The pourtalesiids (Pourtalesiidae) are a family of irregular sea urchins that live in the deep sea.
They are secondarily bilateral-symmetrical and like other representatives of the taxon Holasteroida they lack the lantern of Aristotle, which is typical for many other sea urchins.
The genus Pourtalesia was named after Louis-François de Pourtalès who first collected these animals while dredging at a depth of 600 m. The family is known already from the Upper Cretaceous (Maastrichtian) and is distributed worldwide.
[1] Currently, there are 10 genera with 28 extant and 5 extinct species described.
[2]