Ledumahadi

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Ledumahadi
Temporal range: Hettangian-Sinemurian, 200–195  Ma
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Ledumahadi NT.jpg
Restoration of Ledumahadi mafube
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Lessemsauridae
Genus: Ledumahadi
McPhee et al., 2018
Type species
Ledumahadi mafube
McPhee et al., 2018

Ledumahadi (meaning "giant thunderclap" in Sesotho language) is a genus of lessemsaurid sauropodomorph dinosaur from the Early Jurassic Elliot Formation in Free State Province, South Africa. [1] The type and only species is L. mafube, [1] [2] known from a singular incomplete postcranial specimen. A quadruped, it was one of the first giant sauropodomorphs, reaching a weight of around 12 tonnes (13 short tons), despite not having evolved columnar limbs like its later huge relatives. [1]

Contents

Description

Ledumahadi was likely a quadruped, as determined by analysis of the circumference of its humerus and femur compared to those of other dinosaurs. It would have had very large, robust forelimbs, consistent with those of its relatives. Unlike those of later sauropods, these limbs were naturally flexed, as opposed to being purely columnar. [1] [3]

Size

Size of Ledumahadi compared to a human Ledumahadi size chart with human.png
Size of Ledumahadi compared to a human

At its time in the Early Jurassic epoch, Ledumahadi is thought to have been the largest land animal that had ever lived. [1] At the age of 14 years, L. mafube is estimated to have reached a maximum size of around 12 tonnes (13 short tons) in body mass, significantly larger than its relatives. L. mafube was more comparable to the later sauropod Diplodocus in body mass. [1] [3] An ichnotaxon named Tetrasauropus belongs to a sauropodomorph that is estimated to have a hip height of 2 m (6.6 ft), meaning that it likely belongs to Ledumahadi. [4]

Classification

A phylogenetic analysis of Ledumahadi mafube was performed by McPhee and colleagues, which found it to belong to a recently recognised clade of sauropodiformes called Lessemsauridae, including the closely related South African Antetonitrus and Lessemsaurus from Argentina. Another lessemsaurid described in 2018, Ingentia , could not be included in their analysis but was also recognised as belonging to Lessemsauridae. The results of McPhee and colleagues' analysis are shown in the cladogram below: [1] [3]

Sauropodiformes

The size of the taxon was deemed to be important in the wider picture of sauropodomorph evolution, similar to its other lessemsaurid relatives. Living only a few million years after the Triassic-Jurassic extinction event, it indicates that this event must have either had only a small effect on body size within the sauropodomorph lineage, or may have not affected it at all. Significance was also found in the magnitude of the size itself—it lacked the columnar limbs that characterized its more derived relatives, thought to be a key adaptation in body size evolution. Ornithischian dinosaurs reach their largest sizes around a similar size of 12 to 17 tonnes in weight. This may have been the upper limit for dinosaurs without adopting the characteristics found in true sauropods, which grew to be several times the weight of Ledumahadi. [1] [3]

See also

Related Research Articles

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<span class="mw-page-title-main">Sauropodomorpha</span> Extinct clade of dinosaurs

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<i>Mussaurus</i> Extinct genus of dinosaurs

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<span class="mw-page-title-main">Matthew Bonnan</span> American paleontologist, professor, singer/songwriter

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<span class="mw-page-title-main">Elliot Formation</span> Lithostratigraphic layer of the Stormberg Group in South Africa

The Elliot Formation is a geological formation and forms part of the Stormberg Group, the uppermost geological group that comprises the greater Karoo Supergroup. Outcrops of the Elliot Formation have been found in the northern Eastern Cape, southern Free State, and in the eastern KwaZulu-Natal provinces of South Africa. Outcrops and exposures are also found in several localities in Lesotho such as Qacha's Neck, Hill Top, Quthing, and near the capital, Maseru. The Elliot Formation is further divided into the lower (LEF) and upper (UEF) Elliot formations to differentiate significant sedimentological differences between these layers. The LEF is dominantly Late Triassic (Norian-Hettangian) in age while the UEF is mainly Early Jurassic (Sinemurian-Pliensbachian) and is tentatively regarded to preserve a continental record of the Triassic-Jurassic boundary in southern Africa. This geological formation is named after the town of Elliot in the Eastern Cape, and its stratotype locality is located on the Barkly Pass, 9 km north of the town.

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<span class="mw-page-title-main">Lessemsauridae</span> Extinct clade of dinosaurs

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. 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. A 2021 study by Pol and colleagues also assigned the genera Kholumolumo and Meroktenos to the group.

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References

  1. 1 2 3 4 5 6 7 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.
  2. "†Ledumahadi McPhee et al. 2018". Paleobiology Database. Fossilworks. Retrieved 17 December 2021.
  3. 1 2 3 4 Apaldetti, Cecilia; 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.
  4. Sander, P.M.; Lallensack, J.N. (2018). "Dinosaurs: Four Legs Good, Two Legs Bad". Current Biology. 28 (19): R1160–R1163. Bibcode:2018CBio...28R1160S. doi: 10.1016/j.cub.2018.08.025 . PMID   30300605.