Brachiosaurus brancai Janensch, 1914

Brachiosaurus brancai Janensch, 1914

Giraffatitan brancai ( Taylor, 2009)

Brachiosaurus fraasi Janensch, 1914

The genus Brachiosaurus was introduced in 1903 by the Chicago-based paleontologist Elmar Samuel Riggs to describe finds discovered in western Colorado ( B. altithorax ). The name alludes to the enormous size and unusual length of the dinosaur’s upper arm bones (humeri). 38 It derives from the Greek words βραΧίων / brachíōn (“arm”) and σαυρα / saúra, and roughly means “arm lizard.”

Brachiosaurus brancai was not only the largest dinosaur to be excavated at Tendaguru, it was also among the first of the expedition’s specimens to be rigorously studied and described as a new species. Werner Janensch dedicated the specific name “with gratitude and the greatest admiration and respect” to Wilhelm von Branca, the geologist and paleontologist who headed the Geological and Paleontological Institute and Museum from 1899 to 1917, 39 and described him as “[the man] to whom we owe the launching and organization of the entire expedition.” 40

Shortly after Janensch’s species description was published, however, doubts were expressed regarding his referral of the species to the genus Brachiosaurus , and these doubts were never entirely dispelled. 41 Even so, it took almost one hundred years before the specimen was reclassified. In 2009, British paleontologist Michael P. Taylor performed a comparative analysis of the North American Brachiosaurus altithorax (the type species for Brachiosaurus ) and the East African B. brancai , and came to two conclusions: that they belonged to different genera and that B. brancai should be placed in the genus Giraffatitan , as proposed by Gregory S. Paul in 1988. 42 This Latinized genus name alludes to the dinosaur’s giraffe-like form and enormous—titanic—size. 43