Sauropods had the longest necks of all time. Both in proportion to their bodies and in terms of absolute size, their ranks included animals with insanely elongated anatomy. Take Supersaurus, for example – this Jurassic giant had 14 vertebrae in a neck that stretched 50 feet long! That’s longer than the entire body length of the biggest Allosaurus. But just as not every sauropod was gigantic, not all of these dinosaurs had extraordinarily extended necks. In fact, there’s a sauropod that stands out because its neck was so short.
Brachytrachelopan was not an especially big dinosaur. This 150 million year old sauropod, described by paleontologist Oliver Rauhut and colleagues in 2005 from bones found in Patagonia, was only about 33 feet long.
In other sauropods – like the bigger Diplodocus and Supersaurus that were stomping around North America around the same time – the neck would make up much of the dinosaur’s length. In some of the longest species, the length of the neck might be 400% longer than the length of the sauropod’s back! But the neck of Brachytrachelopan would have only been 75% of the length of the dinosaur’s back, and maybe even less.
Such a short neck would have limited what Brachytrachelopan could eat. The dinosaur wouldn’t have been able to lift is head very high, especially because of another strange feature – elongated spines on the vertebrae that gave this dinosaur a high-ridge of bone running from the back of the neck to the hips. As a result, Rauhut and co-authors proposed, Brachytrachelopan probably snarfed low-lying plants that grew no more than six feet above the soil. While other sauropods held their elegant necks high, Brachytrachelopan kept its head down to feast on ferns.
Rauhut, O., Remes, K., Fechner, R., Cladera, G., Puerta, P. 2005. Discovery of a short-necked sauropod dinosaur from the Late Jurassic period of Patagonia. Nature. 435: 670-672.