an alvarezsaurid theropod dinosaur from the Late Cretaceous of Argentina.
Pronunciation: AHL-vuh-rez-SOR-us
Meaning: Alvarez' lizard
Author/s: Bonaparte (
1991)
Synonyms: None known
First Discovery: Neuquén, Argentina
Acta Ordinal: #358
Alvarezsaurus calvoi
The line between land-dwelling theropod dinosaurs and the flightless branch of our feathered friends is a bit hazy at the best of times, and it became no clearer with the discovery of Alvarezsaurus: a small carnivorous dinosaur that José Fernando Bonaparte initially described as a "strange flightless bird" in 1991.
(Alvarez' lizard)
Etymology
Alvarezsaurus is derived from "Alvarez" (in honor of well reknowned historian Don Gregorio Alvarez) and the Greek "sauros" (lizard).
The
species epithet,
calvoi, honors Argentine geologist and palaeontologist Jorge Orlando Calvo.
ZooBank registry:
urn:lsid:zoobank.org:act:97716A64-4252-4396-8EFA-FF89CF13B2A4.
Discovery
The remains of
Alvarezsaurus were discovered at "Boca del Sapo" in the Bajo de la Carpa Formation (formerly the Bajo de la carpa member) of the Rio Colorado Subgroup (formerly the Rio Colorado Formation) of the Neuquén Group, Neuquén, Argentina.
The
Holotype (MUCPv 54) is a partial skeleton, lacking a skull and forelimbs.
• Bonaparte JF (1991) "Los vertebrados fósiles de la Formación Rio Colorado, de la Ciudad de Neuquén y Cercanías, Cretácico Superior, Argentina" [The vertebrate fossils of the Rio Colorado Formation, from the city of Neuquén and surrounding areas, Upper Cretaceous, Argentina].
Revista del Museo Argentino de Ciencias Naturales Bernardino Rivadavia e Instituto Nacional de Investigación de las Ciencias Naturales. Paleontología 4(3): 17-123.
• Chiappe LM, Norrell MA and Clark JM (2002) "The Cretaceous short-armed Alvarezsauridae.
Mononykus and its kin". Page 87-120 in Chiappe and Witmer (eds.) "
Mesozoic Birds: Above the Heads of Dinosaurs".
• Holtz TR Jr. (2007) "Ornithomimosaurs and Alvarezsaurs".
The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages.
• Paul GS (2010) "
The Princeton Field Guide to Dinosaurs".
• Choiniere JN, Xu X, Clark JM, Forster CA, Guo Y and Han F (2010) "A Basal Alvarezsauroid Theropod from the Early Late Jurassic of Xinjiang, China".
Science, 327(5965): 571-574. DOI: 10.1126/science.1182143
• Xu X, Sullivan C, Pittman M, Choiniere JN, Hone D, Upchurch P, Tan Q, Xiao D, Tan L and Han F (2011) "A monodactyl nonavian dinosaur and the complex evolution of the alvarezsauroid hand".
PNAS 108(6): 2338-234. DOI: 10.1073/pnas.1011052108
• Averianov A and Sues H-D (2017) "The oldest record of Alvarezsauridae (Dinosauria: Theropoda) in the Northern Hemisphere".
PLoS ONE12(10): e0186254. DOI: 10.1371/journal.pone.0186254
• Meso JG, Qin Z, Pittman M, Canale JI, Salgado L and Díez Díaz V (2021)
"Tail anatomy of the Alvarezsauria (Theropoda, Coelurosauria), and its functional and behavioural implications".
Cretaceous Research, 124(7): 104830. DOI: 10.1016/j.cretres.2021.104830
• Geoffrey Guinard (2022) "The forelimbs of Alvarezsauroidea (Dinosauria: Theropoda): insight from evolutionary teratology".
Journal of Morphology (advance online publication)
DOI: 10.1002/jmor.21500
• Qin Z, Liao CC, Benton MJ and Rayfield EJ (2023) "Functional space analyses reveal the function and evolution of the most bizarre theropod manual unguals".
Communications Biology, 6(181).
DOI: 10.1038/s42003-023-04552-4.
Time stands still for no man, and research is ongoing. If you spot an error, or want to expand, edit or add a dinosaur, please use
this form. Go
here to contribute to our FAQ.
All dinos are GM free, and no herbivores were eaten during site construction!
To cite this page:
Atkinson, L.
"
ALVAREZSAURUS :: from DinoChecker's dinosaur archive".
‹
http://www.dinochecker.com/dinosaurs/ALVAREZSAURUS›. Web access: 04th Aug 2026.
