They discover that fish move faster in polar waters than in the tropics

Spain.- Cold-water and polar fish have generated new species for millions of years at twice the speed of tropical species, contrary to what was previously believed, according to one study published in Nature.

The book reveals what biologists consider to be "an evolutionary paradox": despite the fact that in tropical waters there is a great diversity of species, evolution acts faster in the cold waters of high latitudes.

The study, which analyzed the evolutionary relationships between over 30,000 species of fish and generated one of the largest phylogenetic trees to date, was conducted by the University of Michigan (United States) and has had the collaboration of other international scientific institutions, including the Institute of Ocean Sciences (ICM-CSIC) of Barcelona (north-east of Spain) .

The researchers described the results of the work as "paradoxical and unexpected" because "until now, there was a generalized idea that species formation rates are higher in the tropics," he said. ICM researcher Marta Coll.

"In this study, we tested this hypothesis, examining the relationship between latitude, species richness, and rate of formation of new species among marine fish, and we have seen that the trend is the opposite: the generation of new species is faster at high latitudes. "

The authors admit that they can not fully explain their findings because they are inconsistent with the idea that the tropics act as a" cradle " of the evolution "of marine fish diversity.