''Jobaria'' is a genus of

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

dinosaur that lived in what is now

Niger ) , official_languages = , languages_type = National languagesJurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

Period, between 164 and 161

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

. ''Jobaria'' is currently the only known valid sauropod from the Tiouraren, where it was discovered in 1997.

Description

''Jobaria'' was a primitive sauropod, about long and estimated to weigh about . In 2016

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dino ...

gave a lower estimation of and . Its backbone and tail were simple compared to the complex vertebrae and whiplash tail of the later North America sauropods ''

Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπ� ...

'' and ''

Apatosaurus ''Apatosaurus'' (; meaning "deceptive lizard") is a genus of herbivorous sauropod dinosaur that lived in North America during the Late Jurassic period. Othniel Charles Marsh described and named the first-known species, ''A. ajax'', in 1877, an ...

''. It may also have been able to rear up on its hind legs as

Paul Sereno Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites ...

concluded, after comparing the ratios of

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

and

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

circumferences in ''Jobaria'' to extant

elephant Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae an ...

s. The weight distribution of ''Jobaria'' indicates that it was supported by the rear limbs rather than the forelimbs (as in elephants) and is speculated that as elephants can rear up, then ''Jobaria'' would have been able to more easily. The head of Jobaria slightly resembles to ''

Camarasaurus ''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch (Kimmeridgian to Titho ...

'' but elongated.

Discovery

Discovered in the fall of 1997, during a four-month expedition to the Sahara desert led by paleontologist Dr. Paul Sereno, it was found in a mass-death site in the

Tiourarén Formation The Tiourarén Formation is a geological Formation (geology), formation in the Agadez Region of Niger whose strata were originally thought to be Early Cretaceous. However, re-interpretation of the sediments showed that they are probably Middle Jur ...

of Niger. With over 95% of its skeleton preserved it is among the most complete sauropods ever found. The genus is named after a local mythical giant beast, Jobar, whose bones some

Tuareg The Tuareg people (; also spelled Twareg or Touareg; endonym: ''Imuhaɣ/Imušaɣ/Imašeɣăn/Imajeɣăn'') are a large Berber ethnic group that principally inhabit the Sahara in a vast area stretching from far southwestern Libya to southern A ...

s believed the fossils to be. The specific name ''tiguidensis'' comes from the cliff of Tiguidi, the site of discovery. The sediments in which it was found were originally thought to represent the

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by the Va ...

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

stages of the early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Period, dating ''Jobaria'' to approximately 132 million years ago. However, re-interpretation of the sediments showed that they are more likely from the

Bathonian In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Strat ...

to Oxfordian stages of the middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

in age, between 167 and 161 million years ago.

Classification

The phylogenetic relationships of ''Jobaria'' are uncertain; it has been interpreted either as a basal

macronaria Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...

n, or as a non-

neosauropod Neosauropoda is a clade within Dinosauria, coined in 1986 by Argentina, Argentine paleontologist José Bonaparte and currently described as ''Saltasaurus loricatus'', ''Diplodocus longus'', and all animals directly descended from their most recen ...

eusauropod Eusauropoda (meaning "true sauropods") is a derived clade of sauropod dinosaurs. Eusauropods represent the node-based group that includes all descendant sauropods starting with the basal eusauropods of ''Shunosaurus'', and possibly ''Barapasaurus ...

, basal to the neosauropod

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

References

External links

''Jobaria'' in the Dino Directory
{{Taxonbar, from=Q131398 Eusauropoda Middle Jurassic dinosaurs of Africa Bathonian life Oxfordian life Mesozoic Niger Fossils of Niger Fossil taxa described in 1999 Taxa named by Paul Sereno