**2. Biomineralization by silica in electric fish**

Biomineralization by silica is a complicated process observed in living organisms. Of the intriguing topics that are receiving renewed attention, the study of biomineral formation based on organic templates is one of the most fascinating topics today (Ehrlich, 2010; Ehrlich *et al*., 2010). Biosilicification is an evolutionarily old and widespread type of biomineralization both in unicellular and multicellular organisms, including sponges, diatoms, radiolarians, choanoflagellates, and higher plants (Schroeder *et al*., 2008).

We have studied *Psammobatis extenta* electric organs from the Rajidae family, a group of elasmobranch electric fish. Electric organs are structures specialized in the production of electric discharges (Fessard, 1958). Their major cell components, called electrocytes, are highly polarized. We could detect biomineralization by microcrystalline silica in *P. extenta* electric organs (Prado Figueroa *et al*., 2008).
