Nasal Cavity Entrance

This feature is of developmental interest because it relates to patterns of cranial base angulation (Shea, 1988,1993) as well as differential patterns of bone growth and associated drift (Enlow & Hans, 1996; D.E. Lieberman, 2000). The primitive condition is defined by a distinct step into the nasal floor from the posterior nasal clivus (= 0) as observed in Dryopithecus (Begun, 1994; Cameron, 1997a), Graecopithecus (de Bonis & Melentis, 1987; de Bonis et al., 1990; de Bonis & Koufos, 1993; Cameron, 1997a), the "anamensis group" (C.V. Ward et al., 2001), Praeanthropus (Strait et al., 1997; Strait & Grine, 2001), K. platyops (M.G. Leakey et al, 2001), the "garhi group" (Asfaw et al, 1999; Strait & Grine, 2001), H. habilis (Tobias, 1991; McCollum et al., 1993), Gorilla, and Pan. The intermediate condition (= 1) between states 0 and 2 is present in Australopithecus (McCollum et al., 1993). A smooth transition between the posterior clivus and the nasal floor with considerable overlap (= 2) is observed in Pongo (McCollum & Ward, 1997), species of Paranthropus (McCollum et al., 1993), and H. ergaster (Strait & Grine, 2001). Finally, H. sapiens alone is defined by a smooth entrance but with no overlap between the clivus and the palate (= 3) (see McCollum & Ward, 1997; Strait et al., 1997; Strait & Grine, 2001).

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