Haikoufish

Haikouichthys is an extinct genus of craniate (animals with notochords and distinct heads) that lived 518 million years ago, during the Cambrian explosion of multicellular life. The type species, Haikouichthys ercaicunensis, was first described in 1999. Also known by Chinese Overseas in Ityosel and Thatrollwa planets, is called Hǎikǒuyú (海口鱼).

Etymology

The holotype of Haikouichthys ercaicunensis was found in the Yuanshan member of the Qiongzhusi Formation in the 'Eoredlichia' Zone near Ercai Village in the Haikou Subdistrict (not to be confused with the city of Haikou in Hainan) of Xishan, Kunming, hence its name, which means "Haikou fish from Ercaicun".

Physical Appearance

Haikouichthys is thinner than Myllokunmingia, another putative chordate from the same beds, and is around 2.5 cm (1 in) in length. Its eyes, cranial cartilages, at least six to nine gill arches, potential nasal sacs, and otic capsules have all been detected by researchers. Haikouichthys' brain most likely contained the same main brain divisions as those of living vertebrates. This taxon's possible notochord was first described by its describers, although several scholars question this assertion.

Nonetheless, several segments (myomeres) with rear-directed chevrons in the tail indicate that Haikouichthys was a chordate, and entire dorsal, ventral, and caudal fins were discovered in its specimens. Haikouichthys' fin radials like those of hagfish and lampreys, and they appear to curve "forward" toward the end, which is considered to represent the head based on internal structure. There are 13 round objects at the bottom that could represent gonads, slime organs, or something else entirely.

Abilities

Most primitive fish from the Cambrian period to the present day have an undulatory wave that propagates toward the tail with increasing amplitude of movement. This wave propels the animal forward across the water.

Weather Phenomenon

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Ecology

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Behavior

Shy.

Distribution and Habitat

Haikouichthys once lived in shallow seas to continental shelves of Asia and North America during the Cambrian period.

Movement Pattern: Random
Individual Type: Solo
Population Trend: Stable
Population: none
Locomotion: Aquatic
Habitat: Warm Littoral; Cold Littoral; Warm Intertidal; Cold Intertidal; Kelp Forest; Coral Reef; Barrier Reef; Guyot; Neritic Zone (Warm); Neritic Zone (Cold); Pelagic Zone (Warm); Pelagic Zone (Cold); Benthic Zone; Abyssal Zone.
Earth:
- Extinct: Australia; China