''Hesperotestudo'' ("Western turtle") 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 living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

tortoise Tortoises () are reptiles of the family Testudinidae of the order Testudines (Latin: ''tortoise''). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like oth ...

native to North and Central America from the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

to the

Late Pleistocene The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch withi ...

. Species of ''Hesperotesudo'' varied widely in size, with the largest unnamed species from

El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south ...

reaching in carapace length, larger than that of extant giant tortoises. Historically considered a

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between ...

of ''

Geochelone ''Geochelone'' is a genus of tortoises. ''Geochelone'' tortoises, which are also known as typical tortoises or terrestrial turtles, can be found in southern Asia. They primarily eat plants. Species The genus consists of two extant species: A n ...

'', it is now considered to be distantly related to that genus. Its closest relatives are the extant ''

Gopherus ''Gopherus'' is a genus of fossorial tortoises commonly referred to as gopher tortoises. The gopher tortoise is grouped with land tortoises that originated 60 million years ago, in North America. A genetic study has shown that their closest relat ...

'' (gopher tortoises) and the extinct '' Stylemys.'' The ancestor of the three genera arrived in North America during the Early

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

. The bodies of ''Hesperotesudo'' species were extensively covered with large dermal ossicles, which in life were covered in keratin. It has been suggested that species of ''Hesperotestudo'' were relatively tolerant of cold weather. ''Hesperotestudo'' became extinct at the end of the Pleistocene and beginning of the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

co-incident with the arrival of the first humans in North America, and sites have been found where ''Hesperotestudo'' were butchered.

Taxonomy

Species list is based on Vlachos, 2018 *† ''Hesperotestudo'' Williams 1950Williams , E.E. 1950. ''Testudo cubensis'' and the evolution of Western Hemisphere tortoises. ''Bulletin of the American Museum of Natural History'' 95:1–36. **†''Hesperotestudo bermudae'' Meylan and Sterrer 2000 Bermuda, Middle Pleistocene c. 310,000 years

before present Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Beca ...

(YBP) - shell length c. **†''Hesperotestudo crassiscutata'' (Leidy 1889)Leidy, J. 1889. Description of vertebrate remains from Peace Creek, Florida. ''Transactions of the Wagner Free Institute of Science of Philadelphia'' 2:19–31. Florida, Texas, Illinois, South Carolina, Middle-Late Pleistocene shell length c. **†''Hesperotestudo ducateli'' (Collins and Lynn, 1936)

Calvert Formation The Calvert Formation is a geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene epoch of the Neogene period. The formation is a destination for amateur fossil hunters as well as ...

, Maryland, Middle Miocene (

Langhian The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007) The Langhian was ...

–

Serravallian The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/Series, which spans the time between 13.82 Ma and 11.63 Ma (million years ago). The Serravallian follows the Langhian and is followed by the Torto ...

) **†''Hesperotestudo gilbertii'' (Hay, 1899)

Ogallala Formation The Ogallala Formation is a Miocene to early Pliocene geologic formation in the central High Plains of the western United States and the location of the Ogallala Aquifer. In Nebraska and South Dakota it is also classified as the Ogallala Group. ...

, Kansas, Hemphillian, Late Miocene-Early Pliocene ( Tortonian–

Zanclean The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, a ...

) **†''Hesperotestudo orthopygia'' (Cope, 1878) (syn= ''Xerobates cyclopygius'' Cope, 1878 =''Caryoderma snovianum'' Cope, 1886 = ''Testudo rexroadensis'' Oelrich, 1952 = ''Geochelone nordensis'' Holman, 1973) Kansas, California, Nebraska, Late Miocene-Pliocene shell length c. **†''Hesperotestudo osborniana'' (Hay, 1905)(syn= ''Testudo arenivaga'' Hay, 1906 = ''Testudo farri'' Hay, 1908 = ''Testudo impensa'' Hay, 1908 = ''Testudo orthopygia angusticeps'' Matthew, 1924) Colorado, Nebraska, Montana, Early Miocene-Early Pliocene shell length up to **†''Hesperotestudo turgida'' (Cope, 1892) (syn = ''Testudo incisa'' Hay, 1916a = ''Testudo riggsi'' Hibbard, 1944 = ''Testudo wilsoni'' Milstead, 1956 = ''Geochelone johnstoni'' Auffenberg 1962 = ''Geochelone alleni'' Auffenberg, 1966 = ''Geochelone oelrichi'' Holman, 1972a = ''Geochelone mlynarskii'' Auffenberg, 1988) Florida, Oklahoma, Kansas, Texas, Nebraska, Late Miocene-Late Pleistocene shell length c. **†''Hesperotestudo williamsi'' (Auffenberg, 1964)

Oakville Formation The Oakville Formation is a geologic formation in Texas. It preserves fossils dating back to the Neogene period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to paleontolog ...

, Texas, Early Miocene (

Burdigalian The Burdigalian is, in the geologic timescale, an age or stage in the early Miocene. It spans the time between 20.43 ± 0.05 Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian, the Burdigalian was the first and longest w ...

) shell length c. Hesperotestudo

References

{{Testudinidae Testudinidae Miocene turtles Pliocene turtles Pleistocene turtles Cenozoic reptiles of North America Prehistoric turtle genera Extinct turtles