Tendaguru Formation




One of the biggest Late Jurassic rock formations in the world, and also among the most famous, the Tendaguru has for years revealed some of the most famous fossils of all time. One of the best-known is the Berlin brachiosaur, the massive skeleton of a Giraffatitan which is currently mounted in the Museum für Naturkunde, Berlin.

This should be no surprise as Tendaguru in Tanzania was part of German East Africa for many years. Excavation of the area by the German scientists began in 1906 when pharmacist and chemical analyst Bernhard Wilhelm Sattler saw some massive bones in a hill in that region.

There are six members or zones in the Tendaguru, starting from the bottom of the Lower Dinosaur Member to the uppermost Rutitrigonia
bornhardti-schwarzi Member. This is an incredibly long stratigraphy lasting from the Callovian Stage of the Mid Jurassic to the Albian of the Early Cretaceous.

The best-known animals of the formation come from the Late Jurassic, specifically from the Kimmeridgian to the Tithonian Stages of around 150 million years ago. This is roughly equal to the age of the incredibly famous Morrison Formation of western North America which is known for such popular dinosaurs as Allosaurus, Brontosaurus and Stegosaurus.

In terms of the ancient environment, Tendaguru preserves a series of tidal channels, flats and lagoonal environs as well as vegetated inland pools. This area was also filled with the classical Jurassic flora of ferns, cycads and conifers. It grew more humid as the formation neared the Cretaceous.
The place was named "Tendaguru" by the natives after its hilly, rocky nature. The following year, known paleontologist and researcher Eberhaard Fraas visited from Stuttgart and started excavating the remains that Sattler found. They were sauropod bones, all thrown into a wastebasket taxon known at the time as Gigantosaurus. This name is no longer valid, as it contains a mishmash of remains from varied huge, long-necked and big-bodied dinosaurs.

Nowadays, the best-known of the big sauropods from the formation is the massive Giraffatitan brancai. When it was first found, it was assigned to the then well-recognized genus Brachiosaurus. Its bones were discovered in 1914 by Werner Janensch, who oversaw a number of Tanzanian expeditions. Altogether five partial skeletons and three skulls were uncovered and preserved in the Musuem fur Naturkunde in Berlin.

The towering mounted skeleton named Brachiosaurus brancai was once recognized as that of the largest dinosaur ever discovered. However subsequent remains began to gently debunk this idea. For one, the Berlin specimen was reclassified by Gregory S. Paul in 1988. It was renamed as Giraffatitan, a classification that was not supported for a long time. It was only in 2009 that Dr. Michael Taylor looked over the animal again and strengthened this reclassification.

Also, Giraffatitan brancai was far from being the largest dinosaur around. Despite the skeleton's height of 13 meters tall, the animal was severely outclassed in mass by titanosaurs like Argentinosaurus from the Mid Cretaceous of Argentina. The Berlin specimen is not fully grown and so would have to get bigger by at least 15% before reaching adult size.

Even so, an adult Giraffatitan was around 30-40 tons, just half as heavy as an Argentinosaurus, somewhat shorter in length and much less robustly built. Giraffatitan is not even the largest brachiosaur from the formation. Rather a poorly-known relative known as "The Archbishop" might have been much larger. "The Archbishop" brachiosaur was once classified as Brachiosaurus brancai but currently holds no specific description. Its remains are thought to pertain to a true colossus. Unfortunately the bones have not been properly described in scientific literature.

Far lower to the ground in the Tendaguru rocks were several kinds of diplodocoid sauropods. One of the more famous ones is Dicraeosaurus, a very small and stocky representative of its group with a short neck and tall Y-shaped spines on its vertebrae. The animal was another discovery by Werner Janensch from 1914, and a mounted specimen exists at the Museum fur Naturkunde, in the shadow of the vast Giraffatitan.

It was barely half as long as its North American relatives, growing a mere 12 meters long. This is hardly anything compared to animals like Diplodocus and Apatosaurus but is still big by modern standards. The thick-necked Dicraeosaurus probably fed on low-growing vegetation.

Another diplodocoid from the area is the possibly much bigger Tornieria africana. This animal was part of the taxonomic wastebasket of Gigantosaurus. It was only in 1911 that the animal was renamed, in honor of herpetologist Gustav Tornier. The animal was probably more than twice as long as Dicraeosaurus, and may have looked more like some of its relatives from America's Morrison.

The African equivalent of Stegosaurus is Kentrosaurus. Kentrosaurus aethiopicus is smaller than the smaller Stegosaurus species from America. It is also famous for having more spikes along the length of its tail. The animal was described scientifically by Edward Hennig in 1915, and often appears in many popular works of literature. Kentrosaurus is found very often in the Tendaguru, with over 350 specimens in Berlin itself.

There is a wonderful mounted specimen in the Museum fur Naturkunde alongside its giant sauropod contemporaries. At a little over 4 meters though, Kentrosaurus was dwarfed by its fellow sauropods. In life the animal was a low browser which could also rear up on its hind legs to feed from low-hanging branches. Another low browser from the formation is the speedy Dysalotosaurus. This animal was a two-footed ornithopod, a creature similar to the North American Dryosaurus in shape and form.

There is a skeleton of the animal mounted alongside its peers and the mount shows Dysalotosaurus' grace and elegance quite efficiently. In a 2012 study by Tom R. Hubner and Vincent Laudet, it was calculated that the little dinosaur reached skeletal maturity in roughly ten years. This was a new look into these small herbivores, something that had never been done before.
Theropods or meat-eating dinosaurs are somewhat thin on the ground in Tendaguru.

There are fossils associated with the American Ceratosaurus and Allosaurus but these are too fragmentary and cannot be classified with any certainty. One of the better-known theropods from the formation though, is the small Elaphrosaurus. It too is mounted beautifully in the museum along with its contemporaries. Elaphrosaurus was no large predator though. Despite its length of 6.2 meters, it was very lightweight and low-slung, with slender features and a small head.

For a while, this appearance warranted its classification as an ornithomimid or ostrich dinosaur, one of the fast feathered omnivores from the Cretaceous. Recently through, it was reclassified as a noasaurid, a species of ceratosaur. It was a distant cousin of the horned and more famous Ceratosaurus from North America. Even Elaphrosaurus fossils have been associated with North American beds but none of these are valid. There is only one species in the genus, E. bambergi. The animal was described scientifically by Werner Janensch.