#Keyhole Limpet Fossil
11 messages in this thread
A friend recently presented me with a fossil of two keyhole limpets, joined in
a foot-to-foot embrace. I have searched much and found nothing resembling a
Kama Sutra for limpets. I have never so much as caught a live limpet pair in
passionate embrace, so I am much puzzled by this specimen. It probably came
from the Santa Margarita formation, Upper Middle Miocene, and was found in San
Luis Obispo County, Calif.
The specimen is actually a cast, in chalcedony (week green fluorescence in SW),
with none of the original shell material evident. The surface sculpture of the
shells is well preserved, and even the keyhole is clearly visible. It measures
approx 350 mm in diameter and the combined elevation of the two almost equal
sized shells is about 250 mm. A chunk of siliceous shale matrix obscures a
part of the specimen.
Now if some paleontological types with a streak of prurience would like to see
this, I will make a photograph and convert it to a .GIF file and upload it.
And if anyone has knowledge of how limpets do it, please let us know!
Bill
Bill – is that really 350mm by 250mm? Those are some giant limpets! I have
looked through my marine invert books but haven't found a reference to mating
habits. I suspect that they do not move into a mirror image formation, as it
provides no anchor against buffeting currents. More likely they do it side by
side.
Michael (still looking)
Sorry Michael.. Got a little carried away there. 35 by 25 is more better.
My guess would be side by side, too. In fact, I can't imagine a limpet
loosening itself from it rock long enough, if at all, to manage a belly to
belly. But then, how did these two get together? I am photographing it and
will stick a .gif file in shortly. Bill
If the limpets were dead and the interior of their shells were mud filled, then
perhaps they simply adhered to each other. I have a Pecten with a limpet
attached from the Miocene. Interesting death assemblage too.
Michael
A better interpretation, I think, that molloscan conjugation. B.
However……I think you should explain the relative postions to anyone else as
fossilized sex. That is a much more intriguing subject for discussion.
<g>
Michael
Wait until you see the picture. It *is* intriguing!
Hi, Bill–
I figure like you guys that is an improbable position for living limpets to
assume. If you are minded to make more sure, you could try asking in the
biology section – someone there may know about habits of living limpets if not
ancient species.
–Doug
Doug..
The logistics of copulation of limpets is most unlikely to include releasing
themselves from their rock. Reading up on this disclosed that limpets not only
cling to the rock, but when hungry slip out of their berth and mosey about the
rock, but then go home when the mosey is over with. And no other limpets are
supposed to occupy that berth in the absence of its owner. Some little homing
instinct and territoriality here. Interesting.
My first foray into photographing and scanning (el cheapo hand scanner) gave
something I'm not proud enough of to upload. More effort ahead..
Bill
So what happens if a limpet steals a berth from another limpet while
it was just out for a quick stroll around the rock? A fight? Should
we alert ESPN? Maybe this is how your limpets got attached to each
other… 🙂
Were the photos you attempted of minerals? How did they come out
before scanning? A scanner with high resolution is certainly
desirable for this sort of thing – how does the one you used rate?
I was hoping to get something that would help you guys see those limpets in
action. <g>. But I've decided my scanner.. an old sheet fed Dest.. is not
worth the tin its made of. So I was on the phone to my connection to see if I
could manage something better, and I am on the trail of specs for a couple of
machines, the top B&W HP, and equal or worse Microteck (?). If the budget can
stand it, I will have a new scanner, flat bed this time, and with some kind of
decent resolution.. perhaps in a few days. THEN, we can peep at the limpets.
–Bill