Mamoea mandibularis is a species of Desidae that is endemic to New Zealand.
This species was described as Rubrius mandibularis by Elizabeth Bryant in 1935 from female specimens. It was most recently revised in 1973. The holotype is stored in Canterbury Museum.
The female is recorded at 7.99mm in length. The carapace and legs are coloured yellow brown. The abdomen has a pale chevron pattern dorsally.
This species is only known from Wellington, New Zealand.
Under the New Zealand Threat Classification System, this species is listed as "Data Deficient" with the qualifiers of "Data Poor: Size" and "Data Poor: Trend".