The first completely intact hadrosaur tail fossil yet discovered was recently unearthed in the desert of Coahuila in Mexico — the 72 million-year-old fossil tail includes over 50 vertebrae, and is more than 16-feet in length.
This fossil — whose excavation was led by the National Institute of Anthropology and History (INAH) — is the first to provide researchers with a clear understanding of how exactly hadrosaur tails were articulated. Hadrosaur tails — in most species — are thought to have generally been a bit under half the length of the body as a whole — so a 16-foot tail implies a body somewhere around 40-feet in length.
Something to note — the hadrosaur in question appears to have died from natural causes. At the time Mexico would have been located somewhere
Some general information on hadrosaurs from Wikipedia:
“Hadrosaurids, or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. The family, which includes ornithopods such as Edmontosaurus and Parasaurolophus, was a common herbivore in the Upper Cretaceous Period of what is now Asia, Europe and North America. Hadrosaurids are descendants of the Upper Jurassic/Lower Cretaceous iguanodontian dinosaurs and had a similar body layout.”
“Hadrosaurids are divided into two principal subfamilies: the lambeosaurines, which had hollow cranial crests or tubes, and the saurolophines, identified as hadrosaurines in most pre-2010 works (Saurolophinae or Hadrosaurinae), which lacked hollow cranial crests (solid crests were present in some forms). Saurolophines tended to be bulkier than lambeosaurines.”
“The hadrosaurs are known as the duck-billed dinosaurs due to the similarity of their head to that of modern ducks. In some genera, most notably Anatotitan, the whole front of the skull was flat and broadened out to form a beak, which was ideal for clipping leaves and twigs from the forests of Asia, Europe and North America. However, the back of the mouth contained thousands of teeth suitable for grinding food before it was swallowed. This has been hypothesized to have been a crucial factor in the success of this group in the Cretaceous compared to the sauropods, which were still largely dependent on gastroliths for grinding their food.”
“In 2009, paleontologist Mark Purnell conducted a study into the chewing methods and diet of hadrosaurids from the Late Cretaceous period. By analyzing hundreds of microscopic scratches on the teeth of a fossilized Edmontosaurus jaw, the team determined hadrosaurs had a unique way of eating unlike any creature living today. In contrast to a flexible lower jaw joint prevalent in today’s mammals, hadrosaurs had a unique hinge between the upper jaws and the rest of its skull. The team found the dinosaur’s upper jaws pushed outwards and sideways while chewing, as the lower jaw slid against the upper teeth.”
“Hadrosaurs are also notable for their absence of visible fingers, much like sauropods, having their fingers united in a fleshy, often nail-less pad.”