Brachytrachelopan

Phylogeny: Dinosauria > Saurischia > Sauropodomorpha > Plateosauria > Massopoda > Sauropodiformes > Sauropoda > Gravisauria > Eusauropoda > Neosauropoda > Diplodocoidea > Dicraeosauridae

Overview: Aside from their potential to grow remarkably large, sauropod dinosaurs are best known for their elongated necks. Long necks evolved prior to the appearance of true sauropods within the larger clade Sauropodomorpha, allowing many of them to feed from branches that were far out of reach for other herbivorous dinosaurs. Many, like Mamenchisaurus or Sauroposeidon, are believed to have pushed the limits on how long a terrestrial animal’s neck could really be. Then you have the genus Brachytrachelopan, which had the shortest neck of any sauropod known to science. The full length of the animal’s body was about ten or eleven meters, which by itself wasn’t impressive for a sauropod, but the neck grew to be only two or three meters long at most. Proportionately, its neck was almost half the length of those seen on its relatives. It may’ve been a specialized low-browser, filling in a niche that in other parts of the world was filled by ornithopods or stegosaurs.

Brachytrachelopan belonged to the superfamily Diplodocoidea, which made it a distant relative of the genera Apatosaurus and Diplodocus. It belonged to a separate family, however, known as the Dicraeosauridae. Close relatives included Dicraeosaurus and Amargasaurus. Dicraeosaurids tended to have double-pronged neural spines sticking up from their neck vertebrae, which were present on Brachytrachelopan, likely acting as anchor points for strong muscles. Some dicraeosaurids, such as Amargasaurus, had dramatically elongated spines, possibly supporting neck sails, but these weren’t seen on Brachytrachelopan. Despite its short neck, Brachytrachelopan still possessed a rather long tail, which was typical for a diplodocoid sauropod. Fossils of this genus are known from Argentina’s Cañadón Calcáreo Formation. Described in 2005, its name means “short-necked Pan”, referring to its unusual neck, but also to the Greek deity Pan – the patron god of shepherds.