Advertisement

Genetica

, Volume 82, Issue 3, pp 189–201 | Cite as

New Ctenomys karyotypes (Rodentia, Octodontidae) from north-eastern Argentina and from Paraguay confirm the extreme chromosomal multiformity of the genus

  • M. O. Ortells
  • J. R. Contreras
  • O. A. Reig
Article

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.

Keywords

Chromosome Number Reproductive Isolation Patchy Distribution Diploid Number Sperm Morphology 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Altuna, C. A. & Lessa, E. P., 1985. Penial Morphology in Uruguayan species of Ctenomys (Rodentia: Octodontidae). J. Mammalogy 66(3): 483–488.Google Scholar
  2. 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.Google Scholar
  3. 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.Google Scholar
  4. 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.Google Scholar
  5. 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.Google Scholar
  6. 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.Google Scholar
  7. 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.Google Scholar
  8. 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.Google Scholar
  9. 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.Google Scholar
  10. Feito, R. & Gallardo, M., 1982. Sperm morphology of the Chilean species of Ctenomys (Octodontidae). J. Mammalogy 63: 658–651.Google Scholar
  11. Freitas, T. R. O. & Lessa, E. P., 1984. Cytogenetics and morphology of Ctenomys torquatus (Rodentia, Octodontidae). J. Mammalogy 65: 637–642.Google Scholar
  12. 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.Google Scholar
  13. Gallardo, M., 1979. Las especies Chileneas de Ctenomys (Rodentia, Octodontidae). I. Estabilidad Cariotípica. Arch Biol Med Exper, 12: 71–82.Google Scholar
  14. 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.Google Scholar
  15. 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.Google Scholar
  16. Langguth, A. & Abella, A., 1970. Las especies uruguayas del género Ctenomys (Rodentia, Octodontidae). Comunicaciones Zoología Museo Historia Natural Montevideo 10(129): 1–20.Google Scholar
  17. Langguth, A. & Anderson, S., 1980. Manual de identificación de los mamíferos del Uruguay, 10: 1–28. Montevideo, Universidad República, Facultad Humanidades y Ciencias.Google Scholar
  18. Lessa, E. & Langguth, A., 1983. Ctenomys pearsoni, N. SP. (Rodentia, Octodontidae), del Uruguay. Resúmenes Comunicaciones Jornadas Ciencias Naturales, Montevideo 3: 86–88.Google Scholar
  19. Levan, A., Fredga, K. & Sandberg, A. A., 1964. Nomenclature for centromeric position on chromosomes. Hereditas 52: 1–22.Google Scholar
  20. 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.Google Scholar
  21. Nevo, E., 1979. Adaptive convergence and divergence of subterranean mammals. Ann. Rev. Ecol. Syst. 10: 269–308.Google Scholar
  22. 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.Google Scholar
  23. 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.Google Scholar
  24. Reig, O. A. & Kiblisky, P., 1969. Chromosome multiformy in the genus Ctenomys (Rodentia, Octodontidae): A progress report. Chromosoma (Berlin) 28: 211–244.Google Scholar
  25. 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.Google Scholar
  26. 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.Google Scholar
  27. 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.Google Scholar
  28. Vidal-Rioja, L., 1985. Chromosome polymorphism in Ctenomys talarum (Rodentia: Octodontidae) Caryologia 38: 169–178.Google Scholar
  29. 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.Google Scholar

Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • M. O. Ortells
    • 1
    • 2
  • J. R. Contreras
    • 1
    • 2
  • O. A. Reig
    • 1
    • 2
  1. 1.GIBE, Departamento de Ciencias Biológicas FCEyNUniversidad de Buenos AiresNuñezArgentina
  2. 2.Centro Argentino de Primates (CAPRIM-CONICET)CorrientesArgentina

Personalised recommendations