Ever wondered what a skinless cat litter looks like? Neither do we. Photo: Antonello Mulas of the University of Cagliari, Italy
Researchers off the coast of Sardinia have recently revealed something strange: a shark without skin and no teeth. Skin and teeth, as you probably guessed, are important to sharks, so the researchers were a little confused about how the shark lived.
The catfish was caught in a trawl on a fishing boat called the Ruggero in July 2019. The ship sailed from Cape Carbonara in southern Sardinia with the trawl at about 1,600 meters when they caught the foreign fish. “Although this kind of morphological abnormality is potentially fatal,” the abstract from a study published in the journal Fish Biology last, “the observations suggested that the specimen was in good health and well developed. The study was entitled”Naked living: first case of lack of skin-related structures in an elasmobranch, the blackmouth catshark“.
This is the first time a cat’s ear has been found without skin-related structures – epidermis, stratum laxum, dermal teeth, and teeth – that should come as no surprise. Catsharks, along with rays, skates and other species of sharks, are collectively referred to as elasmobranchs. They have a skeleton made of cartilage instead of bone and a specialized type of skin. This skin, which consists of a kind of overlapping tooth structure called dermal teeth, acts as a defense mechanism against predators – from other fish to small parasites.
A comparison between the abnormal (left) and a normal (right) Galeus melastomus, both caught in Sardinia. Image: Journal of Fish Biology
“Elasmobranch skin represents a fundamental organ responsible for multiple functions, due to both the properties of its cellular layers and the particular characteristics of the tooth-like dermal denticles, ‘wrote the study’s authors. The mucus secreted by the column-like secretory cells of the epidermal layer is considered to be the first part of the immune system, because it prevents the colonization of infectious microbes through various mechanisms, such as their continuous production and removal and by antibacterial to contain proteins. ”
Researchers have been puzzled as to how the shark managed to survive without skin and teeth, but they have theorized that it may have something to do with long-term exposure to some kind of polluted part of the ocean, ocean warming, or just a genetic hiccup. Whatever the case may be, understanding what happened to this skinless shark is an important step in protecting other marine animals.
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