''Caenagnathasia'' ('recent jaw from

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

') is a small caenagnathid

oviraptorosauria Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or wi ...

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked co ...

Discovery

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

''Caenagnathasia martinsoni'' was named and described in 1994 by Philip J. Currie, Stephen Godfrey and Lev Nesov. The generic name is a combination of a reference to the species' placement in the

Caenagnathidae Caenagnathidae is a family of bird-like maniraptoran theropod dinosaurs from the Cretaceous of North America and Asia. They are a member of the Oviraptorosauria, and close relatives of the Oviraptoridae. Like other oviraptorosaurs, caenagnat ...

, with Asia, the continent of its provenance. The specific name honours Gerbert Genrikhovich Martinson. The genus is based on

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

N 401/12457, a pair of fused dentaries of the lower jaws. The specimen was found near Dzharakuduk in layers of the

Bissekty Formation The Bissekty Formation (sometimes referred to as Bissekt) is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated ...

, dating to the

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

- Coniacian, around 90 mya, making it the oldest known caenagnathoid. A second specimen was referred to the species, N 402/12457, a right dentary of a slightly smaller individual. Both individuals were adult. In 2015, new material of ''Caenagnathasia'' was described. From the same site as the holotype, the material includes various vertebrae, a

dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

, and a

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...

Description

''Caenagnathasia'' is the smallest known oviraptorosaur and one of the smallest non-avian dinosaurs. The jaw fragments are only a few centimetres long and total skull length has been estimated at . A 2010 estimate by

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dino ...

gave it a length of and a weight of . ''Caenagnathasia'' would presumably have resembled other oviraptorosaurs, which were feathered, bird-like dinosaurs with beaked skulls, long necks, and long limbs. Recent studies suggest it was one of the more primitive members of the Caenagnathidae.

Classification

''Caenagnathasia'' was originally assigned to the Caenagnathidae. It was even included in the definition of that clade published by Hans-Dieter Sues. It has been suggested however, that it might have a more basal position in the

Oviraptorosauria Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or wi ...

, outside of the

Caenagnathoidea Caenagnathoidea ("recent jaw forms") is a group of advanced oviraptorosaurian dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, often wi ...

.Holtz, Thomas R. Jr. (2010) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'
Winter 2010 Appendix.
/ref> In 2015 after the description of new material, it was found that ''Caenagnathasia'' could confidently be referred to Caenagnathidae.

The below cladogram is based on that resolved in the description of ''

Anzu Anzu may refer to: *Anzû, a divine storm-bird in several Ancient Mesopotamian religion, Mesopotamian religions *Anzu (dinosaur), ''Anzu'' (dinosaur), a genus of theropod dinosaur containing the species ''Anzu wyliei'' As a given name is a Japan ...

''.

References

External links

Image of ''C. martinsonii'' at The Dinosauria
{{Taxonbar, from=Q134763 Caenagnathids Late Cretaceous dinosaurs of Asia Fossils of Uzbekistan Bissekty Formation Fossil taxa described in 1994 Taxa named by Philip J. Currie

Discovery

Description

Classification

See also

References

External links