During a chaotic period some 50 million years ago, the strange deep-sea creatures left the ocean bottom and thrived by clamping onto their mates.
(A male anglerfish. Over time, the male can physically fuse with the female, connecting to her skin and bloodstream. Eventually, the male loses its eyes and all internal organs except for the testes.Credit…David Shale/Nature Picture Library, Alamy)
How did the ghoulish creatures known as anglerfish pull off the evolutionary feat that let them essentially take over the ocean’s sunless depths?
It took peculiar sex — extremely peculiar sex.
Finding a mate in the deep sea can be extremely difficult because of the environment’s incomprehensibly vast size. By some estimates, the dark zone amounts to more than 97 percent of the planetary space inhabited by living things, mainly because the ocean plunges to a maximum depth of nearly seven miles. In contrast, land habitats make up less than 1 percent of the planet’s biosphere because the band of life is so narrow, making its volume quite small.
Scientists at Yale University have discovered that a burst of anglerfish diversification began some 50 million years ago as the ancestral line developed a bizarre strategy to ensure successful reproduction in the dark wilderness.
To mate, tiny males would clamp with sharp teeth onto the bellies of much larger females. Some males would let go after mating while others would permanently fuse into the females. The males that stayed attached became permanent organs for sperm production.
posted by f.sheikh