CYTOGENETICS OF SOME

FROM CENTRAL

by

SERGIO I. TIRANTl, B.S.

A THESIS

IN

ZOOLOGY

Submitted to the Gradúate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE

Approved

August, 1996 ^f5 'f\\iV 30-

Ho i^'í> "h

Copyright 1996, Sergio I. Tiranti ACKNOWLEDGMENTS

My special thanks go to Robert J. Baker, my committee chairman, for his encouragement and support throughout my stay at Texas Tech. Committee members Robert D. Bradley and Michael R. Willig, offered comments and suggestions that benefited the final outcome of this thesis. Portions of this thesis were reviewed by John Bickham, Meredith J. Hamilton, Steve Kasper, Karen McBee and Lara E. Wiggins, thus contributing to its improvement. My work in La Pampa , Argentina, was supported by the Subsecretaría de Cultura, where Norma Durango, Gustavo Siegenthaler and Eduardo Fiorucci contributed in many ways to the accomplishment of this research project. Numerous localities visited in this study were sampled as part of Vertébrate Survey. My stay at TTU is supported in part by the Dirección Nacional de Cooperación Internacional, Ministerio de Cultura y Educación, Argentina and the Universidad Nacional de La Pampa, Argentina. Finally, I am heartedly indebted to my parents, Iván and Irene, for their neverending encouragement and support.

11 TABLE OF CONTENTS

ACKNOWLEDGMENTS ü ABSTRACT v LIST OF TABEES vi LIST OF FIGURES vii CHAPTER I. INTRODUCTION 1

II. THE KARYOTYPE OFMYQTIS.LEYIS (CHIROPTERA, VESPERTILIONIDAE). . 7 Introduction...... 7 Material and Methods . . 7 Results and Discussion .... 9 III. CHROMOSOMAL POLYMORPHISM VARL\TION IN THE SCRUB MOUSE MOLINAE (RODENTL\: ) IN CENTRAL ARGENTINA 11 Abstract. . 11 Introduction. 11 Material and Methods . . 13 Results and Discussion . . 15 IV. CYTOGENETICS OF SILKY DESERT MICE, Fí TGMODONTIA SPP. (RODENTL\: SIGMODONTINAE) IN CENTRAL ARGENTINA 20 Abstract...... 20

111 Introduction...... 20 Material and Methods 22 Results and Discussion . . 23 V. CYTOGENETICS OF GRISEOFLAVUS (RODENTL\: SIGMODONTINAE) IN CENTRAL ARGENTINA. ... 29 Introduction...... 29 Material and Methods . . 30 Results and Discussion . . 31 VI. CYTOGENETIC OBSERVATIONS ON OTHERTAXA 38 Introduction. 38 Results and Discussion . . 39 VIL CONCLUSIONS 70 LITERATURE CITED 71

IV ABSTRACT

This study is to assess the karyology of several small mammalian taxa in central Argentina, using chromosomes to assist in identifying species, and to provide new chromosomal data for several species from geographic áreas where studies have not been done. Specimens of small , representing 24 species belonging to 6 families, were live-trapped in 26 localities in 6 of central Argentina. Specimens were subjected to the standard in vivo procedure of colchicine mitotic arrest for obtaining chromosomes from bone marrow. Chromosome slides were observed and photographed and the diploid number and morphology determined for each specimen. Objectives: Clarify the systematic status of the species of silky desert mice () through a chromosomal survey of these species in west- central Argentina. Evalúate the extent of the variation associated with the chromosome 1 polymorphism in the scrub mouse Akodon molinae. Assess the widespread chromosomal variation and geographic distribution of karyotypes of Graomys griseoflavus. Key words: Cytogenetics. karyology. , small mammals, central Argentina. LIST OF TABEES

1. Distribution of karyotypes in Akodon molinae 17

2. Distribution of karyotypes in Graomys griseoflavus . 34

VI LIST OF FIGURES

1 Map of Argentina showing collecting localities ... 5

2. List of localities 6

3. Karyotype of a male Myotis levis dinellii from Argentina, La Pampa Province, Caleu Caleu Department, Ahnacén El 52, TK 27903 10

4. 2n= 42 Akodon molinae karyotype. Estancia Los Toros, Toay Department, La Pampa (TK 40620, male). . 18

5. Pair 1 chromosome polymorphism. a. 2n=43 (KT 40631). b. 2n= 44 (TK 40621). Estancia Los Toros, Toay Department, La Pampa . . 19

6. 2n= 44 karyotype from 25 km SE Puelén, La Pampa (TK 47613 male). ... 26

7. Eligmodontia morgani 2n= 34 karyotype from Laguna Blanca National Park, Neuquén. (TK 47602 male).. 27

8. Distribution of Eligmodontia cytotypes Neuquén and La Pampa provinces, central Argentina with collecting localities: 1. Lagima Blanca National Park. 2. 20 km E Zapala. 3. 25 km SE Puelén. 4. Cerro Colón. 5. Puesto Las Lagunitas. 6. Estancia Los Toros. Asterisks denote the 2n= 44 karyotype and the solid circle the 2n= 34 . 28

9. 2n= 42 Graomys griseoflavus karyotype (TK 49047, male) from Ulapes, La Rioja Province . 35

10. 2n= 38 Graomys griseoflavus karyotype (TK 49169, female) from La Lomita, 10 km SW Santa Rosa, La Pampa . 36

vil 11. 2n= 36 Graomys griseoflavus karyotype (TK 47611, male) from Salitral de La Perra, 25 km SE Puelén, La Pampa. . 37

12. Lutreohna crassicaudata karyotype Córdoba, Arroyo ChucukTK 45615, female 51

13. Monodelphis; dimidiata karyotype , Abra del Hinojo: TK 47654, male 52

14. Thylamys pusülus karyotype. Neuquén, Laguna Blanca: TK 40699, male . 53

15. Desmodus rotundus karyotype. Córdoba, Segunda Usina: TK 40674, male 54

16. Eptesicus fiírinalis karyotype, 2n= 50. La Pampa, Santa Rosa: TK 40689, female 55

17. Eumops perotis karyotype. Córdoba, Segunda Usina: TK 40676, male 56

18. Tadarida brasiliensis karyotype. Córdoba, Coronel Baigorria: TK 40665, female 57

19. Chaetophractus vellerosus karyotype. La Pampa, Naicó, Estancia Los Toros: TK 40261, female . 58

20. xanthorhinus Neuquén, Lagima Blanca: TK 40238, male 59

21. Akodon azarae La Pampa, Laguna Don Tomás: TK 40601, male 60

22. Akodon iniscatus Neuquén, Laguna Blanca: TK 40237, male . 61

vm 23. Bolomys sp. karyotype. La Pampa, Quehué, Estancia Los Molinos: TK 47628, male 62

24. Calomya laucha karyotype. La Pampa, Catriló: TK 47671, female 63

25. Calomvs musculinus karyotype La Pampa, Naicó, Estancia Los Toros: TK 40619, female. ... 64

26. Calomys venustus karyotype Córdoba, Espinillo: KT 49114, male. 65

27. Oligoryzomys flavescens karyotype Córdoba, Coronel Baigorria: TK 40262, female 66

28. rufiís karyotype Córdoba, Espinillo: TK 49118, male 67

29. xanthopygus karyotype. Neuquén, Laguna Blanca: TK 40243, male 68

30. Reithrodon auritus karyotype. La Pampa, Quehué, Estancia Los Molinos: TK 47627, female . . 69

IX CHAPTER I INTRODUCTION

In central Argentina, it is possible to observe the convergence of a wide array of phytogeographical regions, such as the , physiognomically dominated by creosote-bushes (Larrea spp.); the Espinal, characterized by xerophilous scrub forests dominated by Prosopis trees; the Pampean grasslands, and towards the West and South; and the Patagonian shrub-steppe. Each of these regions possess an intermingling of subtropical and températe faunas. The Pampean Sierras, interspersed in an otherwise overwhelmingly flat terrain, offer the opportunity for the development of endemism and the isolation of species of Patagonian or Andean affinities. Additionally, salt flats with their associated biota of halophilous communities, conform distinct imits in the landscape, and harbor a iinique mammahan fauna (Braim and Mares 1995). Although recent research has produced a number of publications on the mammals of some of Argentina's provinces (Mares et al. 1989, Ojeda and Mares 1989, Bárquez et al. 1991, 1993), for many áreas of Argentina there is a virtual absence of information about the mammalian fauna; or if this information exists, it has been ascertained from classical morphological studies (e.g., Siegenthaler et al. 1990 a, b) and has not utilized other approaches, such as cytogenetics. In several cases, there is reasonable doubts about the specific status of many mammalian taxa, particularly in speciose groups such as the sigmodontine and octodontid . Furthermore, other áreas, such as the westem and northwestem portions of Argentina have not been adequately surveyed in terms of its mammal fauna; as illustrated by the frequent discovery of new genera and species (Williams and Mares 1978 a, Braun and Mares 1995). Central Argentina, and especially La Pampa Province, offers the opportunity to study several small mammalian taxa for which limited cytogenetic data are currently available (Massarini et al. 1991, 1992). Chromosomal studies have been shown to be valuable for the identifícation of specific status in many species and have'helped resolve the status of some taxa. For example, the Patagonian scrub mice of the Akodon were thought to represent two different species, A. iniscatus and A. nucus, but their karyotypes have been interpreted as support to the hypothesis that only a single species, A. iniscatus, should be recognized (Barros et al. 1990). Other examples have shown the useñilness of chromosomal studies to reveal the existence, hidden from the viewpoint of classical systematics, of distinct taxa in what was thought of as a single species (Massoia et al. 1968, Baker and Genoways 1975, Cardenal et al. 1977, Liascovich et al. 1989, Liascovich and Reig 1989). Moreover, some taxa, especially among sigmodontine and octodontid rodents, show intrapopulation, interpopulation and interspecific chromosomal polymorphisms (Bianchi et al. 1969, Koop et al. 1983, Nachman 1992) which can pose problems in utilizing chromosomes to identify species. Synmorphic (moiphologically indistinguishable) or very similar taxa that had been considered single species, have been found through cytogenetic studies to represent more than one taxa (e.g., Calomys laucha in Hershkovitz 1962, Baker 1984, Fredga et al. 1990, Nevo 1991). hi a recent example, the genus Eligmodontia inhabiting central and southem Argentina was shown to be composed of two chromosomally distinct species (Ortells et al. 1989, Kelt etal. 1991,ZambeUietal. 1992). Earlier workers considered Eligmodontia to include a single species, E. typus (2n= 43-44) and through karyotypic analyses it is now known that this also includes E. morgani (2n= 32- 33). Eligmodontia typus and E. morgani appear to be synmorphic and taking into accoimt their wide distribution, it is necessary to assess their karyology to be able to produce an accurate systematical identifícation. The study of the cytogenetics of this genus in other localities of central Argentina should contribute to the understanding of the distribution and biogeography of these species. The study of chromosomes would also be useñil for ascertaining the specifíc status of some problematic taxa in this área such as the Akodon (Myers 1989). Therefore, there exists the need of an integrated approach of classical and karyology to board these problems. Another interesting aspect of cytogenetic research is the probable correlation of different cytotypes of one or closely related taxa to a particular phytogeographical área, or in a smaller scales, land features or soil types. Recent evidence has shown that in Northem Scotland chromosomal "races" of house mice occupy different kinds of , such as "mountainous, cold wet, and agriculturally poor" for the standard all acrocentric karyotype, and áreas with terrain that is "relatively warm, dry, prime agricultural land" for the metacentric race (Searle et al. 1993). Similar restrictions of different cytotypes to a particular soil or habitat type have been observed in the pocket gophers Geomys bursarius and ü. knoxjonesi. giving the idea of an adaptiveness of these cytotypes to these land types (Baker et al. 1989, Bradley etal. 1991). Thus, the purpose of this study is to assess the karyology of several small mammal taxa in central Argentina, involving the use of karyotypes as an aid in identifying species, and to provide new chromosomal data for several species from an área in which these studies have not been done to a great extent. Additionally, cytogenetics may provide new insights into the relationships between the different biogeographical regions and their mammalian faunas. Within this context I have addressed the study of an array of small mammals inhabiting central Argentina. From the bulk of specimens obtained from a number of localities (Figures 1 and 2), emphasis was placed on taxa for which cytogenetics would be usefixl in resolving systematic problems. The present thesis is structured as chapters which correspond each to individual manuscripts that are currently: published (II), in press (IV), have been submitted (III), or are in preparation (V and VI). Variation in format among chapters is the result of differences in style required by different joumals. Karyotype fígures have the autosomes arranged in decreasing order of size and the X and Y chromosomes placed as the last members of the series. > so loo 200

Figure 1. Map of Argentina depicting collecting localities. 1. Abra del Hinojo, Sierras de Curamalal, Saavedra Partido, Buenos Aires. 2. Almacén El 52,40 km N Anzoategui, Caleu Caleu Department, La Pampa. 3. Arroyo Chucul, 20 km NE Rio Cuarto, Rio Cuarto Department, Córdoba. 4. Catriló, 10 km S, Catriló Department, La Pampa. 5. Cerro Colón, Puelén Department, La Pampa. 6. Coronel Baigorria, Rio Cuarto Department, Córdoba. 7. Eduardo Castex, 20 km N , Trenel Department, La Pampa. 8. Eleodoro , 2 km E, Pringles Department, San Luis. 9. Espinillo, 2 km S, Rio Cuarto Department, Córdoba. 10. Estancia El Pincén, Toay Department, La Pampa. 11. Estancia Los Toros, 12 km NNE Naicó, Toay Department, La Pampa. 12. Estancia Los Molinos, 10 km W Quehué, Utracan Department, La Pampa. 13. Laguna Blanca National Park, Zapala Department, Neuquén. 14. La Lomita, 10 km SW Santa Rosa, Toay Department, La Pampa. 15. Loma Loncovaca, 10 km S Chamaicó, Rancul Department, La Pampa. 16. Palo Parado, Cruz del Eje Department. Córdoba. 17. Paraje San José, Rio Cuarto Department, Córdoba. 18. Parque Luro, Toay Department, La Pampa. 19. Puesto Las Lagunitas, 60 km SE Puelches, Lihué Calel Department, La Pampa. 20. Rincón de Papagayos, Chacabuco Department, San Luis. 21. Salitral de La Perra, 25 km SE Puelén, Puelén Department, La Pampa. 22. Santa Rosa and Laguna Don Tomás, Capital Department, La Pampa. 23. Segunda Usina, Calamuchita Department, Córdoba 24. Sierra de la Ventana, Tomquist Partido. Buenos Aires. 25. Ulapes, 2 km N, San Martín Department, La Rioja. 26. Zapala, 20 km E, Zapala Department, Neuquén.

Figure 2. List of localities. CHAPTER II THE KARYOTYPE OF MYOTIS LEVIS (CHIROPTERA: VESPERTILIONIDAE)

Introduction Myotis levis (I. Geoffroy, 1824) is distributed in central Argentina, Uruguay, and southeastem Brazil (Redford and Eisenberg 1992; Koopman 1993) and inhabits a wide variety of ranging from transition forests, moist Chaco Serrano forests to Monte Desert scrub (Mares et al. 1995). The systematic status of Myotis levis has been stable since the major revisión of the Neotropical Myotis (La Val 1973). The species is composed of two subspecies; M. levis levis occurs in the eastem áreas of central Argentina and M. levis dinellii occurs in the westem part (La Val 1973) of the species range. Reviews (Baker et al. 1982, Zima and Horacek 1985, Bickham et al. 1986, McBee et al. 1986, Reina et al. 1994, Volleth and Heller 1994) have focused on the karyology of bats of the genus Myoíis. throughout the world. In mainland , twelve species of Myotis are known (Koopman 1993), but among the species that inhabit this continent, karyotypes have been described for only for M. nigricans (Schinz, 1821) and M. keaysi Alien, 1914 (Bickham 1979; Baker and Bickham 1980).

Material and Methods A total of 9 Myotis levis dinellii specimens were coUected with mist nets and by hand. The standard procedure of in-vivo colchicine mitotic arrest was used for obtaining chromosomes from bone marrow (Baker et al. 1982). In most cases the yeast stress method (Lee and Eider, 1980) was used to obtain a higher mitotic index. Slides were produced by dropping the cell suspensión from a height of 50-60 cm into a large drop of distilled water on the surface of the slide (Baker et al. 1982). Chromosome slides were observed and photographed, and the diploid number and chromosomal morphology were determined for each specimen. Karyotypes were prepared in which autosomes were arranged in decreasing order of size and the X and Y placed as the last members of the series. The Y chromosome was tentatively identified as chromosome banding procedures were not made. Voucher specimens were prepared as standard study skins and skuUs and are housed in the coUections of The Museum, Texas Tech University (TTU and TK number references the Tissue CoUection), and in the mammal coUection of the Museo Provincial de Historia Natural (RVP), Santa Rosa, La Pampa, Argentina. Localities, specimens studied, and depository for skins and skuUs are as follows. Córdoba Province: Cruz del Eje Department, Palo Parado; TK 40653 male; Rio Cuarto Department, Coronel Baigorria, Estancia San Gonzalo; TK 40657 female, TK 40658 female, TK 40659 female, TK 40662 female, TK 40663 female (TTU). La Pampa Province: Caleu Caleu Department, Almacén El 52; TK 27901 male, TK 27902 male (TTU), TK 27903 male (RVP).

8 Results and Discussion The karyotype of Myotis levis dinellii (2n= 44, ñindamental number 50) is composed of three pairs of large metacentric elements characteristic of the genus (Bickham 1979; Reina et al. 1994), a small pair of metacentrics and seventeen pairs of acrocentrics. The smallest of the acrocentrics, the last three pairs, are barely discemible in their morphology. The X is a médium sized submetacentric and the Y is a small submetacentric (Figure 3). In general this karyotype does not depart from those described for M. nigricans and M. keaysi except that M. levis has a Y chromosome that appears to be larger than the smallest pairs of autosomes and not the smallest chromosome as has been described for Myotis nigricans (Bickham 1979). Except for these minor variations, as found for the Y chromosome in the genus (Bickham 1979), Myotis levis ñirther documents the chromosomal conservativeness characteristic of this genus and most of the Vespertilionidae (Baker and Bickham 1980). k 1% m flO A o nn fto

o A (VA no í\ {> f\0 Xn A A

A #% /N A ^VVN A A ^ • • - • •

IC .

Figure 3. Karyotype of a male Myotis levis dinellii from Argentina, La Pampa Province, Caleu Caleu Department, Ahnacén El 52, TK 27903.

10 CHAPTER III CHROMOSOMAL POLYMORPHISM VARL\TION IN THE SCRUB MOUSE AKODON MOLINAE (RODENTIA: SIGMODONTINAE) IN CENTRAL ARGENTINA

Abstract A cytogenetic study of 34 specimens of the scrub mouse Akodon molinae from 9 localities in La Pampa and San Luis Provinces, showed 2n= 43 in 18 specimens, 2n= 44 in 8, and 2n= 42 in 8 individuáis. This variation is the resuh of a polymorphism involving chromosome pair 1. Information on the distribution and biogeography of Akodon molinae karyomorphs is provided for central Argentina.

Introduction The scrub mouse, Akodon molinae Contreras, 1968 is one of the most studied sigmodontine rodents in South America (Myers 1989). Molecular (Apfelbaum and Blanco 1984, Apfelbaum and Reig 1989), ecological (Ojeda 1989) and cytogenetical (Bianchi et al. 1969, 1973, 1976, 1979 a, Wittouck et al. 1995) information is described. In central Argentina, this widespread species inhabits Espinal forests predominated by caldén, Prosopis caldenia. It also occurs in scrub vegetation of halophytic shrub communities and Monte Desert habitats, as well as the borders of grasslands and cultivated fíelds, and deforested áreas where there is adequate shrub cover.

11 Akodon mQlina£ is difficult to distinguish morphologically from other members in the varius group, of which it is a member (Myers 1989), and cytogenetics can be useftil as a source for correct identifícation. Akodon niolinae shows a variable karyotype with a diploid number ranging from2n = 42 to 44. The 2n= 43 is the most common variant and the first pair of chromosomes is represented by two submetacentrics and a large metacentric, and the rest of the autosomes are acrocentric except for the smallest pair which is metacentric. The X chromosome is a large acrocentric and the Y chromosome is a small acrocentric (Bianchi et al. 1973). In the 2n= 42 and 44 forms the fírst pair is represented by two large metacentrics and four large subtelocentrics respectively. This balanced polymorphism was fírst found by Bianchi et al. (1969), and subsequently described in greater detall (Bianchi et al. 1971, 1973, 1979 a, Wittouck etal. 1995). Akodon dolores Thomas, 1916, a related if not conspecifíc form, shares chromosomal banding pattems, morphology and electromorphic valúes for proteins with A. molinae. The basic karyotype of Akodon dolores (2n= 34) consists of five pairs of large metacentric or submetacentric chromosomes, eleven pairs of acrocentric chromosomes of decreasing size, and a pair of small metacentrics. The X chromosome is an acrocentric of médium size and the Y chromosome a small acrocentric. Additionally, the fírst fívepair s of biarmed chromosomes can present polymorphisms producing individuáis with 2n= 34-40 diploid numbers (Kibliski et al. 1976, Wittouck et al. 1995). These two species can hybridize in the laboratory and the Fl generation does not have a detectable reduction in fertility (Wittouck et al. 1995). It has been concluded that A. molinae should be considered as a

12 chromosomal or geographic race of A. dolores (Apfelbaum and Blanco 1984, Apfelbaum and Reig 1989; Wittouck et al. 1995). However, nattiral hybridization or sympatiy has not been demonsti-ated. It is possible that both entities may have an independent existence. The disttibution áreas of both do not seem to overiap (Apfelbaum and Blanco 1984). Moreover, at the type locality of Akodon dolores specimens had the karyotype originally described as belonging to A. molinae (Wittouck et al. 1995). For the sake of consistency, in this report the specifíc ñame "molinae" is applied to the 2n= 42-43-44 forms. Herein, additional cytogenetic data for the species is reported from other áreas of central Argentina for which this information has not been published.

Material and Methods Thirty-four specimens of Akodon molinae were collected with a variety of live traps in nine localities of San Luis and La Pampa provinces (central Argentina). In most cases, the yeast stress method (Lee and Eider 1980) was used to obtain a higher mitotic index. The animáis were subjected to the standard procedure of in-vivo colchicine mitotic arrest for obtaining chromosomes from bone marrow. Slides were prepared by dropping the cell suspensión from a 50-60 cm height into a large drop of distilled water on the surface of the slide (Baker et al. 1982). Chromosome slides were Giemsa stained, observed and photographed and the diploid number and chromosomal morphology was determined for each specimen. All voucher specimens were prepared as standard study skins and skulls or fluid- preserved and are housed in the collections of Texas Tech University

13 Museum (TTU), Lubbock, Texas, USA and the mammal coUection of the Universidad Nacional de Rio Cuarto (UNRC), Rio Cuarto, Córdoba, Argentina. Vegetation information for habitats where Akodon molinae specimens were collected in La Pampa Province foUows Cano et al. (1980). Localities and specimens examined: (TK numbers identify cell suspensions and slides assigned to voucher specimens). : Chacabuco Department: Rincón de Papagayos: One female (TK 49190). General vegetation of the área are Chaco Serrano transition-forests with palms. La Pampa Province: Rancul Department: 15 km SW Chamaicó, Loma Loncovaca: One female (TK 49191), open Espinal forests of caldén (Prosopis caldenia). Toay Department: Estancia El Pincén: One female (TK 47625), open Espinal forests of caldén (Prosopis caldenia); 10 km SW Santa Rosa, Chacra La Lomita: One male (TK 49181) and one female (TK49176), crops with pastures and linear habitats along fences with piquillín (Condalia microphylla) and caldén (Prosopis caldenia): 12 km NNE Naicó, Estancia Los Toros: 8 males (TK 27881, 27883, 40613, 40616, 40620, 40621, 40622, 40630) and 8 females (TK 27882, 40609, 40612, 40614, 40617, 40631, 47619, 49182), yoimg (renoval) caldén forests and pastures; Parque Luro: Four males (TK 49192, 49193, 49195, 49197) and two females (TK 49194, 49196), open Espinal forests of caldén rProsopis caldeniaV Capital Department: Laguna Don Tomás, Santa Rosa: Two females (TK 40602, 49198), floodable área with semihalophytic shrubs. Uttacán Department: 10 km W Quehué, Estancia Los Molinos: 2 males (TK 47629, 74630), caldén forests and mixed shrublands of Larrea divaricata, Condalia mJQrophylIa and

14 Chuquiraga erinaoea. Caleu Caleu Department: 40 km N Anzoategui, Ahnacén El 52: 2 males (TK 40636, 40638) and one female (TK 40637), mixed shrubland composed mainly of Condalia microphylla, Larrea dÍYarigata, Acantholjppia seriphiojdes and Condalia microphylla with Prosopis caldenia forests.

Results and Discussion The majority of specimens examined (n= 18; 52.9 %) possessed the 2n= 43 karyomorph. The 2n= 44 cytotype was present in 8 individuáis (23.5 %) and 8 had the 2n= 42 chromosomal variant (23.5 %) (Table 1). Previously, different proportions of these karyomorphs have been reported. Mostly for Chasicó, , the type locality of A. molinae, a total of eighteen specimens possessed the 2n= 42 karyotype, fourteen had the 2n= 43, and one had the 2n= 44 form (Bianchi et al., 1969, 1971, 1973). More recently Wittouck et al. (1995) reported three animáis with 42, nine with 43 and nine with 44 chromosomes for Yacanto and Villa Dolores, Córdoba Province. Although the present information on chromosomal polymorphism variation from a single locality can be assessed only for Estancia Los Toros, it is apparent that all three cytotypes can be present in a single population. In this locality, in a sample of 16 specimens, the 2n= 42 karyomorph (Figure 4) was the least common and was found in two individuáis (one male and one female). The proportion of 2n= 43 (Figure 5a) individuáis (7 specimens; 3 males and 4 females) equaled that of the 2n= 44 karyotype (Figure 5b) (7 specimens; 4 males and 3 females). It has been argued that the 2n= 44

15 cytotype would have a low frequency in naUíre due to a high meiotic non- disjunction rate (Liascovich et. al. 1990) and diminished fítiiessha s been found in the 2n= 44 karyotype (Bianchi and Merani 1980). This does not appear to be the case in Estancia Los Toros and for Yacanto and Villa Dolores (Córdoba Province) where a similar sittiation was observed (Wittouck et al. 1995). From the Parque Luro sample (six animáis), two specimens had the 2n= 42 chromosomal variant (one male and one female) and four specimens had the 2N=43 variant (three males and one female). Akodon molinae appears to be restricted to the south and west part of the dolpres-molinae complex range which is located in the Espinal forests and with some localities (not karyologically studied) inside the Monte Desert. The karyologically studied distribution of theA. dolfíiei karyomorphs is presently restricted to the east of the Cordobean Sierras, except for specimens reported for (Bianchi et al. 1979 b). The sierras could affect the distribution of this polymorphism. A careñil survey may show the extent of the geographic distribution of these forms. It appears that additional information on the geographic distribution of these karyomorphs may shed more light for the assessment of the systematic relations of these taxa.

16 Table 1. Distribution of karyotypes in Akodon molinae.

karyotype, 2n= Locality 42 43 44

Papagayos 1 Loncovaca 1 Los Toros 2 7 7 Ahnacén El 52 2 1 Los Molinos 1 1 El Pincén 1 Lag. Don Tomás 2 La Lomita 1 1 Parque Luro 2 4

Total: 34 8 18 8

17 rtlvi nn n n, nft QO no oi« /^ A

0* f% [fk.0k Al*» .•• / • &.

Figure 4. 2n= 42 Akodon molinae karyotype. Estancia Los Toros, Toay Department, La Pampa (TK 40620, male).

18 11 a

Figure 5. Pair 1 chromosome polymorphism. a. 2n= 43 (KT 40631). b. 2n= 44 (TK 40621). Estancia Los Toros, Toay Department, La Pampa.

19 CHAPTER IV CYTOGENETICS OF SILKY DESERT MICE, ELIGMODONTIA SPP. (RODENTIA, SIGMODONTINAE) IN CENTRAL AREGENTINA

Abstract Chromosomal features of Eligmodontia typus and E. morgani are described for six localities from centi-al Argentina to better understand their geographic distribution. A chromosomal study of Eligmodontia revealed the fínding of a 2n= 34 karyotype, in 15 specimens from Laguna Blanca National Park, Neuquén. This karyotype has been previously described as an intrapopulation polymorphism. Information regarding the distribution of the 2n= 44 karyotype corresponding to E. typus in four localities of La Pampa and one of eastem Neuquén, Argentina is provided.

Inttoduction Chromosomes have been shown to be a valuable means for the identifícation of specifíc status in many animal species. Through cytogenetic studies synmorphic taxa that for long had been considered single species, have been found to represent more than one taxon (Baker 1984). The genus Eligmodontia Cuvier, 1837, whose species are known as highland desert or silky desert mice, has been considered monotypic (Hershkovitz 1962, Nowak and Paradiso 1983), despite the fact that up to seven putative species have been described (Ortells et al. 1989). Recently, the number of species

20 recognized in the genus has ranged from three species which were based on karyological confírmation (Steppan 1995; morgani Alien, 1901, puerulus (Philippi, 1896), and typus Cuvier, 1837) to six species where morphology was used as the primary taxonomic feattire (Braun 1993; hirtipes (Thomas, 1902), mmica Thomas, 1918, moreni Thomas, 1986, morgani, puerulus and typus). In central and southem Argentina this genus is composed of two chromosomally distinct cytotypes (Ortells et al. 1989, Keh et al. 1991, Zambelli et al. 1992), which are Eligmodontia typus with a diploid number of 43-44 chromosomes, and E. morgani with 2n= 32-33. Prior to these fmdings, essentially all Eligmodontia in this área were referred to as E. typus (e.g., Pearson et al. 1987), foUowing the unifying criteria of Cabrera (1961) and Hershkovitz (1962); but lately, Patagonian Eligmodontia have been recognized in ecological studies as E. morgani (Pearson 1994, Saba and Lamo 1994). Recognizing that both taxa appear to be synmorphic and with a wide distribution, it would be necessary to assertain their karyology in order to be able to assign systematic identifícation. Nevertheless a word of caution on the use of "chromosomal formulae as a diagnostic key to species identifícations" was forwarded by Musser and Carleton (1993) on the grounds of "the complex interdigitation of specifíc ranges among the ridges and valleys of the southem " and the need of a revisión of the genus. In addition, the other species of Eligmodontia for which chromosomal information is available are E. puerulus with 2n= 50, inhabiting southem Peni and westem Bolivia (Ortells et al. 1989, Kelt et al. 1991) and E. moreni from northem Argentina with 2n= 34 (Spotomo et al. 1994).

21 Material and Methods A total of 27 Eligmodontia specimens were live-trapped with Sherman, Davis, and wire mesh traps. The standard procedure of in-vivo colchicine mitotic arrest was used for obtaining chromosomes from bone marrow. In most cases, the yeast stress method (Lee and Eider 1980) was used to obtain an increased mitotic index. Slides were prepared by dropping the cell suspensión from a 50-60 cm height into a large drop of distilled water on the surface of the shde (Baker et al. 1982). Chromosome slides were observed and photographed and the diploid number and chromosomal morphology was determined for each specimen. Voucher specimens were prepared as standard study skins and skulls and are housed in the collections of Texas Tech University Museum (TTU), and the coUection of Universidad Nacional de Rio Cuarto (UNRC). Localities sampled (Fig. 1) and specimens studied: TK numbers identify slides and cell suspensions from voucher specimens. Eligmodontia morgani Neuquén: Zapala Department: Laguna Blanca National Park (n= 15). TK 40245 male, TK 40248 female, TK 40266 female, TK 40287 male, TK 40291 female TK 40292 male, TK 40293 male, TK 40294 female, TK 40295 female, TK 40298 female, TK 40299 female, TK 40300 male, TK 47601 male, TK 47602 male, TK 47603 female. Eligmodontia tvpus Neuquén: Zapala Department, 20 km E Zapala (n= 1). TK 40239 male.

22 La Pampa: Toay Department: Estancia Los Toros, 12 km NNE Naicó (n= 7). TK 27886 male, TK 27887 female, TK 27890 male, TK 40618 male, TK 40623 male, TK 40624 female, TK 40629 male. Lihué Calel Departtnent, Puesto Las Lagunitas, 60 km SE Puelches (n= 1). TK 47610 female. Puelén Department, 25 km SE Puelén (n= 2). TK 47612 female, TK 47613 male. Cerro Colón (n= 1). TK 47623 female.

Results and Discussion The karyotypes of Eligmodontia typus and E. morgani are shown in Figures 6 and 7, respectively, and the geographic distribution of cytotypes is shown in Figure 8. Regarding Eligmodontia typus, the common interpretation has been to assume that the 2n= 44 karyotype is representative of this species, existing also a 2n= 43 variant (Ortells et al. 1989, Kelt et al. 1991, Zambelli et al. 1992). The 2n= 44 karyotype described originally from Laguna Chasicó, Buenos Aires Province (Ortells et al. 1989), seems to show little variation and is widespread throughout its range. It consists of a pair of large metacentric autosomes, 20 pairs of acrocentrics, and being the X chromosome a metacentric and the Y a subtelocentric (Figure 6). This karyotype was identifíed from a total of 12 specimens from all La Pampa and E Neuquén localities in which the 2n= 43 variant was not detected. At Laguna Blanca National Park, a 2n= 34 karyotype consisting of 16 pairs of acrocentric autosomic chromosomes, an acrocentric X chromosome and a metacentric Y chromosome, was found in all 15 specimens examined (Figure 7). Originally this karyotype was described by Zambelli et al. (1992)

23 for Eligmodontia sp. from one locality in Neuquén Province, and one locality in Rio Negro Province. This results in a northward extensión of about 120 km for this karyotype. Previously, Ortells et al. (1989) had described 2n= 32-33 karyotypes for specimens of Eligmodontia sp. The 2n= 32 karyotype consisted of 14 pairs of acrocentric autosomes and a pair of small metacenttics. A polymorphism involving an heteromorphic pair composed of one small metacentric and two small acrocentrics produced the 2n= 33 variant. For both karyotypes the X was acrocentric and Y metacentric. Later, Kelt et al. (1991) ñxrther described 2n= 32 karyotypes from other Patagonian localities and gave reasons for the assignment of these forms to E. morgani. Furthermore, the 32, 33 and 34 variants were demonstrated, though G- banding and meiotic studies to "belong to one polymorphic system involving a Robertsonian ñision" (Zambelli et al. 1992, p. 161). What is unusual is that all the specimens studied from the Laguna Blanca population possess the 2n= 34 karyotype, indicating that this chromosomal variant is fixed or that a more extensive distribution of all- 2n=34 populations remains to be discovered. Zambelli et al. (1992) found the 2n= 32-33 and 2n=44 cytotypes, of Eligmodontia sp. and E. typus respectively, in sympatry in two localities of Neuquén and Rio Negro provinces. Unfortunately, detailed habitat data to support habitat segregation of the two species has not been described. In this report both Eligmodontia karyotypes (2n= 34 and 2n =44) were found ca. 50 km apart in Neuquén Province. The site in which the 2n= 34 karyotype was found is located in a typical Patagonian shrub-steppe habitat

24 with Mulinum spinosum being one of the dominant shrubs. Altematively, the 2n= 44 E. typus (a single specimen) locality 20 km E Zapala is found in the Monte Desert shrublands, comprised mostly of creosote bush (Larrea divaricata) and molle (Schinus sp.). How exactly the two cytotypes are distributed in specifíc habitats is yet to be documented. Mares et al. (1981) did fmd the morphological types to be habitat specifíc and this is comparable to the hypothesis that the distribution of cytotypes will reflect the habitat distribution. It has been argued (Musser and Carleton 1993) that the assignment of the 2n= 32-33 karyotype to E. morgani by Kelt et al. (1991) could be doubtful. Especially, considering that the specimens sUidied by these authors did not come fromth e type locality, but from7 0 km away. These same karyotypes described by Ortells et al. (1989) were not assigned to any particular species. Neither the 2n= 34 variant discovered by Zambelli et al. (1992). I suggest that the opinión of KeU et al. (1991) in the use of the ñame morgani for these polymorphic complex of 2n= 32 to 34 should be foUowed until ftirtherresearc h resolves this problem.

25 ñA t(& A O ññ a» hh \(M\

A1^ OíA ft/A 111% vsiA A,*% (A a A f» '

Cl A A A 4\ A t^ H >\ A 4»

Figure 6. Eligmodontia typus 2n= 44 karyotype from 25 km SE Puelén, La Pampa (TK 47613 male).

26 11 i) H ít 11 II 1. ;.

%t {% ^] 4l,^ « ft tí^, Ik* <•;• a*

j_.s*/

Figure 7. Eligmodontia morgani 2n= 34 karyotype fromLagun a Blanca National Park, Neuquén. (TK 47602 male).

27 Figure 8. Distribution of Eligmodontia cytotypes in Neuquén and La Pampa Provinces, central Argentina with collecting localities: 1. Laguna Blanca National Park. 2. 20 km E Zapala. 3. 25 km SE Puelén. 4. Cerro Colón. 5. Puesto Las Lagunitas. 6. Estancia Los Toros. Asterisks denote the 2n= 44 karyotype and the solid circle the 2n= 34.

28 CHAPTER V CYTOGENETICS OF GRAOMYS GRISEOFLAVUS (RODENTIA: SIGMODONTINAE) IN CENTRAL ARGENTINA

Introduction Graomys griseoflavus white-bellied rat or pericote de vienti-e blanco, has been reported to possess widely variable diploid chromosome numbers of 34, 35, 36, 37, 38, 41and 42 (Wainberg and Fronza 1974, Pearson and Patton 1976, Theiler and Cardenal 1994, Zambelh et al. 1994, Theiler and Blanco 1996). Despite being a widespread species (Hershkovitz 1962), and that a growing amount of cytogenetic information is being reported, no data is available on the cytogenetics of this species in La Pampa Province. Additionally, the extent of chromosomal variation remains to be assessed in vast portions of the distribution of the species. The examination of collected specimens and on morphological data, suggest that Graomys griseoflavus is widespread in La Pampa Province (Siegenthaler et al. 1990 a, b). It occurs in habitats generally associated with wooded or shrubbed áreas, in ahnost all the westem part of the Province, and being absent in the eastem Pampean portion. Graomys griseoflavus has been collected along roadside rights-of-ways and along fences associated with woody cover in áreas where the land has been converted to crops and pastures. Additionally, it can be found along rock outcroppings and in human dwellings. hi , the species occupies a variety of

29 habitats including orchards, badlands. Monte Desert and Precordillera up to an altiUide of 1950 m (Rosi 1983). The focus of this sttidy is to ftirther document the extent of chromosomal variation of Graomys griseoflayui and to examine the possible existence of a correlation between the disttibution of the different karyotypes and the two major biomes in the área, the Monte Desert and the Espinal. Herein, additional information of the disttibution of Graomys griseoflavus chromosomal forms is provided for Córdoba, La Pampa and La Rioja provinces.

Material and Methods A total of 19 Graomys griseoflavus specimens were live-ttapped using a variety of Sherman, Davis, and wire mesh ttaps. The standard procedure of in vivo colchicine mitotic arrest was used for obtaining chromosomes from bone marrow. In most cases, the yeast sttess method (Lee and Eider 1980) was used to obtain an increased mitotic index. Slides were prepared by dropping the cell suspensión from a 50-60 cm height into a large drop of distilled water on the surface of the slide (Baker et al. 1982). Chromosome slides were observed and photographed and the diploid number and chromosomal morphology was determined for each specimen. All voucher specimens were prepared as standard study skins and skulls and are housed in the collections of Texas Tech University Museum (TTU), being TK the code for its Tissue CoUection, and in the Colección Mastozoológica Orientación Anatomía Comparada of the Universidad Nacional de Rio Cuarto (UNRC), Rio Cuarto, Córdoba, Argentina.

30 Localities sampled and specimens examined (Table 2): La Rioja Province: General San Martin Department, Ulapes, 2 km N. 1 male (TK 49047), 1 female (TK 49048). Córdoba Province: Cruz del Eje Department, Palo Parado, 30 km NW Cruz del Eje. 2 females (TK 40655-40656). La Pampa Province: Toay Department, 12 km NNE Naicó, Estancia Los Toros: 2 females (TK 27891-27892), 1 male (TK 27893). 10 km SW Santa Rosa, Chacra La Lomita: 3 males (TK49171-49173), 5 females (TK 49169- 49170, 49174-49175, 49177). Caleu Caleu Department, 40 km N Anzoategui, Ahnacén el 52: 3 females (TK 27894-27895,40634). Puelén Department, 25 km SE Puelén, NE border of Salittal de La Perra, Puesto Rogueira: 1 male (TK 47611).

Results and Discussion The four specimens from La Rioja and Córdoba provinces possessed a 2n= 42 karyotype consisting of a pair of large submetacentric chromosomes, two smaller pairs of submetacentrics and the remainder of the autosomes being acrocentrics grading in size from large to small. The X chromosome is a médium sized submetacentric and the Y an acrocentric chromosome (Figure 9). This karyotype has been previously recorded for localities in La Rioja, Córdoba and Catamarca provinces (Theiler and Cardenal 1994, Zambelli et al. 1994). From La Pampa Province, the karyotypic data show the pattem that includes 36, 37 and 38 chromosome diploid numbers. This agrees with data for the neighboring Buenos Aires Province (Chasicó, Médanos), and in Mendoza and Catamarca provinces (Theiler and Cardenal

31 1994, Theiler and Blanco 1996). In the case of the 2n= 38 there exists two extta pairs of acrocenttics instead of the large metacenttic pair as in the 2n= 36 form (Figure 10). The 2n= 36 karyotype consists of a pair of large metacenttics, four pairs of médium sized and small submetacentiics and the rest of the autosomes are acrocentric (Figure 11). These forms are interrelated through a number of chromosomal rearrangements that include pericentric inversions and Robertsonian fíisions (Zambelli et al. 1994). Interbreeding between these forms can happen only between 2n= 36-38 females and 2n= 42 males. The hybrids, produced in the laboratory, are sterile (100% of males) or have diminished fertility (23% of females), and have 2n= 39 or 40 (Theiler and Cardenal 1994, Theüer and Blanco 1996). Individual females in estrus are capable of recognizing odors of compatible homomorphic mating partners. Avoidance of heteromorphic mating partners by these females, allows for premating isolation to occur (Theiler and Blanco 1996). Protein electrophoresis studies comparing both sets of cytotypes showed genetic identity valúes (0.911 and 0.915) that would correspond to the same species (Theiler and Cardenal 1994). This is ñirther evidence of how chromosomal change can lead to without the likewise diversifícation of sttiictural genes (White 1978). The geographic distribution of the 2n= 36, 37 and 38 forms are representative of the Monte Desert and the 2n= 42 forms of the Espinal, with both forms overiapping iñ ttansition áreas (Theiler and Blanco 1996). In this report, the 2n= 36, 37 and 38 karyotypes were found at localities belonging to the Caldén (Prosopis caldenia) District of the Espinal (Los Toros, Ahnacén

32 El 52 and La Lomita), and at one locality belonging to the Monte Desert (Puelén) (Cabrera 1976). Despite the growing evidence that the 42 and 36-38 forms represent different species, the nomenclatorial sittiation that is involved has not been addressed. In the particular case of available ñames for these taxa in centtal Argentina, it would be possible to assign the 2n= 42 forms to cenfralis. type locality Cruz del Eje, Córdoba Province, described as a subspecies of griseoflavus (under the genus Eligmodontia^ by Thomas (1902). The present locality of Palo Parado (30 km NW of Cruz del Eje) is the nearest with a documented 2n= 42 specimen of Graomys. For the 2n= 36-38 forms the ñame griseoflavus Waterhouse, 1837 (type locality. Rio Negro) could be applyed. Nevertheless, before invoking these changes, the status of other named putative taxa inhabiting centtal Argentina, such as medius Thomas, 1919 (Chumbicha, Catamarca) and edithae Thomas, 1919 (Otto Cerro, NE La Rioja), should be assessed. The resolution of these problems should include cytogenetics in their type localities in order to be able to reach a conclusión regarding the systematic status of this species complex.

33 Table 2. Distribution of karyotypes in Graomys griseoflavus.

karyotype, 2n= Locality 42 38 37 36

Ulapes 2 Palo Parado 2 Los Toros 2 El 52 3 Puelén 1 La Lomita 1

Total: 19 4 4 8

34 11 M B M m u m

m:^; aí.^' l Mñ t^ M m§ m

ññ ifM mm i itm

Figure 9. 2n= 42 Graomys griseoflavus karyotype (TK 49047, male) from Ulapes, La Rioja.

35 IR m M u m m u H na fto ftn n ti^ •«

í H n* 18 ^^ í^ ^

Figure 10. 2n= 38 Graomys griseoflavus karyotype (TK 49169, female) from La Lomita, 10 km SW Santa Rosa, La Pampa.

36 y a ftft ñn on o fl «n un un

o A II H QQ iJ o (11A (/> ^

(¿I?; I m. i,

Figure 11. 2n= 36 Graomys griseoflavus karyotype (TK 47611, male) from Salitral de La Perra, 25 km SE Puelén, La Pampa.

37 CHAPTER VI CYTOGENETIC OBSERVATIONS ON OTHER TAXA

Introduction For many small mammal species inhabiting central Argentina, karyotypes have not been described from this área, especially from La Pampa Province and neighboring provinces. Little cytogenetic information exists for the mammal fauna of other zones of central Argentina, such as the Pampean Sierras (Sierras de Curamalal and Ventana) and NW (Barros et al. 1990, Ortells et al. 1988). Furthermore, for some taxa, cytogenetic information is restricted to a particular geographic área (Wainberg and Fronza 1974, Williams and Mares 1978 b, Seluja et al. 1984, Brum-Zorrilla et al. 1988) and the extent of chromosomal variation (if any) for these taxa is unknown. Therefore, chromosomal studies serving as a base for soimd systematic identifícation will contribute to a better understanding of the taxonomy and distribution of several small mammal taxa. The purpose of this study is to provide supplemental cytogenetic data from several small mammal species inhabiting central Argentina. Karyotypes are reported for previously unknown áreas or localities.

Material and methods Specimens were live-trapped using a variety of Sherman, Davis, and wire mesh traps. The standard procedure of in vivo colchicine mitotic arrest was used for obtaining chromosomes from bone marrow. In most cases, the yeast stress method (Lee and Eider 1980) was used to obtain an increased

38 mitotic index. Slides were prepared by dropping the cell suspensión from a 50-60 cm height into a large dróp of distilled water on the surface of the slide (Baker et al. 1982). Chromosome slides were observed and photographed and the diploid number and chromosomal morphology was determined for each specimen. All voucher specimens were prepared as standard smdy skins and skulls and are housed in the collections of Texas Tech University Museum (TTU), being TK the code for its Tissue CoUection, and in the Colección Mastozoológica Orientación Anatomía Comparada of the Universidad Nacional de Rio Cuarto (UNRC), Rio Cuarto, Córdoba, Argentina.

Results and Discussion Family Didelphidae Lutreolina crassicaudata The karyotype of this opossum has a 2n= 22 with three pairs of large acrocentric chromosomes and seven pairs of médium sized acrocentric autosomes. The X is a metacentric and the Y a small acrocentric (Seluja et al. 1984) (Figure 12). Similar karyotypes in Argentina for this species have been described for Buenos Aires Province, Parque Pereyra Iraola (Reig et al. 1977). Specimens examined: Córdoba, Arroyo Chucul: TK 45615, female. TK 47614, female.

39 Monodelphis dimidiata This short-tailed opossum has a 2n= 18 with two pairs of large and medium-sized metacentrics, being the rest of the autosomes submetacentric or subtelocentric. The X is a subtelocentric and the Y a small acrocentric, as described for the typical karyotype for the genus in the species Monodelphis orínoci (Reig et al. 1977) (Figure 13). Karyotypes for M. dimidiata in Argentina have been reported for eastem Buenos Aires Province (Reig and Bianchi 1969). Specimens examined: Buenos Aires, Sierras de Curamalal, Abra del Hinojo: TK 47639, TK 47654, males.

Thylamys pusillus This mouse opossum has a 2n= 14 complement formed by three pairs of submetacentrics, one pair of metacentrics and the rest are two pairs of subtelocentrics. The X chromosome is a small metacentric and the Y chromosome is a very small acrocentric (Reig et al. 1977) (Figure 14). Cytogenetic information for specimens from Argentina is available from Chasicó, Buenos Aires Province (Reig et al. 1977). The extent of chromosomal uniformity in the genus Thylamys has been ñirther documented byPahna(1994). Specimens examined: Neuquén, Lagima Blanca National Park: TK 40699, male. La Pampa: Cerro Colón: TK 47621, female. TK 47622, male.

40 Family Phyllostomidae Desmodus rotundus The karyotype of the common vampire bat, 2n= 28, described among others by Forman et al. (1968), consists of 13 pairs of metacentric or submetacentric chromosomes. The X is a large submetacentric and the Y a small acrocentric (Figure 15), although a biarmed Y chromosome has been reported for a specimen from Trinidad (Forman et al. 1968). Specimens examined: Córdoba, Segunda Usina: TK 40674, male.

Family Vespertilionidae Eptesicus ñirinalis Wilhams (1978) described the karyotype of this species as consisting of 48 acrocentric chromosomes (2n= 50), with the X being a large submetacentric and the Y a small acrocentric (Figure 16). New World Eptesicus all have karyotypes of very similar gross morphology as has been described for the species diminutus and brasiliensis that inhabit South America (Baker and Patton 1967, Williams 1978, Freitas et al. 1992). For Argentina, karyotypes are known from specimens from Tucumán Province (Williams 1978). Specimens examined: La Pampa, Santa Rosa: TK 40689, female. Córdoba, Coronel Baigorria, Estancia San Gonzalo: TK 40660, female.

41 Family Molossidae Eumops perotis The karyotype of this species, 2n= 48, was described by Baker (1970). It consists of one pair of large metacentrics, three pairs of meta- submetacentric chromosomes, two pairs of subtelocentrics and 17 pairs of acrocentrics. The X chromosome is a médium submetacentric an the Y a small acrocentric (Figure 17). In Argentina karyotypes have been reported from specimens from Tucumán Province (Wainberg et al. 1974). Specimens examined: Córdoba, Segunda Usina: TK 40676, TK 40680, TK 40681, males.

Tadarida brasiliensis The karyotype of this species, 2n= 48, has been reported by Wamer et al. (1974) and consists of a pair of large metacentrics, two pairs of smaller metacentrics, one pair of medium-sized subtelocentrics, one pair of small subtelocentrics and 18 pairs of acrocentrics ranging in size from médium to small. The X chromosome is a médium sized submetacentric and the Y chromosome is a small acrocentric (Figure 18). Specimens examined: Córdoba, Coronel Baigorria: TK 40665, female. La Pampa, Santa Rosa: TK 40640, female.

Dasypodidae Chaetophractus vellerosus This armadillo shows a 2n= 62 karyotype with one large pair of metacentrics, three pairs of metacentrics, 11 pairs of submetacentrics, 16

42 pairs of acrocentrics. The X is a large submetacentric and the Y a very small acrocentric (Rahn et al. 1994) (Figure 19). Specimens examined: La Pampa, Eduardo Castex, 20 km N: TK 40651, male. Los Toros: TK 40261, female.

Sigmodontinae Abrothrix xanthorhinus This species of Andean-Patagonian mouse exhibits a 2n= 52 karyotype. It is composed of acrocentric chromosomes except for two submetacentric and one subtelocentric pairs of autosomes. The X chromosome is a subtelocentric and the Y submetacentric. This karyotype has been described for Argentina in Tierra del Fuego (Bianchi et al. 1971) (Figure 20). Similar karyotypes have been described in the species olivaceus. longipilis, andinus, sanbomi and jelski and in the related genera Chelemys and Geoxus (Spotomo et al. 1990, Espinosa et al. 1991). Specimens examined: Neuquén, Laguna Blanca National Park: TK 40238, male. TK 40258, female.

Akodon azarae This chromosomally well studied species has a 2n= 38 and its karyotype is composed of 16 acrocentric pairs and one pair of metacentrics. The X chromosome is subtelocentric and the Y is the smallest of the set and has been interpreted as a small metacentric (Figure 21) (Bianchi et al. 1971, Vitullo et al. 1986). Females of this species have been found (in Buenos Aires Province), to possess a variable confíguration in the X chromosomes

43 existing individuáis that can be XX; Xx, in which the sexual pair is heteromorphic produced by a deletion of part of one X chromosome; or XO, with one of the X chromosomes being totally deleted (Bianchi et al. 1968). Additionally, karyotypes have been described for the subspecies A. a. bibianae for (Vitullo et al. 1986). Specimens examined: La Pampa, Santa Rosa: TK 47633, male. Laguna Don Tomás: TK 40601, male. TK 40606, male. Buenos Aires, Sierras de Curamalal, Abra del Hinojo: TK 47656,' male.

Akodon iniscatus This Patagonian species has a 2n= 34 karyotype with the autosomes composed of a large pair of submetacentrics, three pairs of smaller metacentrics, eleven pairs of acrocentrics, and a pair of small submetacentrics. The X and Y chromosomes are small acrocentrics (Barros et al. 1990) (Figure 22). Karyotypes have been reported for localities in Chubut and Neuquén provinces with the fíndingo f a heteromorphic variant (2n= 33) in which there exists a metacentric chromosome formed by a Robertsonian ñision of two acrocentrics (Barros et al. 1990). Specimens examined: Neuquén, Laguna Blanca National Park: TK 40237, male. TK 40255, female. TK 40256, female. TK 40290, male.

Bolomys sp. This genus possesses a conservative karyotype for most of its species. Vitullo et al. (1986) described a 2n= 34 karyotype for Bolomys temchucki with all acrocentric autosomes except for the smallest pair that is composed

44 of metacentric chromosomes. The X chromosome is acrocentric and the Y a small metacentric (Figure 23). This same karyotype, as Akodon obscurus. has been described for Buenos Aires Province (Bianchi et al. 1971). The systematic status of the species of Bolomys in Argentina is not yet resolved. These mice have been included in Akodon, Zygodontomys. Cabreramys (Cabrera 1961, Reig 1965, Massoia and Fomes 1967, Anderson and Olds 1989). Massoia and Pardiñas (1993) recognized that the described by Ameghino (1889) as conifer, represents what was later known as Bolomys^ and considering this latter ñame a júnior synonym of Necromys. Hershkovitz (1962) synonimized Necromys conifer with Calomys callosus which is not known from the fossil record, and this arrangement has been recently disputed by Massoia and Pardiñas (1993). Nevertheless, in this report the ñame Bolomys is used considering the recent view of mantaining this genus (Salazar-Bravo 1996). Moreover, the number of species in the genus remains unclear. Several authors have reported the existence of an undescribed species in south Buenos Aires Province (Reig 1987, GalHari et al. 1991) and the need of a revisión of the group. For La Pampa Province, the taxon was cited by Contreras and Justo (1974) as Akodon benefactus. Nevertheless, their presence in a distinct phytogeographical unit (the Espinal), warrants caution in developing systematic conclusions. Unfortunately, the lack of suffícient material from this province, and the fáct that members of the genus have an overall very similar 2n= 34 karyotype, makes this situation unsolvable through standard cytogenetics.

45 Specimens examined: La Pampa, Quehué, Estancia Los Molinos: TK 47628, male. Estancia El Pincén: TK 47624, female. Buenos Aires, Sierras de Curamalal, Abra del Hinojo: TK 47649, female. TK 47652, male.

Calomys laucha The karyotype of this species of has been described by Cardenal et al. (1977) from Córdoba Province. It has a 2n= 64 consisting of a pair of large metacentrics, a pair of large submetacentrics, a pair of small metacentrics and a pair of small subtelocentrics, the rest of the autosomes acrocentric and the X chromosome a large submetacentric (Figure 24) and the Y a small acrocentric (Cardenal et al. 1977). Specimens examined: Córdoba, Coronel Baigorria: TK 40685, male. La Pampa, Catriló: TK 47671, female.

Calomys musculinus This species has a karyotype (2n= 38) composed of a large metacentric pair, seven pairs of medium-sized metacentric and submetacentric chromosomes, five pairs of médium subtelocentrics, three pairs of small subtelocentrics, and two pairs of small metacentric chromosomes. The X chromosome is a submetacentric of large size and the Y is apparently an extremely small subtelocentric (Forcone et al. 1980) (Figure 25). Specimens examined: La Pampa, Naicó, Estancia Los Toros: TK 40619, female. TK 27896, male. Catriló: TK 47667, female. San Luis, Eleodoro Lobos: TK 49066, male. Córdoba, Rio Cuarto, Paraje San José: TK 49009, male.

46 Calomys venustus The karyotype of this species is variable (2n= 54, 55, 56). The 2n= 56 specimens show six pairs of metacentric or submetacentric chromosomes, being the rest of the autosomes acrocentric. The X is a large submetacentric and the Y a small subtelocentric (Figure 26). This and similar karyotypes had been described under the ñame Calomys "callosus" by Catalfo and Wainberg (1974) who reported a 2n= 54 karyotype from Famaillá, Tucumán Province. Lisanti et al. (1976) reported 2n= 55-56 karyotypes for £. "callosus" from three localities in Córdoba Province, Argentina; and Cardenal et al. (1977) reported the same 2n= 56 karyotype also from Córdoba. Pearson and Patton (1976) described the karyotype of £. callosus from Paraguay with a 2n= 36 chromosome number and of C fecundus with a 2n= 50 from 160 km N Trinidad, Beni, Bolivia. This allowed the assignment of Paraguayan and Bolivian specimens to these species respectively. Obviously, the differences in chromosomal number between the Paraguayan karyotype warrants recognition of Calomys venustus (Thomas, 1894, type locality Cosquin, Córdoba) as a ñill species (Vitullo et al. 1990) and should not be considered subspecies of £. callosus (e.g. Musser and Carleton 1993). Additionally, a related taxon, £. cdliduihas a 2n= 48 karyotype (Vitullo et al. 1984) and is interrelated with £. venustus (2n= 56) through four Robertsonian rearrangements (Vitullo et al. 1990). Specimens examined: Córdoba, Espinillo: KT 49114, male. TK 49115, male. TK 49116, female. TK 49117, female.

47 Oljgorvzomvs flavescens Variable karyotypes have been reported for this species. In Brazil, 2n= 64-66 have been described by Sbalqueiro et al. (1991). hi Argentina, a 2n= 66 karyotype, has been described for Buenos Aires Province (Brum-Zorrilla et al. 1988). This karyotype sometimes possesses heteromorphic autosome pairs and differences in the Y chromosome that can be a médium sized submetacentric or a very small acrocentric. In Umguay 2n= 66 and 2n= 64 karyotypes with 30 or 29 acrocentric pairs and with 2 small metacentric pairs have been described (Bmm-Zorrilla et al., 1988). In the present case, four female specimens possessed a 2n= 66 karyotype consisting of 29 pairs of acrocentric chromosomes, 3 pairs of small metacentrics or submetacentrics, being the X a large submetacentric (Figure 27). These karyotypes are identical to one described by Brum-Zorrilla et al. (1988) for Punta Lara, Buenos Aires Province. Specimens examined: Córdoba, Coronel Baigorria: TK 40262, female. TK 47604, female. TK 47608, female. TK 47609, female.

Oxymyctems mñis (= O. mtilans^ The hocicudo shows a 2n= 54 karyotype with a pair of large subtelocentrics, three pairs of small metacentrics, and the rest of the autosomes being acrocentrics. The X chromosome is a large submetacentric, and the Y a médium sized acrocentric (Vitullo et al. 1986). Species in this genus seem to be conservative in their karyology, as ü. rutilans and Q. paramensis have basically identical karyotypes (Vitullo el al. 1986).

48 Specimens from Espinillo, Córdoba Province showed the above described karyotype (Figure 28). Specimens examined: Córdoba, Espinillo: TK 49118, male. TK 49119, female. TK 49121, female. Arroyo Chucul, TK 47616, female. Buenos Aires, Sierra de la Ventana: TK 47632, male.

Phvllotis xanthopygus Several species of Phyllotis exist with a diploid number of 38. This karyotype is composed of all metacentric and submetacentric chromosomes (Pearson and Patton 1976, Walker et al. 1984, 1991). Comparisons between some species reveal that they are characterized by differences in constitutive heterochromatin, as manifested through C-bands. These differences range from small or absent C-bands (P. darwini) to large heterochromatic blocks (P. X. vaccamm) (Walker et al. 1991). Karyotypes in Argentina (2n= 38) have been described for P. caprinus and E. darwini for Jujuy and Catamarca provinces (Pearson and Patton 1976). A 2n= 38 karyotype was found in six Phyllotis xanthopygus specimens from Laguna Blanca National Park, Neuquén Province (Figure 29). Specimens examined: Neuquén, Laguna Blanca National Park: TK 40243, male. TK 40234, male. TK 40244, female. TK 40252, female. TK 40253, female. TK 40254, female.

Reithrodon auritus This species has a 2n= 34 karyotype, and is entirely composed of acrocentric autosomes. The X chromosome is a médium sized acrocentric

49 and the Y a small acrocentric chromosome. The few karyotypes that have been reported have resolved the status of Reithrodon typicus (2n= 28) inhabiting Uruguay and southeastem Brazil; and aurims. found in Argentina (2n= 34) (Ortells et al. 1988). A specimen fromL a Pampa showed the karyotype as above described (Figure 30). Specimens examined: La Pampa, Quehué, Estancia Los Molinos: TK 47627, female.

50 11 II II 18 00 I i id aj en o 9

Figure 12. Lutreolina crassicaudata karyotype. 2n= 22: three pairs of large acrocentrics and seven pairs of médium sized acrocentrics. The X is a metacentric. Córdoba, Arroyo Chucul: TK 45615, female.

51 m or> 00 AA

Ü(\ A¡\ v\w ««I •

Figure 13. Monodelphis dimidiata karyotype. 2n= 18: two pairs of large and medium-sized metacentrics, six pairs of submetacentrics or subtelocentrics. The X is a subtelocentric and the Y a small acrocentric. Buenos Aires, Abra del Hinojo: TK 47654, male.

52 xx XI II K«

A A A H

Figure 14. Thylamys pusillus karyotype. 2n= 14: three pairs of submetacentrics, one pair of metacentrics and two pairs of subtelocentrics. The X is a small metacentric and the Y is a very small acrocentric . Neuquén, Laguna Blanca National Park: TK 40699, male.

53 M U m «H nr,

íí K KK HH «X fix

^X ní\ x« i\ ^

Figure 15. Desmodus romndus karyotype. 2n= 28: 13 pairs of metacentric or submetacentric chromosomes. The X is a large submetacentric and the Y a small acrocentric. Córdoba, Segunda Usina: TK 40674, male.

54 00 ad aifi iin (Ao oo o« oi^ o o

A 5 ^ñ Q on f)-o o A A) A;0^ o^ A]«

^ ' A ^; ' f^ I A ^ «M> . .^^ * ' <« « i • ' * > *, A A V"»l»./

Figure 16. Eptesicus furinalis karyotype. 2n= 50: 24 pairs of acrocentrics. The X is a large submetacentric. La Pampa, Santa Rosa: TK 40689, female.

55 XI i* M Añ M« fifi n n tu

AO fio Q o fio on /\r% *a

#> #% Ii0 v^:^ *^ 1^ #%*.-• #<%

Figure 17. Eumops perotis karyotype. 2n= 48: one pair of large metacentrics, three pairs of meta-submetacentric chromosomes, two pairs of subtelocentrics and 17 pairs of acrocentrics. The X is a médium submetacentric an the Y a small acrocentric. Córdoba, Segunda Usina: TK 40676, male.

56 RA x» %H AH H^ i>ñ ft«

• A All nn O* aII tt41 «SA

/> «I í* A A** •• A 0 *^ 0*

KÁ

Figure 18. Tadarida brasiliensis karyotype. 2n= 48: one pair of large metacentrics, two pairs of smaller metacentrics, one pair of medium-sized subtelocentrics, one pair of small subtelocentrics and 18 pairs of acrocentrics. The X is a médium sized submetacentric. Córdoba, Coronel Baigorria: TK 40665, female.

57 fu m ^;íl t:h XIJl 11 iSii

?* ** j^H »• *t ^^ ,, Aift

Aft nn /i n A n /^n o n A© «a

Figure 19. Chaetophractus vellerosus karyotype 2n= 62: one large pair of metacentrics, three pairs of metacentrics, 11 pairs of submetacentrics, 16 pairs of acrocentrics. The X is a large submetacentric. La Pampa, Naicó, Estancia Los Toros: TK 40261, female.

58 M( {)/A oft 8/ft ü A. on «n

ftO ftA AYI /\^. o 1^ A O A A

o ¿I ^p ,í n d A A o n /% '/ A

•• ^ #^ (.^ A í^.4 Ai A

Figure 20. Abrothrix xanthorhinus karyotype. 2n= 52: 22 pairs of acrocentrics, two pairs of submetacentrics, and one pair of subtelocentrics. The X is subtelocentric and the Y submetacentric. Neuquén, Laguna Blanca National Park: TK 40238, male.

59 Al} ;ft n o A ñn n A n A A Ó

/ A O \n A A -^ A A A /\ 1% ^j -* —

^% A

Figure 21. Akodon azarae karyotype. 2n= 38: 16 pairs of acrocentrics and one pair of metacentrics. The X is subtelocentric and the Y a small metacentric. La Pampa, Laguna Don Tomás: TK 40601, male.

60 fí XA XX XA «-'^ -* — (/K.-^

Figure 22. Akodon iniscatus karyotype. 2n= 34: one pair of large submetacentrics, three pairs of smaller metacentrics, eleven pairs of acrocentrics, and a pair of small submetacentrics. The X and Y are small acrocentrics. Neuquén, Laguna Blanca National Park: TK 40237, male.

61 flíl (in nn an DA nn o o

on A A r\,n A o |\,n ,/%-^

I «I A*

Figure 23. Bolomys sp. karyotype. 2n= 34: 15 pairs of acrocentrics, one pair of small metacentrics. The X is acrocentric and the Y a small metacentric. La Pampa, Quehué, Estancia Los Molinos: TK 47628, male.

62 «H m >^ AA SA nn Qi«

ftiA on Oñ rv,/\ (X 0 a A A >v

n <> 00 €kd on 0,8 AiA n,n

A A An A/\ o A A J(> art nm

Ah

Figure 24. Calomys laucha karyotype. 2n= 64: one pair of large metacentrics, a pair of large submetacentrics, a pair of small metacentrics, a pair of small subtelocentrics, and 27 pairs of acrocentrics. The X is a large submetacentric. La Pampa, Catriló: TK 47671, female.

63 «HA UM I » I X M-« lAiJC «A

« C«'; 1 ñ A

Figure 25. Calomys musculinus karyotype. 2n= 38: one pair of a large metacentrics, seven pairs of mediimi-sized metacentrics and submetacentrics, fíve pairs of médium subtelocentrics, three pairs of small subtelocentrics, and two pairs of small metacentrics. The X is a large submetacentric. La Pampa, Naicó, Estancia Los Toros: TK 40619, female.

64 \\¡\ KB m m m M ao

(\n A A Ai) no (0 0 fvñ A A

o A l'VA nn IIO HM A A IVA

A A 10 O A O 7^^'i% A t\ í» «ii i

Figure 26. Calomys venustus karyotype. 2n= 56: six pairs of metacentrics or submetacentrics, 21 pairs of acrocentrics. The X is a large submetacentric and the Y a small subtelocentric. Córdoba, Espinillo: KT 49114, male.

65 m M H na OR u o o o

O Q O A i o A A í> A A A A A A

#>/#• lAA ,A #% «» fN A«» ,«k «B

^' A ,« <% «_,« .#• I ,• j' )|i n »¡ ji : ;f ,K ti

Figure 27. Oligoryzomys flavescens karyotype. 2n= 66: 29 pairs of acrocentrics, 3 pairs of small metacentrics or submetacentrics. The X is a large submetacentric. Córdoba, Coronel Baigorria: TK 40262, female.

66 M íin m o íi y\/> irt o oa

A« r»n oA AA «A f\A ^^ v-v

v%IX fíiA .ii:^ n,|^ /%iA /»v\ / % i#\

•/", .• - - ** -" - - /\ ñ

Figure 28. Oxymyctems mfiís karyotype. 2n= 54: one pair of large subtelocentrics, three pairs of small metacentrics, and 22 pairs of acrocentrics. The X is a large submetacentric, and the Y a médium sized acrocentric. Córdoba, Espinillo: TK 49118, male.

67 I if u u m H n ti M M u u 'a XK

xx K% t't \X\t ti

Figure 29. Phyllotis xanthopygus karyotype. 2n=38: ISpairsof metacentrics or submetacentrics. The X is a large metacentric and the Y a médium sized submetacentric. Neuquén, Laguna Blanca National Park: TK 40243, male.

68 II II fli Ifl nn SiO M n

i*

Figure 30. Reithrodon aurihis karyotype. 2n= 34: 16 pairs of acrocentrics. The X is a médium sized acrocentric. La Pampa, Quehué, Estancia Los Molinos: TK 47627, female.

69 CHAPTER Vn CONCLUSIONS

It is my hope that the present thesis will allow for a better understanding of cytogenetical information available for central Argentina. Also it is hoped that this thesis may serve as a baseline for fiíture studies. In some taxa, there appears to be a correlation between different cytotypes and biogeographic units, which can be inferred from the following examples. First, although the limits of the distribution of the species of Eligmodontia remains to be addressed, it is apparent that one species may be Patagonian in a biogeographic sense, and the other proper of the Monte Desert. In a second example, the distribution of chromosomal forms in the Akodon dolores/molinae complex appears to be affected by the Cordobean Sierras. Additionally, the Graomys griseoflavus chromosomal species complex appears to have one extreme (2n= 42) in the northem portion of the Espinal thom scmb forests, while the other (2n= 36, 37, 38) seems to be distributed in the Monte Desert and in the southem portion of the Espinal. These examples, coupled with fiíture studies, may contribute to determine the existence of pattems in chromosomal variation linked to the biogeography of the área (Spotomo et al. 1994). Eventually, studies including molecular data may show more about the relationships among mammal species in these vast biotic landscapes.

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