Palatine fenestrae, the orangutan and hominoid evolution

Abstract

Although most mammals develop relatively large double anterior palatine fenestrae that patently communicate with the nasal cavity, four extant primates—Homo sapiens, Pongo, Pan andGorilla—do not. While these four have closed-down these foramenal structures,Homo sapiens andPongo are unique in forming a single foramen palatally. Among fossil taxa,Homo, Australopithecus, Sivapithecus (=Ramapithecus) andRudapithecus also develop a single foramen palatally. Dryopithecines, the presumed fossil apes, preserve the two patent fenestrae. In light of dental features that are considered diagnostically “hominid,” which are also found in the orangutan, it is suggested that this “ape,” rather thanPan, is phylogenetically closer toHomo.