First Act of Penetration Discovered in Fish Fossils

Fish fossils reveal reproductive organs in ancient species

First Act of Penetration Discovered in Fish Fossils
First Act of Penetration Discovered in Fish Fossils

A scientist studying fossil records discover penetrative reproduction in fish species.

Placoderms lived in Scotland, Germany, and China more than 300 million years ago. These primitive jawed vertebrates resemble our human species about internal reproduction. Fossils reveal they are armored with a husk-like shell resembling a turtle. The orders of placoderms are numerous. Each one has a varied shape, size, and degree of armor.

Most of the study from these fish comes from fossil remains over the years. At first, when researchers discovered a bony elbow like structure, they assumed these claspers aided the fish in maneuvering themselves. Later, the realization was apparent that these limbs were part of copulation.


Placoderms are most likely related to sharks

They exhibit a joint resembling a jaw, and their nasal capsules are boney. This fish was predatory just as sharks are today. Discovery of the claspers had led many to wonder about their purpose, until today. Considering the placoderm fossils did not consistently show these appendages, it is likely they evolved at certain times.

Nevertheless, we do know that this species demonstrated internal reproduction not spawning. It is assumed that eventually, these very same placoderms evolved into the sharks we know today. Although, it is appropriate to ask, where did their armored coats disappear? This question is better left for the scientists to answer.


YOUTUBE Video(Flinders University):


Microbrashius dicki

An international team of researchers has labeled the fish, Microbrashius dicki. A professor from the Flinders University in Australia, John Long, has deemed this discovery the exact point where internal copulation began. Most fish spawn their young. External fertilization is common and expected in the liquid environment of the sea.

I had the interesting opportunity to view a simulated hypothesis surrounding the mystery put out by Flinders University. The male Microbrashius dicki, has two claspers resembling a T at the bottom of his body. The female has a bony structure with a crevice where the two can lock together briefly for mating. As they come together, the fins on the outside of their hardened bodies link fins to hold each other steady. Meanwhile, floating side by side, the male enters his claspers into the female crevice and stays there briefly to release his sperm. Once released, they break apart and swim away. After the act, each one goes their own way.

However, because the mating was brief and purposeful, it came across as graceful. Maybe I can attribute that to the rhythmic waves of water surrounding the fish or perhaps it was because the act of fertilization in this order is simple.

Sex is meant to be beautiful and for the purpose of reproduction. Many of us forget this basic fact. Maybe the study of placoderms can remind us.


References: International Weekly Journal of Science, BBC News, Wikipedia