Despite the fact that we sometimes forget about it, human beings are nothing more than a newcomer to this planet compared to other animals that have inhabited it for millions of years.
And is that even though 99% of the four billion species that have evolved on our planet they became extinct, a small percentage of them have remained unchanged for thousands of years. We show you some of the strangest animals They have hardly changed since their origins.
platypus
A mammal that lays eggs. There is no doubt that the platypus is very special. Along with the four species of echidna —similar in appearance to hedgehogs—, is the only one that survives today from the order of monotremesthe group that brings together mammals that lay eggs instead of giving birth to live young.
A semi-aquatic animal endemic to eastern Australia and the island of Tasmania, its unique appearance – with a duck-billed snout, beaver tail and otter legs – is a challenge to zoologists. So much so that the first European naturalists They considered it a “fake”. But no, the platypus isn’t a Pokémon, it’s a species that it just evolved in the last 150 million yearswhen its lineage diverged from other mammals.
Zarigueya
Although not as old as the monotremes, this mammal of the marsupial order, which includes 92 living species, is a case of evolutionary convergence: when two similar structures evolved independently from different ancestral structures and very different developmental processes.
In this case, the possum is similar to rodents and shrews, but it is not related to these. Experts have traced the ancestry of these animals to a group of marsupials called Peradectidae, during the dinosaur extinction time: its separation from the rest of the marsupials would have occurred 65 million years ago.
goblin shark
This fish is one of the great mysteries of the depths of the sea. And is that the first known specimen was caught by a fisherman off the coast of Japan in 1898. Since it is restricted to deep waters, about 1,400 meters deep, your knowledge is limited. Its long snout, equipped with sensitive electroreceptors, is used to locate food.
It is one of those animals considered “living fossil”a colloquial term used to designate non-extinct species that evolved very slowly and retain characteristics of more ancient ancestors.
Eel shark
We don’t leave the sea because we have to meet another species of shark, the eel. And that’s it marine environments are considered more favorable due to less fluctuation of basic elements for survival such as temperature, humidity or water: generally, on land, species are more demanding, so they would evolve faster… or they would become extinct.
Thus, the eel shark would be another living fossil from the depths of which there are almost no records of its presence and which, curiously enough, has the longest gestation period of all vertebrates: three and a half years.
Big cats
So far we have seen more or less “strange” or unknown animals, but among the species that have evolved slowly we also find others that are much more popular, case of the jaguar or the tiger. According to experts, their anatomy hasn’t changed much because, since their origin, they were already excellent predators. Furthermore, the fact of adapting to different geographical environments has allowed them to survive as a species.
horseshoe crab
Although its colloquial name, It’s not a crab or a crustacean, but it is a different order of arthropods that lives in shallow coastal waters and on soft, muddy or sandy bottoms. how do you get back to more than 400 million years It would also fall into the category of living fossils. In this sense, the horseshoe crab would be one of the few animals that They managed to survive the age of dinosaurswhen most marine reptiles became extinct.
Coelacanth
This fish is another of evolution’s great mysteries as it was believed to be extinct since the Cretaceous period which ended about 65 million years ago. But in 1938, a live specimen was caught off the east coast of South Africa.spotting another one on Celebes Island two and a half decades ago.
They are said to be the marine living beings closest to terrestrial vertebrates, appearing in the Devonian period. 400 million years ago. After analysis of coelacanths captured in recent years, it has been confirmed that it has a morphology practically identical to its fossil ancestor.
amia bald
It is the only remaining member of the holostean order Amiiformes, a type of fish with an almost totally ossified skeleton that it became abundant in the waters of the planet during the Mesozoic era. One of its most curious traits is that it can breathe the atmosphere through its mouth, lasting up to a day out of water.
Jellyfish
It is one of the great fears of bathers in warm waters, where they can cause real havoc: but it’s his territory, don’t forget that. Like it nut CSIC researcher Laura Prieto “are part of the ecosystem and the solution is not to remove them”.
In fact, they are part of the ecosystem for more than 500 million years, one of the oldest organisms on the planet which, moreover, “has changed practically nothing” since its origin: “this indicates that they have a very high plasticity to changes in the environment”. Cubozoans, nicknamed the “sea wasp”, have the most dangerous poison for humansbecoming lethal within minutes.
sponges
AND study presented by Nature last year showed the possible fossils of porifera, commonly known as sea sponges, with 800 million age which would be the oldest known animal in history.
Although they were originally considered plants, since the mid-18th century, when inland water currents have been discoveredthey came to be considered animals, being the oldest group of living animals: we would therefore be faced with the first forms to branch off the evolutionary tree from the common ancestor of all animals.
