Albinykus is a 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 alvarezsaurid 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...

. Fossils have been found from 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...

-age deposits in the Gobi Desert

Gobi Desert

The Gobi is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Hexi Corridor and Tibetan Plateau to the...

 of Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

. 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...

 A. baatar was named by Sterling J. Nesbitt

Sterling Nesbitt

Sterling Nesbitt , is an American paleontologist.-Biography:Sterling Nesbitt received his B.A. in integrative biology with a minor in geology from University of California Berkeley in 2004. He received his Ph.D from Columbia University in 2009, completing the majority of his research at the...

, Julia A. Clarke, Alan H. Turner and Mark A. Norell in 2011

2011 in paleontology

-Lobopods:-Arachnids:-Insects:-Newly named jawless vertebrates:-Newly named acanthodian:-Newly named cartilaginous fishes:-Newly named bony fishes:-Newly named lepospondyls:-Newly named temnospondyls:-Newly named lissamphibians:...

.

Estimated at under 1 kilograms (2.2 lb) in weight, Albinykus was one of the smallest alvarezsaurs and among the smallest nonavian dinosaurs. The body size of alvarezsaurs decreased throughout their evolutionary history, and Albinykus represents a particularly derived

Derived

In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...

 form. One distinguishing feature of Albinykus not seen in other alvarezsaurids is the complete fusion of the tarsal

Tarsal

Tarsal could refer to:*tarsus *tarsus *superior tarsal muscle...

s to other bones of the leg; the proximal tarsals are fused to the tibia

Tibia

The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

 bone of the lower leg and the distal tarsals are fused to the metatarsal bones of the foot.

The holotype

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...

 skeleton of Albinykus, specimen IGM 100/3004 consisting of the pelvis

Pelvis

In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...

 and the hindlimbs, is postured in a sitting position with feet tucked underneath the body. This posture is similar to that of birds, an indication of the close relationship between nonavian maniraptora

Maniraptora

Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. Ornitholestes and the Alvarezsauroidea...

n dinosaurs and birds. Although oviraptorids and troodontids are known to have assumed this posture, the holotype of Albinykus is the first example of a crouching alvarezsaurid. Scientists are unsure about how the dinosaur died to keep it in the position it was in but it is possible Albinykus suffocated under sand.