In waters near Sardinia, Italy, fishermen accidentally caught a zombie-like shark at a depth of 500 meters under the ocean. It has no skin and no teeth. Except for the eyes, abdomen and gills, the whole body is pale yellow and looks like an imaginary zombie shark.
The fishermen were shocked to think they had discovered a new species, and handed the shark over to researchers at the University of Cagliari. Results showed that this is not a new shark but a local black-mouthed cat shark, but its skin and teeth disappeared for unknown reasons.
In the sharks of the subclass, the skin plays an important role as the organ of defense. Skin secreting mucus is seen as the first line of defense for the immune system, preventing bacteria from forming populations on the surface due to the presence of antibacterial proteins. Composed of denticle, teeth-like structure overlapping, skin is also a strong barrier to deal with predators and parasites.
This is the first case of a lack of skin-related tissue in marine cartilage fish, the researchers said. Black-mouthed sharks have lost their cuticles, horny layers, dermis, and teeth. However, according to research by scientists, it seems that this black-mouthed cat shark has not lost its hunting ability, traces of 14 prey have been found in its stomach. Scientists still cannot be sure what caused this damage to these black-mouthed cat sharks.
The research team speculates that the shark’s condition could be due to natural or human causes. They argue that long-term exposure to areas of chemical pollution and the warming or acidification of the oceans due to climate change could be the reason. Alternatively, this could also be the result of a defective embryo development. Understanding these irregularities is an important step in helping to protect marine animals in constantly changing environments.
The shark’s fine scales cover the entire body, even on the eyeballs, helping to reduce friction in the water and allowing the shark to swim faster. Previous studies have shown that sharks lose 9% of their fine scales after only 9 weeks in acidic water. The zombie shark discovered this time is the first time scientists have seen that its skin and scales have been severely damaged.
The Blackmouth Catshark – Catshark blackmouth is a species of catshark, and part of the family Scyliorhinidae, common in the northeastern Atlantic from Iceland to Senegal, including the Mediterranean Sea.