Despite the various convergent traits between Recluzia and Janthina, they seem to have evolved to their neustonic habit independently, with the former likely being most closely related to Alexania, for their shell characteristics, or Surrepifungium and Epidendrium, for their tissue coloration, while the latter is likely most close to Alora, especially Alora terrenima for its shell's resemblance to early janthinid fossils'. Further differing them from the violet snails, Recluzia have unforked cephalic tentacles, proportionally smaller heads and snouts, teleoconch-parallel protoconch coiling axis, thinner, longer, spineless egg casings, taller shell spires and retained statocysts as adults.[2] Furthermore, they lack epipodia, free-swimming larvae with proto-floats, which instead adhere to the parent's float, one of the protoconch II whorls, having 2.2 instead of 3.2 whorls, shell outer lip sinuses and ianthinin glands.[2]
Description
Shell
The shells of this genus have anywhere from 4.5 to 7 whorls.