Doriopsilla nigrocera, Yonow, Nathalie, 2012

Yonow, Nathalie, 2012, Opisthobranchs from the western Indian Ocean, with descriptions of two new species and ten new records (Mollusca, Gastropoda), ZooKeys 197, pp. 1-130 : 41-42

Doriopsilla nigrocera sp. n. Fig. 15Plate 59

Material.

Holotype: Persian Gulf (Saudi Arabia): 25 × 17 mm pres., Jubail, Dahwat ad Daffi, 03 April 1992, leg. F Krupp, SMF 337105.

Diagnosis.

Creamy yellow elongate oval body with ochre gills and charcoal black rhinophores. Variously sized spiculose tubercles are covered in opaque white lines, with some fainter ones extending from the tubercles to the mantle.

Description.

The photograph depicts an elongate oval animal with a wrinkled and damaged margin in life. Dorsum covered in tubercles, themselves covered and sometimes faintly linked to each other with fine white lines. Body was creamy yellow, plumose gills ochre in colour, darker than dorsum, but the rhinophores were black: the stalk was translucent cream and the approximately 15 fine lamellae were charcoal black. The midline on each side and the tip were dusty white. The gut was visible through the skin, opaque creamy orange with black patches.

The preserved specimen has a pink cast and is semi-translucent. Surprisingly, the retracted rhinophores are no longer black, and not visible by translucence through the pockets or the body wall. The tubercles are full of spicules. Tubercles are largest centrally and become progressively smaller toward the margin (Plate 59); in preservative, many are mushroom-shaped. The margin itself is rather thick (and damaged on the right side). Ventrally, the anterior margin of the foot is simple, not bilaminate, and there is a fold under the mouth (Fig. 15).

Remarks.

The single specimen is unlike any species of Doriopsilla published to date, and different from the photographs available in books and on the internet. The most similar species is Doriopsilla miniata (Alder & Hancock), described from India and occurring throughout the Indo-West Pacific in a wide range of colours from nearly white to bright orange. Usually, there are tracings of white lines crossing the dorsum transversely but these may be absent. More critically, the gills and rhinophores of Doriopsilla miniata are the same colour as the dorsum or a little darker and this, amongst other characteristics, distinguishes this new species. An un-named species of Doriopsilla similar to Doriopsilla nigrocera sp. n. is illustrated in Gosliner et al. (2008), Apte (2009), and Apte et al. (2010) in which only the tubercles are covered in white lines; however, this species has rhinophores and gills the same colour as the mantle and not black and may simply be a colour form of Doriopsilla miniata . These animals were recorded from South Africa and India, but remain unidentified.

Etymology.

The specific epithet refers to the very distinctive black rhinophores, unique to this species of Doriopsilla .