3 NEW KARYOTYPES OF PRICKLY CHINCHILLAS O F THE FAMILY ECHIMYIDAE (RODENTIA)

For the first time, the karyotypes of three species of the family Echi myidae from two localities of Peru - Dactylomys dactylinus, Lonchothri x emiliae, Proechimys sp. are described. D. dactylinus has the highest diploid number in mammals - 2n = 94, NF = 144. The chromosomes includ e 25 pairs of meta- and submetacentrics and 22 pairs of acrocentrics. Heterochromatin is found in the centromeric regions in one pair of sub metacentric, 3 pairs of metacentrics and 19 pairs of acrocentrics. L. emiliae - 2n = 60, NF = 116. The chromosomes include 28 pairs of meta- and submetacentrics and 2 pairs of small acrocentrics. Constitutive h eterochromatin is confined in the centromeric regions of the majority of chromosomes Proechimys sp. - 2n = 34, NFa = 56. The autosomes compl ement includes one pair of large submetacentrics, 10 pairs of medium-s ized small metacentrics and submetacentrics, one pair of large subtelo centrics and four pairs of acrocentrics. The X-chromosome is a medium- sized acrocentric and the Y is a small acrocentric. Constitutive heter ochromatin is confined in the centromeric regions of 10 pairs autosome s. Comparison of the chromosomes stained by G-banding revealed the mai n reconstruction of chromosomes in the species studied that has greatl y changed the degree of homoeology.