Table 2.

Description of the positioning of landmarks on fowl and chicken skulls used for geometric morphometric analysis.

landmark no.	description	type of landmark after [24]
1	distal-most tip of upper jaw in the midline	2
2,3	anterior-ventral tip of the nasal pit	2
4,5	anterior tip of the dorsal nasal processes	2
6,7	medial tip of the posterior part of the nasal pit	2
8,9	posterior-most tip of dorsal premaxilla process	2
10,11	‘point where frontal goes to ventral’	2
12	middle point between 10 and 11 (crest)	3
13,14	posterior end of frontal	2
15	midline junction between frontal and parietal	1
16	midline junction between parietal and supraoccipital	1
17	posterior-most tip of cranium	2
18,19	tip of postorbital process	2
20,21	medial tip of ‘squamosal curvature’	2
22,23	lateral tip of the basitemporal	2
24	middle point of the dorsal foramen magnum	2