This is a chord distance from nasospinale to prosthion, so it is not a measure of subnasal prognathism. Subnasal prognathism is measured in character 49. Subnasal length is defined as an index against orbital height. The mean extant hominid value for this index is 0.72, with 1 standard deviation of 0.13. Thus, an intermediate range is defined by values falling between 0.59 and 0.85. Data for fossil hominins has been taken from B.A. Wood (1991), while all other values have been constructed from unpublished data collective by DWC, unless otherwise specified.
A short clivus (= 0) is observed in H. sapiens with a mean index of 0.53 (n = 8). Intermediate clivus length (= 1) is observed in Graecopithecus specimen XIR-1 (original) with an index of 0.87, H. habilis specimen OH 24 with an index of 0.81, Pongo with a mean index of 0.68 (n = 22), Gorilla with a mean index of 0.73 (n = 35), and Pan also with a mean index of 0.73 (n = 66). While no data are available for Sahelanthropus, the subnasal is described as short (Brunet et al., 2002). A relatively long clivus (= 2) is observed in Australopithecus with a mean index of 0.93 (n = 2), P walkeri specimen (cast) KNM-WT 17000 with an index of 0.95, P boi-sei with a mean index of 1.02 (n = 2), P robustus specimen SK 48, also with an index of 0.93, K. rudolefensis as represented by specimen KNM-ER 1470 with an index of 1.03, and H. ergaster specimen KNM-ER 3733 with an index of 1.00. While no data is available for either Praeanthropus or the "garhi group," the sub-nasal region is said to be even longer than that observed in Australopithecus (Rak, 1983; Asfaw et al., 1999).
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