Microporella speciosa sp. nov. is described from Alaska, USA. The new species is characterized by the following combination of features: 1) semicircular orifice with slightly curved and faintly denticu-late proximal edge having a straight, shallow groove, 2) two distal oral spines, 3) laterally directed avicularian rostrum with a broad, channeled tip, 4) open frontal pores, and 5) completely calcified basal walls. Opercula, avicularian mandibles, the ancestrula, and early ontogeny are also described.
