palaeomorphic
/ˌpalɪə(ʊ)ˈmɔːfɪk/ /ˌpeɪlɪə(ʊ)ˈmɔːfɪk/adjective
Of, relating to, or representing an ancient form or type; (Biology ) designating an anatomical structure or feature that is of ancient origin phylogenetically.
Origin
1920s. From palaeo- + -morphic.