Hypselodoris dollfusi (Pruvot-Fol, 1933)

Yonow, Nathalie, 2018, Red Sea Opisthobranchia 5: new species and new records of chromodorids from the Red Sea (Heterobranchia, Nudibranchia, Chromodorididae), ZooKeys 770, pp. 9-42 : 22-24

Hypselodoris dollfusi (Pruvot-Fol, 1933) Figure 5 , Plate 8

Glossodoris dollfusi Pruvot-Fol, 1933: 126, pl. I figs 7, 8; fig. 40 (Red Sea).

Hypselodoris dollfusi - Gosliner and Behrens 2000: 116, Figs 1B , 4 , 5 (Oman); Yonow 2008: 60, 192 (Red Sea).

Material.

Wreck of ' Rosalie Moller’, near Hurghada, Egypt, 01 Aug 2012, 33 m depth, one specimen approx. 50 mm (approx. 25 × 15 mm preserved, curled), leg. and photographs S Kahlbrock .

Description.

This specimen represents the first and nearest record to its type locality for a species originally described from the Red Sea 80 years ago, and is thereby removed from its incertae sedis status of Yonow (1989). It is clearly distinct and recognisable from all the Red Sea chromodorids: the body is very large, firm, and with a high profile. It is pale to dark yellow with series of large and small spots, which can be shades of red and pink, often with a red margin, and a yellow margin encircling the mantle (Plate 8 ).

The preserved specimen is beige (examined 2013) with an orange margin. The patches and spots remain visible as red or faded red. There are red spots also present on the gill pocket, on the gills, around the margin of the hyponotum (large), and on the top of the foot (small, fading). The gonopore is surrounded by a red ring. The rhinophore pockets are white and retain their red margins. The mantle glands are visible as a series of darker yellow patches at the very posterior of the margin (Figure 5A ).

Ventrally, the body is swollen, cream-coloured, and the red spots visible as opaque white slightly raised spots (Figure 5A ). The head is rounded, the tentacles just visible. The anterior margin of the foot is very angular, bilaminate, with both laminae notched.

The reproductive system of the single specimen preserved in the summer is well developed.

Its radular formula is> 65 × 71.0.71. There is a clear space in the middle of the complete length of the radula. The first laterals on each side are identical and asymmetrical: all the teeth are clearly bicuspid but the first lateral has an additional small sharp cusp on its inner face (Figure 5B ). The remaining laterals are typically hypselodorid and regular along the row. The last 15 or so teeth become rapidly reduced in size with the addition of a line of 3-5 denticles on the lower cusp (Figure 5C ). Along the posterior portion of the radula, from approximately tooth 30 (if not earlier) the teeth are secondarily denticulate (Figure 5D ).

The jaws of Hypselodoris dollfusi are simple pointed rods with a slight curve (Figure 5E ).

Remarks.

It is remarkable that this species was described in 1933 and then not seen again until 1999. Gosliner and Behrens (2000) rediscovered the species based on specimens from the Persian Gulf. Although there is only one specimen from the Red Sea, there have been numerous photographic records from the northern gulfs of Eilat and Suez since Yonow (2008). It has since been photographed with some regularity but appears to be more common in the Persian Gulf (http://www.seaslugforum.net/find/hypsdoll, https://www.facebook.com/pg/uaebranchers/photos/?ref=page_internal).

White (1951) described a specimen from the Bannwarth Collection (NHM) as “… resembling a young individual of Glossodoris luteorosea …”. While she does not describe any remaining pigment, the only species in the Red Sea with large red spots similar to the Mediterranean species is H. dollfusi . However, White describes nine gills (while there are ten in Gosliner and Behrens (2000) and eight in this specimen; one is bifurcated) and “… cream coloured, soft and semi-transparent. The mantle edge is undulating." This does not agree at all with the preserved specimen of H. dollfusi described here. Additionally, she describes a radular formula of 54 × 30.0.30 in an 11 mm-long preserved specimen (66 × 88.0.88 in a non-measured specimen in Gosliner and Behrens 2000), and> 65 × 71.0.71 in this 25 mm-long preserved specimen. Not only does the formula differ considerably, but also the form of the teeth differs in that the first lateral has two denticles and the second lateral has one denticle.

Distribution.

The species is known only from the northern Red Sea ( Yonow 2008), the Persian Gulf ( Glayzer et al. 1984, Dipper and Woodward 1989, Gosliner et al. 2008), and the Gulf of Oman ( Gosliner and Behrens 2000).

Figures

Figure 1. Doriprismatica kyanomarginata sp. n. A ventral view of whole specimen showing colours of the preserved specimen, including the anterior section of the mantle margin B midline area from the anterior portion of the radula C lateral teeth from the posterior section of the radula D jaw rodlets.

Figure 4. Goniobranchus pseudodecorus sp. n. A ventral view of anterior showing head, oral tentacles, and foot margin B midline area from the anterior portion of the radula C lateral teeth from the anterior section of the radula D jaw rodlets.

Figure 5. Hypselodoris dollfusi (Pruvot-Fol, 1933) A ventral view of the whole specimen showing head, oral tentacles, and deep hyponotum with raised spots B midline area from the anterior portion of the radula C lateral teeth from the posterior portion of the radula D lateral teeth from the middle section of the radula E jaw rodlets.

Plate 8. Hypselodoris dollfusi (Pruvot-Fol, 1933), photograph S Kahlbrock.