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Copyright of Revista Mundo de Antes is the property of Revista Mundo de Antes and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Comechingonia: Revista de Arqueología is the property of Comechingonia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article examines the taphonomy of caves and rock shelters in the Argentinian Puna of Atacama. The investigation is aimed to bring forth tools for identifying the effects of the action of foxes on these faunal assemblages and understanding the factors conditioning the characteristics of this action. Accordingly, the aims are integrated in a general concern for understanding the processes of formation of the zooarchaeological record in rock shelters. To give light more on the matter, the identification of three taxonomic group of foxes are presented.

Objective: To describe the calcium concentration of tap and bottled waters from Argentina and to estimate the contribution of drinking water to calcium recommendations. Results: Calcium concentrations provided by water authorities ranged from 6 to 105 mg/L. The mean calcium level of samples analysed at the Laboratorio de Ingeniería Sanitaria, National University of La Plata was 15.8 (SD ± 13.2) mg/L and at the Bone Biology Laboratory of the National University of Rosario was 13.1 (± 10.0) mg/L. Calcium values of samples from supply systems and private wells was similar. Most bottled waters had calcium levels well below 50 mg/L. The intake of one litre of drinking water from Argentina could represent in average between 1.2 and 8.0% of the calcium daily values for an adult. [ABSTRACT FROM AUTHOR]

Among turtles, cases of "gigantism" occur mostly in pleurodiran Pelomedusoides and cryptodirans, but are infrequent among pleurodiran chelids, which are mostly small-medium sized turtles. Yaminuechelys spp. are extinct South American long-necked chelids (from the Late Cretaceous-early Paleocene of Patagonia, Argentina) with caparaces almost three times larger than their extant sister taxon, Hydromedusa tectifera. Since evolutionary changes in size can be analyzed based on growth dynamics, we studied growth strategies from an osteohistological point of view. We sampled both extinct (Yaminuechelys maior) and extant (H. tectifera) species, in order to test hypotheses related to the mechanisms involved in the macroevolution of size within this clade. For this purpose, thin sections of long bone (humerus and femur) shafts of specimens of different ontogenetic stages for these species were prepared. The osteohistological study reveals a similar growth dynamic in both taxa, with a poorly vascularized cortex dominated by parallel- fibered bone and interrupted by lines of arrested growth (LAGs). The huge body size of Y. maior appears to be a consequence of the prolongation of the growth phase, suggesting that it had a longer lifespan than H. tectifera, allowing to reach greater sizes. In this way, and assuming that there is no displacement at the beginning of development (e.g., a delay in the earliest stages of growth) in H. tectifera, the acquisition of a large size in Yaminuechelys would be explained by hypomorphosis of the former or hypermorphosis of the latter, depending on the reconstruction of the ancestral condition of this clade. [ABSTRACT FROM AUTHOR]

The Chañares Formation exhibits one of the most important archosauriform records of early Carnian ecosystems. Here we present new data on the palaeohistology of Chañares archosauriforms and provide new insights into their paleobiology, as well as possible phylogenetically informative traits. Bone microstructure of Lagerpeton chanarensis and Tropidosuchus romeri is dominated by fibro-lamellar tissue and dense vascularization. On the other hand, Chanaresuchus bonapartei is more densely vascularized, but with cyclical growth characterized by alternate fibro-lamellar, parallel-fibered and lamellar-zonal tissues. Dense vascularization and fibro-lamellar tissue imply fast growth and high metabolic rates for all these taxa. These histological traits may be tentatively interpreted as a possible adaptative advantage in front of Chañares Formation environmental conditions. [ABSTRACT FROM AUTHOR]

Recent fossil finds in China and Argentina have provided startling new insights into the reproductive biology and embryology of pterosaurs, Mesozoic flying reptiles. Nineteen embryos distributed among four species representing three distinct clades have been described and all are assumed to be at, or near, term. We show here how the application of four contrasting quantitative approaches allows a more precise identification of the developmental status of embryos revealing, for the first time to our knowledge, the presence of middle and late developmental stages as well as individuals that were at term. We also identify a predicted relationship between egg size and shape and the developmental stage of embryos contained within. Small elongate eggs contain embryos at an earlier stage of development than larger rounder eggs which contain more fully developed embryos. Changes in egg shape and size probably reflect the uptake of water, consistent with a pliable shell reported for several pterosaurs. Early ossification of the vertebral column, limb girdles and principal limb bones involved some heterochronic shifts in appearance times, most notably of manus digit IV, and facilitated full development of the flight apparatus prior to hatching. This is consistent with a super-precocial flight ability and, while not excluding the possibility of parental care in pterosaurs, suggests that it was not an absolute requirement. [ABSTRACT FROM AUTHOR]

Background/objectives: Dual-energy X-ray absorptiometry (DXA) is considered a specific method for measuring body composition to assess obesity and osteoporosis, although few studies have been conducted in preschool children. The aim of this study was to provide sex - and age-specific references for bone mineral density (BMD), bone mineral content (BMC), fat mass (FM) and fat-free mass (FFM) normative data for children aged 2 to <6 years.Subjects/methods: One hundred and eighty seven healthy white children from Buenos Aires City suburbs, Argentina, were studied by the Lunar DPX-L DXA, pediatric software: BMC less head (g), BMD (g/cm2), FM (%) and FFM (g).Results: BMD and BMC increased significantly with age (P<0.0001), but only BMD was significantly different between boys and girls of similar age, being greater for boys (P=0.013). FM was not significantly different among the various age groups of boys and girls. However, the FFM/height was higher in boys and the BMC/FFM was higher in girls. The Z-scores and centile curves were derived separately for each sex and age. Q-Q detrended plots and LMS curves produced robust, unbiased fits that generated references for the 3rd, 50th and 97th percentiles for BMD, BMC, FM and FFM data, respectively.Conclusions: These DXA scans add to the scarcity of accurate measurements of body composition of white young children. The data analyses provided greater accuracy, particularly at the upper and lower ends of the distribution, which is important in clinical settings for identification of children with impaired body composition. [ABSTRACT FROM AUTHOR]