Lognkosauria is 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 ...

of giant long-necked

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 b ...

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 ...

s within the

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

. It includes some of the largest and heaviest dinosaurs known. They lived in South America and likely Asia during the Late Cretaceous period.

Description

Lognkosaurians can be distinguished from other titanosaurs by the wide and unusually thick cervical rib loops on their neck vertebrae, the relatively narrow neural canal, and their huge vaulted

neural arch 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 ...

es. 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. Skull material from ''

Malawisaurus ''Malawisaurus'' (meaning "Malawi lizard") is an extinct genus of titanosaurian sauropod dinosaur. It is known from the Dinosaur Beds of northern Malawi, which probably date to the Aptian stage of the Early Cretaceous. The type species is ''M. di ...

'', the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to Lognkosauria, indicates that lognkosaurians at least began with the big-nosed, rounded head shape of earlier titanosaurs and more basal

macronaria Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...

ns.

Classification

Lognkosauria was defined as the

encompassing the

most recent common ancestor A most recent common ancestor (MRCA), also known as a last common ancestor (LCA), is the most recent individual from which all organisms of a set are inferred to have descended. The most recent common ancestor of a higher taxon is generally assu ...

of '' Futalognkosaurus dukei'' and '' Mendozasaurus neguyelap'' and all its descendants. ''

'' may be related to this group. Lognkosauria has been found to include other giant sauropods, such as '' Puertasaurus'', ''

Argentinosaurus ''Argentinosaurus'' (meaning "lizard from Argentina") is a genus of giant sauropod dinosaur that lived during the Late Cretaceous Period (geology), period in what is now Argentina. Although it is only known from fragmentary remains, ''Argentinos ...

'', ''

Patagotitan ''Patagotitan'' is a genus of titanosaurian sauropoda, sauropod dinosaur from the Cerro Barcino Formation in Chubut Province, Patagonia, Argentina. The genus contains a single species known from at least six young adult individuals, ''Patagotita ...

'', '' Notocolossus'', '' Drusilasaura'' and '' Traukutitan''.

References

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