Opisthocoelicaudia
Encyclopedia
Opisthocoelicaudia was 12-metre-long (39 feet) sauropod dinosaur of the Late Cretaceous Period
discovered in Mongolia
in 1965 by Polish
and Mongolian scientists in what is now the Gobi Desert
. In the Cretaceous, Mongolia had instead lush jungles and murky marshes, which Opisthocoelicaudia might have waded in. The genus was described and named in 1977 by Borsuk-Białynicka as a new type of camarasaur, but studies such as Salgado and Coria (1993) find it to be a saltasaurid titanosaur
instead. Its skull and neck were missing and its carcass had apparently been buried before disintegrating. Borsuk-Białynicka suggested tyrannosaurid scavengers had fed on the carcass, eating the head and neck and leaving noticeable tooth marks on the pelvis
and femur
. Scientists cannot be sure what its head or neck looked like, because neither was ever recovered.
Skeletally, it is generally similar to most other titanosaur
s. It has, however, unique joints in the tail vertebrae which account for its unusual name. Each of the thirty four tail vertebrae has a large dome on the front and a deep hemisperical socket on the posterior, creating a series of strong ball-and-socket joints. There is also notable evidence of immense ligament
and muscle
tissue
attached to the tail. The tail thus tends to slant slightly upwards, not downwards as in other sauropods. One possible explanation is that the tail was used as a prop to form a tripod with its back limbs, thus allowing the animal to reach high foliage.
Opisthocoelicaudia has appeared on stamps in its homeland of Mongolia and in the Republic of Guinea.
Opisthocoelicaudia had more slender radii than Venenosaurus
.
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
discovered in Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
in 1965 by Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
and Mongolian scientists in what is now the Gobi Desert
Gobi Desert
The Gobi is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Hexi Corridor and Tibetan Plateau to the...
. In the Cretaceous, Mongolia had instead lush jungles and murky marshes, which Opisthocoelicaudia might have waded in. The genus was described and named in 1977 by Borsuk-Białynicka as a new type of camarasaur, but studies such as Salgado and Coria (1993) find it to be a saltasaurid titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...
instead. Its skull and neck were missing and its carcass had apparently been buried before disintegrating. Borsuk-Białynicka suggested tyrannosaurid scavengers had fed on the carcass, eating the head and neck and leaving noticeable tooth marks on the pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
and 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...
. Scientists cannot be sure what its head or neck looked like, because neither was ever recovered.
Skeletally, it is generally similar to most other titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...
s. It has, however, unique joints in the tail vertebrae which account for its unusual name. Each of the thirty four tail vertebrae has a large dome on the front and a deep hemisperical socket on the posterior, creating a series of strong ball-and-socket joints. There is also notable evidence of immense ligament
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
and muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
tissue
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
attached to the tail. The tail thus tends to slant slightly upwards, not downwards as in other sauropods. One possible explanation is that the tail was used as a prop to form a tripod with its back limbs, thus allowing the animal to reach high foliage.
Opisthocoelicaudia has appeared on stamps in its homeland of Mongolia and in the Republic of Guinea.
Opisthocoelicaudia had more slender radii than Venenosaurus
Venenosaurus
Venenosaurus named after the Poison Strip Member of the Cedar Mountain Formation in Utah, where the fossils were discovered by a Denver Museum of Natural History volunteer Tony DiCroce in 1998. Venenosaurus dicrocei was first described as a new species in 2001 by Virginia Tidwell, Kenneth...
.