Amphioxus

Amphioxus is a noun for a small translucent lancet-shaped burrowing marine animal; primitive forerunner of the vertebrates.

Amphioxus are usually found buried in sand in shallow parts of termperate or tropical seas . In Asia, they are harvested commercially as food  for humans and domesticated animals . They are an important object of study in zoology as they provide indications about the origins of the vertebrates.. Lancelets serve as an intriguing comparison point for tracing how vertebrates have evolved and adapted. Although they supposedly split from vertebrates more than 520 million years ago, their genomes hold clues about evolution, particularly how vertebrates have employed old genes for new functions.