A collaborative research group of Nagoya University, University of Wisconsin, Kochi University, Mongolian University of Science and Technology, Tohoku University, etc. I found.
This burrow fossil is seen as a round hole from the surface of the earth (that is, the former seafloor), but the two holes are connected inside and have a "U-shaped" structure.It is presumed that the animals that form such burrows have a shape that extends back and forth, and that they have the motility to feed on the one hand and excrete on the other.In addition, it is thought that it had an activity of carving at least 2 cm below the seabed, and from this, it is presumed that it was a multicellular animal in the advanced stage with developed muscle tissue called bilaterian animal. That is.
Until now, these fossil burrows have only been known since the Cambrian (about 5.4-5 million years ago), which is said to be the time when various marine animals evolved explosively, and Ediacaran was the time before that. From the beginning, few fossils of multicellular organisms have been produced.
With this discovery, the "Cambrian agricultural revolution," which was previously thought to have occurred in the Cambrian period, that is, active burrow formation and seafloor disturbance by animals, began earlier in the Ediacaran period in western Mongolia. Was revealed for the first time.The results also provided strong evidence suggesting that bilaterian animals existed in the Ediacaran period.
The explosive emergence and diversification of Cambrian animals is known as a biological mystery since Darwin.This discovery is considered to be an important finding in elucidating the actual situation of this major evolutionary event.
Paper information:[Royal Society open science] Penetrative trace fossils from the late Ediacaran of Mongolia: Early onset of the agronomic revolution
