Geographic Correlates Of Morphological Variation In The Midday Gerbil Meriones Meridianus

114 midday gerbils Meriones meridianus were collected from 7 populations( YZ, MQ, DD, JT ,DS ,DJ, SG) in northwest of China during Apr.-Jul.2006 . Fifteen morphological parameters( body weight, length of body, length of tail, length of hind foot, length of ear; greatest length of skull, maxillary length of tooth row, length of auditory bulla, width of auditory bulla; heart, lung, kidney, liver, spleen dry mass were measured for every specimen.As to know the relation between the morphology ( body size, skull size, organ dry mass) of the midday gerbil and geographical factors (altitude, latitude, mean annual temperature). Spearman correlation analysis was used to test the relation between morphological parameters and altitude, latitude, longitude, mean annual temperature.The results showed that the body size, skull size, organ dry mass(except for spleen dry mass index) were positively correlated with altitude, were negatively correlated with mean annual temperature. The was no significant correlation between body size, skull size and latitude Heart and lung mass were positively correlated with latitude. The correlation between liver, kidney, spleen mass and latitude was not significant..Comparing the habitat where the midday gerbils live, we found that food intake, competition between species was correlated with the morphological trend in the whole region, food intake is a very important factor that effects thegeographical variation in morphology of animal.