Marcelo "Cello" Dias is a former Soulfly bassist. He is one of the four original members of Soulfly. Dias mainly played bass for the first three albums before quitting the band in fall of 2003.
In addition to regular bass guitar on the first album, Dias played acoustic bass on "Soulfly", double bass on "First Commandment", and backing vocals on "Bumba" and "Umbabarauma". On Primitive, he played drums and percussion on "In Memory of...". On 3, he performed backing vocals and percussion on "One", sitar on "Tree of Pain", and keyboards on "Soulfly III".