#atlantosaurus

"Forme et grandeur probables de l'atlantosaure le plus grand des animaux qui aient jamais existé (longueur: 35 mètres)." ["Probable shape and size of the Atlantosaurus, the largest animal that ever existed (length: 35 meters)"] by Jules Blanadet, from Camille Flammarion's Le monde avant la création de l'homme (1886)

Grzimek's Animal Life Encyclopedia. Volume 6: Reptiles. Written by Bernard Grzimek. 1984.

Source: http://dinosaurpictures.org/Atlantosaurus-pictures

Name: Atlantosaurus montanus

Name Meaning: Atlas Lizard

First Described: 1877

Described By: Marsh

Classification: Dinosauria, Saurischia, Eusaurischia, Sauropodomorpha,Plateosauria, Massopoda, Sauropodiformes, Anchisauria, Sauropoda,Gravisauria, Eusauropoda, Neosauropoda, Diplodocoidea, Diplodocimorpha, Flagellicaudata, Diplodocidae, Apatosaurinae

Atlantosaurus is an Apatosaurine that isn’t known from very much material, but it was still the first described Apatosaurine, which makes it interesting that it wasn’t included in the Tschopp et al. analysis. Very interesting. Very suspicious. More on that later. IT’s a dubious genus now and was known from two vertebrae, but it lived in the Morrison Formation in Colorado, about 150 to 155 million years ago, in the Tithonian age of the Late Jurassic. Its size is unknown and it would have been similar to Apatosaurus. It had air-filled pockets in its vertebrae, much like other sauropods. 

Sources: 

https://en.wikipedia.org/wiki/Atlantosaurus

http://www.prehistoric-wildlife.com/species/a/atlantosaurus.html