Rathbunaster
Rathbunaster is a monospecific genus of sea stars belonging to the family Asteriidae. The genus name was given by Fisher as a honorific of the starfish biologist Richard Rathbun of the Smithsonian Institution. He originally ranged this genus under the family Pycnopididae, synonymous with Asteriidae. Description. Original description: It resembles closely Pycnopodia Stimpson, but differing in having a smaller disk, with the rays constricted at base and easily detachable. In the entire absence of rudimentary annular or calcareous ridges at the base of the ray, in the abortion of alternate supermarginal plates beyond the base of theray, and in  the small widely spaced inferomarginals each bearing a slender spine; in the greater prominence of the adambulacral plates which are placed on the same level with the inferomarginals (and each with a single spine as in Pycnopodia); in the less crowded condition of the ambulacral ossicles. The circular isolated plates on abactinal surface of rays are more numerous than in "Pycnopodia" and each bears a wreathed spine, whereas in "Pycnopodia" spines are rare on abactinal plates of arm. There are no large bivalved pedicellariae as in "Pycnopodia". Tube-feet quadriserial except at extremity and base of ray where they are  biserial. Ambulacral plates being less crowded, the tube feet are really intermediate in arrangement between the biserial and quadriserial type. Mouth plates are more prominent than in "Pycnopodia" and approach in form the type common to Brisingidae. The actinostome is wide, like the Brisingidae.