Atercurisaurus ("dark spear lizard") is 16-20 feet long species of stegosaurid dinosaur that is found on Skull Island. The animal is described in the book "The World of Kong: A Natural History of Skull Island" (from 2005).
The last of their suborder, Skull Island’s small population of surviving stegosaurids clings to existence in ferny valleys deep in the interior of the island. Impressively armored with a studded dark-colored hide, tall dorsal plates, and lethal abdominal and tail spikes, Atercurisaurus is not an easy lunch for predators, but competition with more successful herbivores on the island is causing their numbers to dwindle.
Atercurisaurus has a slow metabolism, necessitating almost constant feeding. Overspecialization is the bane of the genus. Atercurisaurus eat only a handful of ferns, all of them rare due to competition from advanced plants. Having to spend time hunting out this rare food (only to have to share it with other, generalist herbivores) will almost certainly lead to the eventual extinction of these remarkable plated thyreophorans.
Small herds of around a dozen females with young are led by matriarchs, with satellite bachelor males who are never far away. In the breeding season males will take turns approaching the herd and displaying, hoping to win the approval of the matriarch and her followers. If accepted, he will be allowed to temporarily join the herd, gaining access to the females for a few short days.
Atercurisaurus is a noisy species, producing a range of sounds, from low-pitched squeals and grunts to deep gizzard rumbles. Specific sounds have different meanings. Reassuring murmurs, made while eating, seem to impact an “all is well” signal to other members of the loosely dispersed herd as they feed. Begging squeaks from youngsters stimulate parents to disgorge their meals, while a similar sound produced by a low-ranking adult conveys submission before the matriarch. Several bellows, each specific to a particular threat, alerts the group to danger, the adults reacting accordingly to protect their young.