''Sefapanosaurus'' was an early, herbivorous

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 lo ...

dinosaur occurring in the southern regions of

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

some 200 million years ago in the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

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� ...

. The sauropodomorphs were the dominant terrestrial herbivores throughout much of the

Mesozoic Era The Mesozoic Era is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles such as the dinosaurs, and of gymnosperms s ...

, from their origins in the mid-

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

(approximately 230 Ma) until their decline and fall at the end of the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

(approximately 66 Ma). A distinctive feature of this dinosaur is the cross-shaped astragalus or

talus bone The talus (; Latin for ankle or ankle bone; : tali), talus bone, astragalus (), or ankle bone is one of the group of Foot#Structure, foot bones known as the tarsus (skeleton), tarsus. The tarsus forms the lower part of the ankle joint. It transmit ...

in its ankle. The generic name is derived from the

Sesotho Sotho (), also known as ''Sesotho'' (), Southern Sotho, or ''Sesotho sa Borwa'' is a Southern Bantu languages, Southern Bantu language spoken in Lesotho as its national language and South Africa where it is an official language. Like all Ba ...

word ''sefapano'', meaning ‘cross’ and the Greek word ''saurus'', meaning 'lizard'. The specific name refers to Zastron, the type locality, where the specimen was discovered.

History of study

This new genus was described in the 23 June 2015 issue of '

Zoological Journal of the Linnean Society The ''Zoological Journal of the Linnean Society'' is a monthly peer-reviewed scientific journal covering zoology published by Oxford University Press on behalf of the Linnean Society. The editor-in-chief is Maarten Christenhusz (Linnean Society) ...

' in an essay titled 'A new basal sauropodiform from South Africa and the phylogenetic relationships of basal sauropodomorphs'. A portion of the left foot and four partial skeletons, including several pieces of spine and limbs, were excavated from the

Elliot Formation 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, so ...

in the late 1930s in the Zastron district in South Africa, some from the

Lesotho Lesotho, formally the Kingdom of Lesotho and formerly known as Basutoland, is a landlocked country in Southern Africa. Entirely surrounded by South Africa, it is the largest of only three sovereign enclave and exclave, enclaves in the world, t ...

border. Until a few years ago these formed part of the large fossil collection curated by the Evolutionary Studies Institute (ESI) at Wits University. When finally studied, the remains were thought to be those of the dinosaur '' Aardonyx''. Further study determined that the remains represented a new dinosaur genus which was intermediate between early bipedal sauropodomorphs and the later giant quadruped sauropods, adding to the list of transitional sauropodomorphs from

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

, and further clarifying their diversification.

Phylogeny

The following cladogram shows the position of ''Sefapanosaurus'' within Massopoda, according to Oliver W. M. Rauhut and colleagues, 2020:

References

{{Taxonbar, from=Q20440451 Massopoda Dinosaur genera Hettangian dinosaurs Elliot Formation Fossil taxa described in 2015 Dinosaurs of South Africa