O. Gy. Dely szerk.: Vertebrata Hungarica 23. (Budapest, 1989)

Cao, van Sung: On the problem of zoogeographical division of the rodent fauna of Vietnam (Mammalia, Rodentia) 57-66. o.

Table 2. Similarity between the rodent faunas of the different zoogeographical districts of Vietnam Number of 1 2 3 4 5 the species 1 1 33 43. 0 62. 8 50. 0 37. 8 1 33 26 27 27 18 2 36 43. 0 52. 0 47. 3 25. 0 2 36 26 X 25 27 14 3 37 62. 8 52. 0 73. 4 54. 3 3 37 27 25 X 36 25 4 48 50. 0 47. 3 73. 4 57. 6 4 48 27 27 36 30 5 34 37. 8 25.0 54. 3 57. 6 5 34 18 14 25 30 In the numerator: similarity coefficient according to JACCARD In the denominator: the number of common species in the two compared territories 1. North-eastern district 2. North-western district 3. North Truong-son 4. South Truong-son 5. Nam Bo As it can be seen from Ta is quite sufficient for reaching crease of the similarity coeffici Truong-son (47. 3). It confirms Hái Van. 100 80 60 40 ble 2 the difference between Nam Bo and the other districts the level of a super-province. At the same time a sudden deent takes place between the Nort-western district and South the existence of a natural boundary running along the ridge © 0 ® © ® Va 80 60 40 20 0 % of similarity 20 0 For elucidating the mutual faunistical connections existing between the different districts, they will be shown by means of a dendrogram (Fig. 1). It can be seen from the dendrograms that a very significant divergence exists only on the level of the provinces. According to it Vietnam can be divided into two provinces; the northern province consists of North-eastern, North-western and North Truong-son district, the southern one has two districts - South Truong-son and Nam Bo. The boundary Fig. 1. Dendrogram of the correlations between the rodent-faunas of different zoological regions of Vietnam 1. = North-East region; 2. =North-West; 3.= North Truong son; 4.= South Truong 5. = Nam Bo son; % of similarity