Tortoises and Turtles
Giant Pleistocene Tortoises
During the Pleistocene epoch, the Midwest was home to a diverse assemblage of turtles, including both species that survive today and several extinct forms. Freshwater turtles such as pond turtles, snapping turtles, and softshell turtles inhabited rivers, lakes, and wetlands, while terrestrial box turtles had become specialized for life outside the water as specialist burrowers. Among the most impressive turtles found in this region were the giant tortoises of the genus Hesperotestudo, which lived across parts of the southern and central United States and could reach shell lengths exceeding one meter. These large herbivores were among the last giant tortoises to inhabit mainland North America.
Western giant tortoise
Hesperotestudo sp.
Temporal Range: 20 million years ago to approximately 10,000 years ago
Geographic Range: Found across southern North America and Central America
Species: H. crassiscutata, H. osborniana, H. turgida, H. ducateli , H. orthopygia
Diet: Herbivorous, grasses, leaves, fruits, some invertebrates
Hesperotestudo was a giant land tortoise that lived in North America during the Pleistocene epoch and was among the largest turtles ever to inhabit the continent. Fossils of several species have been found across the southern and central parts of the US, as well as parts of Central America, where these reptiles occupied warm grasslands, woodlands, and scrub environments. Some North American species grew to shell lengths of more than 3 feet, while others from Central America grew to be nearly 5 feet long, making them much larger than our living types of North American tortoises.
The shell of Hesperotestudo was heavily built and provided protection from large Ice Age predators. It likely fed on grasses, leaves, fruits, and other vegetation available in its environment. It seems to have been able to live in colder environments than many giant tortoises can withstand today.
(BELOW) A labeled diagram of the skeletal anatomy of a tortoise. In this drawing the shell is presented in cross-section in order to reveal the underlying skeletal features. The vertebrae of the animal's back are fused to the tortoise's shell
(BELOW) A labeled diagram of the arrangement of the outer scutes covering the shell of a tortoise. The carapace consists of the bones and scutes found on the dorsal side of the tortoise while the plastron covers the lower part of the body
Media Gallery
Suggested References: Tortoises
Biewer, Jacob; Sankey, Julia; Hutchison, Howard; Garber, Dennis (2016). "A fossil giant tortoise from the Mehrten Formation of Northern California". PaleoBios. 33. doi:10.5070/p9331030312. ISSN 2373-8189.
Dunbar, James S.; Webb, S. David (1996). "17. Bone and Ivory Tools from Submerged Paleoindian Sites in Florida". In Anderson, David G.; Sassaman, Kenneth E. (eds.). The Paleoindian and Early Archaic Southeast. University Alabama Press. pp. 331–353.
Moll, Don; Brown, Lauren E. (2017). "Reinterpretation of the Climatic Adaptation of Giant Fossil Tortoises in North America". Herpetological Journal. 27 (3): 276–286.
Vlachos, Evangelos (2018-04-17). "A Review of the Fossil Record of North American Turtles of the Clade Pan-Testudinoidea". Bulletin of the Peabody Museum of Natural History. 59 (1): 3.