Histampica haimaensis

Lore & Background

Histampica haimaensis was formally described in 2021 by Qihang Li and colleagues. The type locality is the Haima cold seep in the South China Sea, which also inspired the specific name haimaensis. The central disk of the holotype has a diameter of 7 mm, though this can range from 4 to 8.2 mm. There are five arms, which are at least five times longer than the disk. All parts of the species are beige, both when alive and when preserved in alcohol.

Naked, marginally overlapping scales cover the top part of the disk, with ten to nine scales (or five to six in smaller specimens) in a line from the middle to the edge. The radial shields do not touch, are shaped either like triangles or semi-circles, and are nearly half as long as the radius of the disk, but are not as wide. The scales of the underside overlap more than the ones on top. Three or four papillae line each side of the jaw. The two papillae furthest from the center are bigger than the other (or others). The oral shields approach a rhombus in shape.

The upper arm plates are shaped like fans, half as long as they are wide, and do not touch. The first arm plate of the underside is small, hexagon-shaped, and touches the second segment. The other arm plates are larger, pentagon-shaped, and do not touch each other. The arm segments at the base have two or three spines, and the rest have four. These spines are almost as long as the arm segments, swell somewhat at the slower half and diminish steadily to a blunt tip.

Reader's Guide

Histampica haimaensis is a recently described species of brittle star, formally named in 2021 by Qihang Li and colleagues. Its significance lies in its association with the Haima cold seep in the South China Sea, a deep-sea chemosynthetic environment. The species is distinguished by its beige coloration, a central disk ranging from 4 to 8.2 mm in diameter, and arms at least five times longer than the disk. Key morphological features include naked, overlapping scales on the top of the disk, radial shields that do not touch and are triangular or semi-circular, and three or four papillae per jaw side with the two outermost being larger. The oral shields are roughly rhombus-shaped. Arm plates vary: upper plates are fan-shaped and do not touch; the first underside plate is small and hexagonal, while subsequent ones are larger and pentagonal. Spines at the arm base number two or three, increasing to four on other segments; these spines are nearly as long as the segments, swell slightly in the lower half, and taper to a blunt tip. The species is known only from its type locality, the Haima cold seep.