Hypselodoris pulchella

Hypselodoris pulchella (Rüppell & Leuckart, 1830)

• Chromodoris pulchella (Rüppell & Leuckart, 1830)
• Doris pulchella Rüppell & Leuckart, 1830 (original)
• Risbecia pulchella (Rüppell & Leuckart, 1830)

Description
Body with a maximum recorded length of 110mm. The mantle is white or creamy white with numerous small yellow orange spots. The edge of the mantle has a light purple thin band with a series of irregular purple patches growing from the edge into the body, quite variable from one specimen to another and very small in juveniles, that form a reticulate of pale purple hue all over the mantle in mature specimens. The underside of the mantle is white with yellow orange spots and there is a light purple border somewhat wider than the upperside dorsal margin. The front of the mantle forms a large veil that continuously waves when the animal is moving. The sides of the body and the foot are white with yellow-orange spots and the tappered tip of foot has traces of the pale purple reticulate pattern similar to the one on the dorsum, and a light purple edge. The rhinophore stalk is white with a deep purple club with 15-16 lamellae and a white median line on the anterior and posterior sides. The gills are translucent white and edged in purple, often branched and numerous (from 20 to 30) in mature specimens.

Biology
Very little is known about its diet. The study of the gut contents of this species revealed the presence of small fragments of polychaete worms, copepods and very few algal filaments, together with a considerable amount of calcareous sponge spicules, so it seems probable that it feeds on sponges and accidentally eats the other organisms (Aboul-Ela, 1959). When recently spawned, the egg ribbon is reddish orange and it is attached along one edge in a spiral, the free edge being slightly wavy. The anterior part of the mantle waves up and down when the animal is moving. The gills are often waved rhythmically from side to side. There is a characteristic trailing behaviour found in this species, where pairs of animals are often found following each other in single row, the second animal in the line touching the ‘tail’ of the one in front. There are two other dorid species sharing part of the distribution range that could be easily confused with Hypselodoris pulchella: Hypselodoris ghardaqana and Goniobranchus annulatus. Gohar & Aboul-Ela (1957) give differentiation keys that we synthethise in the following comparison chart:

	Hypselodoris pulchella	Goniobranchus annulatus	Hypselodoris ghardaqana
Dorsum color	Creamy white w/yellow spots, purple difuse reticula	translucent white w/yellow spots, purple circles	white w/yellow spots
Max.size	110 x 30 mm	64 x 20 mm	55 x 13 mm
Rhinophores	long, dark blue w/white axis	long, conical, deep purple	short, reddish purple w/pink red axis
Gills	20-30, branched, kept vertical, vibratile	9-12, not branched, kept vertical, vibratile	9-11, not branched, kept horizontal, non-vibratile
Egg-Ribbon	reddish orange, free edge wavy	creamy white, free edge not wavy	white, free edge slightly wavy, single layer of eggs
Photo	Hypselodoris pulchella	Goniobranchus annulatus	Hypselodoris ghardaqana
Picture credits	Erwin Köhler ©	Miquel Pontes ©	Brian Mayes ©

Etymology

• Hypselodoris. From Greek “hypsos”, height, high + “Doris”, a sea nymph in Greek mythology, wife of Nereus, nymph of the waters and mother of Nereids.
• Pulchella. From Latin “pulchellus”, nice, charming.

Distribution
This species is widespread in the Indopacific (it has been cited in Philippines, Thailand, Myanmar, Malaysia, Indonesia, India, Sri Lanka, Seychelles, Kenya, Mozambique, Réunion, South Africa, United Arab Emirates, Oman, Egypt, Saudi Arabia, and Iran) and is common in the Red Sea. A report from Calkidiki, Greece (Savvidis, L., 2/11/2016), still unpublished, is the first record in the Mediterranean, and is probably related to a Lessepsian dispersion event.

Known georeferenced records of the species: Hypselodoris pulchella

Sources:
OBIS GROC 2010-2011 Enric Madrenas João Pedro Silva Bernard Picton GBIF	OPK VIMAR Manuel Ballesteros M@re Nostrum Altres fonts Marine Regions

More pictures

Hypselodoris pulchella @ Sharm-El-Sheikh, Egypt (Red Sea) 27/09/1996 by Erwin Köhler

Hypselodoris pulchella by Erwin Köhler

Hypselodoris pulchella (trailing behaviour) @ Oman by Pete Berry (Nudibase)

Hypselodoris pulchella @ Red Sea by Enric Madrenas

Hypselodoris pulchella @ Red Sea by Enric Madrenas

Hypselodoris pulchella @ Red Sea by Enric Madrenas

Hypselodoris pulchella @ Red Sea by Enric Madrenas

Bibliography

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Bibliography based on the works by Steve Long, 2006. Bibliography of Opisthobranchia 1554-2000 and Gary McDonald, 2009. Bibliographia Nudibranchia, with later updates from other resources.

Further reading

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