Emma B. Casanave

GEOGRAPHICAL VARIATION IN THE DIET OF GEOFFROY'S CAT (ONCIFELIS GEOFFROYI) IN PAMPAS GRASSLAND OF ARGENTINA

Abstract Geoffroys cat (Oncifelis geoffroyi) is a little-known South American felid. We report here the first detailed data on its food habits and variations among 3 areas of the Argentine Pampas grassland. Analysis of 421 scat samples showed a relatively narrow trophic niche, dominated by vertebrates, especially small rodents. Despite a wide overlap in diet composition, geographical variation was found in frequency of occurrence of primary food categories, presence of secondary food items, and mean weight of vertebrate prey. These differences seem to be related to variation in food availability and suggest that Geoffroys cats are able to show a certain degree of adaptability in foraging behavior.

Major plasma lipids and fatty acids in four HDL mammals

Lipid classes and their fatty acids were compared in plasma from four mammals: a laboratory rodent, the mouse; two domestic animals, the cat and dog; and a wild animal, the South American armadillo, Chaetophractus villosus. In all, the most abundant lipoprotein was high-density lipoprotein (HDL). In the total lipid of plasma, phospholipids (PL) predominated in all four species, in correlation with the proportion of HDL, both being largest in dogs. The major PL was phosphatidylcholine (PC), followed by sphingomyelin (SM) and lysophosphatidylcholine. The total plasma lipid from the four species contained long-chain n-6 polyunsaturated fatty acids as the predominant acyl groups, followed by comparable proportions of total saturated and monoenoic fatty acids and small percentages of n-3 PUFA. The percentages of these four major groups of fatty acids in PC, SM, triacylglycerols and cholesterol esters were similar among species, but showed significant differences in the ratios between major individual fatty acids composing these groups.

Scanning electron microscopy study of the dorsal surface of the tongue in Zaedyus pichiy (Mammalia, Xenarthra, Dasypodidae)

Se estudio la superficie dorsal de la lengua de Zaedyus pichiy (Desmarest, 1804), utilizando microscopia electronica de barrido. Se describen papilas filiformes conicas y ramificadas, fungiformes y caliciformes. No se observaron papilas foliadas. Las papilas filiformes conicas se observan en el apice de la lengua, en los bordes laterales y posteriormente a las papilas caliciformes. Las filiformes ramificadas representan el tipo mas 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 mas 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 estan relacionadas con el sentido del gusto, en su superficie se observan poros gustativos. Las papilas filiformes tienen funciones mecanica y de proteccion

Histological Study of the Salivary Glands in Zaedyus pichiy (Mammalia, Xenarthra, Dasypodidae)

Se estudio la histologia de las glandulas salivales del armadillo Zaedyus pichiy (Desmarest, 1804). Se identificaron tres pares de glandulas salivales mayores, tubuloacinares compuestas, parotida, submandibular y sublingual. La parotida es histologicamente una glandula serosa. La glandula submandibular posee dos lobulos. El lobulo anterior esta formado por acinos mixtos y serosos. El lobulo posterior es principalmente mucoso. Un reservorio o vesicula salival se relaciona con la glandula submandibular anterior. La glandula sublingual es mixta y esta compuesta por acinos mucosos con escasas semilunas serosas

The Hypertrophy of the Tympanic Bulla in Three Species of Dasypodids (Mammalia, Xenarthra) from Argentina

Fueron estudiados la morfologia y el tamano relativo de la bula timpanica, en tres especies de dasipodidos de la Argentina, Chaetophractus villosus, C. vellerosus and Zaedyus pichiy. Se observaron una morfologia similar y una hipertrofia evidente en la bula en las tres especies. El grado de hipertrofia fue mayor en C. vellerosus y C. villosus que en Z pichiy. Mediante ANCOVA se demostro que, aunque el craneo de C. villosus es mayor que el de C. vellerosus, el tamano relativo de la bula fue similar en ambas especies. Por otra parte, la bula de Z pichiy es relativamente mas pequena que la de C. vellerosus, a pesar que sus craneos son de tamano similar

Seasonal changes in ovarian steroid hormone concentrations in the large hairy armadillo (Chaetophractus villosus) and the crying armadillo (Chaetophractus vellerosus)

Knowledge of armadillo reproductive physiology is essential for developing ex situ and in situ assisted reproductive techniques for propagating and/or controlling populations of these animals. The present study included assessment of fecal sex steroids by radioimmunoassay, determining reproductive status via monitoring ovarian activity (in the wild) and therefore reproductive status, in wild females of the large hairy armadillo (Chaetophractus villosus) and the crying armadillo (Chaetophractus vellerosus) in the southern hemisphere. Plasma and fresh fecal progesterone concentrations were not significantly correlated in either species. However, in both species, there was a significant positive correlation between plasma progesterone and dry fecal progesterone concentrations (r = 0.82, P < 0.05 and r = 0.60, P < 0.05, respectively). Dry fecal progesterone and estradiol concentrations were measured in one captive C. villosus (average baseline progesterone and estradiol concentrations 28.72 ± 11.75 ng/g dry feces and 3.04 ± 0.80 ng/g dry feces, respectively) and one captive C. vellerosus (average baseline progesterone and estradiol concentrations 14.05 ± 3.03 ng/g dry feces and 3.46 ± 1.20 ng/g dry feces, respectively) to detect hormonal peaks over 1 y; these occurred from late fall to early summer. Feces from wild C. villosus and C. vellerosus were also collected over 1 y to determine progesterone peaks, which occurred in winter and spring in both species (with no peaks during the summer or fall). Accordingly, C. villosus and C. vellerosus had a seasonal reproductive pattern. The significant correlations between dry fecal and plasma progesterone concentrations validated this method for monitoring reproductive status in these species.

SCANNING ELECTRON MICROSCOPY STUDY OF THE DORSAL SURFACE OF THE TONGUE IN Chaetophractus vellerosus (MAMMALIA, DASYPODIDAE)

A traves de la microscopia electronica de barrido, fueron analizadas las caracteristicas de la superficie dorsal de la lengua de Chaetophractus vellerosus. Fueron observadas papilas filiformes simples y ramificadas, fungiformes y caliciformes. Papilas filiformes simples conicas, se observaron en el apice, bordes laterales y tercio posterior, caudalmente a las papilas caliciformes. Las ramificadas estaban densamente distribuidas en toda la superficie dorsal de la lengua. Las papilas fungiformes se observaron entre las papilas filiformes ramificadas. En el tercio posterior fueron visualizadas dos papilas caliciformes. Las papilas filiformes tienen funcion mecanica, en tanto que las fungiformes y caliciformes son gustativas, y en ellas se ubicaban corpusculos y poros gustativos. Con mayor aumento fueron observados micropliegues en todos los tipos de papilas y entre estas

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. Anat Rec 258:286–291, 2000.

Cranial Osteology of the Armadillo Chaetophractus villosus (Mammalia, Xenarthra, Dasypodidae)

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

Interindividual interactions of Molina's hog-nosed skunks Conepatus chinga in the Pampas grassland of Argentina

During one year, we radiotracked two female and two male Molina’s hog-nosed skunksConepatus chinga (Molina, 1782), a little studied mephitid, in the Pampas of central Argentina, to analyze the static and dynamic interactions between individuals. Mean home range overlap was large (44.5%), but males shared a smaller proportion of their home ranges than females. The average percentage of localizations in the overlap area (39.3%) indicates that these areas were not marginal sections of individual home ranges, but this value was greater for individuals of different genders than intrasexual dyads. The Coefficient of Spatial Association confirmed that the distances between individuals of different sexes were smaller than between animals of the same sex. During simultaneous locations, females were closer than males, but reciprocal distances between individuals varied over the time. These patterns are congruent with those described as typical for mustelids and mephitids. Our results confirm that an analysis of home range overlap should not be considered complete without the study of dynamic interactions among individuals and their temporal variations, which are necessary to overcome the limitations of spatial overlap analysis.