snail ID

They may be Bothropoma species rather than Collonistas, but they're in the same family. Good algae eaters either way.

Cheers,


Don

 

Thank you. I'm happy I'm in the clear.

 

Any "ID handles" you can offer for differentiating the two genera?

 

Not particularly. Those genera +Homalopoma are almost exactly alike, and they're even in the same family and subfamily. Chances are pretty good that if you went through all the species of "Collonista" and used the same criteria for separating Homalopoma/Bothropoma/etc., you'd find that a lot of them would change genera. It's not a family that gets a ton of research and revision.


Don

 

Rather like Scorpaeniformes... ;-)

 

Yes, but probably even worse, lol. The most obscure fish families tend to get about a hundred times as much attention as tiny marine gastropod families. The only real tips I can give you is to tell you that about 90% or more of the tiny turbinid hitchhikers belong to one of two or three species. One of the most common and widespread Indo-Pacific species is Bothropoma pilulum (the ones in this thread might actually be juveniles of that species), and the other one that hitchhikes into tanks a lot is what we have been calling Collonista amakusaensis (except that a very similar shell is figured in one of my books as a Homalopoma species, and the holotype of C. amakusaensis doesn't look much like the shells figured in the popular literature as that species). To complicate matters a little, one researcher noted that shells being lumped under the C. amakusaensis name appear to be at least two different species, one that is heavily sculptured with a taller spire and one that has tiny grooves but is otherwise almost smooth, and has a lower spire. I might just start calling them all "colloniids" and dispense with the generic names.


Don