Figure 2
The eyes of anthropoid primates are extremely diverse in shape and colouration. (a) Species represented in this panel are, from left to right, top row: Pygathrix nemaeus, Brachyteles arachnoides, Rhinopithecus roxellana, Rhinopithecus bieti, Hylobates pileatus, Colobus guereza; second row: Trachypithecus cristatus, Papio anubis, Mandrillus sphinx, Macaca fascicularis, Ateles belzebuth, Macaca fuscata; third row: Piliocolobus badius, Ateles hybridus, Colobus angolensis, Macaca mulatta, Cacajao calvus, Macaca fuscata; fourth row: Theropithecus gelada, Gorilla gorilla gorilla, Aotus lemurinus griseimembra, Sapajus apella, Macaca sylvanus, Trachypithecus geei; fifth row: Saguinus bicolor, Cebuella pygmaea, Cebus capucinus, Pithecia pithecia, Theropithecus gelada (infant), Alouatta seniculus. (b) Some species, like Macaca nigra represented here, boast traits for which we lack adaptive explanations, like the temporal wedge. 1: Sclera; 2: conjunctiva; 3: black rings around the iris; 4: temporal wedge; 5: iris. All photographs are reproduced under CC license. Hylobates pileatus by Rhett Butler; Theropithecus gelada, Gorilla gorilla gorilla, Theropithecus gelada (infant), and Macaca nigra by Mogens Trolle.
