How funny! I'm actually in this class right now and came across your deviantart as I was searching for reference tonight. It's nice to see how great all of your assignments turned out - it's a lot of work! Good job!
The crest is simply for show and attracting mates (pictured is a male). The spines have venomous tips as a form of defense (and their colorful tips serve as a warning). I am not sure what you mean by publish. Thank you!
By publish, I just mean upload it to deviantART. Whenever you upload a work of art to deviantART, you publish it and it becomes copyrighted to you. That's why there's the copyright mark to the right of the Deviation's category information.