By Amira El Masaiti
Rabat – 480 million-year-old fossils discovered north of Zagora have revealed one of mollusk’s common ancestors, according to a study published February 6 in the scientific journal Nature.
The discovery of fossils in the Fezouata formation in south-east Morocco has allowed paleontologists to trace the family tree of the mollusk species, particularly that of chitons and marine mollusks, which are still found today in the oceans around the world.
Living species of mollusks vary from 50,000 to a maximum of 120,000 species, from snails and slugs to octopuses and oysters. The variety of kinds found in the species made it hard for scientists to detect the group’s oldest ancestor.
“Mollusks are among the earliest animals documented in the fossil record, but it is difficult to determine what their ancestor resembled because they appeared in a short period of time, making the sequence of evolution difficult to trace,” said Jakob Vinther, one of the authors of the study.
Previous studies on the origin of the species have suggested that the oldest mollusks evolved about 535 million years ago. Previous studies have also estimated that the first mollusks didn’t have shells, but the recent discovery of the fossils in Morocco indicate that the oldest species in the group actually had a hardened structure made out of calcium carbonate that served as a shell.
This is not the first time that researchers have discovered paleontological treasures in Morocco. In early January, a team of Spanish scientists announced the discovery in Fezouata of a new species of trilobite, a sort of marine insect that existed nearly 500 million years ago.
