Re: More photos of Chromodoris cf regalis

October 12, 2007
From: Ray Simpson

Concerning message #20924:

Looking at Caribbean Sea Slugs (Valdes et al.), the adult specimen in the second message seems identical to Chromodoris regalis except for the yellowish background color. C. regalis is shown as having a salmon to orangish background color but this could be individual variation (the specimen pictured from the Gulf has some orange pigment near the center of the dorsum).

This species also matches C. regalis in having small white pustules or dots on the dorsum and a thin white mantle edge with visible white glands. The gills are also similar with no contrasting pigment present.

The other two specimens are definitely something interesting and possibly undescribed. The coloration is quite unlike anything else in the W. Atlantic. There are a few species that have no images available (most by Marcus so unfortunately no color info): C. aila from the Carolinas, C. dictya from Puerto Rico, C. perola from Colombia, and C. roseopicta from Bermuda. The latter seems interesting in that "roseopicta" means red or purple spots right?

Thanks
Ray

P51MustNB@aol.com

Simpson, R.G., 2007 (Oct 12) Re: More photos of Chromodoris cf regalis. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20942

Thanks Ray,

There is a photo on the Forum of what I am identifying as C. regalis, and it is the same species as the one in the book you refer to. These both fit the original description of this species, which includes a colour photo, in having rhinophores with large clubs which are translucent clear with orange edging to the lamellae. The gills of this species are unusual in that the basal half of the inside edge widens out so that the bottom half of the gills is triangular in cross-section. Usually in chromodorids, if one edge is going to widen like this it is the outer edge not ther inner edge. Like the rhinophores, the gills are translucent clear with orange edging.

The chromodorids are well -known for having groups of similarly coloured species living in the same geographic area, such as the red-spotted species of southeastern Australia or the blue species of the Mediterranean region. In some cases, such as the Noumea flava colour group, some species are so similar in colour that we really need to dissect individuals to be sure of their identification, which is not very practical for ecological studies.

With that in mind, the differences I can see in the adult animal in message #20924 are significant enough to flag it as possibly different. The rhinophores are long and tapering, quite different from the swollen club in typical C. regalis, and the colour - orange with a dark purplish tip, is also different. The gills are longer and simple and there is no sign of a widening on the inner edge. In colour they lack any sign of a coloured edge.

What it seems we have in the Caribbean is a group of species with orange or pink markings on the mantle and a yellow border. This group would include C. regalis, C. grahami, and the two? species I have under Chromodoris cf regalis. Species in such colour groups are usually quite easy to distinguish from their internal anatomy, but that is not a practical way to identify animals. I often feel I am overdoing things by contimually asking for photos of egg masses and food sponges etc, but often such observations can confirm potential differences which have suggested themselves from slight differences in colour patterns.

There is really nothing we can do with species that you mention were described with no information on the colour of the living animal.  

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Oct 12). Comment on Re: More photos of Chromodoris cf regalis by Ray Simpson. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20942

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