![]() ![]() 1992 Kimbel & Rak, 1993 Lockwood & Tobias, 1999 Sherwood et al. Since then, qualitative studies of the temporal bone have resulted in detailed descriptions of this anatomical region, but comparisons among them are difficult because morphology can be portrayed or categorized differently by different authors ( Weidenreich, 1943, 1948 Le Gros Clark, 1947 Tobias, 1967, 1991 Clarke, 1977 Olson, 1981, 1985 White et al. Recognition of the value of temporal bone morphology in hominid systematics goes back to the first fossil hominid discoveries, and especially Weidenreich (1943), who characterized the distinctive, autapomorphic form of the Homo erectus temporal bone. Palaeoanthropologists have frequently examined the temporal bone for taxonomic and phylogenetic evidence. Moreover, it is often preserved in the hominid 1 fossil record. Its complex array of morphology is therefore relevant to several functional systems and dense with potential phylogenetic information. The temporal bone participates in forming the neurocranium, articulates with the mandible, houses the apparatus of hearing and balance, and is one surface of attachment for masticatory, neck and throat musculature. These and other characters shared by gorillas and orangutans are probably primitive for the African hominid clade. Gorillas and orangutans lack the extensive preglenoid surface of chimpanzees, and their mastoid processes are less medially inflected. Thus, the analysis contradicts depictions of African apes as a single morphotype. In phenetic cluster analyses, gorillas and orangutans group together with respect to chimpanzees, and all apes group together with respect to humans. Human characteristics such as a coronally orientated petrous axis, a deep mandibular fossa, a projecting mastoid process, and reduced lateral extension of the tympanic element strongly impact the analysis. Principal components analysis of residuals from the GPA shows that the major source of variation is between humans and apes. Generalized Procrustes analysis (GPA) is used to register (adjust for position, orientation and scale) landmark data from 405 adults representing Homo, Pan, Gorilla and Pongo. Twenty-three landmarks on the ectocranial surface of the temporal bone provide a high level of anatomical detail. In this study we use techniques of 3D geometric morphometrics to quantify differences among humans and great apes and discuss the results in a phylogenetic context. Its frequent preservation in the fossil record gives the temporal bone added significance in the study of human evolution, but its morphology has proven difficult to quantify. The hominid temporal bone offers a complex array of morphology that is linked to several different functional systems. ![]()
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