Coe (1951) mentioned similarity to "Lineus geniculatus (Delle Chiaje, 1828) in color but considered the pattern of white markings to differ. The pattern shown for L. stigmatus is very similar to that found on some Caribbean specimens provisionally identified as Notospermus geniculatus. As this potential species complex is studied, the name stigmatus may come to be appropriately applied to that morph. In the meantime, it is best considered a synonym of N. geniculatus, albeit that these should best be referenced as N. cf. geniculatus (Pers opinion, Jon Norenburg).