Fossil Friday!

This week's Fossil Friday is so delicate and lovely, it looks almost like I drew it on parchment. But no, these squiggles were left by a sea creature during the late Jurassic. It was found more recently in modern day Germany. There are many relatives of this fellow around today, but who was this ancestral beauty?

Post your answers in the comments section below. Person to identify it first wins bragging rights for the week.