There are two extant species of the family Chelydridae: Chelydra serpentina, the Common Snapping Turtle, and its larger relative Macrochelys temminkii, the Alligator Snapping Turtle (although the monotypic Asian genus Platysternon has at times been included in this group). Both are endemic to the Western Hemisphere. The hierarchy of scientific classification. ... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... Binomial name Chelydra serpentina (Linnaeus, 1758) Common Snapping Turtle head The Snapping TurtleMexico. ... Binomial name Troost, 1835 Synonyms Macroclemmys temminckii Boulenger, 1889 Chelonura temminckii Troost, 1835 Testudo planitia Gmelin, 1789 The Alligator Snapping Turtle (Macrochelys temminckii) is the largest freshwater turtle in North America. ... World map showing the location of Asia. ... For other uses, see Genus (disambiguation). ... Binomial name Gray, 1831 The Big-headed Turtle (Platysternon megacephalum) is a species of turtle in the Platysternidae family. ... In biology and ecology endemic means exclusively native to a place or biota, in contrast to cosmopolitan or introduced. ... The geographical western hemisphere of Earth, highlighted in yellow. ...

Fossil history

The Chelydridae have a long fossil history, with extinct species reported from North America, Asia and Europe, far outside its present range. The earliest described chelydrid is Emarginachelys cretacea, known from well preserved fossils from the Maastrichtian stage of the Late Cretaceous of Montana. Another well preserved fossil chelydrid is the Late Paleocene Protochelydra zangerli from North Dakota. The carapace of Protochelydra is higher domed than that of the Recent Chelydra, a trait conjectured to be associated with the coexistence of large, chelonivorous (i.e., turtle-eating) crocodilians. Another genus, Chelydropsis, contains several well known Eurasian chelyrdid species that existed from the Oligocene to the Pliocene. FOSSIL is a standard for allowing serial communication for telecommunications programs under DOS. FOSSIL is an acronym for Fido Opus Seadog Standard Interface Layer. ... The Dodo, shown here in a 1651 illustration by Jan Savery, is an often-cited[1] example of modern extinction. ... North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... World map showing the location of Europe. ... The Maastrichtian is the last stage of the Cretaceous period, and therefore of the Mesozoic era. ... The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ... Official language(s) English Capital Helena Largest city Billings Area  Ranked 4th  - Total 147,165 sq mi (381,156 km²)  - Width 255 miles (410 km)  - Length 630 miles (1,015 km)  - % water 1  - Latitude 44°26N to 49°N  - Longitude 104°2W to 116°2W Population  Ranked... The Paleocene, early dawn of the recent, is a geologic epoch that lasted from 65. ... Official language(s) English Capital Bismarck Largest city Fargo Area  Ranked 19th  - Total 70,762 sq mi (183,272 km²)  - Width 210 miles (340 km)  - Length 340 miles (545 km)  - % water 2. ... The term carapace refers to a dorsal section of an exoskeleton or shell, in a number of animal groups. ... black: range of Crocodilia Families Gavialidae Alligatoridae Crocodylidae Crocodilia is an order of large reptiles that appeared about 84 million years ago in the Late Cretaceous Period (Campanian stage). ... Eurasia Eurasia African-Eurasian aspect of Earth Eurasia is an immense landmass covering about 54,000,000 km² (or about 10. ... The hierarchy of scientific classification. ... The Oligocene epoch is a geologic period of time that extends from about 34 million to 23 million years before the present. ... The Pliocene epoch (spelled Pleiocene in some older texts) is the period in the geologic timescale that extends from 5. ...

Classification of known genera

• Family Chelydridae
  • • Genus Acherontemys (extinct)
    • Genus Chelydrops (extinct)
    • Genus Chelydropsis (extinct)
    • Genus Emarginachelys (extinct)
    • Genus Macrocephalochelys (extinct)
    • Genus Planiplastron (extinct)
  • Subfamily Chelydrinae
    • Genus Protochelydra (extinct)
    • Genus Macrochelys
    • Genus Chelydra

References

• de Broin, F. 1969. Contribution a l’etude des cheloniens. Cheloniens continentaux du Cretace Superieur et du Tertiaire de France. Memoires du Museum National D’Histoire Naturelle. Vol. C, No. XXVIII

• Ericson, B. R. 1973. A new chelydrid turtle (Protochelydra zangerli), from the late Paleocene of North Dakota. Scientific Publications of the Science Museum of Minnesota, New Series 2(2):1-16

• Gaffney, E. S. 1975. Phylogeny of the chelydrid turtles: a study of shared derived characters in the skull. Fieldiana Geology, 33:157-178

• Parham, J. F., C.R. Feldman, and J. R. Boore. The complete mitochondrial genome of the enigmatic bigheaded turtle (Platysternon): description of unusual genomic features and the reconciliation of phylogenetic hypotheses based on mitochondrial and nuclear DNA. BMC Evol Biol. 2006; 6: 11. Published online 2006 February 7. doi: 10.1186/1471-2148-6-11.

• Whetstone, K. N. 1978. A new genus of cryptodiran turtles (Testudinoidea, Chelydridae) from the Upper Cretaceous Hell Creek Formation of Montana. University of Kansas Science Bulletin. Lawrence, Kansas. 51(17):539-563.