Editing Alvarezsauridae (section)

{{Short description|Family of extinct long-legged dinosaurs}}
{{Automatic taxobox
| name = Alvarezsaurids
| fossil_range = [[Late Cretaceous]],<br/> {{fossilrange|97|66}}
| image = Mononykus.jpg
| image_caption = Mounted holotype of ''[[Mononykus]]''
| image2 = Alvarezsaurus.jpg
| image2_caption = Skeletal mount of ''[[Alvarezsaurus]]''
| image_upright = 1.2
| taxon = Alvarezsauridae
| authority = [[José Bonaparte|Bonaparte]], 1991
| type_species = {{extinct}}''[[Alvarezsaurus calvoi]]''
| type_species_authority = Bonaparte, 1991
| subdivision_ranks = Subgroups
| subdivision = 
*{{extinct}}''[[Achillesaurus]]''?
*{{extinct}}''[[Alnashetri]]''?
*{{extinct}}''[[Alvarezsaurus]]''
*{{extinct}}''[[Bradycneme]]''
*{{extinct}}''[[Heptasteornis]]''
*{{extinct}}'''Patagonykinae'''?
**{{extinct}}''[[Bonapartenykus]]''
**{{extinct}}''[[Patagonykus]]''
*{{extinct}}'''Parvicursorinae'''
**{{extinct}}''[[Dzharaonyx]]''
**{{extinct}}''[[Jaculinykus]]''
**{{extinct}}''[[Khulsanurus]]''
**{{extinct}}''[[Kol ghuva|Kol]]''
**{{extinct}}''[[Nemegtonykus]]''
**{{extinct}}''[[Ondogurvel]]''
**{{extinct}}''[[Parvicursor]]''
**{{extinct}}''[[Qiupanykus]]''
**{{extinct}}''[[Trierarchuncus]]''
**{{extinct}}'''Ceratonykini'''
***{{extinct}}''[[Albinykus]]''
***{{extinct}}''[[Ceratonykus]]''
***{{extinct}}''[[Xixianykus]]''
**{{extinct}}'''Mononykini'''
***{{extinct}}''[[Albertonykus]]''
***{{extinct}}''[[Linhenykus]]''
***{{extinct}}''[[Mononykus]]''
***{{extinct}}''[[Shuvuuia]]''
| synonyms =
*'''Bradycnemidae'''? <small>[[Colin Harrison (ornithologist)|Harrison]] & [[Cyril Walker (ornithologist)|Walker]], 1975 (in part)</small>
*'''Parvicursoridae''' <small>[[A.A. Karhu|Karhu]] & [[Rautian]], 1996</small>
*'''Mononykidae''' <small>Chiappe ''et al.'', 1998</small>
}}

'''Alvarezsauridae''' is a [[family (biology)|family]] of small, long-legged [[dinosaur]]s. Although originally thought to represent the earliest known flightless [[bird]]s, they are now thought to be an early diverging branch of [[maniraptora]]n [[theropod]]s. Alvarezsaurids were highly specialized. They had tiny but stout forelimbs, with compact, bird-like hands. Their skeletons suggest that they had massive breast and arm muscles, possibly adapted for digging or tearing. They had long, tube-shaped snouts filled with tiny teeth. They have been interpreted as [[Myrmecophagy|myrmecophagous]], adapted to prey on colonial insects such as [[termites]], with the short arms acting as effective digging instruments to break into nests. 

''[[Alvarezsaurus]]'', the [[type genus]] of the family, was named for the [[historian]] [[Gregorio Álvarez (historian)|Gregorio Álvarez]].<ref>i.e. not the more familiar [[physicist]] [[Luis Walter Alvarez|Luis Alvarez]], who proposed that the [[Cretaceous–Paleogene extinction event]] was caused by an [[impact event]]</ref>