The Naxerans were a humanoid race native to the planet Naxera, distinguished by a set of frills extending horizontally on either side of their noses, their ebony-dark skin and gold-colored eyes. However, an off-shoot race, the Weyrie, had white skin and blue eyes. Naxerans did not sleep, nor did they dream.
Naxeran society was divided into castes: the G'Dok, or ruling class; the Leahru, or middle class; and the Efram, or working class. These caste names were incorporated into the individuals names.
Though it's never explicitly stated, the Naxerans are likely not Federation members (at least as of 2336), because of their caste system. Gleemor's membership in Starfleet would then be a singular situation, akin to that of Worf or Nog.