500-Million-Year-Old Sea Creature

Scientists have unearthed extraordinarily preserved fossils of a 520-million-year-old sea creature, one of the earliest animal fossils ever found, according to a new study.

The fossilized animal, an arthropod called a fuxhianhuiid, has primitive limbs under its head, as well as the earliest example of a nervous system that extended past the head. The primitive creature may have used the limbs to push food into its mouth as it crept across the seafloor. The limbs may shed light on the evolutionary history of arthropods, which include crustaceans and insects.

"Since biologists rely heavily on organization of head appendages to classify arthropod groups, such as insects and spiders, our study provides a crucial reference point for reconstructing the evolutionary history and relationships of the most diverse and abundant animals on Earth," said study co-author Javier Ortega-Hernández, an earth scientist at the University of Cambridge, in a statement. "This is as early as we can currently see into arthropod limb development."

The findings were published today (Feb. 27) in the journal Nature.

more here: http://www.livescience.com/27504-cambrian-arthropod-fossil-discovered.html