Hexabranchus petersi 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 : 733

Hexabranchus petersi Bergh, 1878

Description notes Description based on preserved specimens with notes on living animals, external morphology, and internal morphology; illustration of anal opening, kidney pore, and parts of the reproductive system: in life, a red mantle with white edge; size from 32 to 80 mm (preserved); flattened body; broad mantle; rhinophores with 45–50 lamellae; number of gill tufts vary from 6 to 8, commonly five; anal papilla moderately elevated; thick, oval, crenate oral tentacles; teeth hamate; radular formulae 22 × 66.0.66.

Own conclusion/opinion on its taxonomic status Bergh (1878) states that this species has a less flattened profile than H. praetextus , but the color and, in fact, most of the description are very similar. The shape of Hexabranchus spp. varies tremendously according to the preservation process. There is no reason to distinguish H. petersi from H. praetextus and H. sanguineus . Therefore, this species should remain a junior synonym of H. sanguineus .