''Lessemsaurus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', ' lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their ...

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 ...

belonging to

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 ...

Naming and description

The

type species In 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 species that contains the biological type specim ...

, ''L. sauropoides'', was formally described by

José Fernando Bonaparte José is a predominantly Spanish and Portuguese form of the given name Joseph. While spelled alike, this name is pronounced differently in each language: Spanish ; Portuguese (or ). In French, the name ''José'', pronounced , is an old vernacu ...

in 1999 in honor of

Don Lessem "Dino" Don Lessem (born 1951) is a writer of more than 50 popular science books, specializing in dinosaurs. He was the founder of the Dinosaur Society and the Jurassic Foundation, which collectively have raised millions of dollars for dinosaur res ...

, a writer of popular science books. It was found in the

Los Colorados Formation The Los Colorados Formation is a sedimentary rock formation of the Ischigualasto-Villa Unión Basin, found in the provinces of San Juan and La Rioja in Argentina. The formation dates back to the Norian age of the Late Triassic. The up to thick f ...

of the

Ischigualasto-Villa Unión Basin The Ischigualasto-Villa Unión Basin ( es, Cuenca de Ischigualasto-Villa Unión) is a small sedimentary basin located in the Argentine Northwest, Argentina. It is located in the southwestern part of La Rioja Province, Argentina, La Rioja Province a ...

La Rioja Province, Argentina La Rioja () is a province of Argentina located in the west of the country. The landscape of the province consist of a series of arid to semi-arid mountain ranges and agricultural valleys in between. It is in one of these valleys that the capital ...

.Weishampel, David B; ''et al.'', 2004. "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528. . This dinosaur was around long and was discovered in strata dating to the

Norian The Norian is a division of the Triassic Period. It has the rank of an age ( geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic ...

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

, around 210 million years ago. It is estimated to have reached in maximum body mass.

Classification

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

after Pol, Garrido & Cerda, 2011, illustrates a possible placing of ''Lessemsaurus'' and ''

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 origi ...

'' in Sauropodomorpha: In 2018, Apaldetti ''et al.'' recovered it as part of a

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 ter ...

they named

, after ''Lessemsaurus''. Their cladogram is reproduced below: The following cladogram shows the position of ''Lessemsaurus'' outside of Sauropoda, according to Oliver W. M. Rauhut and colleagues, 2020:

References

External links

* Sauropods Dinosaur genera Norian life Late Triassic dinosaurs of South America Fossils of Argentina Triassic Argentina Los Colorados Formation Fossil taxa described in 1999 Taxa named by José Bonaparte {{Sauropodomorph-stub