Monday, July 10, 2023

Meet Marsenina!

 
A fun view of an often overlooked snail — meet Marsenina rhombica!

With a large mantle that almost completely envelops the shell, this snail can be mistaken for a nudibranch.  But note the tentacles, the lack of rhinophores, the inhalant siphon (a short tube visible between the tentacles), and that you can see some of the shell at the top of the mantle (the part that looks white and shiny).
 
Marsenina has adaptive colorationthey are often associated with compound ascidians (colonial sea squirts), but when they're on the sea squirts, they almost disappear!
 
If you're curious about the shell, here's a scan of one I found years ago (see below).  The shell is very thin and shaped like a small abalone with a flattened spire and a very large body whorl:

 
P.S.  Many thanks to Caroline for spotting this snail and for Eric for scanning the shell!

2 comments:

  1. All of your posts are so fascinating and you are such an excellent photographer, I read them every day. Thank you! I especially enjoy learning about new critters, like this one. Recently here on the Olympic Peninsula we had -3.6 tides, and I found a tiny new snail with a proboscis: www.inaturalist.org/observations/171149988

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  2. Hi, Wendy!

    Thanks so much! Wow, -3.6' tides! The best we get down in Bodega Bay is about -2.0'.

    Nice Alia that you found! Finding out that Alia sometimes feeds on the embryos of other snails was one of the more shocking things I observed last year:

    https://bodegahead.blogspot.com/2022/07/the-dove-snail-attacks.html

    Keep an eye on them! Maybe you'll see what they're feeding on up there!

    :) Jackie

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