Diplodocus - Meaning : double beam

Diplodocus (pronounced Di-plod-oh-kuss) meaning "double beam" is a genus of diplodocid sauropod dinosaur which lived in what is now western North America at the end of the Jurassic Period.

The generic name is in reference to its double-beamed chevron bones. Diplodocus, a herbivorous sauropod dinosaur, was one of the more common dinosaurs found in the Upper Morrison Formation, about 150 to 147 million years ago, in an environment and time dominated by giant sauropods, such as Camarasaurus, Barosaurus, Apatosaurus and Brachiosaurus. It is among the most easily identifiable dinosaurs, with its classic dinosaur shape, long neck and tail and four sturdy legs. For many years it was the longest dinosaur known. Its great size may have been a deterrent to predators such as Allosaurus and Ceratosaurus.

One of the best known sauropods, Diplodocus was a very large long-necked quadrupedal animal, with a long, whip-like tail. Its forelimbs were slightly shorter than its hind limbs, resulting in a largely horizontal posture. The long-necked, long-tailed animal with four sturdy legs has been mechanically compared with a suspension bridge.

The skull of Diplodocus was very small, compared to the size of the animal, which could reach up to 27 metres (90 feet).

Diplodocus was herbivorous. Its small teeth were peg-like and positioned only in the anterior part of the jaws. Its braincase was small. The neck was composed of at least fifteen vertebrae.

Diplodocus is the longest dinosaur known from a complete skeleton. While dinosaurs such as Seismosaurus (which might be a large Diplodocus) and Supersaurus were probably longer, fossil remains of these animals are only fragmentary.

At first, diplodocids were often portrayed with their necks held high up in the air, allowing them to graze from tall trees.

More recently, scientists have argued that the heart would have had trouble sustaining sufficient blood pressure to oxygenate the brain. Furthermore, more recent studies have shown that the structure of the neck vertebrae would not have permitted the neck to bend far upwards. Interestingly, the range of movement of the neck would have allowed the head to graze below the level of the body, leading scientists to speculate on whether Diplodocus grazed on submerged water plants, from riverbanks. This concept of the feeding posture is supported by the relative lengths of front and hind limbs. Furthermore, its peglike teeth may have been used for eating soft water plants.