ALVAREZSAURUS
an alvarezsaurid theropod dinosaur from the Late Cretaceous of Argentina.
Pronunciation: AHL-vahr-ez-SOR-us
Meaning: Alvarez' lizard
Author/s: Bonaparte (
1991)
Synonyms: None known
First Discovery: Neuquén, Argentina
Discovery Chart Position: #354
Alvarezsaurus calvoi
The line between land-dwelling 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.
Estimations
Timeline:
Era: Mesozoic
Epoch: Late Cretaceous
Stage: Santonian
Age range: 86-84 mya
Stats:
Est. max. length: 1.4 meters
Est. max. hip height: 0.5 meters
Est. max. weight: 14 Kg
Diet: Omnivore
References
• 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 "
Mesozoic Birds: Above the Heads of Dinosaurs".
• 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
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To cite this page:
Atkinson, L.
"
ALVAREZSAURUS :: from DinoChecker's dinosaur archive".
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http://www.dinochecker.com/dinosaurs/ALVAREZSAURUS›. Web access: 06th Mar 2026.
