Chemical immobilisation of free-ranging Pampas foxes (Pseudalopex gymnocercus): Assessment of ketamine-xylazine and tiletamine-zolazepam combinations.

Two protocols to immobilise free-ranging Pampas foxes for ear-tagging or radio-collaring were evaluated. One hundred fifteen foxes were injected with ketamine-xylazine (K-X) and thirteen with tiletamine-zolazepam (T-Z). The use of both T-Z and K-X combinations typically resulted in a smooth induction and recovery. In 86% of the cases K-X protocol was judged effective (mean±SD, K: 10.7±3.3mg/kg, X: 1.0±1.0mg/kg) while T-Z protocol was judged effective in 92% of the cases (T: 3.6±1.05mg/kg, Z: 3.6±1.05mg/kg). The primary differences between the two drug combinations were that the time necessary for the complete recovery was longer with T-Z, and thermic problems were found more frequently with K-X. Additionally, our results suggest that thermic stress may be a relatively frequent complication for Pampas foxes. This study provides baseline data on some physiologic variables in Pampas foxes captured with different methods and drugs in field conditions.

Scanning electron microscopy study of the dorsal surface of the tongue of dasypus hybridus (Mammalia, Xenarthra, Dasypodidae) / Estudio al microscopio electrónico de barrido de la superficie dorsal de la lengua de Dasypus hybridus (Mammalia, Xenarthra, Dasypodidae)

The dorsum of the tongue of Dasypus hybridus (Desmarest, 1804) studied by scanning electron microscopy, shows conical and branched filiform, fungiform and vallate papillae. No foliate papillae were seen. Conical filiform papillae are placed in the apex of the tongue and posterior to the vallated ones. Branched papillae are compactly distributed over the entire dorsal surface of the tongue. Fungiform papillae are more abundant on the first third of the tongue and they are distributed between filiform papillae. Only two vallate papillae were observed placed in the posterior third of the tongue, surrounded by a deep grove. The presence of taste buds on fungiform and vallate papillae indicate that both are involved in the sense of taste, while the filiform ones have a mechanical and protective role. The morphological characteristics of the tongue of Dasypus hybridus are comparable with those of other species of armadillos.

La superficie dorsal de la lengua de Dasypus hybridus (Desmarest, 1804) estudiada a través de microscopía electrónica de barrido, muestra papilas filiformes cónicas y ramificadas, fungiformes y caliciformes. No se observaron papilas foliadas. Las papilas filiformes cónicas se observan en el ápice de la lengua, en los bordes laterales y posteriormente a las papilas caliciformes. Las filiformes ramificadas se encuentran distribuidas en forma compacta sobre toda la superficie dorsal de la lengua. Las papilas fungiformes se localizan entre las filiformes ramificadas y son más numerosas en el tercio anterior de la lengua. Sólo dos papilas caliciformes fueron encontradas ubicadas en el tercio posterior de la lengua, rodeadas por un surco profundo. La presencia de poros gustativos en las papilas fungiformes y caliciformes indica que ambas se encuentran involucradas en el sentido del gusto, mientras que las filiformes poseen un rol mecánico y de protección. Las características morfológicas de la lengua de Dasypus hybridus son comparables con las de otras especies de armadillos.

Sexual dimorphism in the mandible of the armadillo Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) from northern Patagonia, Argentina.

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.

Sexual dimorphism in the mandible of the armadillo Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) from northern Patagonia, Argentina / Dimorfismo sexual da mandíbula do tatu Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) do norte da Patagônia Argentina

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.

O presente estudo examinou o dimorfismo sexual dos adultos de Chaetophractus villosus (Desmarest, 1804) do norte da Patagônia Argentina. Oito parâmetros mandibulares foram medidos em 37 machos e 34 fêmeas. Análises morfométricas univariada e multivariada foram aplicadas à série de dados. Os resultados mostraram que C. villosus apresenta dimorfismo sexual, com todos os valores absolutos mais elevados nas fêmeas. O comprimento total da mandíbula foi a variável mais importante para discriminar os sexos, seguidos pela altura no nível dos últimos dentes e pelo comprimento do corpo da mandíbula. As porcentagens de discriminação dos sexos foram elevadas, quando uma amostra nova (17 machos, 13 fêmeas) foi testada. As fêmeas têm as mandíbulas maiores que os machos, independentemente de seu tamanho cranial maior. Mostraram também um grau mais elevado de correlação entre variáveis, sugerindo uma forma mais estável para a mandíbula que nos machos.

Scanning electron microscopy study of the dorsal surface of the tongue in Zaedyus pichiy (Mammalia, Xenarthra, Dasypodidae) / Estudio al microscopio electrónico de barrido de la superficie dorsal de la lengua de Zaedyus pichiy (Mammalia, Xenarthra, Dasypodidae

The dorsal surface of the tongue of Zaedyus pichiy (Desmarest, 1804) was examined by scanning electron microscopy. Conical and branched filiform, fungiform and vallate papillae are described. No foliate papillae were seen. Conical filiform papillae are distributed in the apex, both lateral edges and caudally to the vallated ones. The branched papillae represent the most numerous type of lingual papillae; they are distributed over the entire dorsal surface of the tongue. The fungiform papillae are placed among the filiform ones, more densely distributed on the tip of the lingual apex. In the posterior third of the tongue there are two vallated papillae surrounded by a deep circular grove. Fungiform and circumvallate papillae are related to the sense of taste; openings of taste pores are visible on their surface. The filiform papillae have a mechanical and protective role.

Se estudió la superficie dorsal de la lengua de Zaedyus pichiy (Desmarest, 1804), utilizando microscopía electrónica de barrido. Se describen papilas filiformes cónicas y ramificadas, fungiformes y caliciformes. No se observaron papilas foliadas. Las papilas filiformes cónicas se observan en el ápice de la lengua, en los bordes laterales y posteriormente a las papilas caliciformes. Las filiformes ramificadas representan el tipo más numeroso de papilas linguales y se encuentran distribuidas en toda la superficie dorsal de la lengua. Las papilas fungiformes se localizan entre las filiformes ramificadas y son más numerosas en el tercio anterior de la lengua. En el tercio posterior se observan dos papilas caliciformes rodeadas por un surco profundo. Las papilas fungiformes y caliciformes están relacionadas con el sentido del gusto, en su superficie se observan poros gustativos. Las papilas filiformes tienen funciones mecánica y de protección.

The spleen of Zaedyus pichiy, (Mammalia, Dasypodidae): a light and electron microscopic study.

Armadillos are ancient mammals important as models for biomedical, evolutive and ecological studies, because they have adaptive and primitive morpho-physiological characteristics. In this work we study the splenic microarchitecture of the 'Patagonian Piche', Zaedyus pichiy, as an attempt to understand the relationship between the organizational plan of the organ and the particular features of this species. The organ samples were classically processed for light and electron microscopic study. The microanatomy of the organ as well as its different cell types are studied. The spleen is non-sinusoidal, with the typical arrangement for storage functions. White pulp is well defined. Red pulp is a meshwork of circulating, immunocompetent and haemopoietic cells. The general structure of the organ agrees with the semi-fossorial habit and the adaptability of the species. Comparative aspects with other armadillos or other less specialized groups are discussed. Persistence of haemopoietic spleen activity in the adult suggests the existence of specific inductive functions of the stroma. Better knowledge of spleen structure and function in ancient mammals may give important information about their phylogeny.

Ultrastructure and morphometry of ovarian follicles in the armadillo Chaetophractus villosus (Mammalia, Dasypodidae).

Ultrastructural and morphometric changes in oocyte and surrounding granulosa cells during armadillo follicular growth are described. Primordial, intermediary, early and late primary, secondary, tertiary and preovulatory Graafian follicles were found. From primordial to Graafian follicle, granulosa cells increase in height, become multilayered while fluid-filled spaces arise among them in the tertiary follicle stage. As the follicle expands the oocyte is located eccentrically and grows in size. From primordial to secondary stage organelles develop in number and complexity and many vesicles start arising in the cytoplasm at the secondary stage. From tertiary follicle stage the number of mitochondria decreases. In follicular cells, secreting-related organelles expand, but mitochondrial number decreases according to the follicle expansion. Intercellular junctions between both cell types increase. The morphometrical study shows a biphasic pattern of oocyte and follicle growth. The morphological baseline here provided will be essential for further comprehension of the reproductive biology in armadillos.

Ultrastructure and morphometry of ovarian follicles in the armadillo Chaetophractus villosus (Mammalia, Dasypodidae)

Ultrastructural and morphometric changes in oocyte and surrounding granulosa cells during armadillo follicular growth are described. Primordial, intermediary, early and late primary, secondary, tertiary and preovulatory Graafian follicles were found. From primordial to Graafian follicle, granulosa cells increase in height, become multilayered while fluid-filled spaces arise among them in the tertiary follicle stage. As the follicle expands the oocyte is located eccentrically and grows in size. From primordial to secondary stage organelles develop in number and complexity and many vesicles start arising in the cytoplasm at the secondary stage. From tertiary follicle stage the number of mitochondria decreases. In follicular cells, secreting-related organelles expand, but mitochondrial number decreases according to the follicle expansion. Intercellular junctions between both cell types increase. The morphometrical study shows a biphasic pattern of oocyte and follicle growth. The morphological baseline here provided will be essential for further comprehension of the reproductive biology in armadillos

Spleen of Dasypus hybridus (Mammalia, dasypodidae): a light and electron microscopic study.

Armadillos are relictual mammals important as models for biomedical studies. They contain adaptative and primitive characteristics in both anatomical and physiological aspects. In this study we describe the splenic histology and cytology of the "mulita," Dasypus hybridus. Organ samples were processed for light and electron microscopy study. The microanatomy of the organ samples as well as their different cell types are described. The spleen is non-sinusoidal, with the typical arrangement for storage functions. White pulp is lightly diffuse. Red pulp is a meshwork of circulating, immunocompetent and hemopoietic cells. Differences with other studied members of the group are discussed. The general structure of the organ agrees with the semi-fossorial habit of the species. Persistence of myeloid activity in the adult suggests the existence of specific inductive functions of the stroma. Better knowledge of this fact may give further insight on the phylogeny of hemopoiesis.

Decrease of body temperature in armadillos experimentally covered by soil.

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.

Bradycardia in armadillos experimentally covered with soil.

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.

Body temperature of the armadillo Chaetophractus villosus (mammalia, dasypodidae).

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.

Absence of apnea in armadillos covered by soil.

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.

On the presence of a peculiar alpha rhythm in the olfactory tubercle of waking armadillos.

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 that establish an important difference between it and the other 'alpha rhythms' known.

Neocortical and olfactory bulb activity, in armadillos submitted to covering with soil.

Armadillos were submitted to an experimental condition in which their head and thorax were covered by a layer of soil 30 cm high. In this condition the electrical activity of the neocortex and of the olfactory bulbs was studied. Neocortical activity did not show signs of damage remaining without gross changes before, during and after the covering with soil. The olfactory bulbs showed a great decrease of bursting sinusoidal activity which almost instantaneously reversed when the soil was removed. The mechanisms of these changes are discussed.