Barosaurus

Barosaurus ( ) is an extinct genus of giant, long-tailed, long-necked, plant-eating sauropod dinosaur closely related to the more familiar Diplodocus. Definitive remains have been found in the Morrison Formation from the Upper Jurassic Period of South Dakota, Utah and Montana, with other possible remains also found in Colorado, eastern Wyoming and Oklahoma. The generic name, Barosaurus, comes from the Greek words barys (βαρυς) meaning "heavy" and sauros (σαυρος) meaning "lizard", and thus meaning "heavy lizard".

==Description== thumb|left|Life reconstruction of an individual rearing up to defend itself against a pair of Allosaurus Barosaurus was an enormous animal, with some adults measuring about in length and weighing about 12–20 metric tons (13–22 short tons). The estimated tail length of Barosaurus makes up about half the total body length. According to Mike Taylor, the long vertebra BYU 9024, previously identified as part of the type individual of Supersaurus vivianae, may actually belong to Barosaurus. He suggested that, interpreted as belonging to Barosaurus, the vertebra suggests an animal that was long and around in weight making it one of the largest known dinosaurs, with a neck length of at least . In 2020 Molina-Perez and Larramendi estimated it to be slightly smaller at and . However, research presented by Brian Curtice at the Society of Vertebrate Paleontology conference has supported the previous interpretation of BYU 9024 as a Supersaurus vertebra. Despite this, there are other specimens that provide evidence of gigantic Barosaurus individuals which may have been among the longest dinosaurs. One of these is a series of three cervical vertebrae (BYU 3GR/BYU 20815) and the third vertebra is 1110 mm to 1220 mm in length. Dr Mike Taylor and Dr Matt Wedel compared the size of this bone to the same bone in smaller Barosaurus specimens, such as AMNH 6341, and estimated the neck length of the BYU 3GR/20815 Barosaurus at , which would make it one of the longest necks of any dinosaur and indicate a total body length of around . Barosaurus was differently proportioned than its close relative Diplodocus, with a longer neck and shorter tail, but was about the same length overall. It was longer than Apatosaurus, but its skeleton was less robust.