Not stated in the original description. The specific epithet pseudonatrix is composed by the Latin prefix pseudo-, meaning 'false', followed by the name of the species Boccardia natrix (Söderström, 1920), and refers to the superficial resemblance between the two species: "This species has a superficial resemblance to B. natrix Söderström (1920) since the concavity enclosed by the raised margin of the giant hooks is usually filled with debris and the whole simulates the fibrillar hooks of the latter species" (Day, 1961: 493).
Day, J. H. (1961). The Polychaet [sic] Fauna of South Africa. Part 6. Sedentary species dredged off Cape coasts with a few new records from the shore. <em>Journal of the Linnean Society of London.</em> 44(299): 463-560.