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Posted: Nov 13 2010

 Architectonica nobilis Röding, 1798, Common American Sundial

11/17/10 I posted the following inquirey on Conch-L:

"I’ve only found this shell in SE Florida. The Bailey-Matthews Museum lists one specimen from the Sanibel area. Has anyone found it in the Keys or Florida west coast?"

In response, the following locale information was provided:

Jim Brunner reported:

"We have two specimens in our collection (63.1, 57.3mm) that were dredged by scallop boats at 90-110 feet off Panama City, Florida."

A little later
Jim added:

"Linda informs me that I was remiss or at least incomplete in my previous response. We have 15-20 other A. nobilis of smaller size from 3 miles South of PC, FL."

Greg Curry Sr. reported more deep water finds:

"I have gotten them from shrimp boats off of Key West."

Tom Ball:

"Last month I purchased on eBay a lot of "Miscellaneous dredged shells" from 110 fathoms of water, west of Naples, Florida. There were two Architectonica nobilis in this lot."

José Leal explained about the record at the Bailey-Matthews:

"The BMSM "Sanibel" record was originally included in our database as part of a small self-collected collection donated by Dr. Ross Gundersen in the 1990s. The remarks field in the database indicates "Location data questionable." This single specimen was not included in the listing of SW Florida / Sanibel shells published by the Shell Museum in its website.

There are other, similar cases of doubtful locality data originating from the same collection."

Doug Shelton reported numerous records:

"I have numerous lots of Architectonica nobilis from N. W., Florida, Alabama, Mississippi, Louisiana, Texas and Mexico. It is a very common offshore species in the northern Gulf of Mexico and the western Gulf of Mexico. I also have Architectonica peracuta taken from off Alabama. I have seen specimens from off Louisiana and Texas."

Tom Watters:

I have specimens from Lake Worth and dredged off St. Augustine (Yocius).

Harry Lee took us off in a little different direction:

"(1) The Common American Sundial was taken, commonly, natch, in the Panhandle Scallop fishery.

(2) The American congener, to which you made reference, is A. karsteni Rutsch, 1934. It has an interesting story of its own. Originally known as a Neogene fossil in the Caribbean and Panamic deposits, it was "discovered" to have survived into the Recent by DeVries (1985). Actually he collected it but then found no less than 14 museum lots collected in places from the N end of the Sea of Cortez to Ecuador - all languishing in misidentified museum lots.sole


DeVries, T.J., 1985. Architectonica (Architectonica) karsteni (Rutsch, 1934) [sic; parens.]: A Neogene and Recent offshore contemporary of A. (Architectonica) nobilis Röding, 1798 (Gastropoda: Mesogastropoda). The Veliger 27(3): 282-290. Jan. 2."

David Kirsh puzzled:

"I'm a little confused here. Abbott (1974) has Architectonica nobilis and A. peracuta as the west Atlantic congeners. Both Abbott and Keen said A. nobilis is found in the Panamic region as well. (They distinguished A. peracuta from the Panamic A. placentalis).

Is A. karsteni now the recognized name for the Panamic cognate of A. nobilis? I found one at Catch 22 Beach, San Carlos, Sonora, Mexico."

Marlo commented"

"I know really very little about Architectonica. Harry brought up A. karsteni, which I’ve seen presented as a form (subspecies) of A. nobilis. All the treatment of A. peracuta I’ve seen was as a separate species. Maybe Harry or Rüdiger can elaborate on this."

Harry then added:

"Architectonica karsteni and A. nobilis go back a long way together and are clearly distinct species. For around 15 million years they coexisted on both sides of the present-day isthmus of Panama (which runs east-west despite our revisionist geographers' persistent intimations). However, the former seems to have died out in the Caribbean, and the also occurs in western Africa.

"Architectonica" peracuta (Dall, 1889) [= "A." discus (Philippi, 1844)] and "A." placentalis (Hinds, 1844) belong in Discotectonica Marwick, 1931.

Bieler, R., 1993. Architectonicidae of the Indo-Pacific (Mollusca: Gastropoda). G. Fisher, Stuttgart, pp. 1-377 incl. 286 figs., 3 pls."

Rudiger Bieler commented:

"I am currently traveling in Florida and do not have access to a copy of my 1993 Indo-Pacific Architectonicidae monograph where the three are mentioned (I can send scans of the pages later, if needed), but here it is in a nutshell:

A. nobilis occurs in both Atlantic and East Pacific.

A. karsteni has to my knowledge not yet been found in the Atlantic. The two species differ in sculpture and, apparently, ecology (depth ranges).

"Architectonica" peracuta is not a member of the same genus -- I synonymized Solarium acutum under Discotectonica discus in a 1985 paper in the Archiv fur Molluskenkunde.

Hope this helps."

In response to which
David asked:

" So, A. karsteni and A. nobilis both survived in the Panamic region?"

3/3/16, Rusty:  They're pretty rare on treasure coast I only found one and it was a very beaten up bleached one that I only figure from the distinct ridges that coils on underside of shell.

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