Imagine Dinosaurs's video: Nodosaurs: Polacanthus

Discovered by Reverend William D.‭ ‬Fox in‭ ‬1865,‭ ‬Polacanthus has been frustratingly ill preserved with only the hind quarters and parts of armour well preserved.‭ ‬The skull is also unknown,‭ ‬and for this reason modern reconstructions are based upon comparisons with other similar dinosaurs like Gastonia.        What can be ascertained is that Polacanthus was a quadrupedal low browser with heavy armour adaptations along its back.‭ ‬These include spikes over much of its body and a huge‭ '‬shield‭' ‬that‭ ‬covered its hips and sacrum.‭ ‬This shield was built up from a mass of osteoderms and was not connected to any bone structure underneath.‭ ‬It could be that the armour was primarily for defence against theropods like Neovenator and Eotyrannus,‭ ‬which would have only been able to bite down from above.‭        The spikes would've made it difficult to get close without a carnivore impaling its snout,‭ ‬and the sacral armour prevented a bite to the sacrum that could have paralysed Polacanthus.‭ ‬If the tail was also a defensive weapon,‭ ‬the sacral armour would have helped to prevent a predator from disabling its defence.