yellow-winged acornworm

Ptychodera flava (scientific name: Ptychodera flava) is an enterobranchial animal widely distributed in coastal areas of the Pacific and Indian Oceans, belonging to the genus Ptychodera in the family Ptychodera. [1] This species was discovered by naturalist Johann Friedrich von Eschsholz while participating in the second voyage of Russian explorer Otto von Kotzebue. It is the first hemichordate discovered.

Included in the "China National Key Protected Wild Animals List" Level 2.

It is widely distributed in the tropical waters of the Indo-Pacific Ocean. Domestically distributed in Hainan. It inhabits intertidal zones and lurks on sandy or muddy bottoms.

The snout is conical or rounded. The collar narrows in the middle and has an obvious annular groove on its trailing edge. The gills are sausage-shaped and the gill openings are extremely wide. The liver cysts are arranged in regular columns. The epidermal ring pattern is particularly prominent in the liver area. The ring pattern forms small islands on both sides of the back. The ring pattern is weaker on the outer edge of the genital wing and often forms small branches. The tail is swollen.