WHY IS IT NOT A "SHELL"

[diocrisseashells1000]

why is it that a brachiopods does not belong to the mollusk family? it has 2 valves, lives in the sea,looks the same as a bivalve,common name; a lampshell. so why is it not a shell? the chitons, the shell of a cuttlebone squid that belongs to cephalopods family,and even the class monoplachopora are belong to the group. can someone explain it in a simple seashell collectors mind like me, why is it, it doesnt belong to the mollusks family?  i have a piece of a lampshell,i wish i could post it but still im having problem on how to do it :-[ ....pardon me for that....i am just a simple collector. :'(... i hope there are people expert enough to explain the answer to my question. happy shelling   !

[dave r]

Hi there, I will try to answer your question even though I am no expert.
A Brachiopod shell is still a shell, the same as a sea urchin test can be called a shell. Many creatures live in what is called a shell besides Molluscs; turtles, crabs, lobsters, barnacles all have a 'shell'. The creature inside the Brachiopod shell is not a mollusc, there are very many anatomical differences that separate them. Gastropods, Bivalves, Chitons, Squid etc. all share a lot of anatomical characters that place them in the Phylum Mollusca together.
I hope this has helped.
Cheers,
Dave

[diocrisseashells1000]

thanks dave for your answer,but im still confused why not include it in the family of mollusk? there are still living brachiopods more than the the class monoplachopora. (correct me if im wrong). you can only see records of monoplachopora and never seen a live or collected shell of it nor anybody show a picture of one shell,as they say its "extinct".does the anatomy of a mollusk differs of  brachiopods will base the fact it cannot be included in the family? what about their characteristics?
i think scallops and lampshell both do the same kind of feeding and dwelling.

perhaps our scientist is so very intelligent ???, we cannot understand or question them on how they classify or group the living things in the ocean. ???  :-X
if they are out there?...... please,......can you explain it..... > >
thanks again dave and happy shelling

[dave r]

Sorry, I thought I had explained. I will try again.
Just because a creature has a shell does not make it a Mollusc, in fact many Molluscs do not have shells. It is the LIVING ANIMAL INSIDE that is the important thing. Bivalve Molluscs such as Scallops have a left and right hand shell valve, Brachiopods have a top and bottom, there is one way in which they differ. Also Brachiopods are totally sessile, they live attached to the substrate whereas most Scallops are free living and capable of moving around at will.
As I have said it is the living creature that determines what is a Mollusc, not the shell. Also extinction has nothing whatsoever to do with it. Monoplacophora are a very primitive form of molluscs but their anatomy determines them as molluscs, nothing else. Incidentally they are far from extinct just very hard to obtain as they are so small and live in abyssal depths. I have seen some for sale a few years back and was very unimpressed with them, tiny, boring things, but they were still hundreds of dollars each!
I hope this explains things a bit clearer.
Dave

[diocrisseashells1000]

thanks dave,very interesting answer  and now its getting clearer, i salute you ! i hope anytime we ask a question concerning seashells you are there to answer and to offer a very best  of your explanation 8)
perhaps next time i post a subject, there are photos included.
until then, happy shelling 8) 8)

[diocrisseashells1000]

hello there,
  ............. remember the brachiopods?  i got the photos, if you want to view it, here is the link.
i had to put this even tho its late..
 
<!-- m --><a class="postlink" href="http://www.flickr.com/photos/63645283@N06/sets/72157626936576151/">http://www.flickr.com/photos/63645283@N ... 936576151/</a><!-- m -->

[dave r]

That is the most colourful Brachiopod I have ever seen, very nice! If you look inside the shell you will see the internal structure is totally different to any Bivalve.
Thanks for the picture!
Dave

[diocrisseashells1000]

    MANY THANKS DAVE !!! the pleasure is mine