Leonerasaurus
Named after the Las Leoneras Formation in Argentina, where the fossil was found; meaning "Las Leoneras lizard"
Leonerasaurus is a basal genus of sauropodomorph dinosaur. Currently, there is only one species known, named L. taquetrensis by Diego Pol, Alberto Garrido and Ignacio A. Cerda in 2011. The fossil, an incomplete subadult individual, was found in the Las Leoneras Formation in Argentina. This formation is probably Early Jurassic in age. Leonerasaurus was a small non-sauropod sauropodomorph, showing an unusual combination of basal and derived characters. This indicates that the evolution of early sauropodomorphs witnessed a great degree of convergent evolution.
Under dispute
Pol and colleagues (2011) describe Leonerasaurus taquetrensis as a small sauropodomorph with a sauropod-like four-vertebra sacrum, and recover it as the sister of Melanorosaurus plus Sauropoda. Later analyses move it within Sauropodiformes: McPhee and colleagues (2015) find it near the base of Sauropoda, which they attribute to missing data, while Otero and colleagues (2015) and Rauhut and colleagues (2020) recover it in unresolved positions at the base of the clade. It is placed at Sauropodiformes incertae sedis.
Diagnosis
- Anterior teeth with low, spoon-shaped crowns
- Dorsosacral rib attached to preacetabular process of ilium
- Neural arches of primordial sacrals positioned on anterior half of centrum
- Caudosacral rib directed anterolaterally
- Humeral deltopectoral crest low and medially deflected along distal half
- Flattened ischial shafts
Species
Leonerasaurus taquetrensis Pol et al., 2011
Type species
Named for the Sierras de Taquetrén in Central Patagonia, where the Las Leoneras Formation crops out.
- Holotype
- MPEF-PV 1663 , Museo Paleontológico "Egidio Feruglio"
- Material
- Anterior right dentary, isolated teeth, articulated cervical and anterior dorsal vertebrae, posterior dorsal vertebrae, articulated sacrum with ilia, right scapula and humerus, left and right ilia, right ischium, partially preserved femur, articulated metatarsals I and II, pedal ungual.
- Horizon
- upper Las Leoneras Formation, Pliensbachian, Early Jurassic , 192.9–184.2 million years ago
- Locality
- Cañadón Las Leoneras, Chubut, Argentina
References
- Pol, D.; Garrido, A.; Cerda, I. A. (2011). A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum. PLoS ONE 6(1): e14572. Public Library of Science (PLoS). doi:10.1371/journal.pone.0014572 pol2011b
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Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.
Source of the hip height estimate.
jones2026b -
McPhee, B. W.; Choiniere, J. N.; Yates, A. M.; Viglietti, P. A. (2015). A second species of Eucnemesaurus Van Hoepen, 1920 (Dinosauria, Sauropodomorpha): new information on the diversity and evolution of the sauropodomorph fauna of South Africa's lower Elliot Formation (latest Triassic). Journal of Vertebrate Paleontology 35(5): e980504. Informa UK Limited. doi:10.1080/02724634.2015.980504
Recovers Leonerasaurus near the base of Sauropoda, more derived than earlier analyses, and attributes this to missing data.
mcphee2015b -
Otero, A.; Krupandan, E.; Pol, D.; Chinsamy, A.; Choiniere, J. (2015). A new basal sauropodiform from South Africa and the phylogenetic relationships of basal sauropodomorphs. Zoological Journal of the Linnean Society 174(3): 589-634. Oxford University Press (OUP). doi:10.1111/zoj.12247
Recovers Leonerasaurus in a polytomy with Sefapanosaurus, Aardonyx and more derived sauropodomorphs.
otero2015a -
Rauhut, O. W. M.; Holwerda, F. M.; Furrer, H. (2020). A derived sauropodiform dinosaur and other sauropodomorph material from the Late Triassic of Canton Schaffhausen, Switzerland. Swiss Journal of Geosciences 113(1). Pensoft Publishers. doi:10.1186/s00015-020-00360-8
Finds Leonerasaurus and Sefapanosaurus taking several equally parsimonious positions at the base of Sauropodiformes.
rauhut2020a