Atlasaurus
Encyclopedia
Atlasaurus was a moderately large genus
of sauropod dinosaur
from Middle Jurassic
(Bathonian
to Callovian
stages
) beds in North Africa.
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.
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.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of sauropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
(Bathonian
Bathonian
In the geologic timescale the Bathonian is an age or stage of the Middle Jurassic. It lasted from approximately 167.7 Ma to around 164.7 Ma...
to Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
stages
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
) beds in North Africa.
Discovery and species
Atlasaurus was discovered by Monbaron, Russell & Taquet in 1999. It was named after the location of discovery in the High AtlasHigh Atlas
High Atlas, also called the Grand Atlas Mountains is a mountain range in central Morocco in Northern Africa.The High Atlas rises in the west at the Atlantic Ocean and stretches in an eastern direction to the Moroccan-Algerian border. At the Atlantic and to the southwest the range drops abruptly...
range of the Atlas Mountains
Atlas Mountains
The Atlas Mountains is a mountain range across a northern stretch of Africa extending about through Morocco, Algeria, and Tunisia. The highest peak is Toubkal, with an elevation of in southwestern Morocco. The Atlas ranges separate the Mediterranean and Atlantic coastlines from the Sahara Desert...
of Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
(where the Titan
Titan (mythology)
In Greek mythology, the Titans were a race of powerful deities, descendants of Gaia and Uranus, that ruled during the legendary Golden Age....
, Atlas
Atlas (mythology)
In Greek mythology, Atlas was the primordial Titan who supported the heavens. Although associated with various places, he became commonly identified with the Atlas Mountains in north-west Africa...
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
Azilal
Azilal is a town in central Morocco, in the Atlas Mountains. It is located at around ....
Province, Tadla-Azilal
Tadla-Azilal
Tadla-Azilal ) is one of the sixteen regions of Morocco. It is situated in central Morocco. It covers an area of 17,125 km² and has a population of 1,450,519 . The capital is Beni Mellal.The region is made into of the following provinces :...
region, Morocco.
The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the 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.
Classification
A relatively primitive sauropod identified as a "cetiosaur" when first discovered in 1981, Atlasaurus appears to be closer to BrachiosaurusBrachiosaurus
Brachiosaurus is a genus of sauropod dinosaur from the Jurassic Morrison Formation of North America. It was first described by Elmer S. Riggs in 1903 from fossils found in the Grand River Canyon of western Colorado, in the United States. Riggs named the dinosaur Brachiosaurus altithorax,...
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
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
to femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
ratio: 0.99; ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
to tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
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.