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Overosaurus

Coria et al., 2013 oh-VAIR-o-SAWR-us

Named after the Cerro Overo locality in Patagonia, Argentina, combined with Greek sauros (lizard); meaning "Overo lizard".

85.7–83.6 million years ago Santonian, Late Cretaceous
Late Cretaceous stages

Overosaurus is an extinct genus of sauropod dinosaurs, containing only a single species, Overosaurus paradasorum. This species lived approximately 86 to 84 million years ago during the latter part of the Cretaceous Period in what is now Patagonia (in southern Argentina). Overosaurus paradasorum was relatively small compared to other sauropods from Patagonia, like the saltasaurids and other aeolosaurines, estimated as approximately 10 m (33 ft). It was a ground-dwelling herbivore.

Diagnosis

  1. Posterior cervical vertebrae with long pre- and postzygapophyses projecting beyond centrum borders
  2. Postspinal lamina absent in all dorsal neural spines
  3. Wide massive 9th-10th caudal centra with lateral excavations and flat ventral surfaces
  4. Laminar projection on posterior border of second-third dorsal ribs
  5. Ilium proportionally shorter anteroposteriorly and taller dorsoventrally than other lithostrotians
  6. Preacetabular process of ilium strongly deflected laterally with ventrolaterally tapering end

Species

Overosaurus paradasorum Coria et al., 2013

Type species

Named for the Parada family, who found the specimen and provided logistical support during fieldwork, with the Latin genitive plural suffix '-orum'.

Holotype
MAU-Pv-CO-439 , Museo Argentino Urquiza, Rincón de los Sauces
Material
Forty articulated vertebrae (last four cervical, ten dorsal, six sacral, twenty caudal), cervical and dorsal ribs, complete right ilium and left ilium fragments
Horizon
Bajo de la Carpa Formation, Santonian, Late Cretaceous , 85.7–83.6 million years ago
Locality
Cerro Overo, Neuquén, Argentina

References

  1. Coria, R. A.; Filippi, L. S.; Chiappe, L. M.; García, R.; Arcucci, A. B. (2013). Overosaurus paradasorum gen. et sp. nov., a new sauropod dinosaur (Titanosauria: Lithostrotia) from the Late Cretaceous of Neuquén, Patagonia, Argentina. Zootaxa 3683(4). Magnolia Press. doi:10.11646/zootaxa.3683.4.2 coria2013a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the mass and hip height estimates.

    jones2026b