These are Scaly-foot snail (Chrysomallon squamiferum), an iconic vent endemic gastropod known only from the Indian ocean deep-sea hydrothermal vents, at more than 2500 metres deep.

This unique snail species lives just beside black smokers that are churning out superheated water exceeding 350°C. Has also harnessed the power of chemosynthesis, housing endosymbiotic bacteria in an enlarged part of its gut. This produces the energy it needs. it has a food factory inside its body and doesn’t even need to feed! This is likely the reason it can grow to about 45mm in size, when most of its close relatives without endosymbionts are only 15mm or smaller.

Lynn Margulis (1938-2011) was an evolutionary theorist and science author, the first modern proponent of the significance of symbiosis in evolution. Her research fundamentally transformed and established the understanding of the evolution of cells with nuclei. Her work was seen as controversial and was widely rejected for years, until genetic evidence proved it definitively.

Her 1966 paper, “On the Origin of Mitosing Cells”, was rejected for publication by 15 scientific journals initially, but today it is considered a landmark in endosymbiotic theory. She also proposed the Gaia theory, which sees Earth as a self-regulating system.