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Sep 2, 2012 Discussion from Conch-L.

Eddy Wilmet:

"Last week I've been collecting Urosalpinx cinerea in the Oosterschelde-delta in the Netherlands where it's invasive, together with Ocinebrellus inornatus (which is almost a 200km expansion for this species to the North as normally its habitat is French-Brittany, Atlantic Coast). The presence of the Urosalpinx cinerea is overwhelming with large specimens over 25/30 mm. Can anyone give me some considerations about the growing rate of this species and maximum sizes of the American specimens."

Martin suggested:

"I happened upon this site - might be what you want."

http://www.sms.si.edu/irlspec/Urosalpinx_cinerea.htm

Paul Monfils reported:

"There are places in my locality where there are hundreds of Urosalpinx cinerea on the intertidal rocks, so I can be selective, picking out full grown mature specimens. These generally range from 26 to 28 mm, but occasionally larger. Interestingly, Abbott's American Seashells lists the size range of the species as 1/2 to 1 inch (13-25 mm)."

Harry Lee contributed:

"Dick Petit has reminded me that Urosalpinx cinerea form follyensis B. Baker, 1951 was applied to members of a giant population of the species occurring at Folly Creek, VA (Delmarva Peninsula, USA).

I was able to find its original description at http://www.biodiversitylibrary.org/item/34...age/95/mode/1up Note that the holotype measures 51.2 mm and is at the ANSP, quite possibly in the same drawer as that of Fusus cinereus Say, 1822.

My feeling is that the Baker taxon is likely an ecophenotype rather than being genetically isolated.

Beside this Baker (Bernadine Barker, or "Bunny," see http://www.biodiversitylibrary.org/item/34...age/64/mode/1up), there were three (3) others who have made contributions to our knowledge of western Atlantic marine mollusks according to Malacolog 4.1.1: Frank Collins (1867-1942); Horace Burrington, husband of Bunny, (1889-1971); and Patrick (living, well, and working in FL). Biographical data are drawn from 2,400 Years of Malacology (9th Edition) by Coan, Kabat, and Petit. 

Baker, B. B. 1951. Interesting shells from the Delmarva Peninsula. The Nautilus 64: 73-77, pl. 5. Jan."

Steve Rosenthal commented:

"Harry thanks for making that article accessible. i have been interested in that form for some time. would be interesting to know if they are still around there.

in the bicentennial summer of 1976 i lived in Chincoteague as part of an organized summer marine science program. we had an outing for some free beach time at Assateauge one afternoon, everybody hit the ocean
beach, i went to the bay to look for shells, of course. in Toms cove i found two large urosalpinx that appeared to be this form, a mere 36-38mm or so but I assumed it was the same named form. i went back there years later but couldn't find any though I doubt I relocated or even remembered the exact spot they came from.

that number of 51.2 mm is familiar, it appears in several references, including on hardy's http://gastropods.com/ website.

i am wondering if anybody on conch-l has found the large urosalpinx themselves?"

Dr. David Campbell, Visiting Professor Department of Natural Sciences Gardner-Webb University, provided some background:

"The Chincoteague area underwent appreciable rearrangement of the channels in the mid-1900's, so conditions that favored gigantism may have changed somewhat.

Gigantism may (probably among other options) reflect abundant food, extra-long life, or a failure to mature, so that the individual is still growing like a juvenile instead of putting lots of energy into reproduction. The latter may have several causes. In parasitic castration, the parasite feeds on gonads, which avoids killing their host but also may prevent any hormonal signals to start putting less energy into growth and more into reproduction. In species with seasonal cues for breeding, an individual living somewhere that doesn't get the right cue likewise may keep right on growing instead of reproducing. For example, warm-water marine larvae may disperse into places where the water temperature is fine for survival, but rarely or never reaches the temperature that tells the animal that it's time to breed. A particularly problematic situation of this sort comes from freshwater habitats downstream from dams. If the water is released from deep in the lake behind the dam, then it will be cool year round and may never get warm enough to cause the breeding season; if it comes from shallow in the lake it will, at least in summer, be hotter than the river's normal temperature, and if it's a dam that just turns the water on and off (e.g., hydroelectric to meet power demand), without regard for the downstream impacts, then the temperature, flow, oxygen, depth, and other features will vary irregularly."