Fig 1.
Locations of cephalometric landmarks used in this study and angles measured on the skull of a chimpanzee (Pan troglodytes; A) and modern human (Homo sapiens; B) in norma lateralis. (I) n-ba-pn angle. (II) n-ba-pr angle. See variable abbreviations in Table 1.
Table 1.
Cephalometric landmarks used in this study including their abbreviations and definitions.
Points are listed in alphabetical order for ease of reference.
Fig 2.
Comparison of nasal cavity length (ba-pn) to jaw protrusion (ba-pr) in chimpanzees (Pan troglodytes) and modern humans (Homo sapiens).
See variable abbreviations in Table 1.
Table 2.
Descriptive statistics for cranial base length (ba-n), nasal cavity length (ba-pn), and jaw protrusion (ba-pr) in mm for chimpanzees (Pan troglodytes) and modern humans (Homo sapiens).
Angles measured in degrees are also shown.
Fig 3.
Bivariate scatterplots showing regressions for a combined sample of chimpanzees (Pan troglodytes; ◇) and modern humans (Homo sapiens; ◆).
(A) Regression of nasal cavity length (ba-pn) on cranial base length (ba-n). (B) Regression of n-ba-pr angle on n-ba-pn angle. See variable abbreviations in Table 1.
Table 3.
Ordinary least squares linear regressions of nasal cavity length (ba-pn) against cranial base length (ba-n) and n-ba-pr angle against n-ba-pn angle in chimpanzees and modern humans.
Fig 4.
Average difference between observed and predicted values shown for the out-of-group tests performed on six separate species that are outside of the chimpanzee/human training sample.
(A) Differences for nasal cavity length (ba-pn). (B) Differences for n-ba-pn angle. Notice the influence of the phylogenetic position of each species relative to modern humans and chimpanzees, i.e., from Hominoidea to Cercopithecoidea, and how this leads to a progressive increase in approximation error.
Table 4.
Average differences between observed and predicted ba-pn length and n-ba-pn angle for subjects used in the out-of-group tests.
Subjects listed are grouped by species.
Fig 5.
Reduced major axis regression formulae applied in 3D approximations of the nasal region for out-of-group test subjects in norma lateralis.
(A) H. sapiens: Anonymous 29-year-old male subject. (B) P. troglodytes: PRI-7895, 3-years-old. (C) P. paniscus: S9655, 4-years-old. (D) G. gorilla: PRI-Oki, 54-years-old. (E) G. gorilla: PRI-7902, 3-years-old. Scale Bar = 10 cm.
Fig 6.
Reduced major axis regression formulae applied in 3D approximations of the nasal region for extinct hominids in norma lateralis.
(A) Australopithecus genus: Sts 5 (A. africanus) and MH1 (A. sediba). (B) Paranthropus genus: KNM-WT 17000 (P. aethiopicus) and OH5 (P. boisei). (C) Homo genus: KNM-ER 1813 (H. habilis), KNM-WT 15000, (H. ergaster / erectus), LES1 (H. naledi), Kabwe 1 (H. rhodesiensis/heidelbergensis), and Amud 1 (H. neaderthalensis/Neandertals). Scale Bar = 10 cm.
Fig 7.
Bivariate scatterplots with actual values for pronasale position in Pan paniscus (n = 1), Gorilla gorilla (n = 3), Pongo pygmaeus (n = 1), Pongo abelli (n = 1), Symphalangus syndactylus (n = 3), and Papio hamadryas (n = 3) superimposed over the chimpanzee/modern human regression lines.
(A) Regression of nasal cavity length (ba-pn) on cranial base length (ba-n). (B) Regression of n-ba-pr angle on n-ba-pn angle. See variable abbreviations in Table 1.