''Axestemys'' is an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
softshell turtle
The Trionychidae are a taxonomic family of a number of turtle genera, commonly known as softshell turtles. The family was erected by Leopold Fitzinger in 1826. Softshells include some of the world's largest freshwater turtles, though many can ad ...
that lived from the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
to the
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
in western
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
and
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
.
''Axestemys'', like its modern relatives, had no
scute
A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s on its
carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...
, which probably had leathery, pliable skin at the sides. Despite living several million years ago, ''Axestemys'' would have looked very similar to its modern relatives, with a long neck, a sharp beak, and three toes on each foot.
All species of ''Axestemys'' grew to a large size, especially ''A. byssina'', that could reach a total length of or more, being larger than any modern day species of softshell turtle.
Based on the diet of modern softshell turtles, it was an
omnivore
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...
, eating water plants, invertebrates, and perhaps small fish.
See also
* ''
Drazinderetes
''Drazinderetes'' is a large bodied genus of soft shell turtle from the Middle Eocene Drazinda Formation of Pakistan. Its presence in the shallow marine deposits of the Drazinda Formation suggests that ''Drazinderetes'' may have been a partiall ...
'', another enormous trionychid
* ''
Stupendemys
''Stupendemys'' is an extinct genus of freshwater side-necked turtle, belonging to the family Podocnemididae. It is the largest freshwater turtle known to have existed, with a carapace over 2 meters long. Its fossils have been found in norther ...
'', a giant prehistoric freshwater
side-necked turtle
* ''
Archelon
''Archelon'' is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring from head to tail and in body mass. It is known only from the Dakota Pierre Shal ...
'', a giant sea turtle of the Cretaceous
*
Largest prehistoric animals
The largest prehistoric animals include both vertebrate and invertebrate species. Many of them are described below, along with their typical range of size (for the general dates of extinction, see the link to each). Many species mentioned might ...
References
Further reading
*
*
Paleocene reptiles of North America
Trionychidae
Paleocene turtles
Prehistoric turtle genera
Hell Creek fauna
Fossil taxa described in 1945
Extinct turtles
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