Machairasaurus
{{Short description|Extinct genus of dinosaurs}}
{{distinguish|Machairoceratops}}
{{Italic title}}
{{speciesbox
| name = Machairasaurus
| fossil_range = Campanian, {{fossil range|75|71}}
| image = Machairasaurus leptorhynchos by Nick Longrich.png
| image_caption = Forearm and hand in dorsal (top) and ventral (bottom) views, showing the elongate claws
| display_parents = 2
| genus = Machairasaurus
| parent_authority = Longrich, Currie & Dong, 2010
| species = leptonychus
| authority = Longrich, Currie & Dong, 2010
}}
Machairasaurus is a genus of oviraptorid dinosaur which was found in the Bayan Mandahu Formation, China, dating to the late Cretaceous period.{{cite journal|author=Nicholas R. Longrich |author2=Philip J. Currie |author3=Dong Zhi-Ming |year=2010 |title=A new oviraptorid (Dinosauria: Theropoda) from the Upper Cretaceous of Bayan Mandahu, Inner Mongolia |journal=Palaeontology |volume=53 |issue=5 |pages=945–960 |doi=10.1111/j.1475-4983.2010.00968.x|doi-access=free |bibcode=2010Palgy..53..945L }}
Discovery
During the Sino-Canadian expeditions of 1988 and 1990 some skeletons of unknown oviraptorosaurians were discovered by Philip J. Currie in Inner Mongolia. Based on two of these a new genus was named and described by Nicholas Longrich, Philip Currie, and Dong Zhiming in 2010 with the type species Machairasaurus leptonychus. The generic name is derived from Greek {{lang|el|μάχαιρα}} ({{lang|el|makhaira}}), "short scimitar". The specific name is derived from Greek {{lang|el|λεπτός}} ({{lang|el|leptos}}), "slender", and {{lang|el|ὄνυξ}} ({{lang|el|onyx}}), "claw". The species name as a whole refers to the sabre-like claws of the hand.
The holotype, IVPP V15979, was found in layers of the Bayan Mandahu dating from the late Campanian. It mainly consists of a left front limb, including the lower end of the lower arm, two carpal bones, and a complete hand.Some fragmentary foot elements are also known. The other find is the paratype, IVPP V15980, consisting of a very fragmentary skeleton including tail vertebrae, chevrons, ribs, phalanges of the hands, fragments of the second and fourth metatarsals, and pedal phalanges.
Five oviraptorid specimens associated with a nest, the female having been found brooding near the eggs, may belong to Machairasaurus.{{Cite journal | last1 = Fanti | first1 = F. | last2 = Currie | first2 = P. J. | last3 = Badamgarav | first3 = D. | editor1-last = Lalueza-Fox | editor1-first = Carles | title = New specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia | doi = 10.1371/journal.pone.0031330 | journal = PLOS ONE | volume = 7 | issue = 2 | pages = e31330 | year = 2012 | pmid = 22347465| pmc = 3275628| bibcode = 2012PLoSO...731330F | doi-access = free }}
Description
Machairasaurus was a small bipedal theropod, measuring around {{cvt|1.5|m|ft}} long. The describers established a single autapomorphy, unique derived trait: the hand claws are very elongated and blade-like in side view, with a length four times that of the joint height. The long claws would be proof that basal oviraptorids used their hands to pull down branches; the more curved claws of more derived forms would have served to dig up roots.
In 2010, Machairasaurus was assigned to the Oviraptoridae, more precisely to the Ingeniinae. It formed a smaller clade with Heyuannia spp., Conchoraptor, and Nemegtomaia.
See also
{{Portal|Dinosaurs}}
References
{{Reflist}}
{{Oviraptorosauria}}
{{Taxonbar|from=Q1930333}}
Category:Fossil taxa described in 2010
Category:Taxa named by Philip J. Currie