Pourtalesiidae

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.

== Species and genera == Currently, there are 10 genera with 28 extant and 5 extinct species described. genus Ceratophysa Pomel, 1883 Ceratophysa ceratopyga (A. Agassiz, 1879) Ceratophysa rosea (A. Agassiz, 1879) genus Cystocrepis Mortensen, 1907 Cystocrepis setigera (A. Agassiz, 1898) genus Echinocrepis A. Agassiz, 1879 Echinocrepis cuneata A. Agassiz, 1879 Echinocrepis rostrata Mironov, 1973 genus Echinosigra Mortensen, 1907 Echinosigra (Echinogutta) amphora Mironov, 1974 Echinosigra (Echinogutta) antarctica Mironov, 1974 Echinosigra (Echinogutta) fabrefacta Mironov, 1974 Echinosigra (Echinogutta) valvaedentata Mironov, 1974 Echinosigra (Echinosigra) mortensi Mironov, 1974 Echinosigra (Echinosigra) phiale (Thomson, 1873) Echinosigra (Echinosigra) porrecta Mironov, 1974 Echinosigra (Echinosigra) vityazi Mironov, 1997 genus Galeaster Seunes, 1889 † Galeaster carinatus Ravn, 1927 † Galeaster dagestanensis Poslavskaya & Moskvin, 1960 † Galeaster minor Poslavskaya, in Moskvin & Poslavskaya, 1949 † Galeaster muntshiensis Tzaghareli, 1949 † Galeaster sumbaricus Poslavskaya, in Moskvin & Poslavskaya, 1949 † genus Helgocystis Mortensen, 1907 Helgocystis carinata (A. Agassiz, 1879) genus Pourtalesia A. Agassiz, 1869 Pourtalesia alcocki Koehler, 1914 Pourtalesia aurorae Koehler, 1926 Pourtalesia debilis Koehler, 1926 Pourtalesia heptneri Mironov, 1978 Pourtalesia hispida A. Agassiz, 1897 Pourtalesia jeffreysi Thomson, 1873 Pourtalesia laguncula A. Agassiz, 1879 Pourtalesia miranda A. Agassiz, 1869 Pourtalesia tanneri A. Agassiz, 1898 Pourtalesia thomsoni Mironov, 1976 Pourtalesia vinogradovae Mironov, 1995 genus Rictocystis Mironov, 1996 Rictocystis jensenae Mironov, 1996 genus Solenocystis Mironov, 2008 Solenocystis imitans Mironov, 2008 genus Spatagocystis A. Agassiz, 1879 Spatagocystis challengeri A. Agassiz, 1879