Skip to main content
×
Home

Neuroanatomy of Gryposuchus neogaeus (Crocodylia, Gavialoidea): a first integral description of the braincase and endocranial morphological variation in extinct and extant gavialoids

  • Paula Bona (a1), Ariana Paulina Carabajal (a2) and Zulma Gasparini (a1)
Abstract
ABSTRACT

Morphological studies of the braincase and cranial endocast of fossil crocodylians, especially gavialids, are scarce. Here, we present a detailed description of the neuroanatomy of Gryposuchus neogaeus from the Miocene of Argentina, based on CT scans. The cranial endocast is sub-horizontal and the angle formed between the mid-brain and the hind-brain is poorly marked. When compared with Gavialis gangeticus, the mid-brain of G. neogaeus is relatively shorter, although the distribution of cranial nerves is similar. In the floor of the endocranial cavity, posterior to the dorsum sellae, there is a median foramen that leads into a canal that runs anteroventrally through the basisphenoid to penetrate the posterior wall of the pituitary fossa (open foramen for the basilar artery?). The same structure is present in G. gangeticus, but is absent in other living crocodylians, suggesting a potential synapomorphy of Gavialoidea. The pneumaticity of the skull roof and the lateral branches of the pharyngotympanic system in G. neogaeus are markedly reduced when compared with the extant species. Comparisons with the living Gavialis indicate that the pattern of braincase morphology of Gavialidae was present in the Miocene; however, the internal morphology, including brain shape, pneumaticity of the skull roof and basicranium, is different in the two species. This work is the first step to understand the variation of the neuroanatomy in this group of archosaurs and its palaeobiological implication.

  • View HTML
    • 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.

      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.

      Neuroanatomy of Gryposuchus neogaeus (Crocodylia, Gavialoidea): a first integral description of the braincase and endocranial morphological variation in extinct and extant gavialoids
      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 Dropbox account. Find out more about sending content to Dropbox.

      Neuroanatomy of Gryposuchus neogaeus (Crocodylia, Gavialoidea): a first integral description of the braincase and endocranial morphological variation in extinct and extant gavialoids
      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 Google Drive account. Find out more about sending content to Google Drive.

      Neuroanatomy of Gryposuchus neogaeus (Crocodylia, Gavialoidea): a first integral description of the braincase and endocranial morphological variation in extinct and extant gavialoids
      Available formats
      ×
Copyright
Corresponding author
*Corresponding author
References
Hide All
Benton M. J. & Clark J. M. 1988. Archosaur phylogeny and the relationships of the Crocodylia. In Benton M. (ed.) The Phylogeny and Classification of Tetrapods: Volume 1: Amphibians, Reptiles, Birds. The Systematics Association Special Volume 35, 295338. Oxford: Oxford University Press. 392 pp.
Bona P., Degrange F. J. & Fernández M. S. 2013. Skull anatomy of the bizarre crocodylian Mourasuchus nativus (Alligatoridae, Caimaninae). The Anatomical Record 296, 227–39.
Bona P. & Paulina Carabajal A. 2013. Caiman gasparinae sp. nov., a huge alligatorid (Caimaninae) from the late Miocene of Paraná, Argentina. Alcheringa 37, 112.
Brandoni D. & Scillato-Yané G. J. 2007. Los Megatheriinae (Xenarthra, Tardigrada) del Terciario de Entre Ríos, Argentina: aspectos taxonómicos y sistemáticos. Ameghiniana 44, 427–34.
Brochu C. A. 2004. A new Late Cretaceous gavialoid crocodylian from eastern North America and the phylogenetic relationships of thoracosaurs. Journal of Vertebrate Paleontology 24, 610–33.
Burmeister G. 1885. Examen crítico de los mamíferos y reptiles fósiles denominados por Don Augusto Bravard y mencionados en su obra precedente. Annales del Museo Nacional de Buenos Aires 3, 95173.
Cleuren J. & De Vree F. 2000. Feeding in crocodylians. In Schwenk K. (ed.) Feeding: Form, Function and Evolution in Tetrapod Vertebrates, 337–58. San Diego, CA: Academic Press. 564 pp.
Dufeau D. L. 2011. The evolution of cranial pneumaticity in Archosauria: Patterns of paratympanic sinus development. Unpublished PhD Thesis, Faculty of the College of Arts and Sciences of Ohio University, USA. 175 pp.
Franzosa J. W. 2004. Evolution of the brain in Theropoda (Dinosauria). Unpublished PhD Thesis, Faculty of the Graduate School of The University of Texas at Austin, USA. 357 pp.
Galton P. M. 1985. Cranial anatomy of the prosauropod dinosaur Plateosaurus from the Knollenmergel (Middle Keuper, Upper Triassic) of Germany. II. All the cranial material and details of soft-part anatomy. Geologica et Palaeontologica 19, 119–59.
Gasparini Z. 1968. Nuevos restos de Rhamphostomopsis neogeaeus (Burm.) Rusconi, 1933, (Reptilia, Crocodilia) del “Mesopotamiense” (Plioceno medio-superior) de Argentina. Ameghiniana 5, 299311.
Gold M. E. L. 2011. Cranial osteology and braincase morphometrics of Gavialis gangeticus: implications for crocodilian phylogenetics . Master's Thesis, University of Iowa, USA. http://ir.uiowa.edu/etd/2504.
Gürich G. 1912. Gryposuchus jessei ein neues schamalschnauziges Krokodile aus den jüengeren Ablagerungen des oberen Amazonas-Gabietes. Mitteilungen des Mineralogischen, Geologischen Instituts Hamburg 4, 5971.
Holliday C. M. & Gardner N. M. 2012. A new eusuchian crocodyliform with novel cranial integument and its significance for the origin and evolution of Crocodylia. PLoS ONE 7, e30471. doi: 10.1371/journal.pone.0030471
Holliday C. M. & Witmer L. C. 2004. Anatomical domains within the heads of archosaurs and their relevance for functional interpretation. Journal of Vertebrate Paleontology 24(suppl. 3), 71.
Holliday C. M. & Witmer L. M. 2009. The epipterygoid of crocodyliforms and its significance for the evolution of the orbitotemporal region of eusuchians. Journal of Vertebrate Paleontology 29, 715–33.
Hopson J. A. 1979. Paleoneurology. In Gans C., Northcutt R. G. & Ulinski P. (eds) Biology of the Reptilia, Volume. 9: Neurology A, 39146. New York: Academic Press. xv+462 pp.
Jerison H. J. 1973. Evolution of the brain and intelligence. New York & London: Academic Press. 483 pp.
Kawabe S., Shimokawa T., Miki H., Okamoto T. & Matsuda S. 2009. A simple and accurate method for estimating the brain volume of birds: possible application in paleoneurology. Brain Behavior and Evolution 74, 295301.
Knoll F., Witmer L.M., Ortega F., Ridgely R. C. & Schwarz-Wings D. 2012. The braincase of the basal sauropod dinosaur Spinophorosaurus and 3D reconstructions of the cranial endocast and inner ear. PlosOne 7, e30060. doi:10.1371/journal.pone.0030060
Knoll F., Witmer L. M., Ridgely R. C., Ortega F. & Sanz J. L. 2015. A new titanosaurian braincase from the Cretaceous “Lo Hueco” locality in Spain sheds light on neuroanatomical evolution within Titanosauria. PLoS ONE 10(10), e0138233. doi:10.1371/journal.pone.0138233.
Langston W. Jr. 1965. Fossil crocodilians from Colombia and the Cenozoic history of the Crocodilia in South America. University of California Publications in Geological Sciences 52, 115.
Langston W. Jr. & Gasparini Z. 1997. Crocodilians, Gryposuchus and the South Americans gavials. In Kay R. F., Madden N. H., Ciffelli R. L. & Flinn J. J. (eds) Vertebrate paleontology in the Neotropics: The Miocene fauna of La Venta, Colombia, 113–54. Washington DC: Smithsonian Institution.
Lemoine V. 1883. Note sur l'encéphale du Gavial du Mont-Aimé, étudié sur trois moulages naturels. Bulletin de la Société Géologique de France 3, 158–62.
Paulina Carabajal A. 2012. Neuroanatomy of titanosaurid dinosaurs from the Upper Cretaceous of Patagonia, with comments on endocranial variability within Sauropoda. The Anatomical Record 295, 2141–56.
Paulina Carabajal A., Carballido J. & Currie P. J. 2014. Braincase, neuroanatomy and neck posture of Amargasaurus cazaui (Sauropoda: Dicraeosauridae) and its implications for understanding head posture in sauropods. Journal of Vertebrate Paleontology 34, 870–82.
Riff D., Romano P. S. R., Oliveira G. R. & Aguilera O. A. 2010. Neogene crocodile and turtle fauna in Northern South America. In Hoorn C. & Wesselingh F. (eds) Amazonia, Landscape and Species Evolution: a Look into the Past, 259–80. Oxford: Wiley-Blackwell. 464 pp.
Riff D. & Aguilera O. A. 2008. The world's largest gharials Gryposuchus: description of G. croizati n. sp. (Crocodylia, Gavialidae) from the Upper Miocene Urumaco Formation, Venezuela. Paläontologische Zeitschrift 82, 178–95.
Rusconi C. 1933. Observaciones críticas sobre reptiles Terciarios de Paraná (Familia Alligatoridae). Revista de la Universidad Nacional de Córdoba 20, 152.
Salas-Gismondi R., Flynn J. J., Baby P., Tejada-Lara J. V., Wesselingh F. P. & Antonie P.-O. 2015. A Miocene hyper-diverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands. Proceedings of the Royal Society B 282, 20142490. http://dx.doi.org/10.1098/rspb.2014.2490
Sedlmayr J. C. 2002. Anatomy, evolution and functional significance of cephalic vasculature in Archosauria. Unpublished PhD Thesis, Ohio University, USA. 398 pp.
Walsh S. A., Barrett P. M., Milner A. C., Manley G. & Witmer L. M. 2009. Inner ear anatomy is a proxy for deducing auditory capability and behaviour in reptiles and birds. Proceedings of the Royal Society B 276, 1355–60.
Walsh S. A., Iwaniuk A. N., Knoll M. A., Bourdon E., Barrett P. M., Milner A. C., Nudds R. L., Abel R. L. & Dello Sterpaio P. 2013. Avian cerebellar floccular fossa size is not a proxy for flying ability in birds. PLoSONE 8(6), e67176. doi:10.1371/journal.pone.0067176
Witmer L. M., Chatterjee S., Franzosa J. & Rowe T. 2003. Neuroanatomy of flying reptiles and implications for flight, posture and behavior. Nature 425, 950–53.
Witmer L. M., Ridgely R. & Dufeau D. L. 2008. Using CT to peer into the past: 3D visualization of the brain and ear regions of birds, crocodiles and nonavian dinosaurs. In Endo H, & Frey R. (eds) Anatomical Imaging: Towards a New Morphology, 6787. Tokyo: Springer. 146 pp.
Witmer L. M., & Ridgely R. C. 2008. The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture. Anatomical Record 291, 1362–88.
Von Baczko M. B., Barrios F., Desojo J. B., Paulina Carabajal A. & Bona P. 2015. New insights on the development of the flocculus on pseudosuchia (archosauria). XXIX Jornadas Argentinas de Paleontología Vertebrados, Actas 82.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Earth and Environmental Science Transactions of The Royal Society of Edinburgh
  • ISSN: 1755-6910
  • EISSN: 1755-6929
  • URL: /core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords:

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 31
Total number of PDF views: 330 *
Loading metrics...

Abstract views

Total abstract views: 749 *
Loading metrics...

* Views captured on Cambridge Core between 6th January 2017 - 14th December 2017. This data will be updated every 24 hours.