J.E., Hogenson, J.W. & Benton, R.C. (eds): Partners preserving our past, planning our future. Dakoterra 5: 29–38.
Woodward, A.S., 1905. Note on some portions of mosasaurian jaws obtained by Mr. G.E. Dibley from the Middle Chalk of Cuxton, Kent. Proceedings of the Geologists’ Association 19: 185–187.

Keywords

Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of Texas and comments on the phylogeny of Mosasauridae (Squamata)

  • G.L. Bell (a1) and M.J. Polcyn (a2)

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed