Subonoba morioria is a species of sea snail, a marine gastropod mollusc in the family Rissoidae. It is endemic to the waters surrounding the Chatham Islands of New Zealand.
In the original description, Powell described the species as follows:
The shells of the species measure in height and in diameter. It differs from S. foveauxiana in shape, and from S. fumata by having stronger spirals, a shorter spire, and a more inflated body-whorl (nine on the penultimate and 14 across the body-whorl and base).
The species was first described by A. W. B. Powell in 1933. In 1995, Hamish Spencer and Richard C. Willan recombined the species as Onoba morioria. While this remains the preferred name by the New Zealand Organisms Register, the original combination, S. morioria, is the preferred name by the World Register of Marine Species and The Marine Biota of Aotearoa New Zealand (2023).
The holotype was collected by Powell himself in February 1933, from shell sand at Waitangi in the Chatham Islands. The holotype is held by the Auckland War Memorial Museum.
S. morioria is endemic to New Zealand, found only in the waters of the Chatham Islands.