UNITED STATES (OBSERVATORY NEWS) — A study of a mysterious animal that lived in the seas 518 million years ago showed that in the process of evolution it got rid of unnecessary limbs. This is the earliest known example of the loss of body parts to suit changing conditions.
Details are set out in a scientific article published in the journal Current Biology.
Scientists are well aware that the ancestors of snakes had legs , and the distant ancestors of man had a tail. But, adapting to new ecological niches, animals lost parts of the body, the development of which took many generations from their predecessors. Biologists call this phenomenon secondary loss.
When did animals first begin to show such ingratitude and extravagance? Judging by the findings of a recent study, at least 518 million years ago, in the early Cambrian period.
The authors studied the unusual remains of a representative of the species Faci Permis yunnanica. This mysterious worm-shaped creature was less than 10 centimeters in length. At the front end of the body, he had five pairs of spiked limbs, and the rear end of the body was thickened.
This creation has been known to paleontologists for about 30 years, and all this time experts have not been tired of arguing who it is related to. It is attributed to the ancestors of annelid worms, then tentacle, then five-mast.
Perhaps, it is generally accepted that F. yunnanicus belongs to bilateria , that is, bilaterally symmetric animals. But this is an extremely wide group that unites, say, people with insects.
The new version says that F. yunnanilus belongs to the lobopods. This convinced researchers a whole arsenal of mathematical methods used to establish evolutionary kinship. But in foreheads, pairs of limbs are located along the whole body, why is F. yunnanilus distinguished from this series? Therefore, the authors answer that a trumpet has come to excess extremities, vulgarly speaking.
Let’s explain. The uniqueness of the fossil studied by researchers is that the back of the animal’s body is immersed in a solid tube. Its origin is unknown, but in terms of size, it exactly fits the posterior thickened end of the body of F. yunnanilus.
Perhaps the famous intellectual Rabbit would say to this: “Everything is clear, he froze!”. But scientists believe that this is not evidence of the ancient tragedy of a creature that accidentally got where it was not necessary.
On the contrary, the “worm with tentacles” was literally in the house. The hard shell served as an anchor, securely fastening it to the bottom, and, possibly, protection from predators.
With this way of life, the limbs on the body part immersed in the “shell” were useless, and most likely even interfered. Therefore, F. yunnanilus lost them in the process of evolution.
That is how his anatomy, known to paleontologists, with limbs appeared only on the front end of the body (they probably served to capture food). Just for some reason, the hard tubes in the previously studied samples have not been preserved, the authors suggest (although at first glance a solid object is much more likely to remain fossilized than the soft body of this ancient inhabitant of the seas).
“This is the earliest known example of secondary loss seen today in cases such as snake foot loss,” concludes article writer Richard Howard of Yunnan University.
We note that it was in Cambria that animals with a solid skeleton began to appear on Earth, that is, a more or less detailed paleontological record began. Thus, evolution could have benefited from secondary loss even earlier, possibly from the very emergence of multicellular animals , but scientists have not yet found traces of this.
This article is written and prepared by our foreign editors writing for OBSERVATORY NEWS from different countries around the world – material edited and published by OBSERVATORY staff in our newsroom.
Contact us: [email protected]