D. schrani is known from two partial skeletons discovered in Upper Cretaceous (Campanian to Maastrichtian; approximately 76–70 Ma) rocks of the Cerro Fortaleza Formation in Santa Cruz Province, Argentina.

Drexel University paleontologist Kenneth Lacovara, who discovered the species, chose the name Dreadnoughtus, which means “fears nothing", stating “I think it’s time the herbivores get their due for being the toughest creatures in an environment.

[1] American palaeontologist Kenneth Lacovara[2] discovered the remains in the Cerro Fortaleza Formation in Santa Cruz Province, Patagonia, Argentina in 2005.

Due to the large size of the bones and the remote location where they were found, it took his team four austral summers to fully excavate the remains.

Dreadnoughtus schrani fossils were returned to their permanent repository at the Museo Padre Molina in Rio Gallegos, Argentina in March 2015.

The paratype, MPM-PV 3546, consists of a partially articulated postcranial skeleton of a slightly smaller individual whose remains were discovered in the same location as the holotype.

[4] By comparison, this would mean D. schrani weighed more than eight and a half times as much as a male African elephant and even exceeded the Boeing 737-900 airliner by several tons.

They found that any model using the scale-based weight estimate would have meant the animal had an impossible amount of bulk (fat, skin, muscle, etc.)

[12][18] The discovery of Dreadnoughtus schrani provides insight into the size and anatomy of giant titanosaurian sauropods, especially of the limbs and the shoulder and hip girdles.

Estimates based on measurements of the known parts of the skeleton suggest that the only known individual of Dreadnoughtus schrani was approximately 26 metres (85 ft) long and stood about 2 stories tall.

[21] All titanosaurs had what is called wide-gauge posture, a relative term to describe a stance in which the feet fell apart from the body midline.

More derived titanosaurs had a greater degree of wide-gauge posture,[22][23] with their limbs held more widely than their ancestors and contemporaneous counterparts.

The animal's broad sternal bones also demonstrate a wide pectoral girdle, giving it a broad-shouldered, broad-chested appearance.

In the first third of the tail, the bases of the neural spines are extensively subdivided into cavities caused by contact with air sacs (part of the dinosaur's respiratory system).

Camarasauridae Europasaurus Euhelopus Brachiosauridae Andesaurus Argentinosaurus Futalognkosaurus Dreadnoughtus Malawisaurus Rapetosaurus Isisaurus Alamosaurus Opisthocoelicaudia Neuquensaurus Saltasaurus However, in a subsequent analysis of its limb bones, Ullman & Lacovara found that Dreadnoughtus possessed many of the characteristics of lithostrotians (in particular, it shares a number of traits with Aeolosaurus and Gondwanatitan), which collectively may indicate that it is actually a lithostrotian closely related to Aeolosauridae.

While no new phylogenetic analysis was conducted, they suggested that future cladistic analyses should investigate the relationships between Dreadnoughtus, Aeolosaurus, and Gondwanatitan.

[4][27][14] Based on the sedimentary deposits at the site, the two Dreadnoughtus schrani specimens appear to have been buried quickly during a fluvial avulsion event, or break in a levee resulting in a flood.