''Eucnemesaurus'' (; meaning "good tibia lizard", for its robust

tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...

e) is a basal

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

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

usually considered to be a synonym of '' Euskelosaurus''. Recent study by Yates (2006), however, indicates that it is valid and the same animal as putative "giant herrerasaurid" ''Aliwalia''. ''Eucnemesaurus'' was named in 1920 by

Egbert Cornelis Nicolaas van Hoepen Egbert Cornelis Nicolaas van Hoepen (10 November 1884 – 2 May 1966) was a Dutch-born South African paleontologist. Biography Born at Vlissingen, around the age of six he moved with his parents to the South African Republic. When British f ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''Eucnemesaurus fortis''. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

means "strong" in

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

. It is based on

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

TrM 119, a partial skeleton including

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

, part of a pubis, a

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

, and two

e. The remains were found by Van Hoepen in the late Carnian- early Norian-age

Upper Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. T ...

Lower 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 ...

of the Slabberts district,

Orange Free State The Orange Free State ( ; ) was an independent Boer-ruled sovereign republic under British suzerainty in Southern Africa during the second half of the 19th century, which ceased to exist after it was defeated and surrendered to the British Em ...

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 ...

. Yates assigned the genus to the new family

Riojasauridae Riojasauridae is an extinct family of sauropodomorph dinosaurs from the Late Triassic Period (late Carnian to Norian Ages). It contains the genera ''Riojasaurus'' and '' Eucnemesaurus''. The Riojasauridae is considered a stem taxon, and is defin ...

, with ''

Riojasaurus ''Riojasaurus'' (meaning "lizard from La Rioja") was a herbivorous sauropodomorph dinosaur named after La Rioja Province in Argentina where it was found in the Los Colorados Formation in the Ischigualasto-Villa Unión Basin by José Bonaparte. ...

'', usually regarded as a melanorosaurid. Eucnemesaurus tibia

''Aliwalia''

Fossil material now assigned to ''Eucnemesaurus'' was once placed in a separate genus and

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, ''Aliwalia rex'' (the generic name was taken from the Aliwal Park Reserve in the

Union of South Africa The Union of South Africa (; , ) was the historical predecessor to the present-day South Africa, Republic of South Africa. It came into existence on 31 May 1910 with the unification of the British Cape Colony, Cape, Colony of Natal, Natal, Tra ...

, where the first remains were found). The

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

evidence of this species was comparably small, with for many years only

femora The femur (; : femurs or femora ), or thigh bone is the only bone in the thigh — the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg. The top of the femur fits in ...

l fragments and a

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

known, having been sent from South Africa to

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

in 1873 in a shipment with prosauropod bones. The size of the femur led many

palaeontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

s to believe (along with the clearly carnivorous maxilla), that ''Aliwalia'' was a

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

dinosaur of remarkable size for the age in which lived. It would have been comparable to that of the large

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

and

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 ...

theropods Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

, such as ''

Allosaurus ''Allosaurus'' ( ) is an extinct genus of theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period ( Kimmeridgian to late Tithonian ages). The first fossil remains that could definitively be ascribed to th ...

'', that evolved tens of millions of years after ''Aliwalia''. The original material was believed to bear a strong similarity to the

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

n ''

Herrerasaurus ''Herrerasaurus'' is likely a genus of saurischian dinosaur from the Late Triassic period. Measuring long and weighing around , this genus was one of the earliest dinosaurs from the fossil record. Its name means "Herrera's lizard", after the ...

'', so much so that ''Aliwalia'' was originally classified in

Herrerasauridae Herrerasauridae is a family of carnivorous dinosaurs, possibly basal to either theropods or even all of saurischians, or even their own branching from Dracohors, separate from Dinosauria altogether. They are among the oldest known dinosaurs, ...

by Peter Galton. However, later re-evaluation of the material has shown that the maxilla assigned to ''Aliwalia'' does not, unlike the other material, belong to ''Eucnemesaurus'', as it is clearly from a carnivore. In addition, new material clearly demonstrates this latter genus' sauropodomorph affinities.

Sources

*E. C. N. van Hoepen (1920).
Contributions to the knowledge of the reptiles of the Karroo Formation. 6. Further dinosaurian material in the Transvaal Museum
, ''Annals of the Transvaal Museum'' 7(2): 93-141 * Yates, A.M. (2006). "Solving a dinosaurian puzzle: the identity of ''Aliwalia rex'' Galton". ''Historical Biology'', 1–31

References

{{Taxonbar, from=Q133173 Massopoda Dinosaur genera Norian dinosaurs Carnian dinosaurs Elliot Formation Fossil taxa described in 1920 Taxa named by Egbert Cornelis Nicolaas van Hoepen Dinosaurs of South Africa