February 15, 2000
From: Don Barclay
After you suggested that I revisit the location that produced the first specimen of this bubble shell to look for a larger animal, I did as you suggested, only to find a Mitra species, Scabricola caerulea Reeve, 1844, that I have never found before. I didn't find another Bullina sp. (though I did find the little orange-speckled nudibranch I wrote you about), but the miter find was exciting, nevertheless. Most of my time and interest has been devoted to the Prosobranch gastropods, though I can tell a Flabellina from a Phyllidiella three out of four times...
Anyway, my snorkeling/diving buddy, Randy Hart, and I were scheming on what other locations in American Samoa might produce S. caerulea, and I suggested an area on the east side of Pago Pago Harbor, toward the back, which was similar to the original site with shallow water and coarse sand, in a place that was somewhat sheltered. We decided to try out this location last night, but didn't find any of the miters. However, I did find a second, and slightly larger, example of the red bubble shell.
This animal has the same pink coloration with a sprinkling of white which becomes denser around the shell, but the shell itself is slightly more inflated and the protoconch not so prominent. This shell measures approximately 9mm, which is two millimeters larger than the first specimen, and the animal's total length at maximum observed extension was 21mm. This shell also appears to be very thin, and doesn't show any inclination to thicken and become anything that looks very different in the short term. If the shell continued to expand as the animal grew at its current expansion rate, it would be quite a large bubble shell by the time it added one more whorl.
This animal was collected on 8 February 2000, at 0130 local time, crawling on coarse sand in a slightly silty area, in 50cm of water, 20 meters from shore and 100 meters southeast of the boat ramp in Aua village, back (east side) of Pago Pago Harbor, American Samoa. This was an hour before low (+0) tide, with a dark moon (new +3 days).
Thanks for the Pupa nitidula photos. They may have solved one of my mysteries, but they may have presented another (like, whether these small, slender, white to yellowish acteonids that I've been calling P. nitidula are actually another species). The one you posted is exactly like the ones I find in Tonga, but I don't find anything exactly like it in Samoa.
Pago Pago, American Samoa
Barclay, D., 2000 (Feb 15) Re: Red Bubble Shell from Samoa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1880
I'm glad your diligence resulted in a nice mitrid find. And thanks for the extra photos of the Red Bubble Shell - we now have a wonderful collection of live animal shots. I think it is a Bullina but will wait until I can look at the anatomy of the specimen you are sending. Perhaps you should send a few of the thin Pupa over as well so I can identify it for you.