[Old Board Archive] Belemnites!


Staff member
Site Owner
May 30, 2000
What follows is another classic discussion from the "old" TONMO.com Message Board. Enjoy!

Hello everyone. This is my first post on your fascinating website. It's great to see an attractive and informative site with real scientific discussions open to us laymen!

I have a question about belemnites. I have found dozens of fragments of these fossil cephalopods in the Weald clay in Kent (UK) recently datable to about 100mya. I read in a book about invertebrate paleontology recently that a number of these fossils have been found in Tertiary deposits. Is this true, or are these remains redeposits from earlier contexts? I was always under the impression that belemnites became extinct along with ammonites at the end of the Cretaceous period so would be curious to hear your opinions. Unfortunately the book I was reading did not quote the source for the claim.


Re: Belemnites!|steve_oshea|
Hang in there Phil. Obviously you have an interest in the fossil side of things - an area that I know too little about to respond in detail. One thing that is very apparent, however, is that one day someone with more knowledge will log on and say 'wow', someone with similar interests, and respond accordingly.

It is something that I am very interested in, and accordingly will watch, but not an area that I can help out in yet.

If anyone wants to exchange some lovely fossil cephs for a set of giant squid beaks, or other interesting bits and pieces, then I'm very happy to make the offer. I'd love a jolly nice ammonite.

Re: Belemnites!|pikaia|
Hi Phil,Steve
there is this squid called spirula spirula that has an internal coiled shell that is said to be related to belemnites-there still not sure-(most say it is related to cuttle fish)or a very distant relative of the ammonites
I was unable to find any pics of this facinating ceph or very much info but i do know that the challenger expedition found a few in the Sargasso sea.
They are only about three inches in length half of which is tenticles.
there shell is located in the posterior end (away from the tenticles)wich makes this animal constanly in a verticle position.
It also has a bead like light organ on the end of its mantle
In the illustration i have of it it looks kind of like a flash light with tenticles
If any one else has any info on this i would be most obliged:smile:

Re: Belemnites!|phil_eyden|
Thankyou for that information, Serena. I've found one illustration of Spirula and I see exactly what you mean about the internal shell. It seems to take up the posterior third of the body. Apparently it is a loosely coiled phragmacone with a siphuncle running the inner wall of the coil. I must say it does seem to be an extremely archaic structure indeed. It seems that this creature is indeed classified as a squid although its ancestry is uncertain. If this little creature is indeed a squid it seems peculiar that it retains its chambered shell instead of generating ammonia ions to keep in afloat. I'll try and find out some more info.



Re: Belemnites!|steve_oshea|
You'll actually find a few pics of Spirula in TONMO's multimedia/photo gallery section. They're quite common - usually considered to be deep-sea, but the specimen in the photo gallery was actually taken at about 10 metres depth (over several thousand metres seafloor depth). Many of these deep-sea squid actually come very close to the surface at night (at least off New Zealand), and the same probably applies elsewhere.
Cheers, O

I've only just finished my article on 'A brief introduction to Ammonites' yesterday. I'll was thinking on compiling someting similar on belemnites next. I would not really want to jump the gun here until I have done some more research.

Watch this space, though it may not be for a few weeks.


Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.