Abstract
Bone-marrow karyotypes of 68 specimens of the subterranean octodontid rodent genus Ctenomys from 16 different populations of north east Argentina and one from Paraguay have been studied. A surprising variety of chromosome numbers was found, ranging from 2n=42 to 2n=70. Some of the karyomorphs are clearly assigned to named species by topotypy: C. conoveris 2n=50, FN=56; C. argentinus, 2n=44, FN=54; C. perrensi, 2n=50, FN=84; C. dorbignyi, 2n=70, FN=84; C. roigi, 2n=48, FN=80; C. yolandae, 2n=50, FN=78. Four populations of Corrientes Province similar in morphology to C. perrensi were found to be polymorphic and polytypic; they maintain the same FN=84, but diploid numbers increase from 2n=54 to 2n=58 from SW to the NE, thus suggesting Robertsonian rearrangements. In the middle of this cline, a stable karyomorph of 2n=62, FN=84 was found in two different populations, suggesting to belong to an undescribed species. Another karyomorph of 2n=42, FN=76 found in Curuzú Laurel, Corrientes, may also prove to represent another undescribed species. One karyomorph of 2n=52, FN=74, and another of 2n=56, FN=78 from Paraná and Ubajaý (Entre Ríos Province, Argentina) respectively are close to C. rionegrensis. The relationships among these karyomorphs is considered in light of data on sperm morphology. The hypothesis is advanced that karyotypic rearrangements among the FN=84 group may be the result of Robertsonian repatterning from a 2n=70 original widespread form. Fixation of chromosomal variants is correlated with patchy distribution and small size of unstable demes, and may or may not have resulted in reproductive isolation.
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References
Altuna, C. A. & Lessa, E. P., 1985. Penial Morphology in Uruguayan species of Ctenomys (Rodentia: Octodontidae). J. Mammalogy 66(3): 483–488.
Altuna C. A., Ubilla, M. & Lessa, E. P., 1985a. Estado actual del conocimiento de Ctenomys rionegrensis Langguth y Abella, 1970 (Rodentia, Octodontidae). Actas Jornadas de Zoologia del Uruguay: 8–9.
Altuna, C. A., Novello, A. F. & Lessa, E. P., 1985b. Notas sobre la morfología espermática de Ctenomys rionegrensis (Rodentia, Octodontidae) del Uruguay. Brenesia 24: 397–401.
Anderson, S., Yates, T. L. & Cook, J. A., 1987. Notes on Bolivian mammals 4: The genus Ctenomys (Rodentia, Ctenomyidae) in the eastern lowlands. Am. Mus. Novitates 2891: 1–20.
Contreras, J. R., 1988. Ctenomys roigi, Una nueva especie de ‘Anguyá Tutu’ de la Provincia de Corrientes, Argentina (Rodentia: Ctenomyidae). In: Centro de Estudios Almerianos, Diputación Provincial, ed., Homenaje a Antonio Cano Gea: 51–67. Almería, España.
Contreras, J. R. & Berry, L. M., 1982a. Ctenomys bonettoi, una nueva especie de tucu-tucu procedente de la Provincia del Chaco, República Argentina (Rodentia, Octodontidae) Historia Natural (Corrientes) 2: 165–173.
Contreras. J. R. & Berry, L. M., 1984. Una nueva especie del género Ctenomys procedente de la provincia de Santa Fé (Rodentia, Ctenomyidae). Resúmenes VII Jornadas Argentinas Zoología, Mar del Plata: 75.
Contreras, J. R. & de Contreras, A. N. Ch., 1984. Diagnosis preliminar de una nueva especie de ‘anguya-tutu’ (género Ctenomys) para la provincia de Corrientes, Argentina (Mammalia, Rodentia). Historia Natural (Corrientes) 4: 131–132.
Contreras, J. R. & Scolaro, J. A., 1986. Distribución y relaciones taxonómicas entre los cuatro núcleos geográficos disyuntos de Ctenomys dorbignyi en la Provincia de Corrientes, Argentina (Rodentia, Ctenomyidae). Historia Natural (Corrientes) 6 (3): 21–30.
Feito, R. & Gallardo, M., 1982. Sperm morphology of the Chilean species of Ctenomys (Octodontidae). J. Mammalogy 63: 658–651.
Freitas, T. R. O. & Lessa, E. P., 1984. Cytogenetics and morphology of Ctenomys torquatus (Rodentia, Octodontidae). J. Mammalogy 65: 637–642.
Freitas, T. R. O., Mattevi, M. S., Travi, V. H. & Moreira, D. M., 1984. Variacao cromosómica e distribuçao geográfica de duas especies do genero Ctenomys (Rodentia, Octodontidae). Resumos Reuniâo Anual Sociedad Brasileira Progresso Ciencias: 934.
Gallardo, M., 1979. Las especies Chileneas de Ctenomys (Rodentia, Octodontidae). I. Estabilidad Cariotípica. Arch Biol Med Exper, 12: 71–82.
Kiblisky, P., Brum-Zorrilla, N., Perez, G. & Saez, F. A., 1977. Variabilidad cromosómica entre diversas poblaciones uruguayas del roedor cavador del género Ctenomys (Rodentia, Octodontidae). Mendeliana 2: 85–93.
Langguth, A., 1976. Mamiferos. In: Mus. Nac. Hist. Nat. y Depart. Zool. Vert. Fac. Human. y Cienc., ed., Lista de las especies de vertebrados del Uruguay: 1–6. Montevideo, Uruguay.
Langguth, A. & Abella, A., 1970. Las especies uruguayas del género Ctenomys (Rodentia, Octodontidae). Comunicaciones Zoología Museo Historia Natural Montevideo 10(129): 1–20.
Langguth, A. & Anderson, S., 1980. Manual de identificación de los mamíferos del Uruguay, 10: 1–28. Montevideo, Universidad República, Facultad Humanidades y Ciencias.
Lessa, E. & Langguth, A., 1983. Ctenomys pearsoni, N. SP. (Rodentia, Octodontidae), del Uruguay. Resúmenes Comunicaciones Jornadas Ciencias Naturales, Montevideo 3: 86–88.
Levan, A., Fredga, K. & Sandberg, A. A., 1964. Nomenclature for centromeric position on chromosomes. Hereditas 52: 1–22.
Massarini, A., Barros, M. A., Ortells, M. O. & Reig, O. A. (in press). Evolutionary biology of fossorial Ctenomyine rodents. (Caviomorpha: Octodontidae). I. Chromosomal polymorphism and small karyotypic differentiation in Central Argentinian populations of tuco-tucos. Genetica.
Nevo, E., 1979. Adaptive convergence and divergence of subterranean mammals. Ann. Rev. Ecol. Syst. 10: 269–308.
Novello, A. F. & Lessa, E. P., 1986. G-band homology in two karyomorphs of the Ctenomys pearsoni complex (Rodentia: Octodontidae) of neotropical fossorial rodents. Z. Säugentierkunde 51: 378–380.
Reig, O. A., 1989. Karyotypic repatterning as a triggering factor in cases of explosive speciation. In: A. Fontdevila, ed., Evolutionary biology of transient, unstable populations: 246–289. Springer Verlag, Berlin, New York.
Reig, O. A. & Kiblisky, P., 1969. Chromosome multiformy in the genus Ctenomys (Rodentia, Octodontidae): A progress report. Chromosoma (Berlin) 28: 211–244.
Reig, O. A., Busch, C., Ortells, M. O. & Contreras, J. R., 1990. An overview of evolution, systematics, population biology and speciation in Ctenomys. In: E. Nevo & O. A. Reig eds., Biology of subterraneal mammals at the organismal and molecular levels: 71–96. Alan R. Liss, Inc., New York.
Reig, O. A., Olivo, N. & Kiblisky, P., 1971. The idiogram of the Venezuelan vole mouse, Akodon urichi venezuelensis Allen (Rodentia, Cricetidae). Cytogenetics 10: 99–114.
Rossi, M. S., Reig, O. A. & Zorzopulos, J., 1990. Evidence for rolling-circle replication in a major satellite DNA from the south american rodents of the genus Ctenomys. Mol. Biol. Evol. 7 (4): 340–350.
Vidal-Rioja, L., 1985. Chromosome polymorphism in Ctenomys talarum (Rodentia: Octodontidae) Caryologia 38: 169–178.
Vitullo, A., Roldán, E. R. S. & Merani, M. S., 1988. On the morphology of spermatozoa of Tuco-tucos, Ctenomys (Rodentia: Ctenomyidae): New data and its implications for the evolution of the genus. J. Zoology, London 215: 675–683.
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Ortells, M.O., Contreras, J.R. & Reig, O.A. New Ctenomys karyotypes (Rodentia, Octodontidae) from north-eastern Argentina and from Paraguay confirm the extreme chromosomal multiformity of the genus. Genetica 82, 189–201 (1990). https://doi.org/10.1007/BF00056362
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DOI: https://doi.org/10.1007/BF00056362