Mammalian Biology

, Volume 67, Issue 2, pp 105–112 | Cite as

The systematics of Aconaemys (Rodentia, Octodontidae) and the distribution of A. sagei in Chile

  • M. H. GallardoEmail author
  • F. Mondaca
Original investigation


The systematic relationships among populations of fossorial Aconaemys species (Rodentia, Octodontidae) were assessed using chromosome variation patterns. Cytogenetic data was used since classical taxonomic studies have yielded contradictory results due to the environmentally induced morphological variation observed in these fossorial rodents. The interpopulational karyotypic stability and lack of intrapopulational polymorphism observed in Aconaemys make chromosome data a good predictor of specific differentiation. A distinct karyotype differing in diploid and number of chromosomal arms (FN) was found at each type locality. This kind and degree of karyotypic differentiation together with molecular data indicate that three species of Aconaemys can be recognized: A. sagei (2 n = 54, FN = 104), A. fuscus (2 n = 56, FN = 108), and A. porteri (2 n = 58, FN = 112). Five populations on the western slope of the Andes (Chile: Nahuelbuta, Tolhuaca, Rio Colorado, Pedregoso, Reigolil, and Huerquehue), formerly ascribed as A. fuscus shared the same karyotype of A sagei from the type locality on the eastern slope of the Andes (Argentina: Pampa Hui-Hui). Thus, karyotypic data let us ascribe these disjunct populations to A. sagei. The classical morpho-species in Aconaemys, altered into the biological species based on chromosomal and molecular differentiation, indicates that all three species occur in Chile. After this survey, the range of A sagei is extended to the northwestern slope of the Andes by more than 300 km.


Aconaemys Octodontidae Chile karyotypes systematics 

Systematik der Gattung Aconaemys (Rodentia, Octodontidae) und Verbreitung von A. sagei in Chile


Die systematischen Beziehungen von Populationen unterirdisch Lebender Aconaemys-Arter (Rodentia, Octodontidae) wurden an Hand chromosomaler Vaniationsmuster untersucht. Die zytoge-netischen Techniken wurden eingesetzt, da klassische taxonomische Studien bisher aufgrund umweltbedingter morphologischer Variation widersprüchliche Ergebnisse geliefert hatten. Die karyotypische Stabilität und das Fehlen eines Polymorphismus innerhalb der Populationen von Aconaemys sprechen für eine diffenentialdiagnostische Brauchbarkeit der Chromosomenvariation für die Unterscheidung von Arten. Für jeden lokalen Typus ergaben sich deutlich unterschiedliche Karyotypen sowohl hinsichtlich der diploiden Chromosomenzahl als auch hinsichtlich der Zahl der Chromosomenarme (FN). Nach der karyotypischen und molekularen Differenzierung ergeben sich drei Arten für die Gattung Aconaemys: A. sagei (2 n = 54, FN = 104), A. fuscus (2 n = 56, FN = 108) und A. porteni (2 n = 58, FN = 112). Fünf Populationen am westlichen Hang der Anden (Chile: Nahuelbuta, Tolhuaca, Rio Colorado, Pedregoso, ReigoLiL und Huerquehue), die bisher A. fuscus zugeschrieben wurden, zeigten denselben Karyotyp wie A. sagei von der Typus-Lokalität am östlichen Hang der Anden (Argentinien: Pampa Hui-Hui). Die karyotypischen Daten erlauben somit eine Zuordnung der disjunkten Populationen zu A. sagei. Die klassischen Morphospezies von Aconaemys, biologisch umrissen durch chromosomale und molekulare Daten, kommen alle drei in Chile vor. Unsere Daten weisen daraufhin, daß das Verbreitungsgebiet von A. sagei über mehr als 300 km bis zum nordwestlichen Hang der Anden erweitert werden muß.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Baker, R. I.; Haiduk, M. W.; Robbins, L. W.; Cadena, A.; Koop, B. F. (1982): Chromosomal studies of South American bats and their systematic implications. In: Mammalian Biology in South America. Ed. by M. A. Mares and H. H. Genoways. Pimatuning Laboratory of Ecology University of Pittsburgh 6, 303–327.Google Scholar
  2. Begall, S.; Gallardo, M. H. (2000): Spalacopus cyanus (Rodentia: Octodontidae): an extremist in tunnel constructing and food storing among subterranean mammals. J. Zool. (London) 251, 53–60.CrossRefGoogle Scholar
  3. Clapperton, C. M. (1993): Nature of environmental changes in South America at the last glacial maximum. Paleogeogr., Paleoclimatol., Paleoecol. 101, 189–208.CrossRefGoogle Scholar
  4. Clapperton, C. M. (1994): The Quaternary glaciation of Chile: a review. Rev. Chilena Hist. Nat. 67, 369–383.Google Scholar
  5. Contreras, L. C.; Torres-Mura, J. C.; Yáñez, J. L. (1987): Biogeography of octodontid rodents: an ecoevolutionary hypothesis. Fieldiana, Zool. 39, 401–411.Google Scholar
  6. Gallardo, M. H. (1992): Karyotypic evolution in octodontid rodents based on C-band analysis. J. Mammalogy 73, 89–98.CrossRefGoogle Scholar
  7. Gallardo, M. H. (1997): A saltation model of karyotypic evolution in the Octodontoidea (Mammalia, Rodentia). In: Chromosomes Today. Vol. 12. Ed. by N. Henriques-Gil, J. S. Parker, and M. J. Puertas. London: Chapman and Hall. Pp. 347–365.CrossRefGoogle Scholar
  8. Gallardo, M. H.; Reise, D. (1992): Systematics of Aconaemys (Rodentia, Octodontidae). J. Mammalogy 73, 779–788.CrossRefGoogle Scholar
  9. Gallardo, M. H.; Kirsch, J. W. A. (2001): Molecular relationships among Octodontidae (Mammalia: Rodentia: Caviomorpha). J. Mammalian Evol. 8, 73–89.CrossRefGoogle Scholar
  10. Gallardo, M. H.; Bickham, J. W.; Honeycott, R. L.; Ojeda, R. A.; Köhler, N (1999): Discovery of tetraploidy in a mammal. Nature 401, 341.CrossRefGoogle Scholar
  11. Greer, J. K. (1965): Mammals of Malleco Province, Chile. Publications of the Museum, Michigan State Univ. Biol. Ser. 3, 49–152.Google Scholar
  12. Haffer, J. (1979): Quaternary biogeography of tropical lowland South America. In: The South American Herpetofauna: its Origin, Evolution, and Dispersal. Ed. by W. W. Duellman. Lawrence: University of Kansas Press. Pp. 107–140.Google Scholar
  13. Heusser, C. I.; Flint, R. F. (1977): Quatennary glaciations and environments of northern Isla Chiloé, Chile. Geology 5, 305–308.CrossRefGoogle Scholar
  14. King, M. (1993): Species Evolution. The Role of Chromosome Change. New York: Cambridge University Press.Google Scholar
  15. Köhler, N.; Gallardo, M. H.; Contreras, L. C.; Torres-Mura, J. C. (2000): Allozymic variation and systematic relationships of the Octodontidae and allied taxa. (Mammalia, Rodentia). J. Zool. (London) 252, 243–250.CrossRefGoogle Scholar
  16. Lande, R. (1979): Effective deme size during long-term evolution estimated from rates of chromosomal rearrangements. Evolution 33, 234–251.CrossRefGoogle Scholar
  17. Lande, R. (1985): The fixation of chromosome rearrangements in a subdivided population with local extinction and colonization. Heredity 54, 323–332.CrossRefGoogle Scholar
  18. Mares, M. A.; Braun, J. K.; Bárquez, R. B.; Díaz, M. M. (2000): Two new genera and species of halophytic desert mammals from isolated salt flats in Argentina. Ocass. Papers Mus. Texas Tech. Univ. 203, 1–27.Google Scholar
  19. Markgraf, V.; Mcglone, M.; Hope, G. (1995): Neogene paleoenvironmental and paleoclimatic change in southern temperate ecosystems - a southern perspective. Trends Ecol. Evol. 10, 143–147.CrossRefGoogle Scholar
  20. Mercer, J. H. (1983): Cenozoic glaciations in the southern hemisphere. Annu. Rev. Earth Planet Sci. 11, 99–132.CrossRefGoogle Scholar
  21. Moritz, C.; Patton, J. L.; Schneider, C. I.; Smith, T. B. (2000): Diversification of rainforest faunas: an integrated molecular approach. Annu. Rev. Ecol. Syst. 31, 533–563.CrossRefGoogle Scholar
  22. Nachman, N. W.; Myers, P. (1989): Exceptional chromosomal mutations in a rodent population are not strongly underdominant. Proc. Nat. Acad. Sciences, USA 86, 6666–6670.CrossRefGoogle Scholar
  23. Osgood, W. H. (1943): The mammals of Chile. Field Museum of Natural History, Zool. Series 30, 1–268.Google Scholar
  24. Paskoff, R. P. (1977): Quaternary of Chile: the state of research. Quat. Res. 8, 2–31.CrossRefGoogle Scholar
  25. Patton, J. L. (1967): Chromosome studies of certain pocket mice, genus Perognathus (Rodentia, Heteromyidae). J. Mammalogy 48, 27–37.CrossRefGoogle Scholar
  26. Patton, J. L. (1970): Chromosome studies of pocket gophers, genus Thomomys. II. Variation in T. bottae in the American Southwest. Cytogenetics 9, 139–151.CrossRefGoogle Scholar
  27. Patton, J. L. (1973): An analysis of natural hybridization between the pocket gophers, Thomomys bottae and Thomomys umbrinus. J. Mammalogy 54, 561–584.CrossRefGoogle Scholar
  28. Patton, L.; Brylski, P. V. (1987): Pocket gophers in alfalfa fields: causes and consequences of habitat-related body size variations. Am. Nat. 130, 493–506.CrossRefGoogle Scholar
  29. Pearson, O. P. (1984): Taxonomy and natural history of some fossorial rodents of Patagonia, southern Argentina. J. Zool. (London) 202, 225–237.CrossRefGoogle Scholar
  30. Pearson, O. P. (1995): Annotated keys for identifying small mammals living in or near Nahuel Huapi National Park or Lanín National Park, southern Argentina. Mastozool. Neotropical 2, 99–148.Google Scholar
  31. Pine, R. H.; Miller, S. D.; Schamberguer, M. L. (1979): Contributions to the mammalogy of Chile. Mammalia 43, 339–376.Google Scholar
  32. Reig, O. A.; Bush, C.; Ortell, M. O.; Contreras, J. R. (1990): An overview of evoultion, systematics, population biology, cytogenetic, molecular biology and speciation in Ctenomys. In: Evolution of Subterranean Mammals at the Organismal and Molecular Levels. Ed. by E. Nevo and O. A. Reig. New York: Alan R. Liss. Pp. 71–96.Google Scholar
  33. Smith, M. E.; Patton, J. L. (1993): The diversification of South American murid rodents: evidence from mitochondnial DNA sequence data for the Akodontine tribe. Biol. J. Linn. Soc. 50, 149–177.CrossRefGoogle Scholar
  34. Thaeler, C. S. (1968): Karyotypes of sixteen populations of the Thomomys talpoides complex of pocket gophers (Rodentia, Geomyidae). Chromosoma 25, 172–183.CrossRefGoogle Scholar
  35. Thaeler, C. S. (1980): Chromosome numbers and systematic relations in the genus Thomomys (Rodentia, Geomyidae). J. Mammalogy 61, 414–422.CrossRefGoogle Scholar
  36. Venegas, W. (1974): Estudio citogenético en Aco-naemys fuscus fuscus Waterhouse (Rodentia, Octodontidae). Bol. Soc. Biol. Conception 47, 207–214.Google Scholar
  37. Vrba, E. (1992): Mammals as a key to evolutionary theory. J. Mammalogy 73, 1–28.CrossRefGoogle Scholar
  38. Wahrman, I.; Goitein, R.; Nevo, E. (1969): Geographic variation of chromosome forms in Spalax, a subterranean mammal of restricted mobility. In: Comparative Mammalian Cytogenetics. Ed. by K. Benirschke. New York: Springer Verlag. Pp. 30–48.CrossRefGoogle Scholar

Copyright information

© Deutsche Gesellschaft für Säugetierkunde 2002

Authors and Affiliations

  1. 1.Institute de Ecología y EvoluciónUniversidad Austral de ChileValdiviaChile

Personalised recommendations