Table 4.
Qualitative characters of the temporal bone (in alphabetical order) and their relationship to the multivariate analysis. The influence on principal components refers to the analysis of all hominoid taxa, and the signs are analogous to loading coefficients of eigenvectors. The morphocline of expression is derived from a consideration of all three principal components and summarizes the conditions for each taxon. This list of features is intended to facilitate comparison of this study to descriptive statements in the literature and is not exhaustive. All characters are expressions of shape, relative to the overall size of the temporal bone. Many of the characters are probably correlated.
| Influence on principal components | Morphocline of expression | |||||
|---|---|---|---|---|---|---|
| Character | PC1 | PC2 | PC3 | More | Less | |
| Entoglenoid process (and foramen ovale) posteriorly positioned | N | N | + | Pongo | Gorilla/Pan/Homo | |
| Entoglenoid process projection | + | – | – | Gorilla | Pongo/Pan | Homo |
| Entoglenoid process directed postero-inferiorly | – | N | N | Homo | Gorilla/Pongo/Pan | |
| External acoustic porus relatively large | – | N | + | Homo | Pongo/Pan | Gorilla |
| Mandibular fossa depth (and prominence of articular eminence) | – | – | N | Homo | Gorilla/Pongo | Pan |
| Mandibular fossa medially positioned relative to lateral wall of braincase | – | + | N | Homo/Pan | Gorilla/Pongo | |
| Mastoid process inferior projection | – | N | N | Homo | Gorilla/Pongo/Pan | |
| Mastoid process medially inflected | + | + | N | Pan | Gorilla/Pongo | Homo |
| Mastoid process anterior projection | + | N | + | Pongo | Gorilla/Pan | Homo |
| Petrous axis more coronally orientated | – | N | N | Homo | Gorilla/Pongo/Pan | |
| Postglenoid process size (inferior projection) | + | – | N | Gorilla/Pongo | Pan | Homo |
| Temporal bone mediolaterally narrow | – | N | N | Homo | Gorilla/Pongo/Pan | |
| Temporal bone anteroposteriorly compressed | + | N | + | Pongo | Gorilla/Pan | Homo |
| Temporomandibular joint (TMJ) size (relative to temporal bone as a whole) | + | – | N | Gorilla/Pongo | Homo /Pan | |
| TMJ shifted posterolaterally | N | N | + | Pongo | Gorilla/Pan/Homo | |
| TMJ articular surface extends anteriorly (preglenoid plane) | + | + | N | Pan | Gorilla/Pongo | Homo |
| Tympanic wider anteroposteriorly in parasagittal plane of carotid canal | N | + | N | Pan | Gorilla/Pongo/Homo | |
| Tympanic laterally projecting | + | N | – | Gorilla | Pongo/Pan | Homo |
| Tympanic depth (supero-inferior) | – | – | N | Homo | Gorilla/Pongo | Pan |
| Tympanic more sagittally orientated (axis from carotid canal to inferolateral point on tympanic) | – | N | + | Homo | Pongo | Gorilla/Pan |
| Tympanic and mastoid process more closely approximated | – | N | + | Homo | Pongo | Gorilla/Pan |
| Vertical thickness from mandibular fossa to supraglenoid surface | + | N | + | Pongo | Gorilla/Pan | Homo |
Key: +, positively correlated with PC; −, negatively correlated with PC; N, no impact on PC.