Lognkosauria
Encyclopedia
Lognkosauria is a group of giant long-necked sauropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s within the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 Titanosauria, and includes some of the largest and heaviest dinosaurs to ever walk the earth.

Defining characteristics

They were more derived than Andesauridae (primitive titanosaurs such as Argentinosaurus
Argentinosaurus
Argentinosaurus is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered...

) but more basal than lithostrotians (such as Antarctosaurus
Antarctosaurus
Antarctosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, A. wichmannianus, was described by prolific German paleontologist Friedrich von Huene in 1929, who also described a second species in 1929. Three additional...

and Saltasaurus
Saltasaurus
Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...

). Lognkosaurians can be distinguished from other titanosaurs by the wide and unusually thick cervical rib loops on their neck vertebrae, their extremely robust neck neural spines, the relatively narrow neural canal, and their huge vaulted neural arches. They also had very wide dorsal vertebrae with wing-like side processes, and extremely wide rib cages. Their dorsal side processes are also fairly in-line with the level of the neural canal, instead of being attached further up the neural arch as in lithostrotians. They became dominant in the Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...

 and Coniacian
Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...

 epochs, replacing the Andesauridae as the top giant herbivores. Skull material from Malawisaurus
Malawisaurus
Malawisaurus was a genus of sauropod dinosaur . It lived in what is now Africa, specifically Malawi, during the Aptian age of the Early Cretaceous Period. It is one of the few titanosaurs for which skull material has been found.It was named by Louis L. Jacobs and colleagues, and was originally...

, the sister group to Lognkosauria, indicates that lognkosaurians at least began with the big-nosed, rounded head shape of earlier titanosaurs and more basal macronaria
Macronaria
Macronaria is a clade of sauropod dinosaurs from the Middle Jurassic to Late Cretaceous Periods of what are now North America, South America, Europe, Asia and Africa. The name means 'large nostrils' , in reference to the large nasal openings high on the head that probably supported fleshy...

ns.

Members

Lognkosauria was defined as the node clade encompassing the most recent common ancestor
Most recent common ancestor
In genetics, the most recent common ancestor of any set of organisms is the most recent individual from which all organisms in the group are directly descended...

 of Futalognkosaurus dukei and Mendozasaurus neguyelap and all its descendants. Malawisaurus was the sister group to this clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

. Lognkosauria probably also includes another giant sauropod, Puertasaurus
Puertasaurus
Puertasaurus is a genus of titanosaurid sauropod that appeared during the Late Cretaceous. It lived in what is now Patagonia. The type species, Puertasaurus reuili, is named in honor of Pablo Puerta and Santiago Reuil, the co-discoverers in January 2001 of the specimen...

,, as well as Traukutitan
Traukutitan
Traukutitan is a genus of possible lognkosaurian titanosaur sauropod which lived during the late Cretaceous .Fossils of Traukutitan were recovered from the lowermost section of the Bajo de la Carpa Formation in North Patagonia of Argentina and described but not named in 1993 by Leonardo Salgado...

and Drusilasaura
Drusilasaura
Drusilasaura is an extinct genus of possible lognkosaurian titanosaur sauropod which lived during the late Cretaceous of Santa Cruz Province of southern Patagonia, Argentina....

.

External links

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