Comparison of morphological characters of skull between the blue sheep and the dwarf blue sheep
LIU Yande,ZHOU Caiquan,HUANG Chengsi,HU Jinchu
2007, 27(4):
376-379.
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The data on skull morphology of the blue sheep and the dwarf blue sheep were reported in this paper. The data involved the measurement and comparison of skull variables between two species. Measured characters include the following: length of the cheek tooth row,greatest inner length of the orbit,greatest mastoid breadth,least breadth between the orbits,zygomatic breadth,least height of the occipital region,greatest breadth of the occipital condyles,greatest neurocranium breadth,foramen infraorbital breadth (least distance), greatest palatal breadth,least breadth between the bases of the horn cores,least distance between the horn core tips,distance between the horn core tips,greatest tangential distance, horn core basal circumference, greastest (oro-aboral)diameter of the horn core base,least (dorso-basal) diameter of the horn core base,and length of the outer curvature of the horn core. Univariate analysis and discriminant analysis were applied to those measurements. The results indicated that: (1) Skulls of the 2 species were very similar in shape, but thedwarf blue sheep was thinner and narrower. The horn straight also faces on curls upwards,the horn base narrower,and the
older individuals healing together. Compared with the skull of dwarf blue sheep,that of the blue sheep is more spacious, the horn is thicker and longer,and separates more on both sides,has a longer curvature,the inside horn ridge is longer and shows an S-bend,a sharp angle towards the rear base of a wide angle,not merging. (2) The results of univariate analysis indicated: Of 18 measurements of skull morphology, the differences of greatest mastoid breadth, least breadth between the orbits,zygomatic readth,greatest neurocranium bread,greatest palatal breadth,horn core basal circumference, greasiest (oro -aboral ) diameter of the horn core base are extremely significant (P< 0.0 1 ); the differences of least height of the occipital region,greatest breadth of the occipital condyles,foramen infraorbital breadth (least distance),distance between the horn core tips, greatest tangential distance,and least (dorso-basal )diameter of the horn core base are significant (P < 0.05). The univariate analysis showed the accuracy rate of discrimination for the blue sheep was 100.0% and for the dwarf blue sheep was 83.3% . Cross validation is done only for those cases in the analysis. In cross validation,
each case is classified by the functions derived from all cases other than that case. The accuracy rate for the dwarf blue sheep was 83.3% , while for the blue sheep was 100% . The two horn distinctions function may distinguish the blue sheep from the
dwarf blue sheep.