The operculum

Most snails, we are told, have an operculum. A flattened piece of hard material that acts like a door to the opening of the snail shell. While probably an effective barrier to predation, many land snails have abandoned the operculum. Instead, they seal their aperture with a mucous-based material called an epiphragm. In my opinion, the casting away of the operculum is probably the single biggest step towards being successful land invertebrates snails have taken since the evolution of the Pulmonata.

That's all I have to say about that right now - but an out loud thought I have regards extra space in the body whorl of operculates versus non. I suspect non-operculate snails have more extra space in their body whorl, but I don't have the data to back up that hypothesis. Anyone want to write a paper?

A little help?

I've got a snail that's proving hard to ID:



At first I thought it was Neohelix albolabris based on the size (it's 24mm wide) and shape/size of the reflected lip. But, its umbilicate, and Neohelix is not. So... any ideas? Burch's 1962 field guide hasn't helped me here. Perhaps it's an introduced spp? I posted an earlier pic because it has an interesting predation scar pattern.



I'm pretty sure this one is Mesodon given that it's about 2/3 the size of the first and the other characters do match with the description.

Beringia mollusks

Just came across an article - haven't read it beyond the abstract and a quick scan, but it's got some interesting info regarding Beringian mollusks. Primarily they suggest mollusks were introduced by migratory birds to the area. Hmmm...

LAURIOL, B., Cabana, Y., Cinq-Mars, J., Geurts, M.A., Grimm, F.W. 2002. Cliff-top eolian deposits and associated molluscan assemblages as indicators of Late Pleistocene and Holocene environments in Beringia. Quaternary International. 87, 59-79.

Reminds me of a previous post by Aydin regarding a book on a similar topic.

The Circus is in town!

Welcome to the 7th Circus of the Spineless!

We have all manner of posts for you, this month. With this handy dichotomous key, we can help you identify any post you might come across. Be sure to key out your specimen properly, or you might be surprised what "Inverteblogs" will appear.

1a. Post is not about Porifera ........................................ 2
1b. Post is about a sponge:
Circadiana (a.k.a. coturnix) with: sponges have circadian clocks?

2a. Blog is about an arthropod ...................................... 3
2b. Blog deals with a mollusk ........................................ 8
2c. Blog is about an echinoderm:
Medlar Comfits regales us with: Breakers Laundry

3a. Blog deals with Chelicerata ..................................... 4
3b. Blog caontains Lepidoptera ..................................... 5
3c. Blog deals with Diptera ........................................... 6
3c. Blog deals with Coleoptera .......................................7
3d. Blog deals with an insect that looks like another:
Bev provides the audience with: Insect Imposters

4a. Post is about a big spider in New Zealand:
White Tail Spider thanks to Pete
4b. Post is about a smaller spider in the northern hemisphere:
Bev with Spider Ranch

5a. Post is about moths and light pollution:
Rigor Vitae presents a Moth in the night sky
5b. Subject of post looks like a carpet:
Cindy brings us Scaled Wings
5c. Blog has picture of moth just sitting there:
Ben has a picture of A moth hanging upside down.
5d. Moth is in florida:
thingfish23 finds out that Sometimes they come back

6a. Blog discusses halteres:
Budak tells us A tale of two-pteras
6b. Post is about insects eating insects:
Ben has a picture of A light snack?
6c. Perhaps the most disturbing post in the circus:
Thoughts from Kansas forces us to confront Sometheing we don't want to have - ever.

7a. Post gets inspiration from the ancient Egyptians:
Medlar Comfits praises Dung Beetles.

8a. Mollusk has a really funky shell:
Aydin found a Frankensnail.
8b. Mollusk has been attacked, sometimes repeatedly:
Pascal found evidence of Snail predation.
8c. Last but not least:
tai haku has pictures of Colorful Squid

Apologies that this is a little late - I got lots of good posts. Hope you enjoy them as much as I did.

COTS right here!

I'm extending the deadline for the Circus - Blog Carnival has it listed a little later, so please get things to me ASAP, but if you're a little after 4pm - no biggie!

Reminder

Submissions for COTS #7 will be due on the 30th at 4pm. Don't be shy - send me a link!

capn.pituitary AT gmail.com

or, place a comment on one of my COTS threads.

See you here on the 31st!