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 denticulate prox
imal edge having a straight, shallow groove, 2) two distal oral spines
, 3) laterally directed avicularian rostrum with a broad, channeled ti
p, 4) open frontal pores, and 5) completely calcified basal walls. Ope
rcula, avicularian mandibles, the ancestrula, and early ontogeny are a
lso described.