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Historia natural de un roedor raro del desierto argentino, Salinomys delicatus (Cricetidae: Sigmodontinae) Natural history of a rare rodent of the Argentinean desert, Salinomys delicatus(Cricetidae: Sigmodontinae)
DANIELA RODRíGUEZ,CECILIA LANZONE,VERóNICA CHILLO,PABLO A CUELLO
Revista chilena de historia natural , 2012,
Abstract: El ratón delicado de los salares (Salinomys delicatus) es un peque o roedor endémico de Argentina. Ha sido considerado como vulnerable a la extinción dada su distribución restringida y en parches, tama o poblacional peque o y especialización en hábitats salinos. A pesar de que el ratón delicado tiene adaptaciones morfológicas y fisiológicas para la supervivencia en ambientes áridos y salitrosos, poco es lo que se conoce de su historia natural. El presente trabajo tiene como objetivo estudiar la historia natural de S. delicatus, reportar nuevas localidades de ocurrencia, caracterizar el uso de hábitat, su dieta y el ensamble acompa ante, y describir su biología reproductiva y morfología. Se registraron dos nuevos sitios de ocurrencia en ambientes de bosques en galería y bajos salinos en la región noreste de la provincia de Mendoza (Argentina), siendo las primeras citas para esta provincia. S. delicatus presenta una dieta omnívora, como es frecuente en otros roedores de desierto, y consume en igual medida semillas, artrópodos y plantas halófitas. El ensamble acompa ante está compuesto por no más de tres especies de peque os mamíferos que varían según la localidad, siendo esta riqueza similar a otros sitios del Monte. La proporción de sexos y el patrón de dimorfismo sexual mostraron un marcado desvío hacia las hembras (H:M = 3.6:1.1 y H:M = 1.151 respectivamente). La morfología externa y craneal presenta una importante variabilidad intra e interpoblacional, sugiriendo que el aislamiento juega un rol importante. Cuando se consideraron adultos y juveniles, conjuntamente dos de las seis medidas externas (longitud total y longitud de cabeza y cuerpo) y siete de las 22 medidas craneales resultaron significativamente mayores en hembras que en machos. Cuando se compararon solo los adultos, cuatro características externas (longitud total, longitud de cabeza y cuerpo, largo de la cola y peso) y seis medidas craneales fueron significativamente mayores en hembras que en machos. Este trabajo refuerza la importancia del desarrollo de nuevos estudios más detallados sobre la historia de vida de S. delicatus y permite reafirmar la importancia de conservación de esta especie. The delicate mouse (Salinomys delicatus) is a small rodent endemic of Argentina. It has been considered vulnerable to extinction because of its restricted and patchy distribution, small population size and specialization on salty habitats. Besides its morphological and physiological adaptations to survive in arid and salty habitats, there is still little information about the natural history of the del
Historia natural de un roedor raro del desierto argentino, Salinomys delicatus (Cricetidae: Sigmodontinae)
RODRíGUEZ,DANIELA; LANZONE,CECILIA; CHILLO,VERóNICA; CUELLO,PABLO A; ALBANESE,SOLEDAD; OJEDA,AGUSTINA A; OJEDA,RICARDO A;
Revista chilena de historia natural , 2012, DOI: 10.4067/S0716-078X2012000100002
Abstract: the delicate mouse (salinomys delicatus) is a small rodent endemic of argentina. it has been considered vulnerable to extinction because of its restricted and patchy distribution, small population size and specialization on salty habitats. besides its morphological and physiological adaptations to survive in arid and salty habitats, there is still little information about the natural history of the delicate mouse. the objectives of our study are to study the natural history of s. delicatus, report new localities of occurrence, characterize its habitat use, diet and accompanying assemblages and describe its reproductive biology and morphology. we report two new localities of occurrences in gallery woodlands and salt flats in the northeast of mendoza province (argentina), these being the first records for this province. like other south aamerican rodents, s. delicatus has an omnivorous diet consisting in similar proportion of seeds, arthropods and halophytic plants. the assemblages are composed by no more than three small mammal species, varying according to the locality. sex ratio and the pattern of sexual dimorphism shows a strong bias towards females (h:m = 3.6:1.1 and h:m = 1.151 respectively). external and cranial morphology exhibits a clear intra- and inter-population variability. when considering in the analysis adults and juvenile, two of six external measurements (head and body length and total length) and seven of twenty-two cranial measurements were significantly higher in females than in males. when considering only adults, four external measures (total length, head and body length, tail length and weight) and six cranial measurements were significantly higher in females than in males. this integrative analysis highlights the relevance of conducting further and more detailed studies on the natural history of s. delicatus and allows us to reassert the conservation importance of this species.
Ontogenetic and sexual variation in cranial characters of Aegialomys Xanthaeolus (Thomas, 1894)(Cricetidae: Sigmodontinae) from Ecuador and Peru
Prado, Joyce R.;Percequillo, Alexandre R.;
Papéis Avulsos de Zoologia (S?o Paulo) , 2011, DOI: 10.1590/S0031-10492011000900001
Abstract: aegialomys xanthaeolus (cricetidae: sigmodontinae) inhabits the arid montane areas of western ecuador and peru, and higher elevations in the upper mara?ón valley in northern peru. some researchers have included this species in broader systematic assessments over the years, but there are no comprehensive studies focusing on intraspecific variation. there are several sources of intraspecific phenotypic variation, including sexual dimorphism and age. these sources may confound the assessment of similarity/dissimilarity among populations, therefore it is essential that non-geographic variation is evaluated before studies on geographical variation and species delimitation are carried out. here we summarize existing information regarding the geographical distribution of a. xanthaeolus and evaluate variation related to sex and age. we analyzed 19 traditional cranio-dental measurements taken from specimens housed in scientific collections, and organized the collecting localities of specimens examined in a gazetteer and plotted them on a distribution map. uni and multivariate statistical analyses allow us to assert that age variation was significant, as age classes 3, 4 and 5 can be pooled for the subsequent analysis of geographic variation and that sexual dimorphism is not a consistent component of variation within this species in the continental samples, when considering samples from the same locality, or localities close to each other.
A predictive distribution model for Andinomys edax (Rodentia: Cricetidae) in Argentina
Jayat,Pablo; Pacheco,Silvia; Ortiz,E.;
Mastozoolog?-a neotropical , 2009,
Abstract: we studied the distribution of andinomys edax (rodentia, cricetidae, sigmodontinae) in northwestern argentina. presence data obtained from field records, museum specimens and literature were used to model the potential distribution of this species. andinomys edax was known in argentina from only 41 occurrence localities, most of them restricted to jujuy province. here we add new localities from catamarca, jujuy, salta and tucumán provinces. we used the maximum entropy method (maxent) and seven environmental variables to produce a potential distribution map of the species. the 7.015 cumulative threshold (corresponding to the equal test of sensitivity and specificity) was the most efficient hypothetical distribution according to the omission rate. the area under the curve (auc) was of 0.987 for training data. the model indicates that a. edax is mainly distributed on the more humid eastern montane ranges in the region, associated to high altitude grasslands and ecotonal zones between 1500 and 4000 m in yungas, prepuna, puna and high andean environments. these results, as well as the known fossil record for the species in argentina, indicate the ecological plasticity of a. edax, present in the region at least since middle-upper pleistocene times.
A PREDICTIVE DISTRIBUTION MODEL FOR Andinomys edax (RODENTIA: CRICETIDAE) IN ARGENTINA  [cached]
Pablo Jayat,Silvia Pacheco,Pablo E. Ortiz
Mastozoolog?-a neotropical , 2009,
Abstract: Se estudió la distribución de Andinomys edax (Rodentia, Cricetidae, Sigmodontinae) en el noroeste de Argentina. Para modelar la distribución potencial de la especie se usaron datos de presencia obtenidos a partir de registros de campo, de especímenes depositados en colecciones y de la literatura. Andinomys edax se conocía en Argentina por sólo 41 localidades, la mayoría de ellas en la provincia de Jujuy. En este trabajo se adicionan nuevas localidades para las provincias de Catamarca, Jujuy, Salta y Tucumán. El mapa de distribución potencial de la especie fue modelado utilizando el método de máxima entropía (Maxent) y siete variables ambientales. De acuerdo con la tasa de omisión, el umbral acumulativo de 7.015 (correspondiente al test de igualdad de sensitividad y especificidad) determinó la distribución hipotética más eficiente. El área bajo la curva (AUC) para el test ROC fue de 0.987 para los datos de entrenamiento. De acuerdo con el modelo, A. edax se distribuye principalmente sobre las laderas orientales húmedas de los cordones monta osos de la región, asociada a pastizales de altura y sus ecotonos entre 1500 y 4000 m, en ambientes de Yungas, Prepuna, Puna y Altos Andes. Estos resultados, así como el registro fósil de la especie en Argentina, indican una gran plasticidad ecológica de A. edax, presente en la región al menos desde el Pleistoceno medio-superior.
The adjustment of Calomys callosus (Rodentia, Cricetidae) to food deprivation
Ades, César;Kolde, Renate Edla;
Revista Brasileira de Zoologia , 1989, DOI: 10.1590/S0101-81751989000200005
Abstract: the adjustment of calomys callosus (rodentia, cricetidae) to intermittent food deprivation was investigated. animals subjected either to 24-hr or to 48-hr repeated periods of deprivation successfully compensated, showing (1) increases in post-fast intake relatively to the intake by control animals; (2) rapid recovery of the baseline levels of body wieght. the regulatory ability of c. callosus is comparable, in such respects, to the ability of the common rat and some other rodents but it is remarkably different from the hamster's.
Key to the genera of the Tribe Oryzomyini (Rodentia: Cricetidae: Sigmodontinae)
Weksler,Marcelo; Percequillo,Alexandre R.;
Mastozoolog?-a neotropical , 2011,
Abstract: due to recent phylogenetic and revisionary taxonomic work, the systematics of the tribe oryzomyini, the largest group of sigmodontine rodents, underwent profound changes. we present here an artificial key for the genera of this group of rodents, enabling researchers to identify oryzomyines using external, cranial and dental characteristics. we also present the most up-to-date diversity assessment of the tribe, in which we recognize 33 extant and extinct genera (plus three undescribed genus-group taxa) and 130 valid species.
Chromosomal characterization of Irenomys Tarsalis (Rodentia, Cricetidae, Sigmodontinae)
Ojeda,Agustina A.; Ríos,Carolina A.; Gallardo,Milton H.;
Mastozoolog?-a neotropical , 2004,
Abstract: the systematics of i. tarsalis is far from being understood. morphological and molecular analyses have given contradictory results, pointing towards its inclusion or exclusion from the phyllotini. the karyotype of irenomys tarsalis, as well as its c-bands are reported for the first time. the species has 2n = 64 chromosomes (fn = 98) and a c-banding pattern characterized by small amounts of centromeric heterochromatin. although the high diploid number and the c-bands of i. tarsalis support the notion of the species′ ancestral karyotypic condition, its affiliation within the sigmodontines cannot be discerned by the data.
KEY TO THE GENERA OF THE TRIBE ORYZOMYINI (RODENTIA: CRICETIDAE: SIGMODONTINAE)  [cached]
Marcelo Weksler,Alexandre R. Percequillo
Mastozoolog?-a neotropical , 2011,
Abstract: Due to recent phylogenetic and revisionary taxonomic work, the systematics of the Tribe Oryzomyini, the largest group of sigmodontine rodents, underwent profound changes. We present here an artificial key for the genera of this group of rodents, enabling researchers to identify oryzomyines using external, cranial and dental characteristics. We also present the most up-to-date diversity assessment of the tribe, in which we recognize 33 extant and extinct genera (plus three undescribed genus-group taxa) and 130 valid species.
Liaoxiornis delicatus gen. et sp. nov., the smallest Mesozoic bird
Lianhai Hou,Peiji Chen
Chinese Science Bulletin , 1999, DOI: 10.1007/BF02885031
Abstract: Recently, a very small and complete bird specimen was collected from theConfuciusornis-bearing Yixian. Formation. This finding represents a new kind of Mesozoic bird, namedLiaoxiornis delicatus. It is characterized by a short skull with teeth, a long neck and a very small sternum with only posterior process; the humeral head is not internally curved, and the hindlimbs are longer than the forelimbs.Liaoxiornis delicatus is not only much smaller thanConfuciusomis, but also smaller thanCathayomis and other early Cretaceous birds. It is the smallest bird known from Mesozoic deposit.Liaoxiornis provides new evidence indicating that the early adaptive radiation of birds is complicated.
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