Philinopsis speciosa
Pease, 1860

Order: CEPHALASPIDEA
Superfamily: PHILINOIDEA
Family: Aglajidae

PHOTO

Upper: Ulua Beach, Wailea, Hawaii (Maui). Depth: 40-50 ft. 05 and 06 May 2005. Sand. Photographer: Mike Roberts. Lower: Pupukea, Oahu, Hawaii, USA. Locality: Depth: 10 m. Length: 25-50 mm. Mixture of coral and basaltic sand. Photographer: Scott Johnson

Philinopsis speciosa was first reported from Hawaii. The original description of this species, the type of the genus Philinopsis, records the external features and the color:
"Colour above- fawn, spotted and speckled with white; margins more or less varied with blackish and yellow; sides paler. Foot purplish fawn, and closely freckled with whitish, and broadly margined on both sides with the dorsal colours intermixed."

From colour photographs now available, the colour description can be extended. The ground colour of the animal ranges from light translucent brown to an opaque dark brown or even black. There are a pair of yellow to orange-brown parallel lines on the headshield on either side of the midline, and sometimes traces of a second line on each side, further out, similar to those sometimes present in P. cyanea. The white spots range from quite small to very large, the large white markings being somewhat broken by brown speckling. The margin of the parapodia is colored with black, blue and orange-yellow markings, which can sometimes form lines. The foot appears to be of similar colour to the dorsal surface. The colour is extremely variable, and parts of the pattern can be absent in any specimen.

From an earlier investigation (Rudman, 1972a) I can say there are no anatomical features distinguishing P. speciosa from the widespread Philinopsis cyanea, a species which is widespread throughout the Indo-West Pacific and shows an identical range of colour variation. In that earlier study I did not know there was a black colour form and so accepted the prevailing view that P. speciosa was endemic to the Hawaiian Islands, a species with similarities in colour to the SE Pacific Philinopsis taronga and the NE Pacific species P. gigliolii.

It would appear that P. speciosa is a widespread Indo-West Pacific species which has been identified in most places as P. cyanea.  As  P. speciosa is the older name, and the type of the genus, it should replace the more commonly used P. cyanea.   

The position is probabl;y more complicated. I am not quite sure what we should do with Philinopsis depicta from the Mediterranean. I have long felt it was probably the same species as the Indo-West Pacific P. cyanea [or rather P. speciosa]. In fact the two photos on the P. depicta Fact Sheet are almost identical to the two colour forms of Philinopsis speciosa illustrated here from Hawaii.  There also appear to be no major anatomical differences. If we accept that P. depicta also occurs in the Caribbean [see messages #9570 , #14642], perhaps we have here a single species with a circumglobal distribution, like Hydatina physis and Micromelo undata?

• Pease, W.H. (1860)  Descriptions of new species of Mollusca from the Sandwich Islands. Proceedings of the Zoological Society of London 28, 18-36.
• Rudman,W.B. (1972a)  A comparative study of the genus Philinopsis Pease, 1860 (Aglajidae, Opisthobranchia). Pacific Science, 26: 381-399.
• Rudman,W.B. (1972b) Structure and functioning of the gut in the Bullomorpha (Opisthobranchia). Journal of Natural History, 6: 547-560.

Authorship details
Rudman, W.B., 2006 (February 3) Philinopsis speciosa Pease, 1860. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/philspec

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