Sponges are animals of the phylum Porifera. Fossils of all of these types have been found in rocks dated from to million years ago. In addition Archaeocyathids, whose fossils are common in rocks from [ ] million years ago but not after [ ] million years ago, are now regarded as a type of sponge. Image:Mantell's Iguanodon restoration.jpg This article is a . You can help My English Wiki by expanding it.