Top scientists are trying to save a critically endangered mollusc that is only found in the Mediterranean Sea and which is being wiped out by a mysterious parasite threatening the ecosystem in which they play a key role.The Spanish scientists have launched a new project in a bid to save the noble pen shell (Pinna nobilis), a critically endangered species, according to the IUCN's Red List of Endangered Species, and one that is endemic - which means that it can only be found there - to the Mediterranean Sea.(Fundacion Zoo Barcelona/Real Press)