Kunming, November 19 (Xinhua) -- The reporter learned from Yunnan University that the research team of the institute of paleontology of the university recently discovered the hermitage behavior of gill-dragging worms about 500 million years ago in the fossil specimens excavated in the Cambrian section of Lushu Yi and Miao Autonomous County in Kunming City, Yunnan Province, which is also the earliest fossil record of animal hermitage behavior so far, reflecting the complexity of the early Cambrian ecosystem. The results have been published online in the international journal Contemporary Biology.
According to the researchers, hermitage is a behavior that occupies and lives in the shells of other organisms, is widespread in modern ecosystems, and can appear in different animal groups. Among them, the hermit crab is a well-known representative.
A group of animals with hermit behavior. A is a hermit crab, B is a cystic cyst in the shell of a gastropod, and C is a link animal of the Family F. foraminifera in the shell tube. (Courtesy of Yunnan University)
The research team at Yunnan University collected a total of 4 fossil specimens of Cambrian gill trolls. When the researchers looked at the specimen under the microscope, they found that the posterior part of each individual was hidden in the shell of the soft-tongued snail, and the insect body diameter was slightly smaller than the soft-tongue solenoid tube, indicating that the worm was consciously picking the soft-tongue solenoid and "reclusive" in it to avoid predators. This discovery confirms for the first time the hermit behavior of gill-dragging animals.
The study found the parasitic behavior of Cambrian gill traction worms. (Courtesy of Yunnan University)
According to the researchers, the earliest fossil record of the previous sojourn behavior only dates back to the early Jurassic (nearly 200 million years ago), and the fossil record of the sojourn behavior found in this study breaks the traditional understanding of the Cambrian ecosystem in the past. Previous studies have generally believed that the ecosystem in the early Cambrian period was relatively simple, and the pressure of biological competition was not so great. But the findings prove that the ecosystems of the early Cambrian period were far more complex than one might think.
A map of the hermit behavior of gill-dragged worms found in this study. (Courtesy of Yunnan University)
The researchers said that the emergence of hermit behavior in the early Cambrian period about 500 million years ago, together with the various biological dependencies of the early and middle Cambrian periods reported in recent years (such as partial symbiosis, stealing parasitism and endosymbiosis, etc.), suggest that the ecosystems of this period may be more modern than previously thought, that is, the "Cambrian explosion of life" may be characterized by rapidly complex ecosystems with increasing predatory intensity.