''Laplatasaurus'' (meaning "La Plata lizard", named for La Plata,

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 ...

) is a

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 ...

titanosaur Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thr ...

ian sauropod

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 ...

that lived during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

, with the holotype and only known specimen found in the

Anacleto Formation The Anacleto Formation is a geologic formation with outcrops in the Argentine Patagonian provinces of Mendoza, Río Negro, and Neuquén. It is the youngest formation within the Neuquén Group and belongs to the Río Colorado Subgroup. Formerl ...

Naming and description

The genus was named in 1927 by Friedrich von Huene, but without a description, so that it remained a '' nomen nudum''. In 1929 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 specime ...

, ''Laplatasaurus araukanicus'', was described by Huene. The generic name refers to La Plata. The specific name is derived from the ''Araucanos'' or

Mapuche The Mapuche ( (Mapuche & Spanish: )) are a group of indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging ethnicity composed of various groups who s ...

. By accident Huene in 1929 also mentioned a "Laplatasaurus wichmannianus" but that was a ''

lapsus calami In philology, a lapsus (Latin for "lapse, slip, error") is an involuntary mistake made while writing or speaking. Investigations In 1895 an investigation into verbal slips was undertaken by a philologist and a psychologist, Rudolf Meringer and K ...

'' for '' Antarctosaurus wichmannianus''. In 1933 however, he and

Charles Alfred Matley Charles Alfred Matley (1866–1947) was a British paleontologist and geologist in India, the British West Indies and Wales. Matley was educated at Birmingham University, and earned a doctorate in geology (D.Sc.) from the University of London in J ...

renamed ''

Titanosaurus ''Titanosaurus'' (; ) is a dubious genus of sauropod dinosaurs, first described by Richard Lydekker in 1877.R. Lydekker. (1877). Notices of new and other Vertebrata from Indian Tertiary and Secondary rocks. ''Records of the Geological Survey of I ...

madagascariensis'' to ''Laplatasaurus madagascariensis''. This last species is today commonly referred to the original ''Titanosaurus''. Huene based ''Laplatasaurus'' on fragmentary material found in three locations in

, in strata of the

, dating from the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

faunal stage In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convent ...

. It consisted of limb elements, some dorsal vertebrae and a series of caudal vertebrae. Part of the finds had earlier been referred by

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

to ''Titanosaurus australis''. Huene never assigned a

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

, but in 1979 José Fernando Bonaparte chose MLP 26-306 as the

lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

, a specimen consisting of a

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

and a

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity i ...

that perhaps originate from different individuals. Huene assigned those fossils to ''Laplatasaurus'' that seemed to indicate a rather large yet at the same time elegantly built sauropod. The about eighteen metres (60 ft) long ''Laplatasaurus'' was perhaps similar to ''

Saltasaurus ''Saltasaurus'' (which means "lizard from Salta") is a genus of saltasaurid dinosaur of the Late Cretaceous period of Argentina. Small among sauropods, though still heavy by the standards of modern creatures, ''Saltasaurus'' was characterized by ...

''.

Osteoderms Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amphi ...

forming an armored plating on the back, have been referred to ''Laplatasaurus'' but the association is uncertain. These plates had much smaller ridges than those of ''Saltasaurus''.

Taxonomy

Huene placed ''Laplatasaurus'' in the

Titanosauridae Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch ''et al.'' in 2004 as the most recent common ancestor of '' Malawisaurus'' and '' Saltasaurus'' ...

, which is still a common classification. In his 2003 review of South American titanosaurs, Jaime Eduardo Powell assigned ''Laplatasaurus'' to ''

'', creating the new combination ''Titanosaurus aurakanicus''. Others however, continued to treat ''Laplatasaurus'' as valid genus separate from ''Titanosaurus''.Salgado, L. & Coria, R. A. 2005. Sauropods of Patagonia: Systematic update and notes on Global Sauropod evolution. In. Thunder-Lizards. The Sauropodomorph Dinosaurs. Ed. V. Tidwell & K. Carpenter. Indiana University Press. Bloomington and Indianopolis. Indiana University Press430-453. A 2015 re-assessment of ''Laplatasaurus'' found it to be closely related to '' Bonitasaura'', '' Futalognkosaurus'', '' Mendozasaurus'', and '' Uberabatitan''. The genus was restricted to the lectotype, and the material from Rancho de Avila was assigned to cf. ''Bonitasaura'' sp.

References

{{Taxonbar, from=Q135594 Titanosaurs Campanian life Late Cretaceous dinosaurs of South America Cretaceous Argentina Fossils of Argentina Fossil taxa described in 1929 Taxa named by Friedrich von Huene Anacleto Formation