Valdiviathyris quenstedti

[1] V. quenstedti has been found near Chile and around New Zealand, but is assumed to be widespread in the Southern Ocean on hard (rock) substrates.

Both valves are very thin and translucent, have small pores (a state called punctate by science) and are obliquely conical in profile with the tip close to the straight posterior margin.

The outer edge is extremely thin, about 50 μm, and the interior lip of the rim is marked by a coarse granular ridge.

During the growth of this brachiopod their shape changes from thorns on the inner surface, via tapering cylinders at an angle to the valve and slightly diverging mid-size, to transversely flattened, sub-parallel and erect.

In the central cavity of most specimens a wide ridge begins in the middle, gradually becomes wider and higher and ends steeply.