Lessemsaurus

Lessemsaurus Temporal range: mid-Norian ~213  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Reconstructed skeleton
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Clade:	Saurischia
Clade:	† Sauropodomorpha
Clade:	† Sauropoda
Family:	† Lessemsauridae
Genus:	† Lessemsaurus Bonaparte 1999
Species:	†L. sauropoides
Binomial name
†Lessemsaurus sauropoides Bonaparte 1999

Lessemsaurus is an extinct genus of sauropodiform dinosaur that lived in the Norian-aged (Upper Triassic) Los Colorados Formation of what is now Argentina.

Naming and description

The type species, L. sauropoides, was formally described by José Fernando Bonaparte in 1999 in honor of Don Lessem, a writer of popular science books. It was found in the Los Colorados Formation of the Ischigualasto-Villa Unión Basin in La Rioja Province, Argentina. ^[1]

It is part of the La Esquina faunal assemblage, ^{[2] [3]} dating to the mid-Norian stage, around 213 million years ago. ^[4] It is estimated to have reached 10–12 metres (33–39 ft) long and weighed over 7 metric tons (7.7 short tons), possibly up to 8–10 metric tons (8.8–11.0 short tons), in maximum body mass. ^{[5] [6] [7] [8]}

Classification

Exhibit in Singapore

A cladogram after Pol, Garrido & Cerda, 2011, ^[9] illustrates a possible placing of Lessemsaurus and Antetonitrus in Sauropodomorpha:

Sauropodomorpha	Saturnalia Pantydraco Thecodontosaurus Efraasia Ruehleia Plateosaurus Massopoda Riojasaurus Massospondylus Coloradisaurus Lufengosaurus Gyposaurus Yunnanosaurus Anchisauria Anchisaurus Aardonyx Leonerasaurus Melanorosaurus Sauropoda Antetonitrus Lessemsaurus Kotasaurus Vulcanodon Eusauropoda

In 2018, Apaldetti et al. recovered it as part of a clade they named Lessemsauridae, after Lessemsaurus. Their cladogram is reproduced below: ^[10]

Sauropodiformes	Mussaurus Aardonyx Sefapanosaurus Melanorosauridae Camelotia Melanorosaurus Sauropoda Lessemsauridae Antetonitrus Ingentia Lessemsaurus Blikanasaurus Gongxianosaurus Pulanesaura Gravisauria

The following cladogram shows the position of Lessemsaurus outside of Sauropoda, according to Oliver W. M. Rauhut and colleagues, 2020: ^[11]

Massopoda

Eucnemesaurus Riojasaurus Sarahsaurus Massospondylidae Yunnanosaurus Jingshanosaurus Seitaad Coloradisaurus Glacialisaurus Lufengosaurus Massospondylus Adeopapposaurus Leyesaurus Sauropodiformes Xingxiulong Anchisaurus Leonerasaurus Mussaurus Aardonyx Sefapanosaurus Meroktenos Melanorosaurus Camelotia Lessemsaurus Antetonitrus Ingentia Blikanasaurus Pulanesaura Gongxianosaurus Schleitheimia Isanosaurus Tazoudasaurus Sauropoda

References

1. Weishampel, David B; et al., 2004. "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528. ISBN   0-520-24209-2.
2. Bonaparte, J. F. (1999). "Evolución de las vértebras presacras en Sauropodomorpha". Ameghiniana . 36: 115–187.
3. Pol, D.; Powell, J. E. (2007). "New information on Lessemsaurus sauropoides (Dinosauria: Sauropodomorpha) from the Upper Triassic of Argentina". Special Papers in Palaeontology. 77: 223–243.
4. Kent, Dennis V.; Olsen, Paul E.; Rasmussen, Cornelia; Lepre, Christopher; Mundil, Roland; Irmis, Randall B.; Gehrels, George E.; Giesler, Dominique; Geissman, John W.; Parker, William G. (2018-06-12). "Empirical evidence for stability of the 405-kiloyear Jupiter–Venus eccentricity cycle over hundreds of millions of years". Proceedings of the National Academy of Sciences. 115 (24): 6153–6158. doi:10.1073/pnas.1800891115. PMC   6004457 . PMID   29735684.
5. Diego Pol; Alberto Garrido; Ignacio A. Cerda (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. Bibcode:2011PLoSO...614572P. doi: 10.1371/journal.pone.0014572 . PMC   3027623 . PMID   21298087.
6. Foelix, Rainer; Pabst, Ben; Kindlimann, René (2011). "Die Saurier in Frick" (PDF). Mitteilungen der aargauischen Naturforschenden Gesellschaft. 37. doi:10.5169/seals-283430.
7. Apaldetti, C.; Martínez, R.N.; Cerda, I.A.; Pol, D.; Alcober, O. (2018). "An early trend towards gigantism in Triassic sauropodomorph dinosaurs". Nature Ecology & Evolution. 2 (8): 1227–1232. Bibcode:2018NatEE...2.1227A. doi:10.1038/s41559-018-0599-y. hdl: 11336/89332 . PMID   29988169. S2CID   256705065.
8. McPhee, Blair W.; Benson, Roger B.J.; Botha-Brink, Jennifer; Bordy, Emese M. & Choiniere, Jonah N. (2018). "A giant dinosaur from the earliest Jurassic of South Africa and the transition to quadrupedality in early sauropodomorphs". Current Biology. 28 (19): 3143–3151.e7. Bibcode:2018CBio...28E3143M. doi: 10.1016/j.cub.2018.07.063 . PMID   30270189.
9. Diego Pol; Alberto Garrido; Ignacio A. Cerda (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. Bibcode:2011PLoSO...614572P. doi: 10.1371/journal.pone.0014572 . PMC   3027623 . PMID   21298087.
10. Apaldetti; Martínez, Ricardo N.; Cerda, Ignatio A.; Pol, Diego; Alcober, Oscar (2018). "An early trend towards gigantism in Triassic sauropodomorph dinosaurs". Nature Ecology & Evolution. 2 (8): 1227–1232. Bibcode:2018NatEE...2.1227A. doi:10.1038/s41559-018-0599-y. hdl: 11336/89332 . PMID   29988169. S2CID   49669597.
11. 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" (PDF). Swiss Journal of Geosciences . 113 (1): 8. doi: 10.1186/s00015-020-00360-8 . S2CID   220294939.

External links

• Media related to Lessemsaurus at Wikimedia Commons