I've been doing research for the worldbuilding of my planet and I'm going back to design the details of the basic body plan for all creatures. I was interested on using something different than Earth's bone to have fun utilizing different properties, and I was wondering if a use of chitin and silica instead of collagen and hydroxyapatite would be viable and what limits or characteristics it would have?
The planet where these creatures live has 80% of Earth's gravity and a denser atmosphere. I'd love to be able to make large flying creatures if possible. If chitin with obvious extra proteins and silica end up being too brittle please suggest other possible combinations that you think would be interesting and viable? I would love to keep chitin as the matrix for its light and flexible properties but I'm still debating on the biomineral (I do not wish to use steel).