Dear Sérgio

I would be surprised spotting a planktotrophic trochid larva.
Actually, Gibula magus has a lecithotrophic development, as ALL trochids
have (for what I know).

A planktotrophic larval phase has been developed independently by
neritimorphs (Nerita and allied) and caenogastropods (cowries and allied),
and (still independently?) in the heterobranchs (nudibranchs and allied).

The vetigastropods (the group of archaeo to which trochids belong) did not
- and still do not - know the way to develop a planktotrophic veliger.

From an evolutionary point of view, the difference between .. let's say a
Mitra with lecithotrophic development and a Gibbula is that the Mitra
derives CERTAINLY from and ancestor with a planktotrophic development
whilst all ancestors of the Gibbula were lecithotrophic.

cheers


=========================================================
Marco Oliverio - Evolutionary Biology PhD
Research Scientist

Dipartimento di Biologia Animale e dell'Uomo
Viale dell'Universita' 32
I-00185 Roma   ITALY

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