A Living Rock That Reproduces Via Sex With Itself (Video)
Pyura chilensis, a sea creature living in the rocky coasts of Chile and Peru, could be described as a living rock. Here is the animal in its natural habitat, in the process of feeding by inhaling water through its tunicin (“tunics” lined with an epidermis and muscle band, inside of which is the main part of P. chilensis) and filtering out microorganisms.
As Becky Crew explains on Scientific American’s Running Ponies blog, P. chilensis belongs to the “Ascidiacea class of non-moving, sac-like marine invertebrate filter feeders that are otherwise known as sea squirts.” It has a digestic tract that is basically its mouth; has clear blood; accumulates high levels of a very rare element, vanadium (a mineral also found in crude oil and tar sands, notes Grist); attaches itself to hard surfaces via its tunicin.
P. chilensis live in “densely packed aggregations of thousands or small handfuls of just a few” or all on their own. They are hermaphrodites: A 2005 study in Marine Ecology Progress Series by biologists Patricio H. Manríquez of the Universidad Austral de Chile and Juan Carlos Castilla of the Pontificia Universidad Católica de Chile found that P. chilensis is born male and becomes cosexual — acquiring both male and female gonads — in adolescence. The animals reproduce by releasing both sperm and eggs into the water; if any of these successfully mingle, they become tadpole-like creatures that attach themselves to a rock and then mature.
Manríquez and Castilla found that, while P. chilensis‘s preference is to cross-fertilize with another creature, they reproduce by “selfing” — self-fertilizing — just as successfully.
P. chilensis are fished commercially in Chile and local residents eat them raw or make them into a salad or stew. Grist’s Jess Zimmerman says that non-locals describe their taste as “bitter,” “soapy” and with a sort of odd “iodine flavor.”
Traditional mythology and folktales are full of examples of trees and other “inanimate” forms of life that turn out to be sentient and quite alive with an animus (the Latin word for “spirit” and “soul”). An animal like Pyura chilensis suggests that such stories contain some kernal of truth and are perhaps not quite so fantastic as we might tend to think.
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