Mononykus

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Mononykus
Temporal range:
Ma
Reconstructed skeleton at the American Museum of Natural History
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Alvarezsauridae
Subfamily:
Parvicursorinae
Tribe:
Mononykini
Genus: Mononykus
Perle et al., 1993
Type species
Mononykus olecranus
Perle et al., 1993
Synonyms

Mononychus olecranus Perle et al., 1993 (preoccupied generic name)

Mononykus (

alvarezsaurid dinosaur that lived during the Late Cretaceous in what is now Asia on the Nemegt Formation
, about 70 million years ago.

Mononykus was a very small theropod, estimated around 1 to 1.2 metres (3.3 to 3.9 ft) in length with a weight of 3.5 kilograms (7.7 lb). As in

termite mounds
or other insect colonies.

History of discovery

Mounted holotype at the Giga Dinosaur Exhibition 2017, Japan

Mononykus is represented by a single

entomologist.[3] Several other specimens were later misclassified as Mononykus, including specimens with partial tails (initially misinterpreted as being very short, though later specimens showed they were long and thin) and complete skulls showing a distinct, mostly toothless form.[4] However, these specimens have since been reclassified in the new genus Shuvuuia.[5]
Because of this, many reconstructions of Mononykus in art and mounted skeletons in museums are in fact based mainly on Shuvuuia.

While Mononykus was formally described in the 1990s, it was reported that a specimen possibly belonging to this genus had already been unearthed by the Andrews expedition decades before. The specimen had been in the American Museum of Natural History collection, labeled simply as "bird-like dinosaur".[6] However, given the reassignment of the other specimens to related genera, and the difference in age (the AMNH specimen is from the older Djadochta Formation), it is unlikely to be Mononykus.[7]

In 2019, Sungjin Lee and colleagues referred a new specimen from the Nemegt Formation, MPC-D 100/206. This specimen consists of seven caudal vertebrae with a partial left hindlimb, and was discovered on a low slope of the Altan Uul III locality in 2008 by an international team of the Korea-Mongolia International Dinosaur Expedition (KID). The team also found a small assemblage of theropod fossils comprising specimens from other taxa such as Gobiraptor and Nemegtonykus.[8]

Description

Size of Mononykus (in violet) compared to other alvarezsaurids

Mononykus was a small dinosaur around 1 to 1.2 metres (3.3 to 3.9 ft) long and weighing 3.5 kilograms (7.7 lb).

feathers, as in the fossils of its relative Shuvuuia feather traces were discovered, proving that Alvarezsauridae were among the theropod lineages with feathery or downy integument.[11]

Paleobiology

Life restoration

Mononykus was a member of the family

anteaters), and therefore it is possible that they fed primarily on insects.[12]

In a 2001 study conducted by Bruce Rothschild and other paleontologists, 15 foot bones referred to Mononykus were examined for signs of stress fracture, but none were found.[13]

References

  1. .
  2. .
  3. .
  4. ^ Suzuki, S., Chiappe, L. M., Dyke, G.J., Watabe, M., Barsbold, R., and Tsogtbaatar, K. (2002). "A new specimen of Shuvuuia deserti Chiappe et al., 1998 from the Mongolian Late Cretaceous with a discussion of the relationships of alvarezsaurids to other theropod dinosaurs." Contributions in Science, 494: 1–18.
  5. ^ Chiappe, L. M., Norell, M. and Clark (1998). "The skull of a relative of the stem-group bird Mononykus." Nature, 392: 275–278.
  6. ^ Dinosaurs of the Gobi. Mongolia: BBC Horizon. 1993.
  7. ^ Mortimer, M. (2004), "Ornithomimosauria" Archived 2013-09-29 at the Wayback Machine, The Theropod Database, accessed June 30, 2009.
  8. PMID 31664171
    .
  9. .
  10. ^ Schweitzer, M. H., J. A. Watt, R. Avci, L. Knapp, L. Chiappe, M. Norell & M. Marshall. (1999). "Beta-keratin specific immunological reactivity in feather-like structures of the Cretaceous alvarezsaurid, Shuvuuia deserti." Journal of Experimental Zoology, 285: 146–157.
  11. ^ Senter, P. (2005). "Function in the stunted forelimbs of Mononykus olecranus (Theropoda), a dinosaurian anteater". Paleobiology Vol. 31, No. 3 pp. 373–381.
  12. ^ Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 331–336.

External links