In a swamp in Germany, hundreds of fossils of frogs that lived about 45 million years ago have been found, and researchers believe that the cause of these frogs' death may be due to mating.
Frogs died 45 million years ago
Frogs are amphibians, and although they have lived on land for a long time, they cannot be too far away from the water source.
45 million years ago, these frogs should have lived near water sources, where they gathered and roosted. Although frogs are amphibians, adult frogs breathe mainly through their lungs and skin, and when they stay in the water for a long time, they will drown.
For a long time, it was believed that these frogs died mysteriously, either because the oxygen in the lake was exhausted or the lake dried up, and these factors were also one of the main causes of the death of modern frogs.
But the new evidence found that the frogs were healthy when they died, and there was no trace of predators or scavengers on their bones, and there was no evidence that they were washed away by the flood, because the remains of the flood were usually scattered, but the fossil bones of these frogs were very well preserved.
More importantly, frog fossils are very difficult to form, because the conditions for fossil formation are very harsh:
- Organic matter must have hard parts, such as bones, shells, teeth or wooden tissue. But in very special circumstances, sometimes molluscs can leave fossils.
- After the death of organisms can avoid being destroyed, the reason why most animals are difficult to leave fossils is that after the death of animals and plants, their corpses will be eaten by other animals, such as: scavenger vultures will destroy the remains of elephants, the advantage of this is to avoid microbial breeding, reduce the occurrence of epidemic diseases; Second, the speed of cleaning up the corpses can be accelerated, otherwise the whole earth may be tired of bones.
- Organisms can be quickly buried by some kind of substance that can hinder decomposition, such as: Yunnan Chengjiang biota, there are a large number of Ediacaran biological fossils, you know, Edikara organisms lived before the Cambrian explosion, is a very early stage of biological origin, many creatures of the ancient ancestors are here.
The reason why there are so many fossils in Chengjiang, Yunnan, is because it was once an ocean, and the seabed will be indirectly hypoxic, and the organisms at that time will be preserved in the rapidly deposited mudstone after death, not destroyed, and in the long-term petrochemical process, fossils are formed.
- Buried organisms undergo long-term petrification: if some animals, although quickly buried, are later washed out by floods and destroyed by animals, it is difficult to form fossils.
The conditions for forming fossils are so harsh that 99.99% of animals will not form fossils after death, and only a very few can form fossils.
The frogs were able to form fossils, indicating that they were buried quickly shortly after their death, and they were still buried in a substance that could hinder decomposition.
There are not many such conditions on land, but even if the swamp silt is such an environment, it means that when the frogs die, they should be in the water source.
Moreover, these frogs have not yet been preyed upon, decomposed by scavengers, and are still in good health when they die, which shows that they are not due to hunting, or sudden illness, but more likely encountered an accident.
After studying the way the frogs live, the researchers believe that the frogs live on land for a long time and only go to the water during the breeding period, that is, when they die, it should be during the breeding period.
So what exactly caused their deaths?
Scientists have come up with a hypothesis: drowned by male frogs.
The thing is, modern frogs, when they reproduce, also do it in the water, because frogs are in vitro fertilization, and after mating, they will ovulate and sperm in the same waters. During mating, the male frog will lie on the female, which may cause the female frog to drown.
Because the fossilized frogs are not 1 or 2, but hundreds, it can also be seen that for this group of frogs, mating is actually a very dangerous thing, I don't know whether the later frogs have evolved a way to deal with this death.
The stone changes when mating
This is not the case of fossilization at mating, and 47 million years ago there was also a creature that became fossilized during mating.
Researchers found 9 pairs of turtle fossils in the Messer fossil pit in Germany, and these turtles were actually in a mating state.
The researchers were very surprised that several turtles died during the mating period, and after studying, they found that these turtles mated in lakes, and during the mating process, they would slowly sink from the surface of the water to the bottom.
Coincidentally, there is volcanic activity at the bottom of the lake, the crater will release a large amount of poisonous gas, as the turtle sinks to the bottom, they absorb more and more poisonous gas, and eventually both poisoned, leaving fossils that are in the mating period.
Fossils are the cornerstone of paleontologists' study of paleontology and the reconstruction of local ecosystems, but fossils carried too little information in the past.
Fossils like frogs and turtles that change during mating, which carry traces of biological activity, are invaluable to paleontologists, and studying them may solve more archaic mysteries.
#青蛙 #