part_of part of part of results in formation of results in formation of anatomical entity rhombomere formation rhombomere boundary formation biological_process GO:0021654 The process that gives rise to a rhombomere boundary. This process pertains to the initial formation of a boundary delimiting a rhombomere. Rhombomeres are transverse segments of the developing rhombencephalon that are lineage restricted, express different genes from one another, and adopt different developmental fates. Rhombomeres are numbered in anterior to posterior order. anatomical structure formation involved in morphogenesis formation of anatomical boundary rhombomere boundary