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Tesis presentada para optar al Grado de Doctor en Ciencias Naturales Fil: Seitz, Viviana Paola. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

The armadillo Chaetophractus villosus does not stop breathing when experimentally covered with soil. Under that condition, there is a gradual but considerable drop in deep rectal temperature (TB): after 90 minutes, mean +/- SD = 1.7 +/- 0.4 degrees C (n = 8). As soon as the soil is removed and the animal breathes open air, TB gradually increases.

Background: Placental characters vary among Xenarthra, one of four supraordinal clades of Eutheria. Armadillos are known for villous, haemochorial placentas similar to humans. Only the nine-banded armadillo has been well studied so far. Methods: Placentas of three species of armadillos were investigated by means of histology, immunohistochemistry including proliferation marker, and transmission and scanning electron microscopy. Results: The gross anatomy differed: Euphractus sexcinctus and Chaetophractus villosus had extended, zonary placentas, whereas Chaetophractus vellerosus had a disk. All taxa had complex villous areas within the maternal blood sinuses of the endometrium. Immunohistochemistry indicated the validity of former interpretations that the endothelium of the sinuses was largely intact. Tips of the villi and the columns entering the maternal tissue possessed trophoblast cell clusters with proliferation activity. Elsewhere, the feto-maternal barrier was syncytial haemochorial with fetal vessels near the surface. Conclusions: Differences among armadillos occurred in regard to the extension of the placenta, whereas the fine structure was similar. Parallels to the human suggest that armadillos are likely to be useful animal models for human placentation, Facultad de Ciencias Veterinarias

Body temperature of the armadillo Chaetophractus villosus (n = 17) was studied during a period of 15 days. Deep rectal temperature (TB) was recorded at 9 am, 1 pm and 5 pm. Temperature in the laboratory was kept between 24.6 degrees C and 26.0 degrees C. We found two main different profiles of thermal behaviour in our animals, namely: a) one with high variation, mainly due to the daily cycle. b) the other with middle or low variation, with no predominance of the daily cycle. There were great TB differences between hours (P < 0.01). Morning temperatures were lower than the other ones. This is what could be expected in a non diurnal animal like C. villosus.

Three xenarthrans species Chaetophractus villosus, Chaetophractus vellerosus, and Zaedyus pichiy have been used for the analysis of the structure, behavior, and immunochemical features of the XY body during pachytene. In all these species, the sex chromosomes form an XY body easily identifiable in thin sections by the special and regular packing of the chromatin fibers of the internal region of the XY body ("differential" regions) and those of the peripheral region (synaptic region). Spermatocyte spreads show a complete synapsis between the X- and the Y-axis, which lasts up to the end of pachytene. From the early pachytene substages to the late ones, the X-axis develops prominent branches, which in late pachytene span the synaptic region. Synapsis is regular as shown by SYCP1 labeling. Axial development is followed by SYCP3 labeling and in the asynaptic region of the X-axis by BRCA1. Gamma-H2AX labels exclusively the differential (asynaptic) region of the X chromosome. A single focus is labeled by MLH1 in the synaptic region. The location of this MLH1 focus spans from 0.3 to 1.6 μm from the telomere in the analyzed xenarthrans, covering approximately half of the Y-axis length. It is concluded that xenarthrans, as basal placental mammals, harbor the largest pseudoautosomal regions of presently analyzed mammals, and shows the typical features of meiotic sex chromosome inactivation (MSCI).

Armadillos represent the most diverse family of xenarthrans. Although many studies have been done on these mammals, several topics, such as their local distribution, natural history, behavioral ecology and conservation, remain poorly known. Chaetophractus villosus and Zaedyus pichiy are the most common armadillos in extra-Andean Patagonia, a vast area in southern Argentina and Chile that encompasses different ecosystems and has been modified by human activities, mainly by sheep grazing. In this work we present new data on the distribution, natural history, conservation, and ecology of C. villosus and Z. pichiy from central Patagonia (Chubut and Río Negro provinces, Argentina). We registered 60 localities for C. villosus and 35 for Z. pichiy that confirm their presence in wide sectors of central Patagonia. Furthermore, we confirmed that these two armadillo species suffer high rates of mortality due to their use as a protein source, hunting by dogs, road traffic, and poisoning, among others. We conclude that their populations are at risk of overexploitation and local extinction. The basic knowledge provided here will be a first step towards the conservation of these characteristic Patagonian mammals., Facultad de Ciencias Naturales y Museo

The morphological features of the oviduct in the armadillo Chaetophractus villosus (Desmarest, 1804) were studied. In the simple columnar epithelium, ciliated cells, secretory cells, and cells of the bottom of the folds are described. The most remarkable findings are the increase in number of ciliated cells, when present, from the fimbriae to the uterus, being the isthmus practically lined by ciliated cells, and that secretory cells are more abundant in the apical zone of the ampulla and fimbriae, than in the isthmus. Morphological changes along the year in the different portions are described.

The aim of this study was to study the sexual dimorphism in adult Chaetophractus villosus (Desmarest, 1804), from northern Patagonia, Argentina. Eight mandibular traits were measured in 37 males and 34 females. Univariate and multivariate morphometric analysis were applied to the data set. Results showed that C. villosus was sexually dimorphic, with higher absolute values corresponding to females. The total length of the mandible was the most important variable to discriminate sexes, followed by the height at the level of the last tooth and body length. The percentages of sex discrimination were high, as they were when a new sample (17 males, 13 females) was tested. Females have larger mandibles than males independently of their larger cranial size. They also showed a higher degree of correlation between variables, suggesting a more stable shape for the mandible than in males.

We evaluated the effects of land use on the distribution of 3 sympatric species of armadillos, Chaetophractus villosus, C. vellerosus, and Dasypus hybridus, on 34 farms in the eastern Pampas. We characterized 4 soil and vegetation variables around each burrow located during surveys of these farms, and related burrow abundance to 10 variables used to characterize each farm. C. vellerosus was the most specialized, using primarily native woodlands and areas with calcareous soil. D. hybridus was associated with natural grasslands and avoided cultivated pastures, and was negatively related to the number of dogs that lived on the farms. C. villosus, the most abundant species, was found in all 4 types of habitats, but its distribution depended on the intensity of hunting on each farm., Facultad de Ciencias Naturales y Museo

Realizamos estudios morfologico y morfometrico de los componentes oseos del craneo de Chaetophractus villosus. Los huesos son morfologicamente semejantes en ambos sexos y siguen el patron generalizado de la mayoria de los dasipodidos descritos. El analisis morfometrico, sin embargo, demostro que la mayoria de los huesos ubicados en el plano rostrocaudal son mas largos en las hembras, determinando mayores valores de longitudes total, basal y condilobasal del craneo, que son las principales variables que contribuyen a determinar el dimorfismo sexual en esta especie

El quirquincho andino, Chaetophractus nationi (Thomas 1894) es un Dasipodido relativamente raro, con pocos ejemplares colectados a lo largo de su rango distribucional. Como consecuencia del escaso material depositado en colecciones sistemáticas y a la información fragmentada que puede proveer el ejemplar tipo, la identidad sistemática de esta especie se ha mantenido en discusión hasta la actualidad. Hasta el momento los únicos registros documentados de C. nationi para la Argentina pertenecen a la provincia de Jujuy. En este trabajo se extiende la distribución de esta especie hasta la provincia de Tucumán, mediante dos registros obtenidos recientemente y se realiza una comparación del cráneo de C. nationi con C. villosus y C. vellerosus, remarcando diferencias entre estas especies, en la forma de la sutura escamosal-yugal, conducto auditivo y el desarrollo de las crestas conformadas por el proceso mastoideo y la osificación del meato acústico. Fil: Carrizo, Luz Valeria. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina Fil: Sánchez, M. S,. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina Fil: Mollerach, Marcos Ismale. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina Fil: Barquez, Ruben Marcos. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina

The distribution of the vertebrate telomeric sequence (TTAGGG)(n) in four species of armadillos (Dasypodidae, Xenarthra), i.e. Chaetophractus villosus (2n = 60), Chaetophractus vellerosus (2n = 62), Dasypus hybridus (2n = 64) and Zaedyus pichiy (2n = 62) was examined by FISH with a peptide nucleic acid (PNA) probe. Besides the expected telomeric hybridization, interstitial (centromeric) locations of the (TTAGGG)n sequence were observed in one chromosome pair of Chaetophractus vellerosus and Zaedyus pichiy, suggesting chromosome fusion of ancestral chromosomes occurring during the evolution of Dasypodidae. In addition, all the species analysed showed one to four apparently telocentric chromosomes, exhibiting only two telomeric signals. However, the immunodetection study of kinetochore proteins on synaptonemal complex spreads from C. villosus showed that the apparently telocentric chromosomes have a tiny short arm that can be resolved only in the more elongated pachytene bivalents. This finding suggests that none of the species of armadillos possess true telocentric chromosomes. Our present results support a reduction in the diploid number by fusion of acrocentrics with loss of chromosome material as a tendency in Dasypodidae.

Chaetophractus villosus is able to maintain efficient respiratory movements when its nostrils are experimentally covered with soil. Under these conditions, a progressive bradycardia develops. It would depend on hypothermia and asphyxia.

The 30 living species of armadillos, anteaters, and sloths (Mammalia: Xenarthra) represent one of the three major clades of placentals. Armadillos (Cingulata: Dasypodidae) are the earliest and most speciose xenarthran lineage with 21 described species. The question of their tricky phylogeny was here studied by adding two mitochondrial genes (NADH dehydrogenase subunit 1 [ND1] and 12S ribosomal RNA [12S rRNA]) to the three protein-coding nuclear genes (alpha2B adrenergic receptor [ADRA2B], breast cancer susceptibility exon 11 [BRCA1], and von Willebrand factor exon 28 [VWF]) yielding a total of 6869 aligned nucleotide sites for thirteen xenarthran species. The two mitochondrial genes were characterized by marked excesses of transitions over transversions-with a strong bias toward CT transitions for the 12S rRNA-and exhibited two- to fivefold faster evolutionary rates than the fastest nuclear gene (ADRA2B). Maximum likelihood and Bayesian phylogenetic analyses supported the monophyly of Dasypodinae, Tolypeutinae, and Euphractinae, with the latter two armadillo subfamilies strongly clustering together. Conflicting branching points between individual genes involved relationships within the subfamilies Tolypeutinae and Euphractinae. Owing to a greater number of informative sites, the overall concatenation favored the mitochondrial topology with the classical grouping of Cabassous and Priodontes within Tolypeutinae, and a close relationship between Euphractus and Chaetophractus within Euphractinae. However, low statistical support values associated with almost equal distributions of apomorphies among alternatives suggested that two parallel events of rapid speciation occurred within these two armadillo subfamilies.

The late Pleistocene-early Holocene sequence at the Arroyo Seco 2 is one of the most complete record in Pampean Region. Four stratigraphic units are distinguished, three of which contain abundant small mammals fossil. Fossil bones from these units are analysed in order to determine the taphonomic processes and habitat present during the accumulation of their fauna remains. Most of the fossil bones are broken after burial. Bones from the deeper units are recovered of manganese (Mn) produced by the water level oscillations consequence of the successive swamping. Three species of armadillo ( Chaetophractus villosus, Dasypus hybridus and Zaedyus pichiy ) and four rodents ( Akodon azarae, Rheitrodon auritus, Ctenomys talarum and Lagostomus maximus ) are present. Record of micro-mammal plus megafauna evidence show a transition from temperate and semiarid to more humid conditions between 12,000 and 8,500 yrs BP.

s / Placenta 34 (2013) A1–A99 A61 P2.14. CANINE IPSC GENERATION WITH NON-INTEGRATIVE VECTORS Natalia J. Goncalves , Sehwon Koh, Fabiana F. Bressan , Daniele S. Martins , Flavio V. Meirelles , Jorge Piedrahyta , Carlos E. Ambrosio 1 Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, Pirassununga, SP, Brazil; Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA Episomal vector systems have the potential to avoid undesired side effects, since they behave as separate extrachromosomal elements in the nucleus of a target cell. The main goal of gene therapy is to treat loss-offunction genetic disorders by delivering correcting therapeutic DNA sequences into the nucleus of a cell, allowing its long-term expression at physiologically relevant levels. Production of non-transgenic iPS cells is highly desirable especially in large animal models such as the canine model. Adult canine skin fibroblasts (cSFs) were seeded at 8E5 cells per 10-cm dish and maintained in DMEM/F12 and supplements. Episomal vectors containing the murine pluripotency transcription factors (Oct3/4, Sox2, Klf4 and c-Myc, OKSM) and episome plus each of the OKSM were used to generate independent ciPSC cell lines. Nucleofection of episomal plasmids was performed with Amaxa nucleofection protocol. Cells were transfected twice for eight hours, the vectors were removed and culture media was replaced. On day 6 post-infection, the transfected cells were replated into new MEFs, the next day, culture media was replaced by mTESR. Cell cultures were analysed after non-integrated vectors in each treatment and compared with cells transfected with episomal vector only. It was observed morphological changes in the c-myc transfected culture, resembling iPS colonies. These colonies presented alkaline phosphatase (AP) activity and we confirmed pluripotency marker expression using polymerase chain reaction (PCR). Our findings show the way for the generation of iPSC free of vector integration, excluding problems caused by viral integration, and increasing the therapeutic potential of these cells. The efficiency of canine iPSC in this study, however, was increased when c-myc alone was used in combination with OKSM vector. http://dx.doi.org/10.1016/j.placenta.2013.06.182 P2.15. PLACENTAL EVOLUTION IN THE ANTEATERS AND ARMADILLOS (EUTHERIA, XENARTHRA) Andrea Mess , Phelipe Favaron , Christiane Pfarrer , Maria Angelica Miglino 1 Department of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, Sao Paulo, Brazil; 2 Institute of Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany Placental characters vary among Xenarthra, one of four supraordinal clades of Eutheria that was likely in a basal position and makes that their characteristics influence perceptions of evolution. Objectives: Since only 1% of eutherian species have been investigated in relations to the placentation the aim of this research was to investigate the fetomaternal interface in 2 species of anteaters (Myrmecophaga tridactyla and Tamandua tetradactyla) and 3 species of armadillos (Euphractus sexcinctus, Chaetophractus villosus, and Chaetophractus vellerosus). Methods: Placentae samples were investigated by histology, immunohistochemistry, and transmission and scanning electron microscopy. Results: Data indicated differences in gross anatomy: Euphractus and Chaetophractus villosus had extended, zonary placentas and Chaetophractus vellerosus had a disk. In anteaters the gross anatomy varied from an extended placenta from mid to a discoidal placenta in late stages. Data showed that in anteaters remnants of the maternal vessel endothelium inside the placental disc were completely absent, resulting in a fully haemochorial barrier throughout the placenta. Two structurally different parts, the villous and trabecular areas were complexly intermingled. The trabeculae were attached to the decidua and consisted of cellular, proliferative trophoblast and connective tissue. In contrast, all three armadillo taxa had complex villous areas within the maternal blood sinuses of the endometrium. Immunohistochemistry indicated the validity of former interpretations that in armadillos the endothelium of the sinuses was largely intact. In both anteaters and armadillos, the villi contained fetal capillaries and hypertrophied mesenchymal cells that occurred near to the villi surface in advanced gestation. And flat, syncytial trophoblast, interspersed with proliferative trophoblast cells, formed the villi surface. Conclusion: Data indicated fundamental differences in the establishment of the fetomaternal area between anteaters and armadillos. Thus, placental evolution in xenarthrans was more complex than previously thought. http://dx.doi.org/10.1016/j.placenta.2013.06.183 P2.16. PLACENTAL DEVELOPMENT IN NECROMYS LASIURUS (RODENTIA, CRICETIDAE) FUNCTIONAL MORPHOLOGY USING STEREOLOGICAL APPROACH Phelipe Favaron , Andrea Mess , Moacir de Oliveira , Maria Angelica Miglino , Pascale Chavatte-Palmer , Anne Tarrade 3,4 Department of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, Sao Paulo, Brazil; Department of Animal Science, Universidade Federal Rural do Semi-Arido, Mossoro, Rio Grande do Norte, Brazil; 3 INRA, UMR 1198 Biologie du Developpement et Reproduction, Jouy-en-Josas, Paris, France; 4 ENVA, Maisons-Alfort F-94704, Maisons-Alfort, Paris, France The mature chorioallantoic placenta in rodents is organized in labyrinth zone (Lz), junctional zone (Jz), and decidua (Dd). Within rodents, the placental development of murids has been well described but that of cricetids remains less investigated. Objectives: We described the development of the main placental regions in a wild Brazilian rodent Necromys lasiurus. Methods: The volume fraction (VF) of different cell types which constitute the labyrinth was quantified by the one stop stereology using 31 placentae at different stages of gestation. In addition, we investigated the volume changes of the Lz, Jz, and Dd in samples of early gestation (10-11 days, n1⁄43), mid-gestation (15-16 days, n1⁄44), and near term (21 days, n1⁄43) using the Cavalieri principle. 5 mm sections were stained using H&E and fetal vessels were localized by immunohistochemistry using vimentin. Samples were analyzed using the Mercator software and statistical analysis (oneway ANOVA and Mann and Whitney test) was performed using Graphpad Prism . Results: There was a significant increase in absolute placental volume from early (4.427 0.282mm3) to mid-gestation (12.98 1.305mm3, p

Very little is known about the distinct reproductive biology of armadillos. Very few studies have investigated armadillo spermatogenesis, with data available only for Euphractus sexcinctus and Dasypus novemcinctus. In the present study, we analysed male germ cell differentiation in the large hairy armadillo Chaetophractus villosus throughout the year, describing a cycle of the seminiferous epithelium made of eight different stages. Evaluation of the testis/body mass ratio, analysis of the architecture of the seminiferous epithelium and the frequency of defective seminiferous tubules allowed identification of a temporal interruption of spermatogenesis during the period between mid-May to July (mid–end autumn) in correlation with very low testosterone levels. Overall, these results suggest that spermatogenesis is seasonal in C. villosus.

Chaetophractus Fitzinger, 1871. Sitzb. Kaiserl. Akad. Wiss., Wein, 64(1):268. TYPE SPECIES: Dasypus villosus (Desmarest, 1804) by subsequent designation (Yepes, 1928). SYNONYMS: Dasyphractus Fitzinger, 1871; Loricatus Desmarest, 1804 (part); Tatus Olfers, 1818 (part); Tatusia Lesson, 1827 (part). COMMENTS: Formerly included in Euphractus (see Wetzel, 1985b), Published as part of Alfred L. Gardner, 1993, Order Xenarthra, pp. 63-68 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 65, DOI: 10.5281/zenodo.7353136, {"references":["Yepes, J. 1928. Los \" Edentata \" argentinos. Sistematica y distribucion. Revista de la Universidad de Buenos Aires, ser. 2 a, 1: 461 - 515, 6 figs [Reprint separate is independently paginated].","Olfers, I. von. 1818. Bemerkungen zu Illiger's Ueberblick der Saugthiere nach ihrer Vertheilung uber die Welttheile, rucksichtich der Sudamericanischen Arten (Species). Abhandlung X in W. L. von Eschwege, Journal von Brasilien, odor vermischte Nachrichten aus Brasilien, auf wissenschaftlichen Reisen gesammelt. Heft 2 in F. Bertuch (ed.), Neue Bibliothek der wichtigsten Reisebeschreibungen zur Erweiterung der Erd- und Volkerkunde, Band 15: 192 - 237. Weimar.","Wetzel, R. M. 1985 b. Taxonomy and distribution of armadillos, Dasypodidae. Pp. 23 - 48, in The evolution and ecology of armadillos, sloths, and vermilinguas (G. G. Montgomery, ed.). Smithsonian Institution Press, Washington, D. C., 10 (unnumbered) + 451 pp."]}

Chaetophractus vellerosus (Gray, 1865). Proc. Zool. Soc. Lond., 1865:376. TYPE LOCALITY: Bolivia, Santa Cruz, " Santa Cruz de la Sierra." DISTRIBUTION: Chaco Boreal of Bolivia and Paraguay south to C Argentina and west to the Puna de Tarapacâ of Chile. SYNONYMS: boliviensis Grandidier and Neveu-Lemaire, 1908; brevirostris Fitzinger, 1871; desertorum Krumbiegel, 1940; pannosus Thomas, 1902., Published as part of Alfred L. Gardner, 1993, Order Xenarthra, pp. 63-68 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 65, DOI: 10.5281/zenodo.7353136

Chaetophractus nationi (Thomas, 1894). Ann. Mag. Nat. Hist., ser. 6, 13:70. TYPE LOCALITY: Bolivia, Oruro, "Orujo." DISTRIBUTION: Cochabamba, Oruro, and La Paz (Bolivia). COMMENTS: Distribution and status uncertain, may be a subspecies of vellerosus (see Wetzel, 1985b)., Published as part of Alfred L. Gardner, 1993, Order Xenarthra, pp. 63-68 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 65, DOI: 10.5281/zenodo.7353136, {"references":["Wetzel, R. M. 1985 b. Taxonomy and distribution of armadillos, Dasypodidae. Pp. 23 - 48, in The evolution and ecology of armadillos, sloths, and vermilinguas (G. G. Montgomery, ed.). Smithsonian Institution Press, Washington, D. C., 10 (unnumbered) + 451 pp."]}

Chaetophractus nationi is an armadillo species that inhabits in the high Andes of Peru, Chile, and Bolivia at altitudes of over 3000 m. The main threats to this species are habitat loss and over-hunting; in the last 10 years it has been estimated that the population has declined by 30%. The species is categorized as Vulnerable (VU, A2d) by International Union for Conservation of Nature (IUCN) and Peruvian legislation (DS-034-2004-AG) and is listed in appendix II of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Chaetophractus nationi is 1 of 7 species of armadillos in which further studies on their reproductive biology and physiology are considered to be urgently needed. The aim of the present study was to determine the semen ejaculate values of C. nationi males in 2 opposite seasons. Six adult males of C. nationi belonging to the Huachipa Zoological Park (Lima, Peru) collection under the same captive conditions were used. Semen samples were collected coinciding with the Peruvian warm season (February) and cold season (June). The animals were chemically immobilized using ketamine (15 mg kg-1), xylazine (1 mg kg-1), and midazolam (0.4 mg kg-1) i.m. Semen was collected by an electroejaculation technique using commercial equipment (Eletrojet®, Eletrovet, São Paulo, Brazil) and a rectal probe specifically designed in Peru for the species. Progressive electrical stimulation from 2 to 6 V was applied in a protocol of 30 stimuli divided into 3 series: series 1, with 10 stimuli of 3 sec at 2 V; series 2, with 10 stimuli of 3 sec at 4 V; and series 3, with 10 stimuli of 3 sec at 6 V The results (mean ± SEM) for the warm season (26-28°C) were n = 6; volume = 80 ± 10.34 μL; pH = 8.2 ± 0.3; progressive motility = 77% ± 0.06; and sperm concentration/mL = 46.2 ± 2.9 × 106. The results (mean ± SEM) for the cold season (13-18°C) were n = 6; volume = 8.6 ± 2.27 μL; pH = 8.7 ± 0.18; and progressive motility = 80%. Sperm concentration could not be determined on the cold season samples because of the low volume collected. In summary, our results are suggestive of a seasonal pattern in semen characteristics of the Andean hairy armadillo that may be related to its reproductive activity in the wild. J. Pino and B. Shiga (UNMSM), for help with the rectal probe elaboration.

The desert armadillo ( Chaetophractus vellerosus ) survives in portions of the Monte Desert of Argentina where rainfall is as low as 130 millimeters per year. The nine-banded armadillo ( Dasypus novemcinctus ) is not able to exist in arid areas because of a dependence on water. Measurements of kidney relative medullary thickness (RMT) indicate that the Chaetophractus kidney has a higher concentrating ability than expected for a xeric mammal of its weight. The efficiency of the Dasypus kidney is lower than expected for a xeric mammal yet higher than a mesic mammal. On a dehydrated meat diet, Chaetophractus is able to remain in water balance whereas Dasypus is not.

A very regular 8–12 rhythm was found in the olfactory tubercle of the armadillo Chaetophractus villosus. The rhythm was observed during wakefulness. Considerable sinusoidal activity was also observed not only during wakefulness, but during synchronized (slow) and desynchronized (paradoxical) sleep. The significance of this novel rhythm is discussed together with considerations at establish an important difference between it and the other ‘alpha rhythms’ known.

Choice behavior of the armadillo Chaetophractus villosus (Edentata, Dasypodidae) was studied under laboratory conditions. Two groups were trained in a simultaneous visual discrimination task with food-reward. One group was trained with a contiguous spatial-temporal relationship between the discriminative stimulus and the reinforcement. For the second group, a spatial-temporal separation of these relevant stimuli was imposed in order to lengthen the presolution period. Attention was directed at determining which one of four positional strategies (alternation, position habit, win-shift/lose-stay, and win-stay/lose-shift) prevailed during the acquisition of the discrimination. There were no obvious differences in choice strategies between the groups, although the immediate spatial-temporal contiguity between the discriminative and reinforcing stimuli produced a significantly faster acquisition. Position habit was the only spatial strategy consistently observed between animals and maintained for a va...

A comparative study of the temperature regulation and rate of metabolism of armadillos and armadillo-like mammals (hedgehogs and hedgehog tenrecs) is reported. Armadillos are characterized by low body temperatures, low basal rates of metabolism, and high minimal thermal conductances. Strictly temperate species of armadillos are confined in distribution to South America; they have higher body temperatures than tropical species, but these groups show no noticeable difference in basal rate or in minimal conductance. Armadillos that specialize on termites as food (e.g., Tolypeutes and Priodontes ) have much lower basal rates and body temperatures than other species. Hedgehogs, hedgehog tentrecs, and marsupial bandicoots also have low body temperatures, low basal rates of metabolism, and high minimal conductances. The principal reason why armadillos have low rates of metabolism is to prevent overheating in burrows, although termite-eating species may have lower basal rates than other species due to variations in the spatial and temporal availability of prey. The high minimal conductances found in these mammals prevent overheating in burrows and reflect a protective armor of either horny plates (armadillos) or spines (hedgehogs and hedgehog tenrecs). The interaction of low basal rates and high minimal conductances results in temperature differentials between the body and environment that are independent of mass and only about 25% of the values expected in mammals. Studies of daily energy expenditure in Dasypus novemcinctus show a circadial rhythm of activity and indicate that this species responds to a sharp fall in environmental temperature by a reduction in activity and a modest reduction in body temperature. Large individuals may take as long as 3 or 4 days for normal body temperature to be reestablished after such a cold exposure. Armadillos have a limited capacity to invade cold, temperate environments because food is unavailable at environmental temperatures below 0°C and because of their high thermal conductances. Armadillos or other similar mammals enter cold, temperate environments either by storing enough fat to wait for foraging to be possible again ( D. novemcinctus ) or by entering torpor ( Zaedyus, Eri-naceus, Setifer ), a response that requires a small body size. Tolerance to starvation through an increased mass is limited by the necessity to seek refuge in a burrow. Young-of-the-year, lean individuals, and pregnant females are most susceptible to starvation at the geographic and climatic edge of their distribution.

Specimens of Chaetophractus vellerosus are recorded for the first time in Eastern Buenos Aires Province, Argentina. This occurrence is interpreted as a relict of a wider distribution resulting from different climatic conditions during the Late Pleistocene and part of the Holocene. Recent soil conditions and physiologic adaption could be responsible of this disjunctive distribution.

Chaetophractus villosus (Desmarest, 1804). Tabl. Meth. Mamm., 24:28. TYPE LOCALITY: Argentina, Buenos Aires Province, between 35° S. and 36° S. DISTRIBUTION: Chaco of Paraguay; Uruguay, Mendoza, Cordoba, Santa Fe, south to Santa Cruz (Argentina) and Chikchico (Chile); probably Chaco of Argentina and Bolivia. COMMENT: Type locality discussed by Cabrera, 1958:214. ISIS NUMBER: 5301407003003003001., Published as part of James H. Honacki, Kenneth E. Kinman & James W. Koeppl, 1982, Order Edentata, pp. 52-57 in Mammal Species of the World (1 st Edition), Lawrence, Kansas, USA :Alien Press, Inc. & The Association of Systematics Collections on page 55, DOI: 10.5281/zenodo.7352995, {"references":["Cabrera, A. 1958. Dos felidos argentinos ineditos (Mammalia, Carnivora). Neotropica, 3 (12): 70 - 72."]}

Two male and 5 female specimens have been studied with identical results. Two females were collected in Uruguay and Argentina. The others came through the courtesy of Mr. Dennis A. Meritt, Lincoln Park Zoo, Chicago, Illinois, USA. The X chromosome was identified by autoradiography, and the Y is unmistakable. In excellent preparations it is clearly acrocentric. Barr bodies and drumsticks have been reported in females.

Chaetophractus nationi (Thomas, 1894). Ann. Mag. Nat. Hist., ser. 6, 13:71. TYPE LOCALITY: Bolivia, Oruro. DISTRIBUTION: Cochabamba, Orura, and La Paz (Bolivia) and possibly puna of Argentina and Chile. COMMENT: Distribution and status uncertain, may be a subspecies of vellerosus; see Wetzel, 1982, in Montgomery, ed., The evolution and ecology of sloths, anteaters, and armadillos (Mammalia, Xenarthra = Edentata), Smithson. Inst. Press, Washington, D.C. ISIS NUMBER: 5301407003003001001., Published as part of James H. Honacki, Kenneth E. Kinman & James W. Koeppl, 1982, Order Edentata, pp. 52-57 in Mammal Species of the World (1 st Edition), Lawrence, Kansas, USA :Alien Press, Inc. & The Association of Systematics Collections on page 54, DOI: 10.5281/zenodo.7352995

Chaetophractus Fitzinger, 1871. Sitzb. Math-Nat. K. Akad. Wiss., 64(1):268. ISIS NUMBER: 5301407003003000000., Published as part of James H. Honacki, Kenneth E. Kinman & James W. Koeppl, 1982, Order Edentata, pp. 52-57 in Mammal Species of the World (1 st Edition), Lawrence, Kansas, USA :Alien Press, Inc. & The Association of Systematics Collections on page 54, DOI: 10.5281/zenodo.7352995

The armadillo Chaetophractus villosus shows a remarkable respiratory adaptation when the nostrils are completely covered by soil: it is able to maintain efficient respiratory movements with the corresponding filling of the lungs, thanks to a mechanism that allows it to use the air filling the space between the soil particles, without invasion of the nasal cavities by those particles.

Summary This experiment compares spatial learning in the South American opossum (Didelphis albiventris) and armadillo (Chaetophractus villosus) in a Y-maze. Ss learned to turn to one arm of the maze for food reinforcement. To earn further reinforcements, they had to return to the start-box (after consuming the food) where they were restrained for a fixed intertrial interval. The number of entries to the unbaited arm en route to the goal-box (Ri errors), and in the way back to the start-box (Rf errors) were the dependent measures. Opossums and armadillos did not differ in Ri errors. However, only armadillos mastered the task of returning directly to the start-box after each reinforcement. Moreover, a significant within-session improvement in Rf errors was observed in armadillos, but failed to appear in opossums. Results are discussed in terms of species differences in sensitivity to temporal delays.

Skin biopsies of two males and one female were studied. The males originally from Brazil, were supplied and identified by Dr. A. Coimbra Filho, Zoological Garden, Rio de Janeiro. The biopsy of the female was sent from an animal captured in Uruguay by Dr. L. Branda, Montevideo. It was labeled “peludo”, a designation usually given Chaetophractus. The latter species is somewhat similar in phenotype but differs markedly in karyotype (ref. 1). Taxonomy of this group is not easy and few cytogenetic studies have been done to date.

SUMMARYActive Trypanosoma cruzi transmission persists in the Gran Chaco region, which is considered hyperendemic for Chagas disease. Understanding domestic and sylvatic transmission cycles and therefore the relationship between vectors and mammalian hosts is crucial to designing and implementing improved effective control strategies. Here we describe the species of triatomine vectors and the sylvatic mammal reservoirs of T. cruzi, in different localities of the Paraguayan and Bolivian Chaco. We identify the T. cruzi genotypes discrete typing units (DTUs) and provide a map of their geographical distribution. A total of 1044 triatomines and 138 sylvatic mammals were captured. Five per cent of the triatomines were microscopically positive for T. cruzi (55 Triatoma infestans from Paraguay and one sylvatic Triatoma guasayana from Bolivia) and 17 animals (12·3%) comprising eight of 28 (28·5%) Dasypus novemcinctus, four of 27 (14·8%) Euphractus sexcinctus, three of 64 (4·7%) Chaetophractus spp. and two of 14 (14·3%) Didelphis albiventris. The most common DTU infecting domestic triatomine bugs was TcV (64%), followed by TcVI (28%), TcII (6·5%) and TcIII (1·5%). TcIII was overwhelmingly associated with armadillo species. We confirm the primary role of T. infestans in domestic transmission, armadillo species as the principal sylvatic hosts of TcIII, and consider the potential risk of TcIII as an agent of Chagas disease in the Chaco.