Open Paleo

Malarguesaurus

González Riga et al., 2009 muh-LAR-gway-SAWR-us

Named after the Malargüe Department of Mendoza Province, Argentina, combined with Greek 'sauros' (lizard); meaning 'Malargüe lizard'.

89.8–85.7 million years ago Coniacian, Late Cretaceous
Late Cretaceous stages

Malarguesaurus is a genus of titanosauriform sauropod dinosaur from the Late Cretaceous of Mendoza Province, Argentina. Its fossils, consisting of tail vertebrae, chevrons, ribs, and limb bones, were found in the upper Turonian-lower Coniacian Portezuelo Formation of the Neuquén Group. The type species, described by González Riga and colleagues in 2008, is M. florenciae.

Under dispute

Evicted from Titanosauria and placed in Somphospondyli. Malarguesaurus was described as a basal somphospondylan titanosauriform, the sister group of Titanosauria (González Riga and colleagues, 2009), and is recovered by Mannion and colleagues (2013) as a non-titanosaurian somphospondylan in one analysis but as a titanosauroid in others. Its precise position among somphospondylans remains unresolved.

Diagnosis

  1. Slightly procoelous-opisthoplatyan proximal and middle caudal vertebrae associated with procoelous distal caudal centra
  2. Proximal caudal neural spines vertically directed with concave caudal border and caudodorsal corner forming right angle
  3. Distal caudal neural spines with concave and depressed dorsal border

Species

Malarguesaurus florenciae González Riga et al., 2009

Type species

Named in honor of Florencia Fernandez Favaron, who collaborated in years of fieldwork and found the first fossil remains of this species.

Holotype
IANIGLA-PV 110 , Instituto Argentino de Nivologia Glaciologia y Ciencias Ambientales
Material
Incomplete skeleton with proximal, middle and distal caudal vertebrae, chevrons, dorsal ribs, and appendicular bones
Horizon
Los Bastos Formation, Coniacian, Late Cretaceous , 89.8–85.7 million years ago
Locality
Quebrada Norte Quarry, Paso de las Bardas, Mendoza, Argentina

References

  1. González Riga, B. J.; Previtera, E.; Pirrone, C. A. (2009). Malarguesaurus florenciae gen. et sp. nov., a new titanosauriform (Dinosauria, Sauropoda) from the Upper Cretaceous of Mendoza, Argentina. Cretaceous Research 30(1): 135-148. Elsevier BV. doi:10.1016/j.cretres.2008.06.006

    Describing paper; recovered Malarguesaurus as a basal somphospondylan titanosauriform, the sister group of Titanosauria.

    gonzálezriga2009a
  2. González Riga, B. J.; Ortiz David, L. (2013). A new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous (Cerro Lisandro Formation) of Mendoza Province, Argentina. Ameghiniana 51(1): 3-25. doi:10.5710/AMGH.24.12.2013.1889

    Reassigns the Malarguesaurus holotype horizon from the Portezuelo Formation to the Los Bastos Formation, correcting the describing paper.

    gonzálezriga2013a
  3. Mannion, P. D.; Upchurch, P.; Barnes, R. N.; Mateus, O. (2013). Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society 168(1): 98-206. Oxford University Press (OUP). doi:10.1111/zoj.12029

    Recovered Malarguesaurus as a non-titanosaurian somphospondylan in one analysis and as a titanosauroid in others; among the most unstable taxa.

    mannion2013a
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the body length, mass, and hip height estimates.

    jones2026b