I agree....It sounds like, in part, two species are being confused
here by the lab folks.

The 1st paragraph quoted above by John would fit Arctica islandica
pretty well, and the english vernacular name of that shell is "the
ocean quahog". The range fits (mostly; shells from California or
Oregon likely have anthropogenic origins).....and of course followers
of Conch-L have seen many posts about the studies documenting how
long-lived Arctica islandica is....essentially being the longest lived
animals known.

The shell in the photos looks to be the Southern Quahog,  Mercenaria
campechiensis, it does appear that its growth has been stunted.  That
species, including the large individual found and photographed, is
known for its tightly crowded concentric ridges which totally encircle
the shell (whereas they tend to fade out toward the middle in the
closely-related 'Northern Quahog", Mercenaria mercenaria).

Reading between the lines, these folks likely have taken the
research findings for the 'growth rings' in Arctica islandica, and
mistakenly applied them to Mercenaria,
which is not a valid analysis; even if they did realize they were
comparing molluscan apples and oranges it still isn't valid.

Perhaps there are some
studies out there that correlate the ridges to the age of Mercenaria
species?

On 3/4/23, John Jacobs <[log in to unmask]> wrote:
> "It is native to cold waters of the North Atlantic, spanning from North
> Carolina to Labrador, Iceland, the White Sea, Russia and Spain. Living
> animals have not been found outside its native range, but shells have been
> found on shores in California and Oregon."  Via the Smithsonian Institute.
>
> Quahogs (Mercenaria ssp.) are not uncommon in Florida.  I have my doubts
> about either the species ID or the veracity of the story.  It was supposedly
> found alive.  To me, the few pics of it from the article look like an
> abnormal Mercenaria clam.  The size given is not unusual since they can get
> quite large.  I did the measurement for the "WRS" Mercenaria found here in
> Florida.
>
> John
>
> John and Cheryl Jacobs
> COA 2024 Oral/Silent Auction Chairs
> Seffner, FL
> [log in to unmask]
>
> -----Original Message-----
> From: Conchologists List <[log in to unmask]> On Behalf Of Marcelo
> Vanin
> Sent: Saturday, March 4, 2023 7:59 AM
> To: [log in to unmask]
> Subject: [CONCH-L] Florida man finds giant clam estimated to be 214 years
> old
>
> I am curious to know the group’s thoughts about this shell find and
> article:
>
> A man in Florida was walking with his family on a beach when he found an
> abnormally large clam. It turns out, it was not only big, but extremely old
> – and dates back to 1809.
>
> Gulf Specimen Marine Lab, a research lab and aquarium, said Blaine Parker
> was on Alligator Point, a Florida beach on the Gulf of Mexico, when he found
> the quahog clam.
>
> Most of these clams are 2.8 to 4.3 inches, according to the lab, but
> Parker's was six inches and 2.6 pounds.
>
> Full article here:
> https://www.cbsnews.com/news/giant-clam-florida-214-years-old-alligator-point-gulf-of-mexico-abraham-lincoln/
>
> Happy shelling,
>
> Marcelo Vanin
>
> ----------------------------------------------------------------------
> [log in to unmask] - a forum for informal discussions on molluscs To
> leave this list, click on the following web link:
> http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1
> Type your email address and name in the appropriate box and click leave the
> list.
> ----------------------------------------------------------------------
>
> ----------------------------------------------------------------------
> [log in to unmask] - a forum for informal discussions on molluscs
> To leave this list, click on the following web link:
> http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1
> Type your email address and name in the appropriate box and
> click leave the list.
> ----------------------------------------------------------------------
>

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/scripts/wa-UGA.exe?SUBED1=conch-l-L&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------