Dr. Sérgio Ávila (MSc.)
Secção de Biologia Marinha
Departamento de Biologia
Universidade dos Açores
9500 Ponta Delgada
Portugal

Hello Marco:

Thank you for correcting my mistake. During the last 3 years I have been
compilling a database with the geographical distribution, bathymetry and
type of development of the Azorean marine molluscs (especially the shallow
ones, that is, less than 50m depth). I distinguish between a planktotrophic
type of development (that is a free swimming and feeding larva) and a
non-planktotrophic type of development (either lecithotrophic, with a free
swimming but not feeding larva, or direct development).
Actually, as you well said, ALL Trochids have a non-planktotrophic type of
development. They may stay for a few hours (G. magus stays for about
20hours) but do not feed during their pelagic phase (in the common sense of
active feeding).

My only doubt is that you stated that all Vetigastropods are
non-planktotrophics and I believe that Patella spp. are planktotrophs. Of
course I may be wrong, and in that case, I will correct my database. I
looked for the PDF files of the PhD thesis of D. L. Geiger where I think I
took this information, but I was not able to find them either in my
computer nor in the internet. Could you check this?

By the way, do you know the ancestral condition in the Rissoidae (p or
np-developers)?

Best wishes,

Sérgio