''Parviraptor'' is a genus of stem-snake (clade
Ophidia
__FORCETOC__
Ophidia (also known as Pan-Serpentes) is a group of squamate reptiles including modern snakes and reptiles more closely related to snakes than to other living groups of lizards.
Ophidia was defined as the "most recent common ancest ...
)
containing one species, ''Parviraptor estesi'', from the
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987.
In European lithostratigraphy, the name ...
(Tithonian) or Early Cretaceous (Berriasian)
Purbeck Limestone Formation of Dorset, England.
A second species, ''Parviraptor gilmorei'', was described from the Late Jurassic
Morrison Formation of Western North America;
[Foster, J. (2007). "Table 2.1: Fossil Vertebrates of the Morrison Formation." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 58-59.] it was present in stratigraphic zone 4.
[Foster, J. (2007). "'' Enneabatrachus hechti''" ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. p. 137.] However, the second species was subsequently transferred to a separate genus ''
Diablophis''.
An indeterminate species is known from the
Bathonian
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age.
Str ...
aged Kirtlington Mammal Bed (
Kilmaluag Formation,
Scotland
Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...
).
Description
The shape, length, and body form of Parviraptor and other early snakes is not currently known. Parviraptor is classified as a basal snake based on skull morphology. It shares most skull features with modern snakes, but notably does not have the lateral notches in the lower jaw found in modern snakes. Its vertebrae share all diagnostic features of later snakes. Analysis of Parviraptor fossils supports the hypothesis that snake ancestors evolved snakelike heads earlier than snakelike bodies.
Phylogeny
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...
based in the phylogenetic analysis by Caldwell ''et al.'' (2015):
See also
References
Prehistoric snakes
Late Jurassic reptiles of Europe
Morrison fauna
Fossil taxa described in 1994
†
{{paleo-reptile-stub