Pleuredhera haraldi
Marcus & Marcus, 1970

Family: Pleurobranchidae


Western Pacific


Upper: Hawaii - found under rocks on shallow subtidal reefs (about 1 meter depth) and in basaltic ledges and small caves at night at depths of 5-15 meters. Lower: Enewetak, Marshall Islands - usually under dead coral rocks at depths of 2-12 meters. Specimens were in the 25-40mm range. Photos: Sott Johnson.

The shape of the living animal is very similar to that of Berthellina citrina with an elongately oval mantle completely covering the foot, and rolled rhinophores and tentacular oral veil visible anteriorly. The mantle is soft with some raised wrinkles. It is translucent clear with a reddish brown tinge, more dense in some specimens than others. The mantle wrinkles show as a darker irregular pattern. The viscera show through the mantle as coloured patches. It grows to about 40mm long.

The gill has a smooth rachis. The internal shell is calcified, but very thin. It is relatively small [one-third adult body length] and is situated anteriorly above the viscera, as in Berthellina. This species is considered to be the sole member of distinct genus, closely related to Berthellina. To distinguishing features are an accessory denticle on each radular tooth and a large pedal gland. However studies by Willan (1984, 1987) have been unable to find this gland which was described by Marcus & Marcus (1970). Willam (1987) suggests the gland may be an artifact of preservation.

• Marcus, Er. & Marcus, Ev. (1970) Opisthobranch mollusks from the southern tropical Pacific. Pacific Science, 24(2): 155-179.
• Willan, R.C. (1984) The Pleurobranchidae (Opisthobranchia: Notaspidea) of the Marshall Islands, Central-West Pacific Ocean. The Veliger 27(1): 37-53, Figs 1-44.
• Willan, R.C. (1987) Phylogenetic systematics of the Notaspidea (Opisthobranchia) with reappraisal of families and genera. Am. Malacol. Union Bull., 5(2): 215-241.

Authorship details
Rudman, W.B., 2003 (April 6) Pleuredhera haraldi Marcus & Marcus, 1970. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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  1. Pleurehdera haraldi from central Pacific
    From: Scott Johnson, April 8, 2003

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