Atlasaurus

*Atlasaurus imelakei*

**Atlasaurus imelakei** is a Primitive Macronarian from middle Jurassic (Bathonian to Callovian stages) beds in North Africa. It was 59 feet (18 meters) and weighed 35 tonnes (77,161 lbs). It was known from nearly a complete skeleton; possibly an early Brachiosaurid.

## Discovery and species

*Atlasaurus* was discovered by Monbaron, Russell & Taquet in 1999. It was named after the location of discovery in the High Atlas range of the Atlas Mountains of Morocco (where the Titan, Atlas was said to hold up the heavens), and for the animal's gigantic size (about 15 m (50 ft) long). It is known from a nearly complete skeleton with a skull found at Wawmda, in the Middle Jurassic (Bathonian-Callovian) Tiougguit Formation, Azilal Province, Tadla-Azilal region, Morocco.

The type species is *Atlasaurus imelakei* [ee-me-LAH-kay-ie], which comes from Arabic Imelake, the name of a giant; for a large animal found in North Africa.

## Description

The nearly complete skeleton of a large sauropod discovered at Wawmda (High Central Atlas of Morocco) in strata of Bathonian-Callovian age represents a new taxon: *Atlasaurus imelakei* n.g., n.sp. The sauropod appears to be closer to *Brachiosaurus* than any other known sauropod, but possesses (relative to the length of the dorsal vertebral column) a larger skull, shorter neck, longer tail and more elongated limbs. The presence of large sauropods of Middle Jurassic age is very important in understanding the history and the evolution of these Mesozoïc giants.

## Classification

A relatively primitive sauropod identified as a "cetiosaur" when first discovered in 1981, *Atlasaurus* appears to be closer to *Brachiosaurus* than to any other known sauropod based on detailed similarities between the vertebral column and limbs. It differs from *Brachiosaurus*, relative to the estimated length of the dorsal vertebral column (assuming 12 vertebrae, 3.04 m), in having a proportionately larger skull, a shorter neck (with at least 13 cervical vertebrae, shorter and more uniform in length than in *Brachiosaurus*), a longer tail and more elongated limbs (humerus to femur ratio: 0.99; ulna to tibia ratio: 1.15). The lower jaw is about 69 cm long; the neck about 3.86 m long; humerus 1.95 m long; femur about 2 m long; total estimated length: around 15 m (50 ft); estimated weight: 22.5 metric tons. The teeth are spoon-shaped and have denticles.

## JPInstitute.com Description

Atlasaurus was an African sauropod that was much smaller than the huge Brachiosaurus. Since it was discovered very recently, scientists still know very little about its life. We do know that it was a plant-eating dinosaur with a long neck and front legs that were longer than its back legs. Since this dinosaur was only about half the size of its huge American cousin, it is thought that the African environment could not have supported the giant dinosaurs seen in other parts of the world. However, scientists think that Atlasaurus may have eventually grown as large as Brachiosaurus because it is believed that sauropods may have continued to grow throughout their lives.

Compared to Brachiosaurus, Atlasaurus had a larger skull, longer tail and somewhat shorter neck. It fits an important niche in the sauropod family lineage and further study of this fairly complete specimen should provide interesting results.

## Links

https://web.archive.org/web/20031006081156fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_atlas.html

## References

* https://www.sciencedirect.com/science/article/abs/pii/S1251805000800269
* https://dinoanimals.com/dinosaurdatabase/atlasaurus-imelakei/
* https://dinosaurpictures.org/Atlasaurus-pictures
* https://ui.adsabs.harvard.edu/abs/1999CRASE.329..519M/abstract