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The so-called giant Miocene dolphin Megalodelphis magnidens Kellogg (Mammalia: Cetacea) is actually a crocodile (Reptilia: Crocodilia)

Published online by Cambridge University Press:  19 May 2016

Gary S. Morgan
Gary S. Morgan*
Affiliation:
Florida State Museum, University of Florida, Gainesville, 32611
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Abstract

The type specimen of Megalodelphis magnidens Kellogg, 1944, from the Late Tertiary of Florida, is not a long-beaked dolphin of the mammalian order Cetacea as it was originally described. The presence of splenial and angular bones in the holotype mandible, along with a suture for the surangular bone and an external mandibular fenestra, are reptilian characters unknown in the Mammalia. Details of the morphology and placement of the teeth and the conformation of the mandible reveal that this specimen belongs to a crocodilian, and should be referred to the long-snouted estuarine crocodile, Gavialosuchus americanus. Therefore, Megalodelphis magnidens Kellogg, 1944, becomes a junior synonym of Gavialosuchus americanus (Sellards, 1915). The edentulous “rostral” (actually mandibular) fragment referred by Kellogg to M. magnidens does represent a large, long-beaked odontocete cetacean; however, its fragmentary condition does not permit a positive allocation to genus. Pending a revision of the long-beaked odontocetes, this specimen is regarded as Odontoceti incertae sedis.

Type
Research Article
Information
Journal of Paleontology , Volume 60 , Issue 2 , March 1986 , pp. 411 - 417
Copyright
Copyright © The Paleontological Society 

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References

Allen, G. M. 1921. Fossil cetaceans from the Florida phosphate beds. Journal of Mammalogy, 2:144–160.Google Scholar
Auffenberg, W. 1954. Additional specimens of Gavialosuchus americanus (Sellards) from a new locality in Florida. Quarterly Journal of the Florida Academy of Sciences, 17:185–209.Google Scholar
Berggren, W. A. and van Couvering, J. A. 1974. The late Neogene: biostratigraphy, geochronology, and paleoclimatology of the last 15 million years in marine and continental sequences. Palaeogeography, Palaeoclimatology, Palaeoecology, Special Issue, 16(1/2):1–216.Google Scholar
Case, E. C. 1934. A specimen of a long-nosed dolphin from the Bone Valley gravels of Polk County, Florida. Contributions from the Museum of Paleontology, University of Michigan, 4:105–113.Google Scholar
Kellogg, R. 1944. Fossil cetaceans from the Florida Tertiary. Bulletin of the Museum of Comparative Zoology, 94:432–471.Google Scholar
MacFadden, B. J. and Webb, S. D. 1982. The succession of Miocene (Arikareean through Hemphillian) terrestrial mammalian localities and faunas in Florida, p. 186–199. In Scott, T. M. and Upchurch, S. B. (eds.), Miocene of the Southeastern United States. Florida Bureau of Geology, Special Publication 25.Google Scholar
Mook, C. C. 1921. Skull characters and affinities of the extinct Florida gavial Gavialosuchus americanus (Sellards). Bulletin of the American Museum of Natural History, 44:33–42.Google Scholar
Sellards, E. H. 1915. A new gavial from the Late Tertiary of Florida. American Journal of Science, 4th series, 40:135–138.Google Scholar
Webb, S. D. 1973. Pliocene pronghorns of Florida. Journal of Mammalogy, 54:203–221.Google Scholar
Webb, S. D. 1984. Ten million years of mammal extinctions in North America, p. 189–210. In Martin, P. S. and Klein, R. G. (eds.), Quaternary Extinctions, a Prehistoric Revolution. The University of Arizona Press, Tucson.Google Scholar
Webb, S. D. and Crissinger, D. B. 1983. Stratigraphy and vertebrate paleontology of the central and southern phosphate districts of Florida. Geological Society of America, Southeastern Section, Field Trip Guidebook, Central Florida Phosphate District, p. 28–72.Google Scholar
Webb, S. D., MacFadden, B. J. and Baskin, J. A. 1981. Geology and paleontology of the Love Bone Bed from the late Miocene of Florida. American Journal of Science, 281:513–544.Google Scholar
White, T. E. 1942. Additions to the fauna of the Florida phosphates. Proceedings of the New England Zoological Club, 21:87–91.Google Scholar