Corresponding author: Nathalie Yonow (
Academic editor: B.W. Hoeksema
With the complexity of the family
Yonow N (2020) Red Sea Opisthobranchia 6: Phyllidiidae and their paradorid mimic: new species and new records (Heterobranchia, Nudibranchia, Doridina). ZooKeys 1006: 1–34.
Species of the family
Most Indo-Pacific phyllidiid species are characterised by a tough, rubbery, domed body, generally elongate oval, and variably covered in many types of tubercles and/or black lines. Species range in size from approximately 1 to 100 cm, and are generally colourful, but a few are pink, white, or beige with or without black markings. The lamellate rhinophores are orange, black, ochre, or pink and black. Ventrally, they have a foot which is smaller than the body, but its anterior end is sometimes species specific. The foot margin can be rounded, squared, dented, or notched. A bilobed part (termed ‘lips’ in this work) sits just below the mouth but above the foot margin. Above the mouth are oral tentacles which bear a groove on their outer sides but vary in shape between the genera: separate and digitiform, contiguous and triangular, or fused, with some specific variations. They may be coloured orange, yellow, pink, or grey, and tipped with black in some species.
This work describes three species of
Map of the Red Sea showing all the collecting and photograph sites listed in this paper.
The material described and listed in this paper were collected and/or photographed by several divers with one exception, the dredges of the deep-sea expeditions by RV ‘Meteor’. The fifth cruise of this research vessel took place in the Red Sea and the Gulf of Aden in February and March 1987, and among the opisthobranchs collected was a phyllidiid. A map illustrates the positions of the collecting localities of the specimens and photographs included in this paper, ranging from Israel, Sinai, northeast Egypt, Saudi Arabia, Sudan, and the Bab el Mandab (Gulf of Tadjourah) at the mouth of the Red Sea (Map
Georeferenced collection and photographic localities, from north to south.
Main location | Dive site | Latitude / Longitude |
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Eilat |
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Dahab |
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Moray Garden | ||
Sha’ab Mahmoud/ Beacon Rock | ||
Sha’arm el Sheikh |
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Whale Bay | ||
Thistlegorm | ||
Ras Umm Sid | ||
Near Gardens | ||
Hurghada |
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Sha’ab Dorfa | ||
Abu Kafan | ||
Small Gubal Island | ||
Makadi Bay |
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Safaga |
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El Quseir |
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Abu Dabbab |
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Marsa Alam | ||
Jeddah |
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Obhur Creek | ||
Sanganeb reef |
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Lighthouse, Port Sudan |
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Farasan Banks | 18°20' – 20°00'N, 40° – 41°20'E | |
Gulf of Aden, stn 230 KD2 |
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The collected material was not always measured, photographed, or relaxed before preservation, but as soon as the specimens were received, each one was examined under a Leica MZ APO microscope, and measurements, notes, and drawings were made. Some arrived preserved in formalin, others in various alcohols. In some cases, photographs were taken of the preserved specimen. After detailed descriptions of the dorsal and ventral sides were made, the digestive anatomy was examined by making a circular dorsal incision. Final drawings are a composite tracing of a series of printed photographs in combination with the annotated drawings. The features of the radulae and jaws of
In the Material section of each species and in the appendices,
Relatively smooth phyllidiid with pale yellow crests and cones (instead of rounded tubercles). White areas granulate, black areas smooth. Sub-margin with single series of yellow and white patches and small crests and pointed tubercles, margin smooth and pale. Rhinophores black, extending from pale yellow raised sheaths. Very distinctive oral tentacles, trilobed with a median ridge (not digitiform as those of other species of
The photograph of the living specimen depicts an animal which vaguely resembles a smudged
The preserved specimen is curved ventrally but everything is clearly visible (Fig.
Anatomically, the dissection of the single specimen confirms placement in the genus
The internal anatomy of this new species clearly places it in
While
The name was chosen for the wife of the ruler of the sea, Poseidon, in Greek mythology. She was called
These five specimens and the additional photographs all bear a single dorsal black band enclosing both the rhinophores and the anal orifice (Plates
None of the preserved specimens were relaxed before preservation, but they are moderately flat with the margins slightly curled (as reported previously for preserved specimens) and their rhinophores are all retracted. Of the photographic series of living specimens, SK #13 has a few that are focused on the rhinophores, and there are 12–14 lamellae on each clavus with the lower three or four lamellae being white. This lower white portion is visible on all photographs of all animals even if they are not sharp enough to count the individual lamellae. Ventrally, the foot sole has no black line nor are there any other markings on it or on the hyponotum (Figs
A careful search of all photographic records in the author’s archives from Pam Kemp, Woody Pridgen, and Jürgen Kuchinke who were in Saudi Arabia and diving during the 1980s revealed no photographs of
The single large (32 mm) preserved specimen is mostly black, which forms deep scallops around the mantle sides with three elongations on the left and four irregular ones on the right, almost reaching the mantle margin, and a small one on the posterior margin (Plate
The central black area in life bears a few barely discernible pustules, visible only at great magnification. The four large central tubercles are pustulose and irregular. There is one large tubercle just behind the rhinophores followed by two more. These three tubercles are the largest and rugose, with the basal pustules faintly tipped in yellow pigment which deepens towards tips. The white anal papilla is located just behind the third dorsal tubercle and located in a white area; the anal opening is surrounded by tiny black spots. There is one smaller white and yellow pustulose tubercle behind the anal papilla (far right on Plates
The preserved specimen is black and white (Fig.
Ventrally, the spicules of the hyponotum are arranged in a distinctly hatched pattern, and the black pigment shows through from the dorsal side, darkest around the margin (Fig.
A dorsal incision to remove the very thick notum revealed a digestive system (Fig.
The external details of this specimen described in this work clearly fit those given for the holotype by
The individuals photographed (Plates
Internally, the digestive system is as described and illustrated in
One additional character for
The individuals and holotype with less black are similar to the Indo-West Pacific
The genus
Body elongate-oval with a distinct dorsal hump, wide mantle skirt. Dorsum pink, granular, with paler to white nodules, and black lines. Black pattern as four or five paired polygons; first pair around rhinophores with one or two lines extending to frontal margin. Dorsal polygons have short lines extending over skirt to margins. One polygon in front of the gills and one around the gills. Rhinophores black with translucent white stalk; rims of pockets raised, translucent pink, very thin, with an irregular margin. Six gills tri-pinnate, translucent white; pocket large with raised pink rim.
The shape of the species is elongate oval, usually with an angular frontal margin. There is a central dorsal hump and a broad mantle skirt. The black markings are smooth, loosely paired in a series of four or five polygons, with a larger central one just in front of the gills. Each rhinophore and the gills are located within a polygon (Plates
The five preserved specimens (in alcohol or in formaldehyde) are all pale pink with approximately paired, rounded, polygonal, black markings (Fig.
All preserved specimens are curled ventrally to a greater or lesser extent except the holotype
The jaws are formed of three plates (Fig.
This species appears to be relatively common in the northernmost part of the Red Sea, based on the available photographs (
Externally, the black pattern of
The three jaw plates and form of the radulae and teeth are very similar if not identical in both species, albeit based on few specimens, but the numbers vary with fewer teeth per row in
This epithet is based on the Latin noun
‘
This work on the Red Sea phyllidiids brings the total number of species recorded in the family to 16 for the region. Of these, four named species are considered endemic:
No specimens of
The identity of
A second species also remains a mystery, undiscovered since its old record: it was described by
Eliot then goes on to say that the orange tips were harder than the remaining epidermis.
The final species in the check-list needing comment are two
Of the non-endemic species,
Two species from the Red Sea have more extended western Indian Ocean distributions:
The most photographed species in the Red Sea, and therefore presumed to be the most common, are
I would like to thank the scientists who have generously provided their specimens and photographs over the years. Ernesto Mollo/Ángel Valdés (Italian National Research Council, Rome/Cal Poly Pomona, California), Thomas Paulus (GFGmbH, Mainz, Germany), and Bernard Picton (Belfast Museum) sent me their Red Sea collections a very long time ago – thank you so much, and apologies for the delay. Bert Hoeksema (Naturalis, Leiden) kindly sent me all the phyllidiids collected during the Farasan Banks Cruise in May 2017 (under leadership of Prof. Michael L. Berumen, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia) for examination and identification; he has also been a very supportive subject editor, for which I am grateful. I thank A. Martynov (ZMMU) for the radular SEM micrographs; the specimens and stubs are still with him until restrictions are lifted.
I would like to thank Sven Kahlbrock (Hurghada, Egypt), who has photographed and collected material since his encounter with “The Book” (
Finally, I am very grateful to Benoît Dayrat (Pennsylvania State University, USA) and Karin Fletcher (Port Orchard, USA) for valuable discussions and critical comments; I sincerely thank both reviewers for their corrections and comments. Plamen Pankov (ZooKeys layout) has gone above and beyond to help me with the map and figures and has created a beautiful layout with his team – thank you.
This research has received no special funding.
Additional specimens of species previously described from the Red Sea (
Small Gubal Island, Hurghada, Egypt, 10 Sept 2012, 2–5 m depth, 15 mm alive (13 mm pres., alcohol), leg. S. Kahlbrock.
TQ 1, Sanganeb Reef, Sudan, 29 Mar 1991, 4.5 m depth, 25 × 14 mm pres., formalin, leg. T. Paulus (ref # 30).
Lighthouse, south of Port Sudan harbour, Sudan, 18 Mar 1991, 11 m depth, 25 × 10 mm pres. alcohol, leg. and photographs T. Paulus.
Small Gubal Island, Hurghada, Egypt, Oct 2012, one spcm 18 × 8.5 mm pres., formalin, leg. S. Kahlbrock.
Hurghada, Egypt, May–Sept 2010, one specimen 9 × 4 mm curled (pres., formalin), leg. S. Kahlbrock.
Makadi Bay, Egypt, 3 Aug 2013, photograph Hsini Lin.
Tobia Arba, Safaga, Egypt, 13 Dec 2014, two photographs of one individual matching holotype description perfectly, S. Kahlbrock (Plate
Bab el Mandab, Red Sea, ‘Meteor’ cruise 5, stn. 230 KD2, 05 Mar 1987, 214–237 m depth, 18 × 11 mm pres.,
Near Gardens, Sha’arm el Sheikh, Egypt, 24 Dec 1990, 18 m depth, 48 × 18 mm alive; 35 × 16 mm pres., leg. and photographs N. Yonow (ref Sha’arm NY #111; formaldehyde; Plate
Dahab, Egypt, Nov 1990, 43 × 20 mm pres., leg. and photographs J.
Sanganeb Reef, Sudan, 29 Mar 1991, 45 × 27 mm pres., leg. T. Paulus (ref # 38) (black-tipped oral tentacles upon reception of specimen, formaldehyde; no black pigment remaining in 2000).
Jeddah, Saudi Arabia, 1980s, photograph of one individual, W. Pridgen.
Hurghada, Egypt, 2010, photographs of four individuals, S. Kahlbrock.
Eilat, Israel, 2019, photographs of one individual, R. Amar.