Brachiosaurus

About Brachiosaurus

Features

Brachiosaurus reached a length of 25 meters and a height of 16 meters to the top of its head.

A major difference from other sauropodomorphs was that its forelimbs were longer than its hind limbs. This is thought to have allowed it to keep its head high.

At the same time, it faced major challenges. It is presumed that an extremely powerful heart and high blood pressure were necessary to pump blood to a brain more than 10 meters above the ground. Also, to maintain such a huge body and remain active, the energy of a cold-blooded animal like a modern reptile would not have been sufficient. Analysis of the internal structure of its bones suggests that Brachiosaurus may have been a warm-blooded animal with a high metabolic rate.

Where Brachiosaurus Lived

It was once thought that "Brachiosaurus lived in swamps and other bodies of water."

This was because its nostrils were located on top of its head for breathing, and it was thought that it used the buoyancy of water to reduce the burden of its large weight (initially estimated at 80t), much like a modern hippopotamus.

Recent research has shown that its weight was not that great and that it lived on land. Also, a more detailed examination of the head revealed that the nostrils were located at the front of the head, not on top.

It is now estimated to have weighed between 25t and 50t.

Discovery and Classification: The Relationship with Giraffatitan

In 1900, American paleontologist Elmer S. Riggs discovered partial fossils of a sauropod, including a skull, right humerus, right femur, right ilium, right metatarsals, and sacrum, in the Morrison Formation of Colorado, USA. These specimens are now cataloged as FMNH P 25107.
The following year, in 1901, he noted the unusual length of the humerus compared to the femur and the less developed tail compared to other sauropods, suggesting a giraffe-like posture with longer forelimbs than hind limbs and an elevated neck.

In 1903, Elmer S. Riggs published the paper "Brachiosaurus altithorax, the largest known dinosaur," in which he described Brachiosaurus as a new genus.

Between 1909 and 1912, a large number of sauropod fossils were excavated from the Tendaguru Formation in Tanzania, East Africa. German paleontologist Werner Janensch listed the similarities and differences with Brachiosaurus altithorax and in 1914 described it as a new species of Brachiosaurus, Brachiosaurus brancai.
However, Brachiosaurus brancai was later reclassified as a separate genus. In 1988, Gregory S. Paul pointed out differences in the shape of the vertebrae between B. altithorax and B. brancai. In 1998, a comparison with the skull of a Brachiosaurus from the North American Morrison Formation revealed further differences with B. brancai. In 2009, Michael P. Taylor argued that brancai should be included in the genus Giraffatitan at the genus level. (Giraffatitan is included in the family Brachiosauridae).
The original Brachiosaurus genus (from North America) is said to have had a longer torso, a less steeply inclined neck base, and a more modest head crest compared to Giraffatitan (from Africa). Giraffatitan had a more giraffe-like build with a more vertically oriented neck.

At the Natural History Museum in Berlin, famous for its dinosaur hall, the specimen once displayed as Brachiosaurus is now displayed as Giraffatitan. It seems more accurate to consider specimens labeled "Brachiosaurus from Africa, Tanzania (Tendaguru Formation)" seen at mineral shows and elsewhere as belonging to the genus Giraffatitan rather than Brachiosaurus.