Scientists have identified the world’s most perfect ‘living fossil’, an organism that has barely evolved in the past 150 million years.
Theo Live Science, The “living fossil” just mentioned in Evolution magazine is Gar – the strange long-snouted sea monsters of the Americas. They are the slowest evolving of all jawed vertebrates.
This lineage of sea monsters belongs to the family Lepisostedae, with the most anatomically modern species appearing in the fossil record as late as the late Jurassic period (163.5 to 145 million years ago). That means from then until now, their “appearance” has not changed.
Seven species currently live in lakes and rivers in North and South America, while one species occasionally ventures into marine environments.
According to researchers, the term “living fossil” is sometimes controversial because some other “living fossils” may look very similar to their relatives, but internally they have evolved significantly.
But not the strange long-snouted creatures of the Americas.
Researcher Chase Brownstein from Yale University (USA), lead author of the study, said the team performed genetic analyzes on the computer to prove this.
More strangely, they evolve so slowly that two species separated by 100 million years of evolution can still interbreed, for example the case of Alligator gars (Atractosteus spatula) and longnose gars (Lepisosteus osseus – rocket crocodile). .
These two species diverged from each other on the evolutionary tree at the same time as the human and koala lineages diverged from their common ancestor! Therefore, their hybridization is as strange as the hybridization of humans and koalas.
But with Gar, it’s entirely possible because the two species are still very similar. Even their hybrids can still reproduce.
Today’s interspecific hybrids – based on species that recently separated from their ancestors – are often sterile, as is the case with mules.
It all just goes to show one thing: The Gar monster of the Americas still retains its ancient characteristics almost intact, inside and out.
They have kept their bloodline “pure” all that time, not interbreeding with other crocodile species despite sharing the same habitat, one of the reasons why they almost stopped evolving.