Kinkonychelys
Encyclopedia
Kinkonychelys is an extinct genus
of side-necked
turtle
which existed in Madagascar
during the Late Cretaceous
period. It contains the single species Kinkonychelys rogersi, named in honor of its discoverer, Raymond R. Rogers
. The genus and species are based on
UA
9748, a nearly complete skull, which represents the first turtle skull described from the pre-Holocene
era in Madagascar. A number of isolated skull and jaw bones have also been assigned to K. rogersi. These specimens were found in rocks of the Maastrichtian
-age Maevarano Formation
in the Mahajanga Basin of northwestern Madagascar. Another specimen, FMNH
PR 2446, is speculated to represent another species, currently known as Kinkonychelys sp., but consensus on its distinction from K. rogersi remains unclear.
The Maevarano Formation is a nonmarine rock formation that was deposited under a season
al, semi-arid climate. A diverse vertebrate assemblage is known from the formation, including fishes, frogs, other turtles, lizards, snakes, crocodyliforms
, dinosaur
s, birds, and mammals. The rocks of the formation can be subdivided into several members. UA 9748 was found in a claystone
bed from an unnamed upper member; this member has also produced abundant and well-preserved fossils of ray-finned fish
, crocodyliforms, and dinosaurs. The other specimens assigned to Kinkonocheyls were found in the older Anembalemba Formation.
Kinkonychelys is classified as a member of the Kurmademydini group in the family Bothremydidae
, together with the late Cretaceous turtles Sankuchemys
and Kurmademys
, from India
. The classification of Kinkonychelys into this group has helped to support the theory that the island of Madagascar and the subcontinent India were connected to each other prior to the end of the late Cretaceous period.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of side-necked
Pleurodira
The Pleurodira are one of the two living suborders of turtles, the other being the Cryptodira. In many cases in the nomenclature of animals, ranks such as suborder are considered of little importance apart from nomenclatural or taxonomic reasons. However, this is not the case with the suborders of...
turtle
Turtle
Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...
which existed in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
during the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
period. It contains the single species Kinkonychelys rogersi, named in honor of its discoverer, Raymond R. Rogers
Raymond R. Rogers
Raymond Robert Rogers is a professor and chair of geology at Macalester College. He earned his B.S. in geology from Northern Arizona University in 1985, his M.S. from the University of Montana in 1989, and his Ph.D...
. The genus and species are based on
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
UA
University of Antananarivo
University of Antananarivo is the primary public university of Madagascar, located in the capital Antananarivo.The school traces its founding to 16 December 1955 and the formation of the Institute for Advanced Studies in Antananarivo. It quickly established itself as the main center for higher...
9748, a nearly complete skull, which represents the first turtle skull described from the pre-Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
era in Madagascar. A number of isolated skull and jaw bones have also been assigned to K. rogersi. These specimens were found in rocks of the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
-age Maevarano Formation
Maevarano Formation
The Maevarano Formation is an Upper Cretaceous sedimentary rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age, and records a seasonal, semiarid environment with rivers that had greatly varying discharges...
in the Mahajanga Basin of northwestern Madagascar. Another specimen, FMNH
Field Museum of Natural History
The Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...
PR 2446, is speculated to represent another species, currently known as Kinkonychelys sp., but consensus on its distinction from K. rogersi remains unclear.
The Maevarano Formation is a nonmarine rock formation that was deposited under a season
Season
A season is a division of the year, marked by changes in weather, ecology, and hours of daylight.Seasons result from the yearly revolution of the Earth around the Sun and the tilt of the Earth's axis relative to the plane of revolution...
al, semi-arid climate. A diverse vertebrate assemblage is known from the formation, including fishes, frogs, other turtles, lizards, snakes, crocodyliforms
Crocodyliformes
Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians."In 1988, Michael J. Benton and James M. Clark argued that all traditional names for well-known groups of animals should be restricted to their crown clades, that is, used only for...
, dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s, birds, and mammals. The rocks of the formation can be subdivided into several members. UA 9748 was found in a claystone
Claystone
Claystone is a geological term used to describe a clastic sedimentary rock that is composed primarily of clay-sized particles ....
bed from an unnamed upper member; this member has also produced abundant and well-preserved fossils of ray-finned fish
Actinopterygii
The Actinopterygii or ray-finned fishes constitute a class or sub-class of the bony fishes.The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines , as opposed to the fleshy, lobed fins that characterize...
, crocodyliforms, and dinosaurs. The other specimens assigned to Kinkonocheyls were found in the older Anembalemba Formation.
Kinkonychelys is classified as a member of the Kurmademydini group in the family Bothremydidae
Bothremydidae
Bothremydidae is an extinct family of side-necked turtle. They belong to sub-order Pleurodira and order Testudines. Bothremydidae lived in fresh water and were amphibious. They were actively mobile omnivores.-Taxonomy:...
, together with the late Cretaceous turtles Sankuchemys
Sankuchemys
Sankuchemys is an extinct genus of side-necked turtle which existed in India during the late Cretaceous period. It was first named by Eugene S. Gaffney, Ashok Sahni, Herman Schleich, Swarn Deep Singh, and Rahul Srivastava in 2003, and contains the species Sankuchemys sethnai.-External links:* at...
and Kurmademys
Kurmademys
Kurmademys is an extinct genus of side-necked turtle which existed in India during the late Cretaceous period. It was first named in 2001, by Eugene S. Gaffney, Sankar Chatterjee, and Dhiraj K. Rudra, and contains the species Kurmademys kallamedensis. The species name is derived from the Kallamedu...
, from India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. The classification of Kinkonychelys into this group has helped to support the theory that the island of Madagascar and the subcontinent India were connected to each other prior to the end of the late Cretaceous period.
External links
- Kinkonychelys at the Paleobiology DatabasePaleobiology Database' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...