cheap Depakote online Name Meaning: Roofed lizard

http://affordablemaidshousecleaning.com/catalog/view?slug=Actos Location Found: Western United States (specimen is a cast)

Geologic Era: Late Jurassic

Estimated Range; Western North America, Portugal

Size: Up to 9 meters long

Extinction: 155 million years ago

This is a thagomizer, or tail spike, from the end of a Stegosaurus tail. The spike is roughly two feet long, and cast from resin. It may not look sharp, but in life it could have been covered in a keratinous sheath, making it even longer and more pointed than it currently is. This is probably not an item one would want swung in their general direction.

Stegosaurus is a member of the thyreophoran group of dinosaurs, or the shield bearers. Most of this group of animals had armor of some kind, be it spikes and plates like Stegosaurus, or flat bony armor and tail clubs (ankylosaurs). In terms of intelligence, Stegosaurus was likely not the brightest animal to ever roam the Earth, having a brain that weighed less than three ounces with a body well over a ton. This was not an animal that could form complex plans, though it could forage for food and defend itself easily enough. Most animals in Stegosaurus’ environment would have coexisted peacefully with it, as the Morrison formation fauna included several types of sauropod and ornithopods.

Stegosaurus likely lived in groups of multiple aged animals moving around together. Younger animals would find some protection from the local predators in the spikes and plates of the older animals. The plates were likely used for display or visual intimidation, and would also make the animal look bigger. The plates would also serve to make the neck and back a less appealing target, forcing a predator to try an approach from the rear.

This would make a predator such as Allosaurus put itself right in range of the formidable thagomizers. Fossil evidence shows that Stegosaurus could use these structures as a very effective weapon against a predator. Multiple Allosaurus fossils show injuries that match up almost perfectly with a Stegosaurus thagomizer. These injuries seem concentrated toward the tail and pelvic areas, suggesting Allosaurus would try a rear attack, and sometime suffer the consequences. Examples of Stegosaurus inflicted wounds include a punctured tail vertebra, and a punctured pubic bone. In the latter example, the injury resulted in an infection that ultimately killed the Allosaurus. The fact that these bones were punctured shows the strength with which Stegosaurus could swing its tail and defend itself.

Image Credits:

Life Restoration: By Nobu Tamura (http://spinops.blogspot.com) – Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=19459399

Skeleton: By Susannah Maidment et al. & Natural History Museum, London – Maidment SCR, Brassey C, Barrett PM (2015) The Postcranial Skeleton of an Exceptionally Complete Individual of the Plated Dinosaur Stegosaurus stenops (Dinosauria: Thyreophora) from the Upper Jurassic Morrison Formation of Wyoming, U.S.A. PLoS ONE 10(10): e0138352. doi:10.1371/journal.pone.0138352, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=45275061