Epigonichthyidae

The family Epigonichthyidae is a group of marine invertebrates belonging to the subphylum Cephalochordata. These small, fish-like creatures are considered among the closest living relatives to vertebrates.1

Key characteristics of Epigonichthyidae include:
* Notochord: They possess a notochord, a flexible rod that runs along their body, which is retained into adulthood.1
* Gill Slits: Like vertebrates, they have pharyngeal gill slits.1
* Gonads: A distinguishing feature of the genus Epigonichthys (the type genus for this family) is that their gonads are located only on one side of the body. In contrast, the other family in Cephalochordata, Branchiostomatidae, has gonads on both sides.12
* Habitat: They inhabit soft bottoms along tropical and temperate coastlines, often buried in sand or gravel with their mouths exposed for filter-feeding.1

While edible, lancelets like those in Epigonichthyidae are not significant food sources. Their primary importance lies in their evolutionary connection to vertebrates, offering insights into the history of life.1