''Ledumahadi'' (meaning "giant thunderclap" in

Sesotho language Sotho () or Sesotho () or Southern Sotho is a Southern Bantu languages, Southern Bantu language of the Sotho–Tswana languages, Sotho–Tswana ("S.30") group, spoken primarily by the Basotho people, Basotho in Lesotho, where it is the nati ...

) is a genus of lessemsaurid

sauropodomorph Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had lon ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

from the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...

Elliot Formation The Elliot Formation is a geological formation and forms part of the Stormberg Group, the uppermost geological Stratigraphic unit, group that comprises the greater Karoo Supergroup. Outcrops of the Elliot Formation have been found in the northern ...

Free State Province The Free State, known as Orange Free State until the 28th of June 1995 when its name was changed, is a province of South Africa. Its capital is Bloemfontein, which is also South Africa's judicial capital. Its historical origins lie in the Boer ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. The type and only species is ''L. mafube'', known from a singular incomplete

postcrania Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...

l specimen. A quadruped, it was one of the first giant sauropodomorphs, reaching a weight of around , despite not having evolved columnar limbs like its later huge relatives.

Description

''Ledumahadi'' was likely a quadruped, as determined by analysis of the circumference of its

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

and

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

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.

Size

At its time in the

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

, ''Ledumahadi'' is thought to have been the

largest Large means of great size. Large may also refer to: Mathematics * Arbitrarily large, a phrase in mathematics * Large cardinal, a property of certain transfinite numbers * Large category, a category with a proper class of objects and morphisms (or ...

land animal that had ever lived. At the age of 14 years, ''L. mafube'' is estimated to have reached a maximum size of around in body mass, significantly larger than its relatives. ''L. mafube'' was more comparable to the later sauropod ''

Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπ� ...

'' in body mass. An

ichnotaxon An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxa'' comes from the Greek ίχνος, ''ichnos'' meaning ''track'' and ταξις, ''taxis'' meaning ...

named ''Tetrasauropus'' belongs to a sauropodomorph that is estimated to have a hip height of , meaning that it likely belongs to ''Ledumahadi''.

Classification

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

of ''Ledumahadi mafube'' was performed by McPhee and colleagues, which found it to belong to a recently recognised

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

sauropodiformes Massopoda is a clade of sauropodomorph dinosaurs which lived during the Late Triassic to Late Cretaceous epochs. It was named by paleontologist Adam M. Yates of the University of the Witwatersrand in 2007. Massopoda is a stem-based taxon, define ...

called

Lessemsauridae 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 sa ...

, including the closely related South African ''

Antetonitrus ''Antetonitrus'' is a genus of sauropod dinosaur found in the Early Jurassic Elliot Formation of South Africa. The only species is ''Antetonitrus ingenipes''. As one of the oldest known sauropods, it is crucial for the understanding of the origin ...

'' and ''

Lessemsaurus ''Lessemsaurus'' is an extinct genus of sauropod dinosaur belonging to Lessemsauridae. 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 ...

'' from

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. Another lessemsaurid described in 2018, ''

Ingentia ''Ingentia'' is a genus of early sauropod dinosaur from the Late Triassic (late Norian-Rhaetian) of Argentina. The type specimen of ''Ingentia'', PVSJ 1086, was discovered in the Quebrada del Barro Formation of northwestern Argentina. It was des ...

'', 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: 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''.

References

{{Portal bar, Dinosaurs, South Africa Sauropodomorphs Early Jurassic dinosaurs of Africa Hettangian genera Sinemurian genera Jurassic South Africa Fossils of South Africa Fossil taxa described in 2018

Description

Size

Classification

See also

References