**Atlantosaurus: The Atlas Lizard**
Atlantosaurus is a type of dinosaur that lived during the Late Jurassic period, about 150 million years ago. This dinosaur belongs to a group known as sauropods, which were large, long-necked dinosaurs.
**Scientific Classification**
– **Kingdom**: Animalia (animals)
– **Phylum**: Chordata (animals with a backbone)
– **Class**: Reptilia (reptiles)
– **Clade**: Dinosauria (dinosaurs)
– **Clade**: Saurischia (a group of dinosaurs)
– **Family**: Diplodocidae (related to other long-necked dinosaurs)
Atlantosaurus was first named by a famous paleontologist named Othniel Charles Marsh in 1877. The name “Atlantosaurus” means “Atlas lizard,” referring to its massive size.
**Discovery and Naming**
The first fossils of Atlantosaurus, specifically its vertebrae, were discovered in Colorado by Arthur Lakes. Marsh initially called it Titanosaurus montanus but later changed the name to Atlantosaurus montanus because “Titanosaurus” was already used for another dinosaur.
Marsh estimated that Atlantosaurus could reach around 24 meters in length, which is about as long as two school buses. However, since he based this on only a few bones, it became difficult to tell if this dinosaur was truly unique or similar to others.
**Other Species**
Marsh also named a second species called Atlantosaurus immanis in 1878. This name means “the immense one” and was based on a more complete set of bones. Marsh estimated it could grow to around 35 meters long, making it one of the largest land animals at the time.
However, as scientists studied Atlantosaurus more, they found it hard to tell if these species were distinct. Some researchers think they might even be the same as other dinosaurs like Apatosaurus.
In summary, while Atlantosaurus was once believed to be a massive and unique dinosaur, ongoing research has led to questions about its exact classification. Many parts of its story show how paleontology can change as new discoveries are made.