Hexabranchus faustus Bergh, 1878

Tibiriçá, Yara, Pola, Marta, Pittman, Cory, Gosliner, Terrence M., Malaquias, Manuel A. & Cervera, Juan Lucas, 2023, A Spanish dancer? No! A troupe of dancers: a review of the family Hexabranchidae Bergh, 1891 (Gastropoda, Heterobranchia, Nudibranchia), Organisms Diversity & Evolution (New York, N. Y.) 23 (4), pp. 697-742 : 732

Hexabranchus faustus Bergh, 1878 (Fig. 26R)

Description notes Description based on an illustration of living specimens and three preserved specimens; internal and external morphological details provided; notes from a living specimen (and its illustration) provided by Semper: living animal 80 mm; preserved specimens from 65 to 95 mm: body oval, depressed, slightly wider posteriorly; notum pale red with whitish marks and darker dots; mantle expansion with dark purple spots on its inner sides followed by a white band and dark reddish-gray marginal band around the mantle edge (except anteriorly); rhinophores and gills colored like the notum except for yellow tips on the gill tufts; rhinophores slightly arched backward with 50 lamellae; text describes six triple pinnate gill branches arranged in six tufts but the illustration shows seven; radula with 48 rows of teeth, 15 rows more developed; curved teeth; reproductive system enclosed by connective tissue; penis almost cylindrical forming about five spirals.

Own conclusion/opinion on its taxonomic status Geographic distribution, external morphology (in particular the distinct white/red mantle marginal band), and the penis forming spirals clearly confirm the identification as H. lacer . Therefore, H. faustus is here transferred from a junior synonym of H. sanguineus to a junior synonym of H. lacer .