Questions tagged [molluscs]

For questions about members of the phylum Mollusca, a large monophyletic group of unsegmented bilaterally symmetric invertebrates. Major subgroups include gastropods (snails and slugs), cephalopods (e.g.s: squids and octopuses), and bivalves (e.g.s: clams, oysters, muscles). The study of these organisms is known as malacology.

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What is the name of this creature?

What is the name of this creature? It looks like either a crustacean or a conch.
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1 vote
0 answers
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What is this black worm-like creature with a yellow underbelly

This was found in the Malay Peninsula around noon. Unfortunately it was doused in hot water by my grandmother. Image below is after having been killed by hot water. It is about 1.5cm-ish long. It was ...
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Does the radula sac in any mollusc serve a purpose other than sheathing the radula?

According to Barne Gat Shellfish: When not feeding the radula is retracted into this chamber which protects the mouth from the sharp teeth of the radula. Does the radula sac serve any other purpose?
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What terrestrial Gastropod (specifically snails) has the fastest reproductive rate?

I am looking to do a series of experiments to test the adaptation of snails to different environments (Controlled environments in a lab setting. No organisms would be released into the wild under any ...
2 votes
1 answer
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What is this snail? (Location: Bangkok, Thailan; size: 3 cm long, 5 mm wide; color: mostly black)

What is this snail? (Location: Bangkok, Thailan; size: 3 cm long, 5 mm wide; color: mostly black) Video: https://youtu.be/vxig5QOSoss
4 votes
1 answer
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What kind of hot pink eggs are these? [duplicate]

I saw a dozen or more clusters of what I think are insect eggs attached to a few vertical sticks protruding from a small pond, and a few more to stalks of grass nearby. Location is in Hsinchu County, ...
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4 votes
1 answer
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What is this sea shell?

Found in Belgrade, possibly carried back from the Mediterranean or Aegean coast.
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3 votes
1 answer
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Is this some kind of parasite crawling about in my yard?

I've been living in Jamaica 25 years now and never seen something like this until recently they started popping up around my house at nights by the dozens. They appear to be blackish purple or maybe ...
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2 votes
1 answer
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Helix aspersa or Cornu aspersum

The common garden snail was originally assigned as Helix aspersa and stayed that way for over 200 years. Recently, some biologists assigned it to the genus or subgenus Cornu renaming it to Cornu ...
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1 answer
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How to define ammonites?

I miss the definition of ammonite. In my opinion, many authors confuse the term "Ammonite" and "Ammonoid". Ammonoids (Ammonoidea) are large group of cephalopods including for example goniatites (...
4 votes
2 answers
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What is this agglomeration of pink cells I found attached to a stone?

Photo taken in a garden in Singapore. The organism is attached to a stone, close to water. Many of these were there. Size approx 3cm. The shell of this eggs is very soft. When touched, a pink ...
5 votes
1 answer
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What's the relationship between snail movement and rain?

I have a question about the relationship between snail and rain. A few days ago I found snail shells in a moist area and I brought them in for crafts work (I thought they were empty because snail ...
3 votes
0 answers
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(Aquatic gastropod) Physae identification

I need help to identify a physa. What are the identification keys to make the difference between: physa fontinalis, physa marmorata , physa acuta (syn. Physella acuta) The difference ...
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3 votes
1 answer
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Sex determination in cephalopod?

I see some source say octopus do not have sex chromosome. So what's the sex determination mechanism for cephalopods?
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1 answer
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Why does the funnel-mantle locking apparatus exist, and how / why does it work?

I was looking up argonauts, and found this article. As someone who builds things for a living, I was intrigued, but could find no information on how it actually functions in order to help the ...
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What percentage of genome do slugs and scallops have in common?

We can know genetic distance of thousands of species. The OTT tree of life gives genetic distance for nearly all species. Is there a resource to compare the genomes of any sequenced animals to know ...
2 votes
2 answers
724 views

What is the relationship between snails/slugs and clams/mussels?

Slugs and clams are both phyla in mollusca, but how can I tell which features they inherited from an ancestor? Basically, I'm curious about how excatly these organisms are related but can't find any ...
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1 vote
1 answer
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Im trying to find out what type of snail this is

The snail is pretty large and located in texas.
2 votes
1 answer
396 views

Shell in garden snail

I was wondering that how does shell of garden snail "grows " with growth of snail. Small snail possess shell as its size but as it grows shell grows. How do they enlarge cavity inside shell?
7 votes
1 answer
179 views

Do cuttlefish know how to mimic animals since the moment they are born or do they learn by observing?

I can't seem to find information anywhere else so I hope somebody can help me out. So, as the question states, I saw a cuttlefish mimicking a hermit crab the other day and I was wondering if ...
4 votes
1 answer
556 views

Is this a variety of banana slug (Ariolimax columbianus)? (California)

These very dark (dark grey to black) banana slugs are an anomaly. I live on the north coast of California and see many slugs every day. These particular slugs I find only on the west-facing headlands ...
11 votes
1 answer
489 views

What species of snail is this?

I found it in Washington state, in a city south of Seattle. I found it next to a bush after it rained on someone's driveway. Here are two pictures of it: ( originally posted in instagram ) If anyone ...
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4 votes
2 answers
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Can an octopus survive if one of its three hearts stops working?

While reading the book "The Soul of an Octopus" by Sy Montgomery, I learnt that Octopuses have three hearts. This is very fascinating. According to a Wikipedia article, two of the three are used to ...
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3 votes
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Why might the chirality of gastopods be dominantly dextral?

This wikipedia page on gastropods provides a definition of chirality, and briefly describes the genetic mechanisms behind why a shell is wound left (sinistral) or right (dextral) handed. It also ...
34 votes
2 answers
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How long can an octopus survive out of the water?

I saw videos of octopuses crawling on the ground and I was wondering how long an octopus can survive when out of the water? Does it depend on either its size (i.e., does a big octopus from deep sea ...
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9 votes
1 answer
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Aquarium snail identification

Many of these little snails suddenly appeared in our aquarium from nowhere. I suspect that some snail eggs hitched a ride with some recently purchased plants. Can anyone identify the species? I am ...
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10 votes
1 answer
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What happened to this seashell?

We found this seashell on a Mediterranean beach in the south of France. While most of the shells we found were quite intact, this one caught our attention. It is light and littered with tiny holes, ...
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8 votes
2 answers
238 views

How do we know that ammonites are a kind of cephalopod rather than another type of mollusc?

On a recent fossil hunting trip, I found a small fossil that an expert identified for me as an ammonite beak. He told me such fossils are not uncommon, but are not normally found with their parent ...
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5 votes
2 answers
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Age of shells on beach

As a child I watched tiny fiddler crabs living in conical shells, and many years later I find that people study fossil turritellids. So now I wonder: how old are shells, typically, that you see on ...
8 votes
3 answers
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What determines the colors and patterns of a clam shell?

Earlier this week I was looking at some bivalve shells that had ornate patterns which ranged in color from a light orange-pink to a deep orange-red. Here is an image I found online that seems to be of ...
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