Recursos de colección

Universidad Nacional de La Plata (75.269 recursos)

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vol. 08, no. 01

Mostrando recursos 1 - 20 de 22

  1. Lista propuesta de anfibios y reptiles amenazados de extinción

    Bertonatti, Claudio
    A preliminary list on endangered amphibians and reptiles of Argentina is presented. On the basis of published and unpublished information, and following the UICN criteria, 123 of 370 herp species were categorized.

  2. Estado de conservación de la herpetofauna del Parque y Reserva Nacional Nahuel Huapi, Argentina

    Úbeda, Carmen A.; Grigera, Dora; Reca, Alfredo R.
    The conservation status of the fauna of amphibians and reptiles of the Nahuel Huapi National Park and Reserve is evaluated in the present work. Fourteen species of amphibians and 11 of reptiles in the study area were considered in the methodology which consists in assessing the degree of conservation of each species through an index made up by 12 survival-related variables (Reca el al. 1994). A list of species ordered according to their conservation indices for Argentina was obtained. The addition of two variables accounting for the particular situation of the species within the study area, allowed the elaboration of...

  3. Estado actual del registro de escamados extinguidos de América del Sur y sus implicancias paleoambientales

    Albino, Adriana María
    The record of the South American fossil Squamata extends from the Late Cretaceous to the Holocene. The recorded families are Iguanidae s.l., Teiidae, Gekkonidae, ?Scincidae, Amphisbaenidae, Boidae, Aniliidae, Colubridae and Viperidae Dinilysiidae from the Late Cretaceous of Patagonia and Palaeopheidae from the Late Eocene of Ecuador are the only known extinct recorded families. The families distribution during the Cretaceous and most of the Tertiary apparently was more extensive than at present, due to more generalized subtropical climatic conditions. The geological events during the Cenozoic would have caused climatic and environmental changes that would have favoured the appeareance of new adaptative...

  4. Reptiles de la reserva de usos múltiples Caleta de los Loros, Río Negro, Argentina

    Vega, Laura Estela; Bellagamba, Patricio J.
    A list of reptiles from Caleta de los Loros Reserve including their habitat association is given. In order to carry out censues and collection of specimenes, three surveys wich lasted 10 days each, were made in the study area. The resulting list contains 16 species: 1 tortoise, 8 lizards, 1 amphisbaenian and 6 snakes. The highest percentages of habitat associations were obtained for the monte (56%) and sand dunes (50%).

  5. Espectro trófico de Chelonoidis chilensis (Chelonii: testudinidae) en la provincia fitogeográfica del monte (Mendoza, Argentina)

    Richard, Enrique
    Between 1983 and 1991, 83 field trips were made to the biogeographical province of Monte, in Mendoza province, Argentina, in order to study the trophic spectrum of Chelonoidis chilensis, among other ecoethological aspects. The trophic period extends from September to April. Adults are herbivorous in strict sense, but this may change according to the available resourees. Trophic spectrum is composed by 14 items (Families) of vegetables. Some items have toxic or potentially toxit substances. Finally, the diet of Ch. chilensis is compared with the one of Ch. donosobarrosi and with other desert tortoises.

  6. Reconocimiento de olor feromonal con específico en Waglerophis Merremii (Serpentes: colubridae)

    Chiaraviglio de Torres, Margarita; Gutiérrez, Mercedes
    Tongue flicking responses of adult male and female Waglerophis merremii were tested with cloacal glands chemical stimuli of male and female conspecifics and control substance, ah l presented on cotton-tipped applicators. Tongue flicking rates by both sexes were significantly higher from cloacal chemical stimuli than from control, indicating that W. merremii detected conspecific cloacal chemicals. Postreproductive males treated with testosterone ernitted significantly more tongue-flicks in response to female than to male cloacal chemicals. Postreproductive females treated with estradiol emitted significantly more tongue -flicks in response to male than to female cloacal chemicals. Both results showed that W. merremii can chemically...

  7. Actividad reproductiva en Homonota horrida (Sauria: gekkonidae) del Chaco occidental en Argentina

    Cruz, Félix B.
    Gonads from 100 individuals of Homonota horrida from Salta province were examined. Most exemplars were captured with pit-fall traps during a period of 19 months, approximately. The population activity (based on the captures) was year round, being more trapped during spring-summer seasons. The minimum size observed in mature females was 39.1 mm snout-vent length (x=49.2; S.E.=1.56; n=16), and clutch size was constant (two eggs). The beginning of the reproductive activity in females was November and they were active until January. No female was observed carrying both eggs into the oviducts, in all cases one egg was into one oviduct, while...

  8. Actividad reproductiva en Vanzosaura rubricauda (Sauria: teiidae) del Chaco occidental en Argentina

    Cruz, Félix B.
    A population of Vanzosaura rubricauda was studied. The exemplars came from the locality of J.V. González, Anta Department, Salta Province. Sexual dichromatism and dimorphism was observed, being males colored on throat region and with a head wider than females, but the later were larger in body size. The population activity was year round, but during the dry and cold months it dropped. Clutch size was constant (2 eggs). Cyclic reproduction was observed, and the major reproductive activity was given in early spring through summer.

  9. Osteología craneal del género Philodryas (Serpentes: colubridae)

    Lobo, Fernando; Scrocchi, Gustavo
    We studied the skulls of eleven species of Philodryas. The skull of Philodryas patagoniensis is described, and some characters that show interspecific variation are recognized. These characters are used for phylogenetic inferences. We obtained three trees using Hennig86. The pair of sister species wich is presented in the three cladograms is P. mattogrossensis - P. varius: in only ene tree: P. buroni - P. burmeisteri.

  10. Análisis comparativo de la composición de tres comunidades de Squamata de la Sierra Grande de Córdoba, Argentina

    Martori, Ricardo; Aun, Liliana
    The differences and similarities of lizard assemblages can be explaned by historical or ecological factors or by the interaction of both. To examine these hypothesis we selected three communities with similar environmental influences in the Sierra Grande de Córdoba (Argentina). The sites selected where: Villa Las Rosas (31°56', 65°03'), dep. San Javier on the west side of the Sierra, Tanti (310,22, 64°36') dep. Punilla on the east side of the Sierra and Achiras (33°10', 64°59') dep. Rio Cuarto on the southem extreme of the Sierra. All these sites have more than eight species of lizards. The diversity of each site...

  11. Biología de una población de Homonota horrida

    Aun, Liliana; Martori, Ricardo
    A population of Hornonota horrida was studied in Tanti (31°22', 64°36'), Punilla Dep. Córdoba, Argentina. The activity of this population starts in September and continues to March. In October, females have yolked follicles, and oviductal eggs are present in November. The largest testes were found in September. Mature males ranged from 3.6 cm to 6.0 cm. Reproductive females ranged 3.5cm to 6.2 cm snouth vent lenght. H. horrida has one clutch of one egg per year. Numerically, Isoptera was the most common prey; vollumetrically, Lepidoptera larvae where the most common item.

  12. Cariotipo y región organizadora del núcleo en Teius teyou (Daudin, 1802) (Squamata: teiidae)

    Hernando, Alejandra B.
    Specimens of Teius teyou (Daudin, 1982) from Formosa and Chaco, Argentina, were citologically analyzed. A karyotype characterized by 54 chromosomes and 2 pairs of ribosomal chromosomes were identified.

  13. Variabilidad poblacional en el género Kentropyx (Squamata: teiidae) del Norte argentino

    Tedesco, María Esther; Cei, José M.; Porcel, Eduardo; Álvarez, Blanca Beatriz
    Variability of population of Kentropyx from northern Argentina was studied using characters of lepidosis and coloration. A subspecific taxonomic level, Kentropyx viridistriga lagartija is proposed for Kentropyx lagartija, considering this subspecies a western form of the eastern one Kentropyx viridistriga viridistriga.

  14. Biogeografía de los anfibios anuros de la región central de la República Argentina

    Bridarolli, María E.; Tada, Ismael E. di
    The distribution of sixty anuran taxa in central Argentina (28°- 36°S, 60°-68°W) is analyzed, as well as its correspondence with natural environments, taking into account phytogeographic formations, geomorphology, climatologic zones and zoogeographic regions. An isoline map of anurans diversity was constructed. High diversity occurs in the central-east zone of the study area, coincidently with plain environments and heterogenous phytogeographic formations; low values are found in homogenous phytogeographic formations. A dendrogram was obtained following UPGMA procedure, distinguishing 6 groups of phytogeographic associations based on amphibian distributions. A correspondence between natural environments and anurans presence is reported.

  15. Estado sistemático y distribución geográfica de Argenteohyla siemersi (Mertens, 1937) en la República Argentina (Anura: hylidae)

    Williams, Jorge Daniel; Bosso, Andrés
    Argenteohyla siemersi pederseni n. subsp. is described from the province of Corrientes, Argentina. The new subspecies is differentiated from Argenteohyla siemersi siemersi by the coloration pattern and the presence of two longitudinal black lines in the dorsum. Comments on the habitat and biogeography are added.

  16. Una nueva especie de Batrachyla (Anura: leptodactylidae: telmatobiinae) de Argentina

    Basso, Néstor Guillermo
    A new species of telmatobiinae leptodactylid frog genus Batrachyla is described from the Nothofagus forest of Chubut province, Southern Argentina. Batrachyla fitzroya sp. nov. is more closely related to B. antartandica than to any other species of the genus. A cladistic analysis of the genus Batrachyla applying parsimony is presented using morphological and osteological characters. Polarity was based on the outgroup comparison method. The data were analysed using Farris's phylogenetic program Hennig86, using the implicit enumeration option. In the preferred phylogeny B. taeniata is the sister species of the clade B. leptopus-(B. antartandica-B. fitzroya).

  17. Aportes preliminares sobre la reproducción en una comunidad de anuros chaqueños en Argentina

    Peroti, María Graciela
    In the present study the reproductive modes and some reproductive characteristics from an amphibian community of the chacoan region in Argentina were determined. There are four modes of reproduction recognized. Fifty percent of the species exhibit the most common reproductive mode (mode 1), while the rest of the species exhibit a variety of characteristics related to terrestrial life. The reproductive characteristics determined in 11 of 22 species are female size, egg size, number of mature eggs, and female weight. Species with terrestrial habits have fewer eggs than aquatic ones. Without consideration of reproductive mode, a negative correlation between clutch size...

  18. Variación estacional en la proporción relativa de los estadios de la oogénesis en Bufo arenarum (Anura: bufonidae)

    Echeverría, Dinorah Diana; González, Beatriz N.
    The Anova repeated measure design was used to compare the percentage of oocytes in female toads (Bufo arenarum) at stages 1 to 5 and at different physiological ovary periods (or phases: production, before ovulation, after ovulation). Individual comparisons among stages and between phases have been made with the minimum significant difference method at 0.05 probability level. The statistical analysis at percentage of oocytes showed that: a) Stages 1 and 2 have few variation. They are the permanent oocytes group. b) Stage 3 (late vitelogenesis oocytes) are absent previous to the breeding season. Their rate increases in summer and decreases in...

  19. Estereoultraestructura del pulmón de anuros bufónidos

    Hermida, Gladys; Fiorito de López, Luisa E.
    Scanning electron microscopy was used to determined the inner morphology of the Bufo arenarum lung. The observations let conclude that the lung presents three types of folds which divide the organ into alveolar spaces. The inner surface of the lung, as well as the lateral wall of the folds are lined with respiratory epithelium, except in the apex of the primary folds (ciliated surface with goblet cells) and in the secondary folds (ciliated surface).

  20. Alimentación en Melanophryniscus stelzneri (Anura: bufonidae)

    Filipello, Ana María; Crespo, Francisco Antonio
    The alimentary categories of a population of Melanophryniscus stelzneri are studied cuantitatively and cualitatively utilizing a sample of 57 specimens obtained from "El Trapiche", province of San Luis, Argentine, in order to know the grade of trophic overlap and predation strategies. The main alimentary categories for males and females are: Formicidae, Collembola, Acari, Coleoptera, Isoptera and larvae. Although the diets of both sexes show a high grade of trophic overlap, males and females differ in the amount of each resource used. Adults and juveniles present a low grade of trophic overlap. The juveniles follow the "widely foraging" strategy and the...

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