Sunday, November 27, 2016

Help with a mystery object?

Okay, this one is a true mystery.  We found this object while walking Dillon Beach on 25 November 2016:


Our best guess right now is that it's the periostracum (outer covering) from a large bivalve.  (It measured ~6.5 cm long by ~5 cm wide.) 

However, the material and its transparency seem different than other bivalve coverings that we've seen, so we're open to any other thoughts or suggestions.  The inner surface appeared to have a chalky white residue (perhaps from the middle shell layer of a clam?).

And even if it is the outer covering of a clam, we are uncertain about which species it's from.

Here's another view, this time from the side:


Let me know if you have any ideas about its identity.  I'm still working on it, but it would great to solve this mystery!

ADDENDUM (28 November 2016): Several people have suggested this could be the operculum ("trap-door") of a large snail, e.g., a whelk.  That's a strong possibility, and at this time I think I'm leaning that way.

ADDENDUM (1 December 2016): For the identity of this mystery object, see the post on 28 November 2016.

2 comments:

  1. Looks like a bleached out Velella.

    https://youtu.be/ZJGO_bSsR3w

    http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwi8wt3G5czQAhVC8mMKHUJtAqwQjRwIBw&url=http%3A%2F%2Fwww.cnn.com%2F2014%2F08%2F19%2Fus%2Fcalifornia-sea-creatures%2F&bvm=bv.139782543,d.cGw&psig=AFQjCNEI5_-9rZ-MVfnqtM4DovfT9noI7g&ust=1480468551581166

    Fun stuff. John W

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  2. Hi, John!

    Eric mentioned the similarity to Velella also, at least when the "mystery object" was dried out. See the next post from 28 November 2016 for the answer!

    Jackie

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