Many of the major locomotor transitions during the evolution of Archosauria. the lineage including crocodiles and birds as well as extinct Dinosauria. were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and function in several lineages. https://atlanticknifers.shop/product-category/fixed-blade-closeout/