https://apnews.com/76118ed31d4d4115d1cbb76ab919757b

ATHENS, Greece (AP) — A fan mussel found only in the Mediterranean was officially added to the list of critically endangered species, after scientists recorded a dramatic decline in its population numbers caused by a newly discovered pathogen.

The International Union for Conservation of Nature said in a press release this week that its updated Red List includes the noble pen shell, or Pinna nobilis, the Mediterranean’s largest mollusk. The pen shell, which can grow to more than a meter (3 feet) tall, contributes to clear water by filtering out organic particulates. For centuries it provided humans with food and one of the world’s rarest materials: sea silk spun from the fibers with which it secures itself to the seabed.