Dasypus Hybridus Research Articles

Diet and isotopic niche variation of mammals associated with road zones in Uruguay

AbstractThe understanding of the resource use and partitioning of medium and large terrestrial mammals in anthropogenic environments such as road areas is crucial for comprehending ecosystem dynamics and reveals how species coexist and adapt to environmental changes. The aim of this work was to characterize trophic aspects of medium and large terrestrial mammals, including the quantification of resource use, variation in isotopic trophic niche breadth and overlap among sympatric species within a road zone influence in Uruguay. To this end, stable isotope ratios (δ13C and δ15N) were examined in hair samples collected from 57 individuals from road‐killed animals including 9 medium and large mammals species, as well as potential resources. The isotopic results reflected a community that contains four trophic levels, with Galictis cuja as a predator while the species Dasypus hybridus and Subulo gouazoubira were in the primary consumer levels. Furthermore, the results showed varying degrees of isotopic trophic niche breadth, suggesting different feeding strategies and degrees of dietary specialization. Additionally, a high degree of overlap in resource use was observed among these sympatric species with the exception of Galictis cuja, suggesting that spatial and temporal differentiation in resource use could help to explain the coexistence patterns. Diet composition estimated using Bayesian stable isotope mixing models revealed that in most species, the basal food source was represented by a combination of natural grasslands of types C3 and C4. This trophic behaviour with the incorporation of diverse and variable food items helps to explain the occurrence of these species within this complex environment.

New Paraguayan records of Xenarthra with a review of the species present in Neembucu department

This article provides an update of the distribution of the Xenarthra fauna of Paraguay. Tamandua tetradactyla is confirmed to occur in all Paraguayan departments. New departmental records of Myrme-cophaga tridactyla are reported for Neembucu, Paraguarí, and San Pedro. Dasypus novemcinctus is reported for Neembucu department for the first time. Two previous species (Dasypus hybridus and Cabassous tatouay) considered to occur in Neembucu department based on specimens in the Basel Natural History Museum are now considered doubtful. A public interest in reports of Myrmecophagidae in Paraguay is noted and it is suggested that it could be utilized to benefit the conservation of these species in the Oriental region, where both species are rarely encountered.

The Dorsal Integument of the Southern Long-Nosed Armadillo Dasypus hybridus (Cingulata, Xenarthra), and a Possible Neural Crest Origin of the Osteoderms. Discussing Evolutive Consequences for Amniota

Osteoderms are present in most tetrapod lineages with considerable lineage-specific variation. It has been hypothesized that osteoderms are a case of “deep homology” in craniates, but the embryonic origin of osteoderms -and other related postcranial exoskeletal elements- is still under debate. Most authors support its mesodermal origin, while others suggest that osteoderms are derived from neural crest scleroblastic cells in sauropsids. The armadillos (Xenarthra, Cingulata) are the only living mammals and the only extant synapsids with osteoderms. Here, we aim to identify skeletogenic neural crest cells in the dorsal skin of armadillos in order to assess if osteoderms have a neuroectodermal origin in mammals, similar to what is observed in sauropsids. For this purpose, skin samples from fetuses and newborn specimens of Dasypus hybridus were processed and the embryological development of osteoderms was characterized using different immunohistochemical markers (HNK-1, PDGFR α, S-100, and C5). For the first time, we report cell populations that were reactive to skeletogenic neural crest markers, indicating an ectomesenchymal origin of the mammalian osteoderms. Our results demonstrate similar molecular expression for mammals as in sauropsids and, therefore, this strongly suggests that osteoderms in both groups would have a homologous embryonic origin.

Dental enamel structure in long-nosed armadillos (Xenarthra:Dasypus) and its evolutionary implications

AbstractMost xenarthrans have a reduced and simplified dentition that lacks enamel. However, the presence of prismatic enamel has been recorded in the Eocene armadillos Utaetus buccatus (Euphractinae) and Astegotherium dichotomus (Astegotheriini). Among extant xenarthrans, the occurrence of enamel has been recognized only in the long-nosed armadillo, Dasypus novemcinctus (Dasypodinae), but its microstructure has never been described. In this contribution, we analyse the enamel microstructure in deciduous and permanent teeth of four Dasypus species. In deciduous molariform teeth of some species, we identify an apical cap of vestigial enamel (without crystalline structure), interpreted as an amorphous ameloblastic secretion. In permanent teeth, a thin layer of true enamel is found in the apical portion of unworn molariforms. The enamel is prismatic in D. novemcinctus, but in Dasypus hybridus, Dasypus sabanicola and Dasypus punctatus it is prismless. Taking into account the Eocene species of armadillos, the ancestral condition of enamel in cingulates could have been more complex (as in other placentals) and undergone progressive reduction, as shown in the Dasypus lineage. In light of previous genetic and developmental studies, we review and briefly discuss the processes that can account for the reduction/loss of enamel in extant and extinct armadillos. The retention of enamel and the fact that this genus is the only living xenarthran with two functional generations of teeth support the early divergence of the Dasypus lineage among living cingulates. This is in agreement with morphological and molecular analyses.

Comparative analysis of the helminth fauna of Dasypus hybridus and Chaetophractus villosus (Xenarthra: Cingulata) in the Pampas region, Argentina

Abstract Chaetophractus villosus and Dasypus hybridus are the most widespread and abundant armadillos inhabiting the Pampas grasslands. Studies on the parasitic fauna from an ecological perspective are scarce in both species. We describe and compare the component communities of C. villosus and D. hybridus in the Pampas ecoregion of Argentina and analyse if the composition and structure of the parasitic communities of these host species reveal trophic behaviour and/or habitat use. In the population of C. villosus 10 species of helminths were found, namely Ancylostoma caninum, Aspidodera fasciata, Aspidodera scoleciformis, Mazzia bialata, Moennigia celinae, Orihelia anticlava, Strongyloides sp., Trichohelix tuberculata (Nematoda) and Mathevotaenia sp. (Cestoda), whereas in the population of D. hybridus four species were found, A. fasciata, Delicata abbai, Pterygodermatites chaetophracti and Strongyloides sp. Only A. fasciata and Strongyloides sp. were present in both species. Prevalences and intensities were similar in Strongyloides sp. In A. fasciata, however, there were differences regarding mean intensity. Diversity was higher in C. villosus than in D. hybridus. The differences may be related to the diet, behaviour, evolutionary histories or immune response of the species studied. A combination of several of these factors would possibly influence the composition of their parasitic fauna.

A New Rictulariid (Nematoda: Spirurida) in Xenarthrans from Argentina and New Morphological Data of Pterygodermatites ( Paucipectines) Chaetophracti.

Pterygodermatites is a cosmopolitan genus of nematodes from mammals, and it is frequently encountered in the parasite fauna of armadillos (Mammalia, Xenarthra, Cingulata). In this work, a new species, Pterygodermatites ( Paucipectines) argentinensis, is described, and new morphometric data, new host records, and the geographical distribution of Pterygodermatites ( Paucipectines) chaetophracti are provided. We examined 109 hosts belonging to Chaetophractus vellerosus, Chaetophractus villosus, Cabassous chacoensis, Dasypus hybridus, Tolypeutes matacus, and Zaedyus pichiy, from several regions of Argentina. Pterygodermatites ( Paucipectines) argentinensis can be distinguished from P. ( P.) chaetophracti by the morphology and size of esophageal teeth of both sexes, by subequal and longer spicules, by having only 1 precloacal cuticular semicircular fan in males, and by a greater number of cuticular processes in females. Cabassous chacoensis and Zaedyus pichiy are new hosts for Pterygodermatites ( P.) chaetophracti.

The scratch-digger type in two armadillos (Dasypodidae, Xenarthra): ontogeny of the hand skeleton and digit variability.

Ontogenetic and comparative studies on the hand skeleton of armadillos (Dasypodidae, Xenarthra) are scarce. In this paper adult autopodial skeleton of two species of extant armadillos, Dasypus hybridus (Dasypodinae) and Chaetophractus villosus (Euphractinae), are characterized. In addition, fetal morphology of the cartilaginous hands is compared to that of the bony adult hands. Adult specimensincluded 38 skeletons of C. villosus (n=34), and D. hybridus (n=4). Fetal cartilaginous hands were studied from serial histological sectioning of two specimens, belonging to D. hybridus and C. villosus. A comprehensive description of the adult hand skeleton, and a qualitative comparison with the fetal hand of both species is provided. The hand of C. villosus is clearly pentadactylous, being the third finger the larger one. In the carpus, elements are largely interlocked betwen them, and with the metacarpals. Therefore, this species fits well into the scratch-digger category. In contrast, D. hybridus shows a reduced five digit, narrowing the entire hand, and there is a similar size of digits II and III. This condition is tie to a series of modifications in the carpus, including a less contact among carpals and metacarpals. Fetal carpus of C. villosus is similar to adult skeleton, while in D. hybridus some differences are recorded. Considering that a relict of the fifth finger is present in D. hybridus, the presence of this finger as a diagnostic character of D. (Hyperoambon) kappleri should be discarded. In addition, a comprehensive revision of this character should be extensive to the rest of the species of Dasypus.

Dasypus hybridus(Cingulata: Dasypodidae)

Dasypus hybridus ([Desmarest, 1804][1]) is commonly known as the southern long-nosed armadillo. Like all armadillos, it bears a carapace of ossified dermal scutes covered by epidermal scales. This diurnal species mainly inhabits grasslands on humic soils in Argentina, Uruguay, Paraguay, and southern Brazil. D . hybridus is omnivorous with a tendency to myrmecophagy and gives birth to 6–12 presumably genetically identical offspring. Listed as “Near Threatened” by the International Union for Conservation of Nature and Natural Resources, it is mainly threatened by habitat loss and hunting. [1]: #ref-43

Comparative histology and ontogenetic change in the carapace of armadillos (Mammalia: Dasypodidae)

Among extant mammals, the presence of osteoderms is limited to armadillos (Xenarthra, Dasypodidae), being one of its distinctive features. The osteoderms are articulated to form a carapace that covers their body dorsally. In this paper we study the integumentary structures of the armadillos Chaetophractus vellerosus, Chaetophractus villosus, Euphractus sexcinctus, and Zaedyus pichiy (Euphractinae), Dasypus hybridus, and Dasypus novemcinctus (Dasypodinae) within a comparative framework, aiming to identify patterns common to the family and to the subfamilies Dasypodinae and Euphractinae, as well as peculiarities of each species. Differences between the two subfamilies were observed in the dorsal integument, related to the production of blood cells and the mobility of the carapace. The Euphractinae present more numerous and larger cavities filled with adipose tissue in the osteoderms, as well as more marginal follicles than the Dasypodinae. These provide thermal insulation that could be related to their distribution in cooler climates. The sebaceous glands associated with surface follicles are also more developed in the Euphractinae and could be related to preventing the desiccation of the cornified scales in arid climates.

Análisis zooarqueológico del sitio laguna El Doce (Depto. Gral. López, Sta. Fe, Argentina)

The results from taxonomic and taphonomic analyses of the first evidence of archaeofaunal record recovered in systematic excavation carried out at Laguna El Doce archaeological site (Santa Fe province, Argentina), whose chronology covers different moments of the Holocene, are presented in this paper. The bone assemblage includes even-toed ungulates (Lama guanicoe, Ozotoceros bezoarticus), rodents (Rodentia, Ctenomys sp., Lagostomus maximus), armadillos (Chaetophractus villosus, Dasypus hybridus, Tolypeutes matacus, Zaedyus Pichiy, Eutatus seguini), carnivores (Canidae, Pseudalopex gymnocercus) and birds (Bird, Rhea americana). Low stages of weathering, low frequency of rodents, carnivores and roots marks and chemical depositions (MnO2 and CaCO3) characterized the sample. Also show evidence of anthropic modifications such as fractures, thermal alterations and cut mark.

Ontogenetic criteria to distinguish vertebral types on the debated xenarthran synsacrum.

The presence of a synsacrum formed by the fusion of vertebrae that come into closed contact with the ilium and ischium is a feature that characterizes the clade Xenarthra. Nevertheless, the proper identity of each vertebral element that forms it is a matter of discussion. In this article, we provide ontogenetic information about skeletal ossification of the xenarthran synsacrum and define the position of the sacrocaudal limit within it. We analyzed the synsacrum of 25 specimens of nonadult and 101 adult armadillos and anteaters: Dasypus hybridus, D. novemcinctus, Chaetophractus vellerosus, C. villosus, Tamandua tetradactyla, and Myrmecophaga tridactyla. Two sets of vertebrae were identified: an anterior set, often attached to the iliac bones, in which transverse processes are originated mainly from an expansion of the base of the neural arches, and secondarily from a lateroventral ossification center. A posterior set is characterized by a series of vertebrae along which extra lateral ossifications (described here for the first time) are developed and form exclusively the transverse processes. Among armadillos, the sacrocaudal limit is set between the last vertebrae attached to the iliac bones and the first vertebrae that form the dorsal border of the sacroischial fenestra. In addition, anterior free caudals also showed extra lateral ossifications forming exclusively the transverse processes, supporting the notion that more posterior synsacrals are in fact caudal vertebrae that were incorporated to the synsacrum. In pilosans, the sacrocaudal limit is set between the first vertebrae that come into contact with the ischial bones and the immediately anterior one. However, the pattern of homologies is obscured by the low resolution in the ontogenetic sequence when compared to that of armadillos.

Burrowing activity by armadillos in agroecosystems of central Argentina: Biogeography, land use, and rainfall effects

Land use change and agricultural practices are among the main factors affecting biodiversity, and require understanding of how differing species responses shape wildlife communities in rural landscapes. During the last 2–3 decades, the Pampas of central Argentina have experienced an agricultural expansion along with rapid adoption of a non-tillage system. In some areas armadillos are increasingly considered agricultural pests, not only because they can damage and contaminate silo bags and may act as direct consumers of crops, but also their burrowing activities interfere with farming practices. Here, we describe variations in activity of armadillos in the Pampas of Buenos Aires province, central Argentina, and discuss how biogeography, land use, and rainfall may have affected these species in the rural landscape. We carried out four sampling sessions between December 2011 and June 2013 (including two periods of normal rainfall and two periods of high rainfall), surveying 392 plots (196 crop fields and 196 rangelands) at 25 different localities (covering the five different ecological units of the Pampas). In each plot, we surveyed for signs (burrows and holes) along a 600×6m transect, in order to assess armadillo activity. Chaetophractus villosus (large hairy armadillo) showed the highest activity, with 5968 signs at 79% of the plots surveyed; whereas, 1866 signs of Dasypus hybridus (southern long-nosed armadillo) were found in 36% of the plots. Generalized linear mixed models revealed that C. villosus is more active mainly in the Inland Pampas and in cropland plots, whereas, D. hybridus is more active in the Flooding Pampas at plots with active livestock use. Both species showed less burrowing activity during the second year of surveys, in a period of exceptionally high rainfall. Our results suggest that the omnivorous C. villosus may have benefited from agriculturization and non-tillage, particularly in the Inland Pampas where sandy soils favor burrowing, whereas, the more myrmecophagous D. hybridus may be in retraction.

Distribution and Status of the Extant Xenarthrans (Mammalia: Xenarthra) in the Southern cone Mesopotamian Savanna, Argentina

The Southern Cone Mesopotamian savanna (MS), located in northeastern Argentina, is one of the least protected ecoregions (0.11%) of the country. Five of the seven historically present species of xenarthrans in this region are of conservation concern at the national level. This work reviews, updates and analyzes the current distribution and conservation status of the xenarthrans using a georeferenced database including records from four complementary methods: field surveys, interviews with local stakeholders, participatory monitoring, and bibliography review. Results were then compared with existing distribution maps. In total, 304 occurrence records were documented in 127 localities. Considering their relative presence (number of localities where the species is present divided by the total number of localities), the species with most records were Dasypus novemcinctus (71.7%) and Dasypus hybridus (63%); Euphractus sexcinctus and Tamandua tetradactyla were detected in a lower proportion (48.8 and 35.4%, respectively). Cabassous tatouay and Myrmecophaga tridactyla are rare species in the ecoregion. The extant xenarthrans that inhabit the MS are reviewed and information gaps for certain species are identified. We emphasize the importance of contributions from the local community, who provided 80% of the collected information for this study.

Epidemiology of Ornithodoros brasiliensis (mouro tick) in the southern Brazilian highlands and the description of human and animal retrospective cases of tick parasitism

Ornithodoros brasiliensis, also known as the “mouro” tick, is an argasid tick found exclusively in the southern Brazilian highlands. O. brasiliensis parasitism is frequently associated with severe symptoms directly induced by the tick bite, a condition compatible with the definition of tick toxicosis. The objectives of this work include (i) the determination of the distribution of O. brasiliensis in farms located in the tick-endemic region, (ii) the description of the characteristics of O. brasiliensis habitats, (iii) the analysis of risk factors associated with O. brasiliensis, and (iv) the retrospective description of cases of human and animal parasitism by O. brasiliensis. Of the 30 farms included in this study, O. brasiliensis was identified on 5 farms (frequency 16.7%), in which several ticks found in high density buried in soil were collected. Information regarding the tick habitats and the local population was recorded. The data indicated that O. brasiliensis feeds on humans, dogs, armadillos (Dasypus hybridus), and possibly skunks (Conepatus chinga). The analysis of risk factors indicated that the presence of house basements with an unpaved (natural soil) floor on farms and insufficient sanitary conditions significantly enhanced the probability of identifying O. brasiliensis. Additionally, we describe retrospectively cases of tick parasitism in 28 humans and 11 dogs including the most common symptoms associated with tick toxicosis. This is the first study concerning O. brasiliensis epidemiology, distribution, and habitat, and the report represents the most comprehensive characterization of Ornithodoros bite-associated toxicosis syndrome.

A New Molineid (Nematoda: Trichostrongylina) Parasite ofDasypus hybridus(Xenarthra: Dasypodidae) from Argentina

Delicata abbai n. sp. collected from the small intestine of the southern long-nosed armadillo, Dasypus hybridus, from Argentina is herein described. This new species is characterized by vulvar opening within second half of body length, female tail conical, ending bluntly with a terminal spine, complex spicules, presence of a bursal membrane supported by 2 small rays, and a synlophe with bilateral symmetry and 26 cuticular ridges. By the morphology of the caudal bursa, caudal end of female, and shape of spicules, the new species resembles Delicata cameroni Travassos, 1935 and Delicata variabilis Travassos, 1935 . However, it differs from D. cameroni by having rays 5 and 6 diverging more proximally, rays 8 shorter than the dorsal ray, and spicules with a different shape. Delicata abbai n. sp. is distinguished from D. variabilis mainly by the spicules, which have a different shape and proportion of their constitutive parts. This is the first report of a species of Delicata in Argentina.

Development of the integument of Dasypus hybridus and Chaetophractus vellerosus, and asynchronous events with respect to the postcranium

The integument of extant armadillos (Xenarthra, Cingulata) is a unique organ in which complex glandular systems are associated with pilose follicles, dermal ossifications, and cornified scales. Up to date, papers have focused on neither comparative morphology of the skin (dorsal and ventral) nor chronology of the development of interspecific homolog structures. In order to clarify the way in which events occur during development of the integument structures, maturity of other tissues (e.g. skeletal tissues) should be considered. Therefore, we will be able to identify events that have been pre- or post-displaced during ontogenetic development. The aim of this paper is to describe in a developmental and comparative framework the integumentary system of neonates of Dasypus hybridus and Chaetophractus vellerosus. In order to understand the morphology of the different integumentary structures serial histological sections were prepared. Staining techniques included H–E, Masson Trichrome, PAS, orcein and reticulin. To study ossification of postcranial elements, the specimens were cleared and double-stained with alcian blue and alizarin red. Determinations of ossification centers and their progress were recorded through the early uptake of alizarin. The dorsal dermis of neonates from D. hybridus is clearly differentiated into a superficial and deep layer, as in fetuses of Dasypus novemcinctus. In C. vellerosus, however, these layers could not be identified. This suggests a less connective tissue differentiation in the latter species at this stage. Osteoderms in D. hybridus are well differentiated unlike C. vellerosus where no condensations of osteoprogenitory cells are observed. Conversely, pilose follicles and glandular tissues are less developed in D. hybridus. Regarding postcranial elements, ossification centers are less advanced in C. vellerosus than D. hybridus, this is particularly notorious for the vertebral column, sternal, and pelvic girdle elements. Asynchronies between neonates of both species observed on integumentary and postcranial skeletal tissues could match with specific adaptive strategies related to distribution in different environments, and/or different postnatal care.

Nuevos aportes a la historia natural de la mulita pampeana Dasypus hybridus (Mammalia, Dasypodidae)

En este trabajo se presentan nuevos aportes sobre la historia natural de la mulita pampeana Dasypus hybridus (Desmarest, 1804) (Mammalia, Xenarthra, Dasypodidae). Los estudios de campo fueron llevados a cabo en 100 ha de cuatro establecimientos agropecuarios de la provincia de Buenos Aires, Argentina. Durante tres años se realizó un muestreo estacional de armadillos por captura y liberación. Se obtuvieron datos de hábitos alimentarios, uso del espacio y del tiempo, comportamiento, termorregulación, datos poblacionales y morfológicos. Se realizaron 71 capturas. En la dieta el ítem principal registrado fue material vegetal, seguido por hormigas e insectos coleópteros; no se observó una diferencia estacional en los hábitos alimentarios. La actividad de las mulitas se concentra durante el día, existió una baja en la frecuencia de observación durante las estaciones frías (otoño e invierno). La mulita pampeana prefiere suelos húmicos, terrenos altos y pastizales densos y altos; asimismo seleccionan los montes para refugiarse. Son individuos asociales. La temperatura rectal mostró correlaciones positivas con la temperatura ambiente. La proporción de sexos fue cercana a uno y no se observó dimorfismo sexual. Los resultados obtenidos concuerdan parcialmente con lo observado para otras especies del género, destacando las tendencias observadas en los hábitos alimentarios y en la estrategia termorregulatoria. Este trabajo representa un aporte en varios aspectos de una especie poco estudiada en una zona bajo importantes presiones de uso y modificación de hábitat.

The rete mirabile of the tail, an effective site for sampling sterile blood from armadillos (Dasypodidae, Xenarthra)

Armadillos constitute a neotropical endemic mammalian group in the American continent and the main diversity is distributed in Argentina. Several species of this family are in danger of extinction. Blood collection in armadillos is difficult because of their anatomy. In the present work, in latex-perfused material, the rete mirabile of the coccygeal artery of the tail was recognized as an appropriate venipuncture site for sterile blood collection. From cadaveric material, histological sections of the tail of six species of five genera of armadillos were used to determine the diameter and the distance to access the main artery of the rete mirabile ventrodorsally. Field studies were carried out in wild animals. A total of 232 blood samples were obtained from the following species: Chaetophractus villosus (70), C. vellerosus (105), Zaedyus pichiy (15), Euphractus sexcinctus (8), Dasypus hybridus (25), and Tolypeutes matacus (9). The animals were restrained with the thumbs pressing the abdomen ventrolaterally and the rest of the fingers holding the carapace. Punctures were carried out between the first and second rings of the tail with a 21-gauge needle. Alternatively, an immobilization device was designed to allow sampling by a single operator. Blood cell integrity was evaluated through histological analysis and ulterior development in lymphocyte culture. We concluded that the rete mirabile of the tail of armadillos is an effective venipuncture site for field studies that allows obtaining sterile blood samples, avoiding animal mortality, high-risk venipuncture sites, anesthetics and excessive stress.

Ecological differences between two sympatric species of armadillos (Xenarthra, Mammalia) in a temperate region of Argentina

Morpho-physiological specialization related to foraging can act as constraints on behaviour and ecological patterns of abundance and distribution. We tested this prediction in two species (weeping or screaming hairy armadillos Chaetophractus vellerosus Gray, 1865 and mulitas Dasypus hybridus Desmarest, 1804) that represent the two subfamilies of armadillos (Dasypodidae, Xenarthra): Euphractinae and Dasypodinae. The first subfamily possesses a well-developed masticatory apparatus that is considered primitive within the Xenarthra, while Dasypodinae show reductions in various aspects of cranial morphology. We sampled signs (burrows and foraging holes) and captured both species on 34 farms randomly selected in the north-eastern Pampas region of Argentina. We analyzed several niche dimensions. The two species showed significant differences in habitat use, seasonal patterns and diet. Weeping armadillos were generalists in their diet and active throughout the year. They were associated with calcareous-sand soil, as expected for a burrowing animal of the deserts. They tolerated a wide range of environmental conditions. We found that mulitas are myrmecophagous, and that they demonstrated a reduction in body temperature and activity during the cold season. As expected from their geographical distribution, mulitas used mainly vegetation with high cover and were associated with humic soils. Niche segregation between the two species of armadillos appeared to originate from different degrees of dietary specialization.

Eto-Ecología y Conservatión de Tres Especies de Armadillos (Dasypus hybridus, Chaetophractus villosusyC. vellerosus) en el Noreste de la Provincia de Buenos Aires, Argentina

Abstract A capture-recapture study was performed to obtain data on abundance of three armadillo species inhabiting a highly modified habitat—the Argentinean pampas—and the intrinsic factors affecting this parameter. A total of 144 live armadillos (42 Dasypus hybridus, 15 Chaetophractus villosus and 87 C. vellerosus) were caught and 49 dead animals (30 D. hybridus, 15 C. villosus and 4 C. vellerosus) were collected on four farms subjected to different degrees of land use. Armadillos were negatively affected by habitat use and hunting pressure. Densities varied between 0.07 and 0.6 armadillos per hectare, with higher densities occurring on farms farther away from urban settlements, with few domestic dogs, low hunting pressure, conservative land use, and well-preserved natural grasslands. The results suggest the existence of source-sink metapopulations.