Pentametrocrinus paucispinulus, new species, is described from a specimen collected on Pioneer Seamount off California in 1768 m. Like its closest congeners, it bears the first pinnule on the second brachial, but it differs in several characters. For example, P. varians and P. australis have longer tapered cirri with more segments, and P. spinosus has multiple rows of thorny stumps on the proximal arms. This is the first record of the genus from the eastern Pacific Ocean. A key to the species in the genus Pentametrocrinus is included.