modern snail looks like heteromorph ammonites

Discussion in 'Cephalopod Fossils' started by monty, May 28, 2009.

  1. monty

    monty Colossal Squid Staff Member Supporter

    Joined:
    Mar 8, 2004
    Messages:
    4,887
    Likes Received:
    11

    Attached Files:

  2. tonmo

    tonmo Titanites Staff Member Webmaster Moderator

    Joined:
    May 30, 2000
    Messages:
    8,739
    Likes Received:
    516
    Location:
    Pennsylvania
    Thanks Monty - nice find.
     
  3. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    too bad it doesnt have septa and a ventral siphuncle to further complicate its' life :wink:

    It certainly does look like Nipponites.
     
  4. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

    Joined:
    Sep 16, 2005
    Messages:
    4,891
    Likes Received:
    236
    Location:
    Pittsburgh, PA
    It's tiny, 1.5 mm high. Can you imagine searching for live snails that small? :bonk:
     
  5. hallucigenia

    hallucigenia O. bimaculoides Supporter

    Joined:
    Oct 19, 2006
    Messages:
    72
    Likes Received:
    1
    It looks stunningly like Nipponites! And the best part is that they're apparently always twisted the same ways -- it would be really interesting to watch their developmental trajectory and what it does to their ecological status. Might give some insight into the question "Why the hell did they get to be that shape?"
     
  6. Neale Monks

    Neale Monks Cuttlefish Registered

    Joined:
    Jun 29, 2003
    Messages:
    22
    Likes Received:
    0
    There are actually numerous gastropods that have uncoiled shells, most notably perhaps the infaunal, non-mobile Vermetid snails. These use long, whiskery threads to pull organic detritus and small prey into their shells for consumption. They're pretty common on reefs, and many people keeping marine aquaria will have seen their cobweb-like nets.

    The problem is that there's no obvious reason why what a Vermetid snail does tells us anything at all about heteromorphs. Yes, both have uncoiled shells, but heteromorphs retain neutral buoyancy throughout their evolution, and there's no sign at all that things like spetae and siphuncle become degenerate, as would be the case had they become non-mobile or even simply animals that crawled about rather than swum or floated.

    Cheers, Neale
     
  7. Jean

    Jean Colossal Squid Supporter

    Joined:
    Nov 19, 2002
    Messages:
    4,218
    Likes Received:
    138
    Location:
    Dunedin, New Zealand

    yes I had to do it this week for a mollusc lab on Wed!!!!! Not Vermetids but a teeny tiny bivalve called Modiolarca minutissima which gets o about 1.5 mm for a big one!!! So cross eyed :bonk: :bugout:, fortunately they like a common seaweed so at least I know where to look! Thank goodness for hand lenses! :grin:
     

Share This Page