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Post by brunni on Sept 30, 2011 15:24:24 GMT
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boone
Achatina achatina
Posts: 54
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Post by boone on Sept 30, 2011 15:34:34 GMT
"skalarid" Archachatina (marginata (marginata))?  |
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Post by ness on Oct 2, 2011 21:07:43 GMT
"skalarid" Archachatina (marginata (marginata))? Sounds like a good guess. Not that I know, just sounds very plausable. It's a fascinating shell Brunni. |
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Post by brunni on Oct 3, 2011 13:52:58 GMT
Hi Boone.  Good guess !! but...... Its not an Archachatina marginata and I don't think its a scalariform mutation. See : www.molluscs.at/gastropoda/morphology/scalariform.htmlHere the coils become detached, they are not joined together at the suture and this gives the shell an elongate shape, longer than normal shells of that species. In some cases the coils are widely spaced giving the shell the appearance of a corkscrew : www.malacsoc.org.uk/the_Malacologist/BULL47/scalariform.htmIn all these cases the whorls themselves are ROUNDED and DETACHED. In my specimen the whorl is flattened on the top, then inward sloping on the sides ( so that the upper part of the whorl is wider at the top than the bottom ) and strongly sutured. Here's more detail.  Attachments:
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Post by brunni on Oct 6, 2011 9:00:20 GMT
Probably this shell has a defect in its early growth that has caused this CARINATED mutation. A similar abberation ( though not so extreme) is reported in a specimen of Bulimulus sporadicus (d’Orbigny, 1835) from Paraguay. Click this link then scroll down to " Unusual carination" www.ashbreure.nl/snailblog/files/tag-paraguay.html So question is still open - what species is it ? |
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coyote
Archachatina papyracea
Cochleas ego amo
Posts: 2,955
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Post by coyote on Oct 6, 2011 18:23:43 GMT
That was a fascinating article, brunni. I would not have thought that an injury during its juvenile stage would continue to manifest throughout the rest of the shell growth.
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Post by brunni on Oct 7, 2011 16:56:01 GMT
Indeed Coyote, if we take a closer look at the early whorls of this snail there is ( marked in my photo with a RED DOTTED LINE ) evidence of a severe trauma. After this incident growth continued abnormally. Quite remarkable actually that the animal could continue to survive, adapt and grow after this incident. The larger the shell grew, the more pronounced the abnormality became.  Attachments:
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coyote
Archachatina papyracea
Cochleas ego amo
Posts: 2,955
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Post by coyote on Oct 7, 2011 17:01:17 GMT
I would have thought that only genetics would determine shell growth patterns. But in a case like this, I would assume that any offspring of a snail such as this would not show any similar growth abnormalities without undergoing a trauma themselves.
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Post by brunni on Oct 8, 2011 16:35:28 GMT
The abnormal growth is not genetic, but can be traced directly back to severe damage in the baby snail. Why doesn't the animal fully recover after this incident to produce a regular shell ? It would seem that the organs that secrete and form the upper half of the shell are irreparably damaged. The similarity to the deformation caused by trauma to a snail shell reported from Paraguay is unmistakeable ( linked in my earlier tab ). Thanks to Bram Breure for his image of that specimen. Attachments:
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Post by brunni on Oct 12, 2011 8:59:11 GMT
Answer : I am an Achatina fulica, and I was found with other normal looking fulicas of similar size. As an infant my shell was damaged and after that it grew in a strange way for the rest of my life. I am a carinated fulica. |
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coyote
Archachatina papyracea
Cochleas ego amo
Posts: 2,955
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Post by coyote on Oct 13, 2011 6:09:23 GMT
Well, needless to say I would never have guessed it was a fulica. |
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Post by ness on Oct 14, 2011 23:32:30 GMT
Thanks Brunni, I've enjoyed this thread  |
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Post by brunni on Oct 16, 2011 6:11:14 GMT
Thanks Ness for your input. But I'm beginning to wonder if there's not a bit more to this ? 2 different species on 2 different continents, suffering a similar damage to the embryonic whorls, leading to the same kind of abnormal growth.............the chances would seem so remote !
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Post by brunni on Nov 21, 2011 21:33:37 GMT
Another reticulated fulica has turned up, very similar to the type of distortion I mentioned in the first specimen from the Cameroons, though this one is not quite so extreme. The shell is 95mm long and has been collected in the Philippines. Around the 4th whorl the shell's coils change from being rounded and smooth to rather angular with straight sides. The subsutural area becomes congested with wrinkled pleats.  It appears this animal also led a normal life after the incident. ;D |
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Post by SojMad on Nov 21, 2011 21:37:36 GMT
Very interesting! |
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Post by prowljazz on Nov 22, 2011 18:29:57 GMT
My Best Freind has a Living one.... Mr ScarFace....  |
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Post by ness on Nov 23, 2011 20:25:40 GMT
The ones in brunni's photos are quite extreme and striking, and I've not seen any personally like that, but I have had a few similar to the one in Prowljazz's photo, so perhaps they arre not that uncommon in the milder form.
I read somewhere of a scientist managing to induce a scalarid state by interfereing with the embryo. Not that I approve, but it was an interesting result.
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Post by brunni on Nov 28, 2011 18:53:01 GMT
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Good guess !! 
