Longest spikes on a dinosaur

The dinosaur with the longest spikes was Loricatosaurus, a genus of herbivorous stegosaur that lived in England 160–164 million years ago, during the Middle Jurassic Period. Preserved as fossils these spikes, which appeared on the tail, were 1 m in length, but in life they may have been covered by a horny sheath, which if so could have made them up to twice as long as that. These formidable spikes were probably used as weapons against potential attackers, and may also have served to attract or impress mates.