Mononykus

*Mononykus olecranus*

***Mononykus*** (meaning "one claw") is an extinct genus of alvarezsaurid theropod dinosaur from late Cretaceous Mongolia (Nemegt Formation, about 70 million years ago). The type and only species of this genus is *M. olecranus*.

## Description

*Mononykus* was a small dinosaur, only convert|1|m|ft long. Other characteristics include fused wrist bones similar to those of birds, and a keeled breastbone. It differed from close relatives *Shuvuuia* and *Parvicursor* in several details of its skeleton, including a pubic bone that is triangular in cross section, and different proportions in the toe bones. It had long, skinny legs and moved about on two legs, was likely very nimble and could run at high speeds, something that would have been useful in the open desert plains where it lived. It had a small skull, and its teeth were small and pointed, suggesting that it ate insects and small animals, such as lizards and mammals. Its large eyes might have allowed *Mononykus* to hunt by night, when it was cooler and there would have been fewer predators about. *Mononykus* was originally named "Mononychus" in 1993, but later that year, it was renamed because the original name had already been used for a beetle named by Johann Schueppel, a German entomologist.

## History of Discovery

*Mononykus* is currently represented by a single holotype specimen, catalog number IGM N107/6. This specimen consists of a partial skeleton lacking a tail, and only small fragments of skull bones, including a complete braincase. 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. However, these specimens have since been reclassified in the new genus *Shuvuuia*. 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 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". 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*.

## Paleobiology

*Mononykus* is usually reconstructed with a covering of feathers. Indeed, in the fossil of its relative *Shuvuuia* feather traces were discovered, proving that Alvarezsauridae were among the theropod lineages with feathery or downy integument.

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.

## Appearance in other media

### *Jurassic Park*

* Although they didn't appeared in the *Jurassic Franchise*, Five *Mononykus* appear as a taxidermy in the Lockwood Manor in *Jurassic World: Fallen Kingdom*. They are green, with red legs and throat pouches. They possess black and white quills on their arms and the end of their tail.

## References

1. ↑ 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.
2. ↑ Chiappe, L. M., Norell, M. and Clark (1998). "The skull of a relative of the stem-group bird *Mononykus*." *Nature*, **392**: 275–278.
3. ↑ Template:Cite video
4. ↑ Mortimer, M. (2004), "Ornithomimosauria", *The Theropod Database*, accessed June 30, 2009.
5. ↑ Senter, P. (2005). "Function in the stunted forelimbs of *Mononykus olecranus* (Theropoda), a dinosaurian anteater". *Paleobiology* Vol. 31, No. 3 pp. 373–381.
6. ↑ 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.
7. ↑ 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.