This may look like a rock, but as with many things occurring in nature, it is full of surprises. Cut open this gray lump and one will find a red mass of internal organs oozing clear blood.
Meet Pyura chilensis, which hails from the rocky Pacific coast along Chile and Peru, according to a recent story in Scientific American. It has been harvested and eaten there for thousands of years, going by the local name piure.
Turbaco volcanos painted by Alexander von Humboldt, from his book Views of the Cordilleras 1810-1813. Courtesy of the Beinecke Rare Book and Manuscript Library, Yale University
As ceviche, in stews or fried, this vanadium-producing member of the Ascidiacea family, a “class of non-moving, sac-like marine invertebrate filter feeders that are otherwise known as sea squirts,” as Scientific American describes it, is a longstanding staple in the region.
Although that may sound astonishing enough, P. chilensis’s defining distinction is its reproductive habits. Though it prefers company, this hermaphroditic creature (it’s born male, then becomes both sexes as it matures) is quite content to spew both eggs and sperm into the ocean water around it, if it finds itself without a mate, and reproduce by itself in a practice aptly termed selfing.
The outer covering is made of tunicin, “a hardy matrix of molecules that help the animal attach itself to a hard surface on which it will carry out its days,” Scientific American tells us. “The insides of this tunic are lined with an epidermis and a muscular band, and inside these layers lies the main part of the animal.”
The animal seems to make vanadium, “a mineral also found in crude oil and tar sands—creatures like P. chilensis can have up to 10 million times more vanadium in their bodies than is found in the surrounding water, for no obvious reason,” notes Grist. Experts have not determined how that happens, or why.
Read Pyura chilensis: the Closest Thing to Getting Blood From a Stone in Scientific American
See it being prepared, below.