According to recent research published in the journal Nature, an international assemblage of scientists have found a fish called Microbrachius dicki is actually the first-known creature to have sex instead of spawn in order to reproduce. The ancient bony fish was approximately 8cm long and inhabited various lakes almost 385 million years ago in what is presently Scotland.
Lead author of the report Professor John Long of Flinders University in Australia said that this discovery came about largely because he was looking through a container of fish fossils. He spotted an M. dicki specimen had a strange L-shaped appendage. Long shortly discovered that the appendage in question was actually male fish sex organs.
Long elaborated: “The male has large bony claspers. These are the grooves that they use to transfer sperm into the female.” The female fish had a little bony structure at the rear that locked the male organ into position for sex.
Long believes the fish had to engage in coitus “side by side.” He states: “They couldn’t have done it in a ‘missionary position’. The very first act of copulation was done sideways, square-dance style.”
He noted that the fish held their position by using their arm-like fins. “The little arms are very useful to link the male and female together, so the male can get this large L-shaped sexual organ into position to dock with the female’s genital plates, which are very rough like cheese graters. They act like Velcro, locking the male organ into position to transfer sperm (during sex).”
Long stated: “We have defined the very point in evolution where the origin of internal fertilization in all animals began. “That is a really big step.”
Long and his colleagues are quick to add, however, that this first try at internal reproduction could not have been around very long. They point out that fish reverted back to spawning as they evolved. A few million years later copulation came back thanks to ancestors of rays and sharks.
Dr Matt Friedman, from the University of Oxford, England told the BBC: “The placoderm group (which includes Microbrachius dicki) is a well known group – the fossils are pretty common. It is very remarkable that we haven’t noticed this before.”
Something Fishy About Sex