Fig. 1

Geographic distribution of Palaeognathae, showing color-coded species based on their geographical occurrence: Struthio (purple), Apteryx (green), Casuarius (blue), Dromaius (orange), Crypturellus (light green), and Rhea (pink). The dated species tree was obtained from [20]. Representative idiograms for the Z (light blue) and W (light red) sex chromosomes are provided, together with information on their C-banding (black) patterns (except for Apteryx). Data was retrieved from [25,26,27] and present data). A geological scale with key periods is depicted on the left (N = Neogene; P = Paleogene)