''Lessemsaurus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 ...

of sauropodiform

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 ...

belonging to Lessemsauridae.

Naming and description

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 ...

, ''L. sauropoides'', was formally described by José Fernando Bonaparte in 1999 in honor of Don Lessem, a writer of popular science books. It was found in the

Los Colorados Formation The Los Colorados Formation is a sedimentary geological formation, rock formation of the Ischigualasto-Villa Unión Basin, found in the provinces of San Juan Province, Argentina, San Juan and La Rioja Province (Argentina), La Rioja in Argentina. ...

of the Ischigualasto-Villa Unión Basin in

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

.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. . It was discovered in strata dating to the

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

stage Stage, stages, or staging may refer to: Arts and media 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 Brit ...

, around 210 million years ago. It is estimated to have reached long and weighed over , possibly up to , in maximum body mass.

Classification

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

after Pol, Garrido & Cerda, 2011, illustrates a possible placing of ''Lessemsaurus'' and '' Antetonitrus'' in Sauropodomorpha: In 2018, Apaldetti ''et al.'' recovered it as part of a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

they named Lessemsauridae, 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

* {{Taxonbar, from=Q135039 Anchisauria Dinosaur genera Norian dinosaurs Los Colorados Formation Fossil taxa described in 1999 Taxa named by José Bonaparte Dinosaurs of Argentina