Sertularella pinnata Clark, 1876 [Invalid]

Was mistakenly described as a Bryozoan, Caberea pinnata Lamouroux 1816

Infertile material of Sertularella quadridens, Sertularella diaphana and Sertularella pinnata cannot be easily distinguished on microscopic characters alone, a situation that has probably led to much past misidentification of species. When fertile they are, however, readily separated, the gonothecae of S. quadridens and S. decipiens being more or less tubiform and ridged, that of S. diaphana is conical with longitudinal pleats while that of S. pinnata is conical and transversely corrugated.