Haikouichthys ercaicunensis

Shallow (2.5 cm) water chordate. The primitive cartilaginous spine allowed him to swim in a completely different way than arthropod animals do. The small body of haikouwihtis was devoid of fins, but the animal had eyes, gills and a brain, which made it the most advanced inhabitant of the Cambrian seas. It is possible that haikouihtis was a hermaphrodite and laid eggs, from which tiny larvae hatch. The skin of haikouihtis, like its distant descendants, modern lampreys and mixins , was covered with mucus.

Apparently, haikouihtis lived in large flocks of several hundred individuals, which helped them escape from predators. Judging by the small size and peculiar shape of the body, haikouihtis swam poorly. Mostly they stayed near the seabed, where they collected small particles of food. On some well-preserved haikouihtis fossils, even imprints of internal organs and glands that produce mucus have been preserved.

The fossil remains of haikouihtis were first discovered in 1999 in the vicinity of Haikou . Since then, scientists have found several dozen well-preserved fossils of this animal, which allow to study in detail the structure of even its eyes and internal organs.

Haikouihtis is one of several species of jawless animals whose remains have come down to us from the early Cambrian period. Some other species: pikaya - similar to lancelet , haikouella - chordate, with a cartilaginous skull, as well as Myllokunmingia . These animals are the oldest representatives of the chordate and cranial . The exact origin of the jawless is unknown, but, as recent DNA studies show, their ancestors apparently separated from the rest of the chordates as far back as the Precambrian (about 600 million years ago).