Biology:Lessemsauridae
| Lessemsaurids | |
|---|---|
| |
| Skeletal mount of Lessemsaurus | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Clade: | †Lessemsauridae Apaldetti et al., 2018 |
| Genera | |
Lessemsauridae is a clade of early sauropodiform dinosaurs that lived in the Triassic and Jurassic of Argentina , South Africa and possibly Lesotho. A phylogenetic analysis performed by Apaldetti and colleagues in 2018 recovered a new clade of sauropodiforms uniting Lessemsaurus, Antetonitrus, and Ingentia which they named Lessemsauridae. It is a node-based taxon, defined as all descendants of the most recent common ancestor of Lessemsaurus sauropoides and Antetonitrus ingenipes.[1] Depending on the definition of Sauropoda, Lessemsauridae is either one of the most basal sauropod taxa, or a sister taxon of Sauropoda. An additional member of the clade was named later in 2018, Ledumahadi.[2] A 2021 study by Pol and colleagues also assigned the genera Kholumolumo and Meroktenos to the group.[3]
Description
Lessemsaurids were quadrupeds. Unlike later sauropods, which had columnar limbs, the forelimbs of lessemsaurids were flexed.[2] Sauropodomorph trackways have been found with widely-spaced front feet, indicating they were made by a trackmaker with flexed forelimbs as in lessemsaurids.[4]
Lessemsaurids could reach large sizes, with Lessemsaurus estimated to have reached a mass of 7 tonnes[1] and the later Ledumahadi estimated to have reached a mass of 12 tonnes.[2]
They had highly pneumatic cervical and dorsal vertebrae, very antero-posteriorly short but tall cervical vertebrae, robust cervicals, a very expanded distal scapula blade, and upright arms.[1][2]
Evolution and biogeography
Lessemsaurids first appeared during the middle Norian age of the Triassic. A specimen of an unnamed lessemsaurid from the Elliot Formation of South Africa probably dates to approximately 218 million years ago.[5] Lessemsaurus is a member of the La Esquina Local Fauna,[3] which probably dates to at least 213 million years ago.[6] Antetonitrus and Ledumahadi are found in the Upper Elliot Formation, which dates to the Hettangian and Sinemurian ages of the Jurassic.[7] Lessemsaurids are known from South Africa and Argentina.
References
- ↑ 1.0 1.1 1.2 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. doi:10.1038/s41559-018-0599-y. PMID 29988169. Bibcode: 2018NatEE...2.1227A. https://staff.mef.org.ar/images/investigadores/diego_pol/papers/95.pdf.
- ↑ 2.0 2.1 2.2 2.3 McPhee (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. doi:10.1016/j.cub.2018.07.063. PMID 30270189.
- ↑ 3.0 3.1 Pol, Diego; Otero, Alejandro; Apaldetti, Cecilia; Martínez, Ricardo N. (2021-01-11). "Triassic sauropodomorph dinosaurs from South America: The origin and diversification of dinosaur dominated herbivorous faunas". Journal of South American Earth Sciences 107: 103145. doi:10.1016/j.jsames.2020.103145. ISSN 0895-9811. Bibcode: 2021JSAES.10703145P.
- ↑ Sciscio, Lara; Bordy, Emese M.; Lockley, Martin G.; Abrahams, Miengah (2023-09-28). "Basal sauropodomorph locomotion: ichnological lessons from the Late Triassic trackways of bipeds and quadrupeds (Elliot Formation, main Karoo Basin)". PeerJ 11: –15970. doi:10.7717/peerj.15970. ISSN 2167-8359. PMID 37790620.
- ↑ Moopen, Atashni; Viglietti, Pia A; Choiniere, Jonah N (2023-12-15). "Anatomy and phylogenetic relationships of a possible lessemsaurid with associated plant fossils from the lower part of the Elliot Formation". Palaeontologia Africana 56: 190–212.
- ↑ Kent, Dennis V.; Santi Malnis, Paula; Colombi, Carina E.; Alcober, Oscar A.; Martínez, Ricardo N. (2014-06-03). "Age constraints on the dispersal of dinosaurs in the Late Triassic from magnetochronology of the Los Colorados Formation (Argentina)". Proceedings of the National Academy of Sciences 111 (22): 7958–7963. doi:10.1073/pnas.1402369111. PMID 24843149. Bibcode: 2014PNAS..111.7958K.
- ↑ Viglietti, P.A.; McPhee, B.W.; Bordy, E.M.; Sciscio, L.; Barrett, P.M.; Benson, R.B.J.; Wills, S.; Chapelle, K.E.J. et al. (2020-06-01). "Biostratigraphy of the Massospondylus Assemblage Zone (Stormberg Group, Karoo Supergroup), South Africa". South African Journal of Geology 123 (2): 249–262. doi:10.25131/sajg.123.0018. ISSN 1012-0750. Bibcode: 2020SAJG..123..249V. https://pubs.geoscienceworld.org/gssa/sajg/article/123/2/249/587462/Biostratigraphy-of-the-Massospondylus-Assemblage. Retrieved 2021-02-17.
Wikidata ☰ Q55454676 entry
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