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Sigournea multidentata, a new stem tetrapod from the Upper Mississippian of Iowa, USA

Published online by Cambridge University Press:  11 August 2017

John R. Bolt  and
R. Eric Lombard
John R. Bolt
Affiliation:
Department of Geology, Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, Illinois 60605,
R. Eric Lombard
Affiliation:
Department of Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th Street, Illinois 60637,
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Abstract

Sigournea multidentata n. gen. and sp., an early tetrapod, is described from the Late Mississippian Delta locality of southern Iowa, USA. The holotype and only known specimen, a right mandible, is unique in the structure of the symphysial region, and in addition has a unique combination of characters that are shared with other tetrapods. The free ventral border of the single exomeckelian fenestra is formed by infradentary bones. Its visible portion shows several arch bases, separated by notched or straight intervals. This morphology is interpreted as indicating that the arch bases and intervals between them reflected a series of Meckelian fenestrae that were partly exo- and partly endoskeletal, due to the fact that the exoskeletal arch bases continued dorsally in Meckelian cartilage. We suggest that this may exemplify a stage in the evolution of exomeckelian fenestrae, in at least some lineages of early tetrapods. The relations of Sigournea are indeterminate. That it is a tetrapod is indicated by the presence of pit and ridge ornamentation, an open lateral line sulcus, a dorsally directed glenoid, a single elongate exomeckelian fenestra, absence of intercoronoid fossae, absence of coronoid fangs, a single row of marginal teeth on the dentary, and an absence of dentition on the prearticular. It is at present impossible to determine its relationship with other early tetrapods, and we conclude that Sigournea is best considered as an early tetrapod incertae sedis.

Information

Type
Research Article
Information
Journal of Paleontology , Volume 80 , Issue 4 , July 2006 , pp. 717 - 725
Copyright
Copyright © The Paleontological Society 

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References

Ahlberg, P. E., and Clack, J. A. 1998. Lower jaws, lower tetrapods – a review based on the Devonian genus Acanthostega . Transactions of the Royal Society of Edinburgh: Earth Sciences, 89:11–46.CrossRefGoogle Scholar
Beaumont, E. H., and Smithson, T. R. 1998. The cranial morphology and relationships of the aberrant Carboniferous amphibian Spathicephalus mirus Watson. Zoological Journal of the Linnean Society, 122: 187–209.Google Scholar
Bolt, J. R., and Lombard, R. E. 2001. The mandible of the primitive tetrapod Greererpeton, and the early evolution of the tetrapod lower jaw. Journal of Paleontology, 75:1016–1042.Google Scholar
Clack, J. A., and Ahlberg, P. E. 2004. A new stem tetrapod from the Early Carboniferous of Northern Ireland, p. 309–320. In Arratia, G., Wilson, M. V. H., and Cloutier, R. (eds.), Recent Advances in the Origin and Early Radiation of Vertebrates. Verlag Dr. Friedrich Pfeil, Munchen.Google Scholar
Clement, G., Ahlberg, P. E., Blieck, A., Blom, H., Clack, J. A., Poty, E., Thorez, J., and Janvier, P. 2004. Devonian tetrapod from Western Europe. Nature, 427:412–413.Google Scholar
Daeschler, E. B. 2000. Early tetrapod jaws from the Late Devonian of Pennsylvania, USA. Journal of Paleontology, 74:301–308.Google Scholar
Daeschler, E. B., Schubin, N., Thompson, K. S., and Amaral, W.W. 1994. A Devonian tetrapod from North America. Science, 265:639–642.Google Scholar
Goodrich, E. S. 1930. Studies on the Structure and Development of Vertebrates. MacMillan, London, 837 p.Google Scholar
Jarvik, E. 1952. On the fish-like tail in the ichthyostegid stegocephalians. Meddelelser om Grønland, 114:1–90.Google Scholar
Lombard, R. E., and Bolt, J. R. 1995. A new primitive tetrapod, Whatcheeria deltae, from the Lower Carboniferous of Iowa. Palaeontology, 38:471–494.Google Scholar
Lombard, R. E., and Bolt, J. R. In press. The mandible of Whatcheeria deltae, an early tetrapod from the Late Mississippian of Iowa. In Carrano, M., Gaudin, T. J., Blob, R., and Wible, J. (eds.), Amniote Paleobiology: Perspectives on the Evolution of Mammals, Birds, and Reptiles. University of Chicago Press.Google Scholar
Romer, A. S. 1969. A temnospondylous labyrinthodont from the Lower Carboniferous. Kirtlandia, 6:1–20.Google Scholar
Ruta, M., Coates, M. I., and Quicke, D. L. J. 2003. Early tetrapod relationships revisited. Biological Reviews, 78:251–345.Google Scholar
Schultze, H.-P., and Bolt, J. R. 1996. The lungfish Tranodis and the tetrapod fauna from the Upper Mississippian of North America. Special Papers in Palaeontology, no. 52:31–54.Google Scholar
Smithson, T. R. 1980. A new labyrinthodont amphibian from the Carboniferous of Scotland. Palaeontology, 23:915–923.Google Scholar
Warren, A., and Turner, S. 2004. The first stem tetrapod from the Lower Carboniferous of Gondwanna. Paleontology, 47:151–184.Google Scholar
Watson, D. M. S. 1929. The Carboniferous amphibia of Scotland. Palaeontologia Hungarica, 1:219–252.Google Scholar
Zhu, M., Ahlberg, P. E., Zhao, W., and Jia, L. 2002. First Devonian tetrapod from Asia. Nature, 420:760–761.Google Scholar