Fossil fish with intermediate eyes

2008/09/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Eboluzioa
• Zoologia
• Paleontologia
• Arkeologia

The Museum of Natural History in Vienna found fossils of fish that had begun to migrate their eyes but had not yet reached the other side, in a collection of fossils that had not been studied. Heteronectes chaneti is the new asymmetric fish discovered. Scientists have stated that it was a kind of intermediate step towards the creation of pleuronectiform fish.

In fact, the eyes of the pleuronectiform fish, like the sole, have a special characteristic: at birth they are on both sides of the head, but as they grow, one changes place and ends on the same side of the other.

Scientists have long been discussing how pleuronectiform fish arrived and, above all, their eyes to have the current appearance. Some say that they developed little by little, in several generations, while others adopt the present form by abrupt leaps of evolution. Researchers say the discovery reinforces the first idea that fish evolved gradually.