Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
SuperOrder: Dinosauria
SubOrder: Sauropodomorpha
Family: Diplodocidae
Genus: Brontosaurus

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The Brontosaurus was one of the largest creatures to ever walk the earth, dinosaur or otherwise. It grew to gargantuan sizes. Its adult length is estimated to be 70 to 77 feet. Its weight is thought to be about 2.8 metric tons, but scientists speculate that some specimens could grow to 3.4 to 3.6 metric tons.
The Brontosaurus existed in the late Jurassic period. Its fossils were discovered in America in 1877. The timeline of the existence of the Brontosaurus is believed to be 151 to 149 million years ago. This lies in both the Kimmeridgian and Tithonian ages of the Jurassic period. It was a sauropod dinosaur.
Like other sauropods, the Brontosaurus was a plant eating dinosaur. Due to its dimensions, adult dinosaurs were rarely attacked by the carnivorous theropods. But young dinosaurs were very vulnerable to predators.
In the early twentieth century, paleontologists started noticing similarities between the Apatosaurus and the Brontosaurus. Riggs published a paper stating that the two dinosaurs were synonymous and some scientists concurred. But the name Brontosaurus was finally disregarded in 1979.
Yet, the Brontosaurus has been a pop culture icon. Cartoon characters such as the Flintstones were seen eating ‘bronto burgers (ignoring the fact that early humans appeared on the earth about 140 million years after the extinction of the Brontosaurus!).

Etymology
The name Brontosaurus is derived from Greek words. ‘Bronto’ translates to ‘thunder’ in English. The suffix ‘-saurus’ is coined from the Greek word ‘sauros’ which translates to ‘lizard’. Thus, Brontosaurus denotes ‘thunderous lizard’.
The word ‘Apato’ means ‘illusory’.
The species name B. excelsus translates to ‘transcendent’. The Brontosaurus excelsus is now the Apatosaurus excelsus.
All of these names were coined by O. C. Marsh.

Discovery of fossils
The errors in the identification and classification of the Brontosaurus had arisen because of the competitive nature of the ‘Bone wars’ between O. C. Marsh and E. D. Cope.

• Marsh had discovered the fossils of a large dinosaur in 1877 in Colorado and named it Apatosaurus ajax. There were limited bones found during that excavation and he hurriedly assembled them and went forward to search for more remains.
• In 1879, Marsh discovered another large dinosaur in the Cosmo Bluff in Wyoming and christened it ‘Brontosaurus’. In his haste to try and uncover more fossils, Marsh did not notice that the Brontosaurus was the same dinosaur as the Apatosaurus. Only the second remains were better preserved and included more bones.
• Since then, many fossils were discovered all throughout Oklahoma, Utah and Wyoming and were attribute to the Brontosaurus.
• The remains of another larger sauropod were discovered in Wyoming in the early 1900s and were name the Ellosaurus parvus. These were later grouped as a sub species of the Apatosaurus.

Classification

• The size of the Brontosaurus and its characteristic bones were enough to signify that it was a sauropodomorph dinosaur. The only difficulty was identifying sub species.
• O. C. Marsh had mounted a wrong skull on the original Apatosaurus specimen and this created a lot of confusion about the Apatosaurus. Due to this, no other fossils were ascribed to the Apatosaurus and those of the Brontosaurus kept increasing in number.
• In the late 1960s, the investigators at the Carnegie Museum realized that the skull of the Apatosaurus was incongruous with the post cranial skeleton. They finally found the correct skull for the Apatosaurus in 1979. This was discovered in Utah and remained unclassified.
• After the right skull was linked to the Apatosaurus, it was realized that the Brontosaurus was the same dinosaur as the Apatosaurus. Since the name Apatosaurus was coined first, it was retained and the name Brontosaurus was deemed invalid.

The Bone Wars

The contention between Othniel Charles Marsh and Edward Drinker Cope had escalated to the event termed as ‘The Bone Wars’.
Marsh and Cope each wanted to outdo the other in the number of fossils found by them. To this end, they hired men to recover as many bones as possible in the shortest period of time. While doing this, they used unethical means such as bribery, intimidation and even desecration of fossils to achieve their goals.
Each tried to have the other’s work discredited. Slanderous remarks and harsh criticisms were frequently dished out from both parties.
Although their motives were not all that noble, the impact of the findings of both Cope and Marsh on the field of paleontology was colossal. Their efforts have revealed over a hundred new species and have increased the paleontological data base many fold.

Physical characteristics

• The Brontosaurus was the typical Jurassic sauropod. It grew to about 20 to 25 meters in length and attained an adult weight of about 30,000 to 35,000 kilos.
• The head of the Brontosaurus was small and its neck was long and flexible.
• The neck had a downward inclination.
• The forelegs of the Brontosaurus were slightly shorter than its hind legs, giving it a hunched appearance.
• Its tail was long; broad at the base and tapering towards the end.

Habits and habitat

• Due to their body mass, scientists had speculated that dipldocids like the Brontosaurus aquatic dinosaurs. But this theory is considered incorrect, with most modern scientists agreeing that the Brontosaurus was terrestrial.
• The Brontosaurus was a quadruped. It is unlikely that the Brontosaurus was able to balance itself on its hind legs.
• It was an herbivorous dinosaur.
• To maintain its size, the Brontosaurus needed to consume huge quantities of food and water each day.
• The habitat of the Brontosaurus comprised of plentiful lakes, rivers, marshes and other water bodies. Rainfall was likely present all throughout the year, but was heavier during certain months.

Related and coexisting species

The Brontosaurus was related to other diplodocids like the Barosaurus, the Supersaurus and the Diplodocus.
It most likely co inhabited with sauropods like the Brachiosaurus, Camarasaurus and Diplodocus. The other dinosaurs that lived alongside of the Brontosaurus were the Stegosaurus, Dryosaurus and Camptosaurus.
The predators of the young ones of the Brontosaurus were most likely theropods like the Allosaurus and Ceratosaurus.

Concluding notes on the Brontosaurus
The name Brontosaurus is no longer scientifically appropriate. Apatosaurus is the right name for the Brontosaurus. But despite of this, the name Brontosaurus is almost universally resonant even today. The United States government had issued Brontosaurus stamps even after the name was declared void.
Technically correct or not, the Brontosaurus is one the most widely known dinosaurs in the world.

Just for fun we have a soundclip available for you to hear what a Apatosaurus could've sounded like. Click to the Dinosaur Sounds area to hear it. Please note that the dinosaur sounds are only for entertainment and are not an actual fact.