Euphractus Research Articles

Thermal evidence of the invasion of a stingless bee nest by a mammal.

Melipona bicolor, an inhabitant of the Atlantic Rainforest, nidifies in hollows of live or dead trees. In order to study thermoregulation of a nest of this species, a temperature data logger was installed inside a hollow tree. After this, an intruder dug a hole, invaded the nest, and probably consumed its honey, pollen and bees, having remained there during three days. Thermal evidence and its behavior allowed the delimitation of a small number of suspects, which we analyzed here. The intruder was a small mammal, predominantly nocturnal, that takes shelter in burrows, probably the yellow armadillo (Euphractus sexcinctus). Other evidence, if collected immediately after invasion, could precisely indicate precisely the species.

Ticks Associated with Armadillo (Euphractus sexcinctus) and Anteater (Myrmecophaga tridactyla) of Emas National Park, State of Goias, Brazil

This study was conducted in October 1998 and November 1999 in the Emas National Park (131,868 ha), a savanna-type cerrado region situated in the far south of Goias State, Brazil, near the geographic center of South America (15 degrees -23 degrees S; 45 degrees -55 degrees W). Animals were captured with the aid of nets and anesthetized (15 mg/kg ketamine + 1 mg/kg xylasine) in order to collect ticks for identification and to establish laboratory colonies. They included giant anteaters (Myrmecophaga tridactyla) (n = 4) and yellow armadillos (Euphractus sexcinctus) (n = 6). Free-living ticks (larvae, nymphs, and adults) were collected from the field by using a 1 x 2-m flannel cloth. Free-living ticks were identified as Amblyomma sp., A. cajennense, and A. triste. Adult ticks collected from anteaters were identified as Amblyomma cajennense and A. nodosum and from armadillos as A. pseudoconcolor and A. nodosum. The relevance of these host-tick relationships to possible mechanisms underlying emergence of tick-borne pathogens of importance to public health is discussed.

GEOMETRIC MORPHOMETRICS AND THE DEVELOPMENT OF COMPLEX STRUCTURES: ONTOGENETIC CHANGES IN SCAPULAR SHAPE OF DASYPODID ARMADILLOS.

Abstract The ontogenetic development of the scapula of Euphractus sexcinctus and Dasypus novemcinctus was studied using geometric morphometrics techniques. The relative importance of uniform, large, and small scale shape changes on ontogenetic development was assessed both by multivariate regression of shape on size and by relative warps analysis. The scapular development in both species is very similar and is characterized (and dominated) by an enlargement of the teres major process. This process serves as origin for the teres major muscle, which is responsible for limb retraction (an important function for digging behavior). There is also a global increase in relative anteroposterior length, increasing the moment arm of this muscle. The uniform shape changes during development are responsible for a small percentage of the size-based shape variation in Euphractus , and for a large percentage in Dasypus . The large scale localized shape changes (which depict the teres major process enlargement) are responsible for a large percentage of size-based shape variation. The region of the coracoid process and glenoid cavity are almost unaltered during the ontogeny in both species.

Infecção natural por Entamoeba histolytica Schaudinn, 1903 em Euphractus sexcinctus (tatu) mantidos em cativeiro

Fecal samples of two species of armadillos Euphractus sexcinctus (Xenarthra, Dasypodidae), kept in captivity were analysed by direct and sedimentation methods. Entamoeba histolytica Schaudinn, 1903 and E. coli Grassi, 1879 (Amoebida, Endamoebidae) cysts were observed, the former for the first time in armadillos. This parasitism is worthy of registration in the literature because of the possibility of transmission to the human being when these animals are kept in captivity.

The masticatory apparatus of the armadillo Eutatus (Mammalia, Cingulata) and some allied genera: paleobiology and evolution

The eutatines are a group of fossil armadillos traditionally regarded as herbivorous due to the particular morphology of the skull and teeth. Nevertheless, they have never been the subject of a detailed morpho-functional analysis. The masticatory apparatus of Eutatus (late Pliocene-early Holocene) is analyzed and compared with other eutatines (Proeutatus and Stenotatus from the Mio- cene, and Doellotatus and Ringueletia from the Pliocene) and with living armadillos (Euphractus and Dasypus). The masticatory muscles were reconstructed from origin and insertion scars; the occlusal pattern and mandibular movements were determined through the study of the craniomandibular joint, the shape and arrangement of the teeth and the symphysis, and the moment arms of the lines of action of the masseter and temporalis muscles were estimated. Skull and mandible shapes were compared using the Procrustean method Resistant-Fit Theta-Rho-Analysis (RFTRA). The analysis of the masticatory apparatus of the eutatines allows us to state that Eutatus and Proeutatus exhibit the most specialized morphology known for an herbivore with an armadillo-like skull pattern. Ad- ditionally, we can identify a morphological group from the Miocene Stenotatus to the Pleistocene Eutatus, including the Pliocene Doellotatus and Ringueletia as intermediate stages of a morphological line; Proeutatus deviates from this pattern. This morphological separation may reflect an early di- chotomy within the well-defined clade of eutatines.

Nematodes of Armadillos in Paraguay: A Description of a New Species Aspidodera esperanzae (Nematoda: Aspidoderidae)

Twelve species of nematodes comprising 9 genera were recovered from the gastrointestinal tract of 2 Euphractus sexcinctus and 2 Dasypus novemcinctus captured in the Department of San Pedro, Paraguay. All armadillos were infected with 1 or more species of nematode. The following nematodes were recovered: Mazzia mazzia, Spirura guianensis, Trichohelix tuberculata, Ancylostoma sp., Moennigia complexus, Moennigia pintoi, Ascaris dasypodina, Cruzia tentaculata, Aspidodera fasciata, Aspidodera scoleciformis, Aspidodera esperanzae n. sp., and Heterakinae gen. sp. This report describes a new species of the Aspidodera nematode, Aspidodera esperanzae n. sp., the first species to be reported bearing cephalic cordons made up of 7 longitudinal loops in the subfamily of Aspidoderinae. This study also documents a new host record for S. guianensis and shows a new geographical distribution in Paraguay for M. mazzia, S. guianensis, T. tuberculata, M. complexus, and M. pintoi.

As vias bilíferas dos tatus (Dasypus novemcinctus e Euphractus sexcinctus)

Os autores esquematizam as vias biliferas de 2 espécies de tatus (Dasypus novemcinctus e Euphractus sexcinctus) oriundos do Pantanal Matogrossense, Brasil. A dissecação foi efetuada após o preenchimento do sistema excretor do fígado com látex Neoprene 650 corado e da fixação das peças em solução aquosa de formol a 10%. O ductus choledocus, em ambas as espécies, provém da reunião do ductus cysticus com o ductus hepaticus. Este, por sua vez, resulta da convergência do ramus principalis dexter e do ramus principalis sinister. Na formação dos ramus principalis dexter e sinister participam vários ramos oriundos dos lobos hepáticos e seus processos.

Trypanosomes of the subgenus Megatrypanum from armadillos (Xenarthra: Dasypodidae)

A new species of trypanosome, Trypanosoma (Megatrypanum) peba, is described from the peripheral blood of the armadillo Euphractus sexcinctus setosus from Bahia State, Brazil. Ten out of 29 specimens of the armadillo Dasypus novemcinctus from Pará State were found to have trypanosomes, including epimastigote forms, in impression smears of subcutaneous lymph nodes. The trypanosomes from D. novemcinctus are illustrated and were identified as belonging to the subgenus Megatrypanum on the basis of their general appearance, although they failed to multiply in blood-agar culture medium and no bloodstream forms were seen. This is the first published record of trypanosomes of this subgenus from armadillos and the first demonstration of epimastigote trypanosomes in the mammalian host other than in the bloodstream, or in the anal glands of opossums.

The anatomy and function of the feeding apparatus in two armadillos (Dasypoda): anatomy is not destiny

The morphology and function of the masticatory apparatus in two armadillos, Dasypus novemcinctus and Euphractus sexcinctus are compared. Euphractus sexcinctus, a species restricted to South America, is omnivorous, eating a wide range of foods, including significant amounts of plant material and carrion. Dasypus novemcinctus is geographically the most widespread of all armadillos, ranging from northern Argentina into the United States. It is insectivorous‐omnivorous, apparently consuming whatever it encounters in the leaf litter. In South and Central America, this leads to a diet with a large proportion of ants and termites; in North America, the diet is considerably broadened. The teeth, jaws and jaw musculature of E. sexcinctus are large and the configuration of the jaws maximizes force production. Dasypus novemcinctus possesses derived morphology relative to the primitive condition in armadillos and exhibits many characteristics of ant and termite‐eating mammals, including reduced jaw muscles, teeth and facial bones. The apparent morphological specializations for myrmecophagy in D. novemcinctus do not, however, constrain its diet to ants and termites. It is broadly omnivorous, especially in North America. Our data highlight the difficulties in predicting diet from morphological analysis and raise questions concerning the behavioural limits imposed by morphological specialization.

Interrelação entre acari Ixodidae e hospedeiros Edentata da Serra da Canastra, Minas Gerais, Brasil

Recebemos para exame uma pequena coleção de carrapatos no Parque Nacional da Serra da Canastra (MG), entre 1979 e 1980. Os autores demosntraram a existência de uma larga co-acomodação de Amblyomma pseudoconcolor em edentados da familia Dasypodidae, sendo Dasypodini a tribo mais ajustada a sta infestação. De acordo com as Figs. 1 e 2, Dasypodini são, provavelmente, os hospedeiros reais de A. pseudoconcolor e também os hospedeiros mais antigos. Pela primeira vez, A. pseudoconcolor é também registrado e, Cabassous tatouay, C. unicinctus, priododntes maximus e Euphractus sexcinctus. Também, pela primeira vez, A. pseudoconcolor e A. calcaratum foram registrados no Estado de Minas Gerais. os ectoparasitos estão depositados no Departamento de Parasitologia da Universidade Federal de Minas Gerais, Brasil.

Characteristics and Use of Burrows by Four Species of Armadillos in Brazil

An investigation of four species of armadillos (Priodontes maximus, Euphractus sexcinctus, Cabassous unicinctus, and Cabassous tatouay) revealed differences in their burrow dimensions and choice of burrow sites. Measurements of burrow width alone separated P. maximus and C. unicinctus from E. sexcinctus and C. tatouay; those of burrow height separated all three genera, but not C. unicinctus from C. tatouay. Together, these two measurements were adequate to identify the burrows of each species. The slopes of the burrow and of the surface around the burrow, and the direction at which the burrow entrance was dug, were similar for all four species. The time spent in a burrow and the type of site into which burrows were dug differed among species.

Tapeworms of the Chaco Boreal, Paraguay, with two new species.

Mathevotaenia paraguayae sp. n. is described from Euphractus sexcinctus. It differs from M. didelphidis (Rud.) in having a transverse cirrus pouch anterior to the vagina. Monoecocestus mackiewiczi sp. n. was found in Phyllotis sp. It differs from M. parcitesticulatus Rego in having a much smaller scolex, a poral ovary, and a cirrus pouch 360 to 440 micrometers long. Other species reported are Taenia macrocystis, Taenia omissa, Spirometra mansonoides, Spirometra gracilis, Spirometra longicollis, Diphyllobothrium trinitatis, Atriotaenia parva, and Mathevotaenia tetragonocephala.

Oncicola martini sp. n., and Other Archiacanthocephala of the Chaco Boreal, Paraguay

Archiacanthocephalans are reported from mammals of Paraguay. Oncicola martini sp. n. is described from Felis geoffroyi. It is most similar to O. lamasi (Freitas et Costa 1964) comb. n., differing in having larger hooks, all except the smallest of which are barbed. Other species recorded are Oncicola oncicola from Felis geoffroyi (new host record), O. paracampanulata from Felis yagouaroundi, O. luehei from Nasua nasua, Oligacanthorhynchus microcephala from Didelphis albiventris, and O. tortuosa from Euphractus sexcinctus (new host and South American records).

Development of Six‐banded armadillos at Wroclaw Zoo

Development of Six‐banded armadillos at Wroclaw Zoo

Anatomy and Function of Expanded Ribs in Certain Edentates and Primates

Anteroposteriorly expanded ribs occur in all three species of myrme-cophagids (Cyclopes didactylus, Tamandua tetradactyla, and Myrmecophaga tridactyla). Similar rib expansion occurs in some armadillos (for example, Dasypus novemcinctus, Priodontes giganteas, Euphractus sexcinctus) and in some primates (Arctocebus calabarensis, Perodicticus potto, and Loris tardigradus). In C. didactylus and A. calabarensis rib expansion is so extensive that adjacent ribs imbricate. the epaxial and hypaxial musculature related to the expanded ribs in all three myrmecophagid species is described. the intercostal spaces in T. tetradactyla and M. tridactyla are approximately 50 per cent narrower than in various other mammals with unexpanded ribs; the intercostal musculature of these two species is approximately twice as thick as that in other mammals with unexpanded ribs. the proportion of intercostal musculature in C. didactylus is comparable to that in other mammals. Functionally, expanded ribs may increase the stability of the thorax, which, in turn, increases the stability of the vertebral column. This specialization in T. tetradactyla and M. tridactyla probably relates to their fossorial habitus; the trunk is stabilized during fossorial activity by xenarthrous processes in the lumbar region and by expanded ribs and robust intercostal muscles in the thorax. in strictly arboreal forms such as C. didactylus and A. calabarensis, lumbo-thoracic stability may be employed in methodical arboreal locomotion. C. didactylus, at least, is able to anchor itself with hind feet and tail and extend its trunk and forelimbs to reach an adjacent branch—a feat requiring unusual lumbothoracic stability.

The application of immunological tests of sera from captured wild animals to the study of yellow fever epidemiology.

SummaryA study has been made of the response of some of the more common vertebrates of Brazil to yellow fever virus introduced by the bites of infected mosquitoes. The results obtained are summarized in Table 11.Akodon arviculoides, Orzomys and Didelphis paraguayensis failed to circulate virus following such exposure; Metachirops opossum, Proechimys dimidiatus, Dasypus novemcinctus and Euphractus sexcinctus either circulated virus only occasionally or in too low concentrations to be epidemiologically significant. Metachirus nudicaudatus circulated virus with sufficient regularity and abundance to be a potential source of infection for blood-sucking arthropod vectors.A. arviculoides, Oryzomys and D. paraguayensis fail to develop neutralizing antibodies following the bites of infected mosquitoes; in M. opossum, P. dimidiatus, D. novemcinctus and E. sexcinctus these antibodies appear irregularly or in barely demonstrable concentrations; furthermore, in the first two species mentioned they are not permanent. M. nudicaudatus produces neutralizing antibodies with regularity but they tend to disappear within a few months. Consequently, negative neutralization test results obtained in immunity surveys based on sera from any of these animals are of no value. Positive results obtained with sera from M. opossum or M. nudicaudatus would, if specific, indicate recent infections; positive results with sera from E. sexcinctus or D. novemcinctus might indicate either a recent or an old infection. Complement fixation tests are applicable only to sera from P. dimidiatus; a positive result with sera from this species indicates a recent infection.Immunity surveys based on the immunological examination of sera from captured wild animals are valid only when it is well established that animals of the species under consideration are capable of forming antibodies with regularity following the bites of infected insect vectors. Consideration must also be given to the length of time during which these antibodies, if formed, persist in a demonstrable concentration in the serum of the infected animal.