thank you, for your quick anwser Mr Perez. i send you more pictures. i’m a software developer so I do not have experience on fossil identification (or living sea animals identification either) <span lang=”en”>but I have to notice that the piece was on the seashore in an area of hard waves with many stones around it, I guess a non-vertebrate structure could not resist such hard waves. Also the piece have almost a conic shape, i have seen pictures of aristotle’s lantern of sea urchin they have a lot of irregularities on his shape maybe erosion give it that shape? i thinks it’s difficult because it’s almost a perfect cone. also the size of the piece is 5 cm in lenght it’s hard to imagine such a big sea urchin or clam so close to the seashore. Any way as i tell you i have no experience on identification fossils or animals pieces and i know it’s very hard only using a picture. Thank you again for your help.