Historia natural de un roedor raro del desierto argentino, Salinomys delicatus (Cricetidae: Sigmodontinae)

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.