Aristonectes
Encyclopedia
Aristonectes is an extinct
genus
of plesiosaur
from the Late Cretaceous
of what is now South America
and Antarctica. The type species
is Aristonectes parvidens, first named by Cabrera in 1941.
Aristonectes has been classified variously since the 1941 description, but a 2003 review of plesiosaurs conducted by Gasparini et al. found that Aristonectes was most closely related to elasmosaurid plesiosaurs like Elasmosaurus
. A similar plesiosaur, Morturneria, may be a junior synonym of Aristonectes, the study found.
Aristonectes has been recently placed within its own family, along with Tatenectes
, Kaiwhekea
, and Kimmerosaurus
, by O'Keefe and Street (2009). Aristonectids are the sister family of the polycotylid cryptoclidoids.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally 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 recover may have been lost before this point...
genus
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 plesiosaur
Plesiosaur
Plesiosauroidea is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods...
from 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...
of what is now South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
and Antarctica. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Aristonectes parvidens, first named by Cabrera in 1941.
Aristonectes has been classified variously since the 1941 description, but a 2003 review of plesiosaurs conducted by Gasparini et al. found that Aristonectes was most closely related to elasmosaurid plesiosaurs like Elasmosaurus
Elasmosaurus
Elasmosaurus + σαυρος sauros 'lizard') is a genus of plesiosaur with an extremely long neck that lived in the Late Cretaceous period , 80.5 million years ago.-Description:...
. A similar plesiosaur, Morturneria, may be a junior synonym of Aristonectes, the study found.
Aristonectes has been recently placed within its own family, along with Tatenectes
Tatenectes
Tatenectes is an extinct genus of cryptoclidid plesiosaur known from the Upper Member of the Sundance Formation of Wyoming. It was named by O'Keefe and Wahl in 2003 and the type species is Tatenectes laramiensis....
, Kaiwhekea
Kaiwhekea
Kaiwhekea is an extinct genus of plesiosaur from the Late Cretaceous of what is now New Zealand. The type species, Kaiwhekea katiki, was first described by Arthur Cruickshank and Ewan Fordyce in 2002. Kaiwhekea was approximately 7 meters long and lived around 69-70 million years ago...
, and Kimmerosaurus
Kimmerosaurus
Kimmerosaurus is an extinct genus of plesiosaur from the family Cryptoclididae, closely related to Tatenectes.-Etymology:...
, by O'Keefe and Street (2009). Aristonectids are the sister family of the polycotylid cryptoclidoids.