![]() The discovery of this unique immune system points to possible new ways of improving immune defence in patients who suffer from the consequences of a congenital or acquired immune disabilities.ĭeep-sea anglerfishes employ an incredible reproductive strategy. They found that the unusual mode of reproduction is associated with changes in the genome that disable key functions of the acquired immune system and instead must rely on much improved innate facilities to deal with infections. Researchers at the MPI of Immunobiology and Epigenetics in Freiburg, Germany, and the University of Washington in Seattle, USA have now solved this enigma, and describe the mechanism by which the fusion of two individuals of the same species can so readily occur. This phenomenon is known as sexual parasitism which avoids the rejection reaction that usually happens after organ transplantation. The male essentially turns into a sperm-producing parasite. Tiny males attach themselves to gigantic females so tightly that the tissues of the two animals eventually fuse. Widderĭeep-sea anglerfishes have evolved a curious reproductive strategy. Then Maclaine will send his drawings to the world’s leading anglerfish expert, Ted Pietsch at the University of Washington, to see if he has, indeed, found a new species.A female specimen of the deep-sea anglerfish species Melanocetus johnsonii of about 75 mm in size with a 23.5 mm large male fused on her belly. “After preservation, a picture won’t really do it justice,” he says. For this kind of identification, drawings are more useful than photographs. Just six specimens of footballfish have so far been found, so Maclaine’s catch may be one of those – or something new, he says.Īs soon as the research ship returns to the UK in a couple of months and Maclaine has access to the specimen, he plans to make detailed drawings of its lure, unfurling the intricate tendrils that will have been scrunched up. This feature is only known in footballfish. Maclaine realised it was unusual because of its elaborate lure, like a minute bouquet of flowers. A black, golf-ball sized juvenile was brought up in a trawl net off Saint Helena in the mid-Atlantic on a recent expedition as part of the Blue Belt programme, which studies the waters around the UK’s Overseas Territories. “I don’t know whether that’s just desperation or misidentification,” Maclaine says.Ī new species of anglerfish may have just been discovered. Sometimes, scientists find males fixed to a female of a different species. Others, including those seeking permanent attachment, clamp anywhere on the females including her head and even glowing lure. In some species, the males always fix in a similar place, usually near her rear where eggs are released. “The record that I’m aware of is eight,” says Maclaine. This extreme strategy of anglerfish mating was filmed for the first time in the wild in 2018.Ī female anglerfish can collect several males. “He will connect to her blood supply and feed off the nutrients in her blood like a little vampire,” says Maclaine. ![]() Only then does he grow a pair of testes and become sexually mature. A male latches on to a female, their body tissues fuse and he never lets go. In other species – such as the stargazing seadevil ( Ceratias uranoscopus) and the triplewart seadevil ( Cryptopsaras couesii) – it’s a permanent arrangement. ![]() When she releases her eggs, he fertilises them then swims off into the dark to search for another mate. In some species of anglerfish, including a very rare footballfish ( Himantolophus melanolophus), the small male tracks down a female and bites on to her. And when other specimens of these little fish were found on their own, they were thought to be a totally different family of anglerfish.īut in both cases they turned out to be diminutive males that belonged to families of anglerfish that had already been discovered. When people saw smaller fish attached to larger anglerfish, they presumed they were juveniles stuck to their mothers. The truth about the sex lives of anglerfish was discovered in 1925 by Charles Tate Regan, an ichthyologist at the Natural History Museum. “No other vertebrate group comes close to anglerfish in terms of variety and number of forms at that depth,” says Maclaine. There are at least 170 deep-sea anglerfish species. Photograph: Chris Fletcher/NHMĪnglerfish reign supreme in the permanent darkness of the ocean’s midnight zone, between 1,000 and 4,000 metres down. Males of this species do not attach permanently to the female. A young female black seadevil anglerfish.
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