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 1 (continued) Families and species Zoogeographical ranking Zoological reg ions Families and species Zoogeographical ranking 1 2 3 4 5 34. Berylmys berdmorei (Blyth, 1851) • •:. + + + 35. B. bowersi (Anderson, 1879) IC. s. + + + + 36. Chiromyscus chiropus (Thomas, 1891) IC. P. + + 37. Chiropodomys gliroides (Blyth, 1856) IC. s. + + 38. Hapalomys delacouri Thomas, 1927 IC. + 39. Leopoldamys edwardsi (Thomas, 1882) IC. S. P. + + + + 40. L. sabanus Thomas, 1887 IC. s. + + + + 41. Maxomys moi (Rob. et KL, 1922) E. + + 42. M. surifer (Miller, 1902) IC. s. + + + 43. Micromys minutus Pallas, 1771 IC. P. + 44. Mus caroli Bonhote, 1902 IC. s. + + + + + 45. M. cervicolor Hodgson, 1845 IC. S. I. + + + + + 46. M. cooki Ryley, 1914 IC. + + 47. M. musculus Linnaeus, 1766 c. + + + + + 48. M. puhari Thomas, 1916 IC. P. + + + 49. Niviventer bukit (Bonhote, 1903) IC. s. + + + + + 50. N. confucianus (Milne-Edwards, 1871) IC. P. + 51. N. cremoviventer (Müller, 1900) IC. s. + + + + + 52. N. niviventer (Hodgson, 1836) IC. I. P. + + + + + 53. Rattus argentiventer (Rob. et KL, 1916) IC. s.w. + + + + 54. R. exulans (Peale, 1848) IC. s.w. + + + 55. R. flavipectus (Milne-Edwards, 1871) IC. + + + 56. R. germani Milne-Edwards, 1872 E. + 57. R. koratensis Kloss, 1919 IC. I. + + + + + 58. R. losea (Swinhoe, 1870) IC. s. + + + + 59. R. molliculus Rob. et Kl., 1922 IC. + + + + 60. R. nitidus (Hodgson, 184 5) IC. I.W. + + + 61. R. norvegicus (Berkenhout, 1789) c. + + + + 62. R. osgoodi Musser, 1985 E. + 63. Vandeleuria oleracea Bennett, 1832 IC. I. + + Signs and abbreviations IC.= Indo-Chinese subregion 1. North-East District S. = Sundan 2. North-West I. = Indian 3. North Truong Son P.= Palearctic 4. South Truong Son W. = Wallacean 5. Nam Bo E.= Endemism northern territories of Vietnam. In consequence of this in the middle zone of Vietnam we can find significantly more species of "mixed character". Here runs the southern boundary of the range for species of the north and on the contrary the northen limit of the range for species of the south. It is clear that the boundary between the two main groups of rodents runs through the middle of the territory of Vietnam, but on the other hand, we are not forced to draw the zoogeographical boundary at the same place. For settling this problem exactly we tried to use the quantitative analysis method according to JACCARD's (1902) formula. By using this method it was possible to draw the boundary not only on the level of geographical provinces, but on that one of very low districts, too. The values obtained for the similarity coefficients between the different territories of Vietnam are summarized in Table 2.