part of part of in taxon develops from develops from derived from ancestral fusion of derived from ancestral fusion of composed primarily of Archosauria tibia hindlimb skeleton tarsal bone bone tissue hindlimb bone tibiotarsus UBERON:0008194 Wikipedia:Tibiotarsus The tibiotarsus is the large bone between the femur and the tarsometatarsus in the leg of a bird. It is the fusion of the proximal part of the tarsus with the tibia. A similar structure also occurred in the Mesozoic Heterodontosauridae. These small ornithischian dinosaurs were unrelated to birds and the similarity of their pes bones is best explained by convergent evolution. tibiotarsus cartilage element tibiotarsus endochondral element