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Tehuelchesaurus

Rich et al., 1999 tay-WAYL-chay-SAWR-us

Named in honor of the Tehuelche people, the indigenous inhabitants of the Argentinian province of Chubut where the fossil was first found, combined with Greek 'sauros' meaning 'lizard'.

161.5–143.1 million years ago Oxfordian–Tithonian, Late Jurassic
Late Jurassic stages

Tehuelchesaurus is a genus of eusauropod dinosaur from the Late Jurassic (Oxfordian to Tithonian) of Argentina. It is named in honor of the Tehuelche people, native to the Argentinian province of Chubut, where it was first found.

Under dispute

Tehuelchesaurus was originally interpreted as a camarasauromorph, a position supported by Carballido and Sander (2013), the camarasaurid analysis of Mocho and colleagues (2014), and Mannion and colleagues (2013). More recent analyses instead pull it out of Macronaria: Mannion and colleagues (2019) recover it in Turiasauria under equal weighting (but a macronarian under implied weighting), and Mocho and colleagues (2023) recover it outside Macronaria as a basal eusauropod-grade taxon.

Diagnosis

  1. Two accessory laminae in the infradiapophyseal fossa of the middle dorsal vertebrae
  2. Accessory laterally oriented lamina on the lateral surface of the intrapostzygapophyseal lamina
  3. Strongly anteroposteriorly expanded and robust distal end of the humerus
  4. Absence of the prezygoparapophyseal lamina in the middle and posterior dorsal vertebrae
  5. Accessory posterior centrodiapophyseal lamina giving a ventrally bifurcated appearance
  6. A single intrapostzygapophyseal lamina in the mid-dorsal vertebrae supporting a weakly developed hyposphene
  7. Dorsal neural spines longer anteroposteriorly than wide transversely
  8. Absence of lateral expansion at the dorsal end of the dorsal neural spines
  9. Absence of a postspinal lamina in the dorsal neural spines
  10. Acromion process of the scapula almost four times the minimum width of the scapular shaft

Species

Tehuelchesaurus benitezii Rich et al., 1999

Type species

Named for Aldo Benitez, who discovered the holotype in Chubut Province, Argentina.

Holotype
MPEF-PV 1125 , Museo Paleontológico "Egidio Feruglio"
Material
Partial postcranial skeleton with 10 articulated presacral and 4 sacral vertebrae, ribs, right scapulocoracoid, right humerus, left radius and ulna, partial pelvis, both femora, and skin impressions.
Horizon
lower Cañadón Calcáreo Formation, Oxfordian–Tithonian, Late Jurassic , 161.5–143.1 million years ago
Locality
Estancia Fernández, Chubut, Argentina Carballido and colleagues (2011) place the holotype in a lacustrine silt-sandstone at the base of the formation, "some 15–20 m above the discordant contact" with the Lonco Trapial Formation, and note that Rich and colleagues' (1999) figured section was a composite. Cúneo and colleagues (2013) call its host the "middle lacustrine section", citing Carballido and colleagues.

References

  1. Cúneo, R.; Ramezani, J.; Scasso, R.; Pol, D.; Escapa, I.; Zavattieri, A. M.; Bowring, S. A. (2013). High-precision U-Pb geochronology and a new chronostratigraphy for the Cañadón Asfalto Basin, Chubut, central Patagonia: implications for terrestrial faunal and floral evolution in Jurassic. Gondwana Research 24(3-4): 1267-1275. Elsevier BV. doi:10.1016/j.gr.2013.01.010

    Places Tehuelchesaurus in the "middle lacustrine section" of the formation, citing Rich and colleagues (1999) and Carballido and colleagues (2011).

    cúneo2013a
  2. Rich, T. H.; Vickers-Rich, P.; Giménez, O.; Cúneo, R.; Puerta, P.; Vacca, R. (1999). A new sauropod dinosaur from Chubut province, Argentina. Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs 15: 61-84. rich1999a
  3. Carballido, J. L.; Rauhut, O. W. M.; Pol, D.; Salgado, L. (2011). Osteology and phylogenetic relationships of Tehuelchesaurus benitezii (Dinosauria, Sauropoda) from the Upper Jurassic of Patagonia. Zoological Journal of the Linnean Society 163(2): 605-662. Wiley. doi:10.1111/j.1096-3642.2011.00723.x

    Osteology and redescription; corrects the type formation to Cañadón Calcáreo, dates it Oxfordian–Tithonian, and provides the emended diagnosis.

    carballido2011a
  4. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the mass estimate.

    paul2024a
  5. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b
  6. Mocho, P.; Royo-Torres, R.; Ortega, F. (2014). Phylogenetic reassessment of Lourinhasaurus alenquerensis, a basal Macronaria (Sauropoda) from the Upper Jurassic of Portugal. Zoological Journal of the Linnean Society 170(4): 875-916. Oxford University Press (OUP). doi:10.1111/zoj.12113

    Reassessment of Lourinhasaurus; its analysis recovered Tehuelchesaurus as a camarasaurid, a basal macronarian.

    mocho2014a
  7. Mannion, P. D.; Upchurch, P.; Schwarz, D.; Wings, O. (2019). Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution. Zoological Journal of the Linnean Society 185(3): 784-909. Oxford University Press (OUP). doi:10.1093/zoolinnean/zly068

    Recovered Tehuelchesaurus in Turiasauria under equal weighting, but as a non-titanosauriform macronarian under implied weighting.

    mannion2019a
  8. Mocho, P.; Escaso, F.; Gasulla, J. M.; Galobart, À.; Poza, B.; Santos-Cubedo, A.; Sanz, J. L.; Ortega, F. (2023). New sauropod dinosaur from the Lower Cretaceous of Morella (Spain) provides new insights on the evolutionary history of Iberian somphospondylan titanosauriforms. Zoological Journal of the Linnean Society 201(1): 214-268. Oxford University Press (OUP). doi:10.1093/zoolinnean/zlad124

    Recovered Tehuelchesaurus outside Macronaria, in a basal clade with Bellusaurus, Haestasaurus and Janenschia — not within Turiasauria.

    mocho2023a
  9. Carballido, J. L.; Sander, M. P. (2013). Postcranial axial skeleton of Europasaurus holgeri (Dinosauria, Sauropoda) from the Upper Jurassic of Germany: implications for sauropod ontogeny and phylogenetic relationships of basal Macronaria. Journal of Systematic Palaeontology 12(3): 335-387. doi:10.1080/14772019.2013.764935

    Postcranial study of Europasaurus that recovered Tehuelchesaurus as a basal camarasauromorph.

    carballido2013a
  10. 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 Tehuelchesaurus as a non-titanosauriform (basal) macronarian.

    mannion2013a