Polacanthus, deriving its name from the Ancient Greek poly-/πολυ- "many" and acantha/ακανθα "thorn" or "prickle", was an armored, spiked, plant-eating ankylosaur from the early Cretaceous period. It lived 132 to 112 million years ago.

Polacanthus was a primitive ankylosaur. These creatures lived in Europe. They grew to between 4 and 5 meters long. Polacanthus was an ornithischian or "bird-hipped" dinosaur. There are not many fossil remains of this creature, and some important anatomical features, such as its skull, are poorly known.

Polacanthus had a large sacral shield, a single fused sheet of dermal bone over its hips (sacral area) which was not attached to the underlying bone and decorated with tubercles. This feature is shared with other Polacanthine' dinosaurs such as Gastonia and Mymoorapelta.

Discovery and species

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Polacanthus foxii was discovered by the Reverend Fox on the Isle of Wight in 1865 and named by Richard Owen the same year.

P. rudgwickensis was named in 1996 by W.T. Blows, after review of some fossil material found in 1985 and thought to have been Iguanodon, which was on display at the Horsham Museum in Sussex. The material is fragmentary and includes several incomplete vertebrae, partial scapulocoracoid, the distal end of humerus, a nearly complete right tibia, rib fragments, and two osteoderms. P. rudgwickensis seems to have been about 30% larger than type species P. foxii and differs from it in numerous characters of the vertebrae and dermal armor. It is named after the village of Rudgwick in West Sussex and was discovered at a Rudgwick Brickworks Company quarry, at the quarry floor in gray-green marl beds of the Wessex Formation. Barremian age, approximately 124-132 million years ago.

Polacanthus species

• P. foxii
• P. rudgwickensis

A possible third species is known as Hoplitosaurus marshi, which may or may not be Polacanthus

Popular Culture

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Despite its dramatic appearance, Polacanthus is not often depicted in popular culture. However, it did appear on the fourth episode of Walking with Dinosaurs, but only for a brief time. It and Iguanodon are said to travel together.

Early depictions often gave it a very vague head as it was only known from the rear half of the creature.

Polacanthus bones can be seen in Bexhill museum in East Sussex, and Horsham museum in West Sussex.

References

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• Blows W.T. 1996 A new species of Polacanthus (Ornithischia; Ankylosauria) from the Lower Cretaceous of Sussex, England. Geological Magazine, 133 (6): 671-682

External Links

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• Bexhill Museum
• Horsham Museum

Cretaceous dinosaurs | ankylosaurs | European dinosaurs

Polacanthus | Polacanthus | ポラカントゥス | Polacanto | Polacanthus