Dipsacaster Alcock, 1893 Dytaster Sladen, 1889 Koremaster Fisher, 1913 Leptychaster E.A. Smith, 1876 Lonchotaster Sladen, 1889 Macroptychaster H.E.S. Clark...

are the sister species, Trophodiscus uber, from the Sea of Okhotsk, Leptychaster kerguelenensis from the extreme south of the Indian Ocean and Ctenodiscus...