Snail ID help please: Pyramidellids or Rissoids

fatoldsun · 03/19/2012, 10:25 PM

I have several of these small white (tan-ish) snails and I'm trying to ID them as Pyramidellids or Rissoids. I broke out the microscope and tried to take some pics as an article suggested that Pyramidellids (the evildoer of the 2) has heterostrophic shell coiling, they apparently have no operculum and the inner edge of their shell apertures have a "fold". Well I read and re-read the description of heterostrophic shell coiling and I don't get it so maybe someone can look at my pics and offer an opinion. Oh, for the record, I've seen these for well over a year. I have no clams and never seen them on a foot of any of my (invited) CUC snails. It seems that Pyramidellids will die out without a food source and Rissoids eat algae and detritus -so good bit my look at these pics points to Pyramidellids but if I'm correct what are they living on?

Ok here's a shot to show scale. This dish is maybe 2" in diameter...

Here's the operculum or lack of...

And the best shots I could get of the coiling

Thoughts?

fatoldsun · 03/20/2012, 08:53 AM

thought this was helpful for anyone following along - it was posted on my local club's site
Definitely look like Rissoid, this may help:

http://reefkeeping.com/issues/2008-02/nftt/index.php

03/19/2012, 10:25 PM	#1
fatoldsun Registered Member Join Date: Jan 2011 Posts: 449	Snail ID help please: Pyramidellids or Rissoids I have several of these small white (tan-ish) snails and I'm trying to ID them as Pyramidellids or Rissoids. I broke out the microscope and tried to take some pics as an article suggested that Pyramidellids (the evildoer of the 2) has heterostrophic shell coiling, they apparently have no operculum and the inner edge of their shell apertures have a "fold". Well I read and re-read the description of heterostrophic shell coiling and I don't get it so maybe someone can look at my pics and offer an opinion. Oh, for the record, I've seen these for well over a year. I have no clams and never seen them on a foot of any of my (invited) CUC snails. It seems that Pyramidellids will die out without a food source and Rissoids eat algae and detritus -so good bit my look at these pics points to Pyramidellids but if I'm correct what are they living on? Ok here's a shot to show scale. This dish is maybe 2" in diameter... Here's the operculum or lack of... And the best shots I could get of the coiling Thoughts?

03/20/2012, 08:53 AM	#2
fatoldsun Registered Member Join Date: Jan 2011 Posts: 449	thought this was helpful for anyone following along - it was posted on my local club's site Definitely look like Rissoid, this may help: http://reefkeeping.com/issues/2008-02/nftt/index.php