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European marten shark (Mustelus mustelus) joined the animals for which the ability to reproduce without the participation of a male was confirmed. This phenomenon is called parthenogenesis and occurs in some species of fish, reptiles and even birds.
A study on this topic was published in the journal Scientific Reports. An unexpected case of "virgin birth" involving this fish was recorded in an aquarium in Italy in 2021, but genetic evidence was only found now.
Scientists believe that marten sharks observe facultative parthenogenesis, that is, they can reproduce without the participation of a male, but under normal conditions they still look for a partner to conceive offspring.
It is believed that the need to switch to such a specific form of reproduction arises when the number of males in the population decreases, and therefore is most often manifested in captivity, where representatives of the two sexes are usually kept separately.
In the new study, genetic samples were taken for detailed study. The scientists found that the young sharks turned out to be female and very similar to the mother, but not exact clones of her, which is typical during a type of parthenogenesis called automixis. In this case, the fusion of germ cells (gametes) occurs, which leads to self-fertilization.
Scientists have established that this process can be repeated annually in marten sharks and was recorded in at least two adult females. The exact number of offspring they gave birth to in this way is not known.
The European marten shark can reach two meters, but rarely exceeds 1,2 meters. It is found in the Mediterranean Sea and near the Atlantic coast of Europe and North Africa. These fish live at depths of less than 200 meters and do not pose any threat to humans.
