Scientists studying fossils have discovered that the intimate act of sexual intercourse used by humans was pioneered by ancient armoured fishes, called placoderms, about 385 million years ago in Scotland.
In an important discovery in the evolutionary history of sexual reproduction, the scientists found that male fossils of the Microbrachius dicki, which belong to a placoderm group, developed bony L-shaped genital limbs called claspers to transfer sperm to females.
Females, for their part, developed small paired bones to lock the male organs in place for mating.