The discovery of a five-eyed shrimp-like creature that lived about 520 million Years Ago may end a long-running debate about the evolution of Earth's most common animals.

Arthropods, ranging from lobsters and crabs to spiders and millipedes, make up around 80 percent of all animal species alive today and are characterized by their hard exoskeleton.

Enter Kylinxia zhangi, a shrimp-like creature preserved in fossils found in China's Yunnan province -- a discovery that researchers now say could be a key "missing link" in arthropod evolution.

"Kylinxia represents a crucial transitional fossil predicted by Darwin's evolutionary theory," said Han Zeng, first author of a study published in the journal Nature on Wednesday.

In fact, when the first of the fossils was revealed, only its front legs were visible, and researchers assumed it was another specimen of Anomalocaris, said Diying Huang, a professor at NIGPAS.

"It looked strange, like a frontal appendage of Anomalocaris attached to the body of a common arthropod," Huang, the study's corresponding author, told AFP.