Chromosomal characterization and relationship between two new species of Ctenomys (Rodentia, Ctenomyidae) from Northern Córdoba province, Argentina

GIMENEZ, M. D.; BIDAU, C. J.; ARGUELLES, C. F.; CONTRERAS, J. R.

ZEITSCHRIFT FUR SAUGETIERKUNDE-INTERNATIONAL JOURNAL OF MAMMALIAN BIOLOGY

ELSEVIER

Lugar: Jena; Año: 1999 vol. 64 p. 91 - 106

0044-3468

Karyotypes of two recently described species of Ctenomys from northern Cordoba province (Argentina) were studied. C. osvaldoreigi is only known from the type locality in the high valleys of the Sierras Grandes at more than 2000 m above sea level. The karyotype consists of 2n = 52 chromosomes with FN = 56 and includes 22 pairs of telocentric autosomes that decrease gradually in size, a pair of subtelocentric autosomes (n degrees 8), two pairs of small metacentrics and a pair of sex chromosomes. Three populations from the northeastern plains of Cordoba province (including one from the type locality) of C. rosendopascuali were analyzed. All individuals were 2n = 52 but FNs of the three populations were different. Individuals from Los Mistoles showed FN = 62 and the karyotype consists of a large subtelocentric autosomal pair, a medium-sized subtelocentric (n degrees 8), twenty telocentric and three small metacentric pairs plus a pair of sex chromosomes. Candelaria specimens had FN = 64; the karyotype includes a second large subtelocentric pair which replaces a large telocentric, the remainder of the complement bring similar to Los Mistoles. A further large subtelocentric occurs in the Mar Chiquita population, thus FN = 66; the remainder of the karyotype does not differ from the two other populations In order to compare the new species to a known species of the same general geographical area, four populations of C. bergi from northwestern Cordoba were karyotyped. All specimens had 2n = 48, FN = 90. The: three karyotypes found in C. rosendopascuali are remarkably similar and obviously related to that of C. osvaldoreigi through relatively simple chromosomal rearrangements, which confirms their morphological and molecular proximity.