Histampica haimaensis

Histampica haimaensis belongs to the brittle star family Ophiothamnidae. Scientists led by Qihang Li first described it in 2021. The species gets its name from the Haima cold seep in the South China Sea, which is both its type locality and the inspiration for the name.

The central disk of the type specimen measures 7 mm across, but disk diameter can vary from 4 to 8.2 mm. The five arms are at least five times longer than the disk. The entire animal is beige, both alive and preserved in alcohol.

The upper surface of the disk is covered with naked, marginally overlapping scales. From the center to the edge, there are nine to ten scales in a row (or five to six in smaller individuals). The paired radial shields at the base of each arm do not touch; they are triangular or semicircular, nearly half as long as the disk’s radius but narrower.

The scales on the underside overlap more than those on top. Each side of the jaw bears three or four papillae, with the two farthest from the center being larger than the rest. The oral shields are roughly rhombus-shaped.

The upper arm plates are fan-shaped, half as wide as they are long, and do not touch. The first lower arm plate is small and hexagonal, touching the second segment; subsequent lower arm plates are larger, pentagonal, and do not touch each other. At the base of the arm, segments have two or three spines; farther out, they have four. These spines are nearly as long as the arm segments, slightly swollen in the lower half, and taper to a blunt tip.