Pathological ammonites

Nautilus deformation "black shell syndrome"

Good day all, a bit of information and more to come on the topic when I have my notes and images in front of me. The Nautilus seems to develop quite quickly in captivity this may be due a variety of factors. One of the many symptoms of captivity is the deformation of the shell "black shell syndrome.” I will post some images when I get the chance. These may be stress related due to water chemistry, lack of vertical migration (pressure change), food, light etc... The natural environment of the Nautilus is at mid depth on the reef shelf 200ft and below. Therefore, changes in shell development are to be expected but some of them are rather startling. The pathology report done at the National Zoo to one of the Nautilus which died a few years back as well as pathology on living specimens do not indicate infection or hosts as the result although there are host living opportunistically in the locality of the deformation. So the best guess is... environmental factors are at play causing abnormal shell development.

More to come

Regards

Carl


:grad:

PS:if you want to find a wonderful text, Treatise on Invertebrate Paleontology, which includes three volumes on Cephalopods (only two available) try these sites locations

http://www.ku.edu/~paleo/treatise.html

http://rock.geosociety.org/bookstore/default.asp?oID=0&catID=13&rslID=2

http://rock.geosociety.org/bookstore/default.asp?oID=0&catID=13&pID=TREK
 
Thanks Carl,

Do you know of any parasitic shell deformation in wild Nautilus shells? I seem to recall that Peter Ward broke some Nautilus shells just to see how they repaired themselves and what affect it had on their bouyancy, but I cant remember anything about parasites.

And thanks for the heads up on the treatise.
 
Nautilus shell reply

Thank you for the question and the reminder, I posted the mail from work and forgot to add the obvious. The American Museum of Natural History has a wonderful collection of Nautilus shells. Dr. Landman has permited me on occasion to examine these (no big deal really) and what we found was that in fact in the wild Nautilus do exhibit the shell deformation that is common or ever present in captivity. Though I am not sure about those kept at Palau (need to check on this). So it seems that this is a natural state for some reason for some Nautilus the big question is why. One of the things on my list of things to do is to check the collection at the Smithsonian, when I get the chance to breath, and see what they have.

As a side bar I think that the Spirula Spirula has been overlooked and I am trying to avocate a more intensive study of them, perhaps a good Phd. project for someone, I wish I had the time to do it! :bugout: hahahahaha

more later and pix to I promise

CjB

"freedom from tyrrany"
 
Looking closer at some of my fossils, I found this Eosyngastrioceras hesperium (Late Mississippian, Arnsbergian Stage) with a small pathology

Top Picture:
Lateral and ventral view, the pathology is on the right side of the ventral view


Lower Picture:
a closeup of the pathology
 

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Bite marks!

:madsci:


This is exciting, well sort of I suppose.

A quick note and I trust others will confirm my opinion, the "nick" or "grove" exhibited in the pic (previous post, good shot too) is that of a predatory bite. You can view such "blemishes" on modern day Nautilus shells, they are often attributed to Octopus bites (P.D. Ward etc...).

I know I promised some images on deformed Nautilus shell and I will. Although I loath excuses here is the current one, these pics live on my sons computer at home and I have had little time to log on in the evening due to travel and work at the Smithsonian. I will get these out as well as some additional images of the bite marks on Nautilus shells for comparison.

Regards

CjB
 
It looks like blemishes like that would be caused by damage to the shell producing part of the mantle, and not damage to the shell. Or is it both?

Another thing that I have wondered about are the small pits seen on the surface of the shell around the blemish. They are found on alot of the cephalopods I find in soft shale of the Chainman Formation. Could these be caused by sponges or something clinging to the shell on the sea floor? They seem to be all around the fossil, more dense in some areas.

Below is another fossil with the pits, Stenoglaphyrites merriami (Late Mississippian, Pendleian Stage).
 

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Not so boring

Sorry to say that I still have not had the chance to upload the images of the Nautilus perhaps this week. In the meantime the link below is a paper (Pseudoborings in Ammonite Molds: The Combined Result of Predation and Taphonomic-reworking ) that deals with certain aspects of the topic at hand, hope it answers some questions while creating others.

regards

CjB :heee:


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Nautilus deformities

Good day all, the attached photographs of Nautilus shells are from specimens that were kept at the National Zoological Park here in Washington DC. The keepers at the NZP have successfully kept Nautilus alive for many years now. This is not an easy task since they require specific temperature and water chemistry, as with most cephalopods this is critical, unlike many other cephalopods they are more long lived, 5 years is not an unusual occurrence. The shells in these photographs indicate the type of shell “blackening” associated with Nautilus in captivity, this is likely due to a variety of factors previously discussed. In addition, they also show the deformities in the shell development, specifically at the lip (as the shell develops this section is softer than the previous septum’s). To my knowledge, this has not been witnessed before in other specimens, kept or in the wild. It is my opinion that the shells developed this way due to a combination of factors, which include diet, the lack of the pressure gradient (they live at a much greater depth 300-1500ft) , water chemistry (Nautilus living in tanks with water closer to their environment exhibit less blackening which I believe is related to the deformations), stress, etc…

CjB

PS: this will appear as multiple posts to get all the pix uploaded to the site :sleeping:
 
Thanks for the pictures Carl.

Most of the nautiluses look like they have normal shell growth in the early stages. Are they raised from eggs at the aquarium, or are they shipped in? Does the malformation start after they are captured?

The nautilus in the last photo (Nautilus_8) is quite interesting, it looks like pieces of the shell were floating on the mantle and then stuck in place with new shell formation.
 
more on Nautilus shells

Actually there have been only a few instances world wide were Nautilus were raised from eggs to maturity, though none to my knowledge have ever been able to reproduce. Therefore generally speaking, Nautilus on display are young that have been captured and shipped world wide. Keep in mind that these are hardy animals since their normal range is 100 to 500 meters depth in what we should recognize is a very specific ecological niche off of a coral reef shelf. The shell deformation begins very soon after captivity and there is always a clear delineation on the shell of this event, if you look at the pictures you will notice this division point. The deformation continues and the apex of this manifestation is obviously as the Nautilus reaches maturity when septum development ceases. There is an actual "sloughing off" of shell and rebuilding going on at this point, it is a marked event of this process as you can see in pic #8. At times the delamination becomes quite intense, one thing that has been noted is there is opportunistic nematode infestation, whether this exacerbates the process is still not clear, but I believe as do others that it is not the cause but rather a side effect of the shell deformities. I still need to post the images of the beak bites on the Nautilus shell to compare to the earlier pics of the ammonite fossils. One more thing I would like to mention there seems to be more research done on Nautilus by paleobiologists than invertebrate zoologists, curious, more stuff to come...

CjB :grad:
 
Re: more on Nautilus shells

Carl J. Bobrow said:
One more thing I would like to mention there seems to be more research done on Nautilus by paleobiologists than invertebrate zoologists, curious,
Paleontologists rely on the comparative anatomy of living forms to see how extinct forms looked and lived. There are thousands of forms of fossil cephalopod shells, and only the Nautilus to compare them too. I dont know how they would have classified nautiloids and ammonoids if Nautilus and Spirula had went extinct.
 

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