family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of
turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...
s that has seven extinct and two extant genera. The extant genera are the snapping turtles, ''
Chelydra
''Chelydra'' is one of the two extant genera of the snapping turtle family, Chelydridae, the other being ''Macrochelys'', the much larger alligator snapping turtle. The snapping turtles are native to the Americas, with ''Chelydra'' having three ...
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
to the
Western Hemisphere
The Western Hemisphere is the half of the planet Earth that lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian. The other half is called the Eastern Hemisphere. Politically, the te ...
Emarginachelys
''Emarginachelys cretacea'' is a turtle belonging to the group Cryptodira, known from well preserved fossils from the Maastrichtian stage of the Late Cretaceous of Montana. Its exact phylogenetic position within Cryptodira is uncertain; different ...
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
history, with extinct species reported from North America as well as all over Asia and Europe, far outside their present range. The earliest described chelydrid is '' Emarginachelys cretacea'', known from well-preserved fossils from the
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval ...
stage of the Late
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
of
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...
. Another well-preserved fossil chelydrid is the Late
Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...
''
Protochelydra zangerli
''Protochelydra zangerli'' is an extinct species of chelydid in the extinct genus ''Protochelydra'' of Chelydridae
The Chelydridae is a family of turtles that has seven extinct and two extant genera. The extant genera are the snapping turtles ...
'' from
North Dakota
North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, So ...
. The carapace of ''P. zangerli'' is higher-domed than that of the recent ''Chelydra'', a trait conjectured to be associated with the coexistence of large, turtle-eating
crocodilia
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest livi ...
ns. Another genus, ''Chelydropsis'', contains several well-known
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
n chelydrid
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58C. acutirostris'') only occupy the northwestern corner of the continent, reflecting their recent arrival from Central America as part of the Great American Interchange.
Gallery
Chelydropsis murchisoni 01.jpg, '' Chelydropsis murchisoni'' fossil remains: left: juvenile, right: adult
Common Snapping Turtle Close Up.jpg, Common snapping turtle at Taum Sauk Mountain State Park
Submerged Snapping turtle.jpg, Two-year-old captive-raised snapping turtle from
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
Snapping turtlewithcan.jpg, Female next to can to show size
Alligator Snapping Turtle Skeleton.jpg, Skeleton of alligator snapping turtle at the Museum of Osteology
References
* de Broin, F. (1969). ''Contribution a l'etude des cheloniens. Cheloniens continentaux du Cretace Superieur et du Tertiaire de France. Memoires du
Muséum National d'Histoire Naturelle
The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is loc ...
.'' 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
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spe ...
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 (2006). The complete
mitochondrial genome
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial ...
of the enigmatic bigheaded turtle (''Platysternon''): description of unusual genomic features and the reconciliation of phylogenetic hypotheses based on mitochondrial and
nuclear DNA
Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. I ...
. ''BMC Evol Biol.'' 6: 11. Published online February 7, 2006. .
* Whetstone, K.N. (1978). A new genus of cryptodiran turtles (Testudinoidea, Chelydridae) from the Upper Cretaceous
Hell Creek Formation
The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of ...
of Montana. ''The
University of Kansas
The University of Kansas (KU) is a public research university with its main campus in Lawrence, Kansas, United States, and several satellite campuses, research and educational centers, medical centers, and classes across the state of Kansas. T ...