it could have been easy for snakes, but their closest Relatives are frogs, salamanders, and Co: The Schlei, Chen amphibians include about 200 species, which lives in the tropical regions of the earth's winds. Some small representative resemble earthworms, but the others can be up to 1.5 meters long. It is one of the most mysterious groups of vertebrates, because there is comparatively little about this hidden living amphibians are known. "The investigation of the Schlei Chen amphibians may provide for some Surprises," says Carlos Jared from the Butantan Institute in São Paulo.

Mysterious creature in the crosshairs

teeth with poison glands are. (Image: Carlos Jared)

Already since some time, the biologist and his colleagues with the South American Ringelwühle (Siphonops annulatus) deal. This up to 40-centimeter-long species lives in the ground and hunt there, especially earthworms, which captured them with a tooth occupied mouth. In a previous study, the researchers were able to show that the Ringelwühle poison to your rear end produces. "These animals give off two types of secretions – to crawl a toxic on the tail end and the head, and a mucus, which helps as a kind of lubricant through the earth," explains Jared. The toxic slime on the tail is used, however, to prevent a robber at the tracking through the Tunnel. But as the new study now shows that this is not the only toxic strategy of the Ringelwühle.

"In studies of the mouth struck me then-unknown glands in the area of the teeth," says the first author of the study Pedro Luiz Mailho-Fontana. The closer analysis showed that it is a series of small, fluid - filled glands in the upper and lower jaws, their long ducts open at the base of each tooth. Through studies of the embryonic development Mailho-Fontana was able to show then, from what tissue the glands are apparent on the teeth. "The venom glands of the skin originate from the Epidermis, but these glands in the mouth develop from the dental tissues," says the biologist. "Thus, it is the same process of development that you find in the venom glands of reptiles". It is the first Time that glands have been discovered in the case of a representative of amphibians, say scientists.

The oldest concept of toxic acrimony?

It is obvious, that the Secretions of the dental glands, serves prey animals hydrolyse to para. "Since the wood neither arms nor legs, rooting have, the mouth is the only tool that can be used for hunting," says Co-author Marta Maria Antoniazzi. "We suspect that you activate your mouth glands in the Moment you bite,“ says the scientist. The toxic potential of the secretion must identify the researchers, although only in more detail. However, an initial chemical analysis showed already Phospholipase A2 a Protein that is of the poisons of other animals known. "The Phospholipase-A2 Protein is non-toxic kinds of unusual, but we find it in the toxins of insects and many species of reptiles," says Mailho-Fontana. The biological activity of the Phospholipase A2 of the secretion of the Ringelwühle was even higher than that of some rattlesnake species, the researchers report. Perform further biochemical analysis in order to confirm the toxic potential of the secretion.

explain How the researchers could be the newly discovered concept of to have the oldest evolutionary Design of an oral toxicity. "Snakes appeared during the Cretaceous period, probably 100 million years ago, but the grinding and Chen amphibians are much older," says Jared. "In contrast to the snakes, which have only a few glands with a large gift amount, has glands, the Ringelwühle with little Secretion, but very many. Perhaps this is a primitive Form of poison glands development“. His colleague, Antoniazzi added: "For snakes and Schlei Chen amphibians the head is the only unit that can explore, fight, and kill. May be this is the common origin of the development of Gift concepts for legless animals," says the scientist.

source: Cell Press, journal article: iScience, doi: 10.1016/j. isci.2020.101234

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Date Of Update: 03 July 2020, 14:27