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Podocnemis unifilis, the yellow-spotted Amazon River turtle (Podocnemididae), is widespread in the Amazon and Orinoco drainages of northern South America (Zug, 1993; Iverson, 1992; King and Burke, 1992).

The podocnemidids are a group of pleurodire, or side-necked, turtles known today from South America, Africa, and Madagascar. They enjoyed a broader distribution in the past (i.e., Hamadachelys), occurring in North America, Europe, and India in the Cretaceous and Tertiary (de Broin, 1988; Pritchard and Trebbau, 1984). The living pleurodires consist of the Chelidae (Australia, South America) and the Pelomedusoides (Podocnemididae; and the African Pelomedusidae, i.e., Pelusios).

This specimen, a female, was collected by H. Bassler in 1930 from the Rio Ucayali, Contamana, Peru. It was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Dr. Gene Gaffney of the American Museum of Natural History, in collaboration with Dr. Timothy Rowe of The University of Texas at Austin. Funding for scanning was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Rowe.

The specimen was scanned by Richard Ketcham and Matthew Colbert on 01 November 2000 along the coronal axis for a total of 444 slices, each slice 0.190 mm thick, with an interslice spacing of 0.190 mm. The animations displayed below were reduced for optimal Web delivery from the original, much higher resolution CT data. Several unreduced sample CT slices are presented on this page to illustrate some key anatomical features of Podocnemis.

de Broin, F. 1988. Les Tortues et le Gondwana. Studia geologica Salamanticensia. Studia Palaeochelonologica II:103-142.

Ernst, C. H., and R. W. Barbour. 1989. Turtles of the World. Smithsonian Institution Press, Washington, D.C., 313 pp.

Gaffney, E. S. 1972. An illustrated glossary of turtle skull nomenclature. American Museum Novitates 2486:1-33.

Gaffney, E. S. 1979. Comparative cranial morphology of recent and fossil turtles. Bulletin of the American Museum of Natural History 164:65-376.

Gaffney, E. S. 1990. Comparative osteology of the Triassic turtle Proganochelys. Bulletin of the American Museum of Natural History 194:1-263.

Gaffney, E. S., and P. A. Meylan. 1988. A phylogeny of turtles; pp. 157-219 in M. J. Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds. Systemtics Association Special Volume 35A, Clarendon Press, Oxford.

Iverson, J. B. 1992. A revised checklist with distribution maps of the turtles of the world. Privately printed, Richmond, Indiana, 363 pp.

King, F. W., and R. L. Burke. 1989. Crocodilian, Tuatara, and turtle species of the world, a taxonomic and geographic reference. Association of Systematic Collections, Washington, D. C., 216 pp.

Meylan, P. A. 1996. Skeletal morphology and relationships of the early cretaceous side-necked turtle, Araripemys barretoi (Testudines: Pelomedusoides: Araripemydidae), from the Santana Formation of Brazil. Journal of Vertebrate Paleontology 16:20-33.

Pough, F. H., R. M. Andrews, J. E. Cadle, M. L. Crump, A. H. Savitzky, and K. D. Wells. 1998. Herpetology. Prentice Hall, Upper Saddle River, New Jersey, 577 pp.

Pritchard, P. C. H., and P. Trebbau. 1984. The turtles of Venezuela. Society for the Study of Amphibians and Reptiles Contributions to Herpetology Number 2, 403 pp.

Schumacher, G. H. 1973. The head muscles and hyolaryngeal skeleton of turtles and crocodilians; pp: 101-199 in C. Gans and T. S. Parsons (eds.), Biology of the Reptilia, Volume 14. Academic Press, New York.

Zug, G. 1993. Herpetology, an Introductory Biology of Amphibians and Reptiles. Academic Press, San Diego, 527 pp.

Links

The Chelonian Research Foundation

The Tortoise Trust

Gene Gaffney's Phylogeny of Turtles (AMNH) (requires Flash plug-in)

Podocnemis unifilis on CalPhotos.

None available.