Hypselodoris violacea Gosliner & R. F. Johnson, 2018

Location: Nasog Point, Boracay, Philippines
Date: 2016/11/24
Length: 30mm
Depth: 10.0m
Water temperature: 25.0℃

Description

Living animals are moderately large, reaching 50 mm in length. The entire dorsal surface is deep, dark purple with a thick, solid opaque white band encircling the margin of the notum. Sides of the body and margin of the foot are the same colour as the notum. Ten to eleven unipinnate gill branches, which may be divided further basally or apically, are deep purple. Gill pocket is well elevated and deep purple. Bulb and base of rhinophores are deep purple throughout, with about 31 densely packed lamellae, and the base of the rhinophore sheath is deep purple. Mantle glands are entirely absent from the mantle margin.

Distribution

Known only from Palawan (Philippines) and northern Borneo (Malaysia). Type locality: Magic Reef, Bintuan Barangay, Coron, Busuanga Island, Palawan, Philippines, 10 m depth.

Etymology

Verbatim from the original description (Epstein, Hallas, Johnson, Lopez & Gosliner, 2019, Zoological Journal of the Linnean Society 186: p.167):

The name violacea is Latin for violet, referring to the intense purple body colour that ornaments the body, gill and rhinophores of this species.

Remarks

Hypselodoris violacea is sister to Hypselodoris variobranchia and is externally very similar. H. violacea can be distinguished by its purple (not orange) rhinophores and consistently deep purple gill branches. The radula is similar in both, but in H. violacea the innermost teeth have a longer, more acutely pointed inner cusp on the bifid cusps. In the reproductive system the uterine duct emerges from the distal third of the vagina in H. violacea, whereas in H. variobranchia it emerges from the proximal portion. COI divergence is 8.8-9.0%.