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Cranial Morphometrics
- Texas A&M University Press
- Chapter
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Study of the Arch Lake Site 30 Cranial Morphometrics ✦ o nly a limited cranial morphometric analysis was possible because of distortion during burial, as described elsewhere in this report. Measurements obtainable from Arch Lake are presented in table 5. Many of these are approximations, but ones in which there is considerable confidence. It is immediately evident from the values in table 5 that the Arch TAbLe 5. CrANiAL MeASureMeNTS FOr ArCh LAKe. Measurement Abbr. mm glabella-occipital length gol* (171) Basion-bregma height Bbh (136) Maximum cranial breadth xcb* 146 Biauricular breadth Aub* 120 Biasterionic breadth Asb* 116 Nasion-prosthion height Nph* 64 Alveolar breadth Mab 67 Alveolar length Mal 58 Orbit height Obh* (31) Orbit breadth Obb* (40) interorbital breadth Dkb* 20 inferior malar length iml 36 Maximum malar length xml 54 Cheek height wmh* 26 Frontal chord Frc* (102) Frontal subtense Frs* (20) Frontal fraction Frf (59) parietal chord pac* 113 parietal subtense pas* 30 parietal fraction paf 59 Occipital chord Occ 97 Occipital subtense Ocs 26 Occipital fraction Ocf 44 Nasion radius Nar (80) Bregma radius Brr (118) Lambda radius Lar 111 Opisthion radius Osr 45 *Measurements used to compare Arch Lake to seven other Paleoamerican crania: Spirit Cave, Wizards beach, Gordon Creek, horn Shelter No. 2 (male), browns valley, Pelican rapids, and buhl. 30 31 Lake cranium departs from other ancient American crania in that it is short and wide. The cranial index is 85.3, placing it in the brachycranic range. Thirteen of the measurements presented in table 5 (those marked with *) were used to compare the Arch Lake cranium to seven other Paleoamerican crania (Spirit Cave, Wizards Beach, Gordon Creek, Horn Shelter no. 2, Browns Valley, Pelican Rapids [Minnesota Woman], and Buhl). Buhl measurements were obtained from Green et al. (1998) and Herrmann et al. (2006); all others were measured in the Howells system as described in Jantz and Owsley (2001). Measurements included were those common to the comparative sample . Analysis was performed as described in Jantz and Owsley (2001), using twenty-four world samples from Howells and two additional native American samples (Blackfoot and Zuni). Figure 15 shows the samples displayed on the first three principal coordinates , accounting for 63.17% of sample variation. Table 6 gives the structure coefficients indicating the variables that contribute to the principal coordinate scores. Arch Lake has an extreme positive location on the first axis, which primarily reflects a short, wide vault. In this feature it is set off from most other Paleoamericans, which have longer, narrower crania. On PC 2, Arch Lake has a strong positive score, along with several other Paleoamerican specimens, including Pelican Rapids, Buhl, Gordon Creek, and the adult male from Horn Shelter no. 2. This axis reflects vault breadth, particularly at the base, without regard to length. Arch Lake and the other Paleoamerican crania are similar to several recent native Americans on this axis. Arch Lake has a low score on PC 3, which it shares with all other Paleoamerican specimens except Wizards Beach. This axis reflects face height and parietal length. Modern populations with low scores on this axis are Africans and Southwest Pacific populations, as opposed to native Americans, who have high scores. Table 7 presents Mahalanobis distances (D) of the early American fossils from each other, using the pooled covariance matrix from the modern groups as described in Jantz and Owsley (2001). These distances may be compared to a random expectation of the distance between two crania drawn at random from a single population with the specified covariance matrix (Defrise-Gussenhoven 1967). Arch Lake exceeds the random expectation for all crania except Gordon Creek, although the Horn Shelter no. 2 to Arch Lake distance is only marginally greater than the random expectation. Cranial Morphometrics [44.200.169.91] Project MUSE (2024-03-29 00:03 GMT) Study of the Arch Lake Site 32 Early American crania differ from modern native Americans in having large vaults (Jantz and Owsley 2005). Vault size can be evaluated by using the geometric mean of cranial length, breadth, and basion-bregma height. Table 8 presents summary statistics for vault sizes of Arch Lake, three other female Paleoamerican crania (Gordon Creek, Buhl, and Pelican Rapids), and five modern native American female samples. Arch Lake’s size falls completely outside the range of variation of all modern groups except for the Blackfeet, where Arch Lake is near the maximum for this group. Comparing Arch Lake to the other Paleoamericans reveals astonishing homogeneity. Arch Lake, Buhl, and...