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This paper explores how significant are the ecological and climatic variables to influence the stable isotopes of guanacos. Lama guanicoe bone collagen carbon and nitrogen stable isotope ratios are assumed as a macro regional average value in west Argentina, mostly as a baseline to model archaeological human diet. If stable isotopes on mammals reflex ecology and climate, we need to know how those variables influence mammals bone stable isotope ratio. This paper analyses the 13C/12C and 15 N/14N ratio on bone collagen on 122 guanacos from Northwest Patagonia during the Holocene. The results confirm significant variation in both isotopes between Monte and Andean-Patagonian specimens. Guanacos from Monte shows higher δ13C and δ15N than those from Andean-Patagonian. Temporal trends indicate variation through Holocene but this variation is not spatially homogeneous. In this paper we suggest that Medieval Climatic Anomaly had stronger effect in Monte desert than in Patagonia desert, generating driest and/or hottest conditions between 1250 and 600 years BP. Those variations need to be considered to reconstruct human diet at least during the second part of the Holocene. [ABSTRACT FROM AUTHOR]

In this paper, we carry out an isotopic study to learn about the diet and mobility patterns of the human groups that inhabited different areas and environments of western Catamarca, Argentina, over almost 2500 years. We present and discuss the results of the isotopic composition of 26 bioarchaeological remains (δ13C and δ15N on bone collagen, and δ13C and δ18O on bone apatite) with their respective calibrated absolute dates, from different settings and elevations of the province of Catamarca. They account for the sociocultural development of both the first agropastoral village societies and the Inca society. We also present the regional isotopic context of autochthonous animal and plant food resources. The isotopic composition (δ13C and δ15N on bone collagen) of 47 samples of pre-Hispanic camelids recovered from archaeological sites located at different altitudes of the Fiambalá and Chaschuil regions are studied and discussed. In addition, the δ13C values of 52 native modern and archaeological plant samples are compiled, including samples from the region as well as information from the bibliography. Finally, isotopic analyses of water samples (δ18O) recovered from different environments in the study region are also shown. The data from δ13C and δ15N on bone collagen and δ13C on bone apatite show a high variability of the human diet of the populations of western Catamarca, and suggest that the societies that inhabited the region during the first millennium AD had a balanced diet that combined proteins and carbohydrates, while those dated after the thirteenth century AD reduced their protein intake, which would have significantly affected their health status. The first trends in the δ18O values indicate that individuals had low mobility patterns during their lives, except for some unusual cases of possible non-local individuals. [ABSTRACT FROM AUTHOR]

Abstract: Osteological reference collections play a key role in bioanthropological research; they allow the development and testing of methods for sexing and ageing individuals using various bone and dental attributes. This paper presents the first stage results of the ongoing Chacarita Research Project, which aims to generate and study a reference collection of adult skeletons representative of the contemporary population of Buenos Aires city. The Chacarita Collection consists of unclaimed human remains of individuals of known nationality, sex, age, cause and date of death from the Chacarita Public Cemetery. Unlike other similar endeavours, this sample has been completely exhumed using archaeological techniques. So far, a total of 146 adult skeletons have been recovered (60 females – 41.1% and 86 males – 58.90%), the majority of which have ages-at-death in the range of 71–90 years. They were born primarily in Argentina (n =133; 91.1%), although other nationalities are also represented. Dates of death range between 1987 and 2000. In the short term, the osteological study of this collection will allow assessment of the performance of classical methods of sex determination and age-at-death estimation in a local setting. A special priority will be given to the study of osteological changes in individuals over 50 years. As the sample is being retrieved by exhumation, the impact of taphonomic agents on the most diagnostic bone structures is also being assessed. In the long term, this osteological collection will be available to generate new population-specific techniques and to develop comparative biological studies. [Copyright &y& Elsevier]

Abstract: The following paper presents the results of the analysis of the avian prey bones found in uneaten remains of crested caracara (Caracara plancus, Aves, Falconiformes) from La Pampa province, Argentina. Anatomical parts representation and taphonomic modifications were evaluated and compared to results of the evaluation of bone remains recovered from crested caracara’s pellets and to previous studies of other diurnal birds of prey. The results suggest a preferential consumption of some body parts of avian prey, as evidenced in the high frequency of wing elements in the uneaten prey remains. This analysis helps to support interpretative data concerning the origins of avian remains in the zooarchaeological and paleontological record, and contributes to the knowledge of a common predator found throughout diverse environments in South America. [Copyright &y& Elsevier]

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 genus Prochelidella is the oldest known panchelid taxon. It is widely distributed in several Cretaceous basins throughout Patagonia, Argentina. It was previously known from three named species. A fourth species presented herein, Prochelidella buitreraensis sp. nov., preserves both cranial and postcranial material from the Candeleros Formation (La Buitrera Area) of Río Negro Province, Argentina. Features observed in the nuchal bone (i.e. wide, trapezoidal cervical vertebrae, shallow nuchal notch) allow us to assign this specimen to the genus Prochelidella. Several specific traits (i.e. a large open retropterygoideum foramen, and a strongly developed muscle attachment site on the basisphenoid) suggest that the form from the Candeleros Formation is a new species of the genus Prochelidella. A phylogenetic analysis that includes the three best-preserved species of Prochelidella recovers this taxon as monophyletic. The Cenomanian age of this new taxon allows us to compare the panchelid turtles from the Patagonian (Neuquen) and Australian (Surat) basins. [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]