Description of cranial measurements.

<p>A skull of a lion is shown with diagrammatic representations of the 29 cranial measurements used in the morphometric analyses. The actual measurements are Euclidean distances between two points on the skull specimen and are not two-dimensional projections as depicted here. 1, <i>L</i>_SkT: total skull length (distance between inion and prosthion). 2, <i>L</i>_Face: face length (distance between prosthion and naso-frontal suture). 3, <i>W</i>_iof: distance between infraorbital foramina. 4, <i>W</i>_o: distance between orbits. 5, <i>W</i>_POC: width across postorbital constriction. 6, <i>W</i>_POP: width across postorbital processes. 7, <i>W</i>_BC: maximum braincase width (greatest distance between lateral margins of braincase). 8, <i>W</i>_sn: snout width (measured at level of snout mid-length). 9, <i>W</i>_C1s: width across the snout (measured between bases of upper canines [C1s]). 10, <i>W</i>_NA: nasal aperture width (measured at rostral projection of nasals). 11, <i>L</i>_N: nasal length (measured parasagittally between naso-frontal suture and dorsal margin of external narial opening). 12, <i>L</i>_NT: total nasal length (measured parasagittally as the distance between the naso-frontal suture and the anteriormost tip of the nasal). 13, <i>W</i>_MFS: width across the nasals (measured between the left and right maxillo-frontal sutures [MFS]). 14, <i>W</i>_IC1s: inter-canine width (measured between the upper canines). 15, <i>W</i>_I3s-I3s: width across the incisor arcade (measured between left and right third upper incisors [I3s]). 16, <i>L</i>_C1sP3s: length of upper ‘diastema’ (measured as the distance between C1s and upper third premolars [P3s]); although species that possess upper second premolars (P2s) do not show a diastema, we regarded their <i>L</i>_C1sP3s as the topological equivalent of the mandibular diastema. 17, <i>W</i>_Sk: maximum skull width across zygomatic arches. 18, <i>W</i>_P4s-P4s: palate width (measured between labial surfaces of upper fourth premolars [P4s]). 19, <i>W</i>_Pal: palate width (measured posterior to P4s and between lateral surfaces of maxillae). 20, <i>L</i>_Pal: palate length (measured parasagittally as the distance between the prosthion and the posterior extremity of the palatal surface). 21, <i>W</i>_PN: internal width of postnarial opening (measured as the distance between left and right pterygoid flanges). 22, <i>W</i>_PN.ant: internal width of anterior postnarial opening (measured immediately posterior to palate). 23, <i>W</i>_MP: width across mastoid processes. 24, <i>W</i>_PocP: width across paroccipital processes. 25, <i>W</i>_OC: occipital condyle width. 26, <i>H</i>_OC: occipital condyle height. 27, <i>W</i>_FM: internal width (transverse diameter) of foramen magnum. 28, <i>W</i>_FMV: ventral width of foramen magnum (distance between left and right occipital condyles). 29, <i>L</i>_P4s: length of superior fourth premolar or carnassial.