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Praderio A.,Centro Regional Of Investigacion Y Desarrollo Cultural | Gil A.,Museo de Historia Natural de San Rafael | Gil A.,National University of Cuyo | Forasiepi A.M.,Museo de Historia Natural de San Rafael
Mastozoologia Neotropical

A new record of a ground sloth, referred to Megatherium cf. M. americanum, in the south of Mendoza province (locality of Manqui-Malal, Malargüe department) is presented. The material is described and analyzed in its paleoecological context. 14C dating provided an age of 12 300 ±120. The analysis of isotopes of δ13C on the collagen and apatite provided values of -16.4‰ y -8.8‰, respectively. This data suggests a mixed diet with an important component of C4 plants. The δ15N provided values of 7.6‰, similar to the high values reached by guanacos (Lama guanicoe) today in the region. The δ18O on the apatite provided values of -10.3‰ which is to be expected for an individual that drank water of about -14.5‰, as present today in the area. A paleoecological and paleoclimatic change occurred at about 14 000 AP in the area with the establishment of the vegetation of the Monte. The isotopic information of the described specimen and its comparison with other latest Pleistocene herbivores from middle latitudes of South America suggest that these ground sloths successfully changed their diet about 14 000 AP, following the vegetation change. Despite the weak evidence of association between megafauna and humans in the south of Mendoza Province, this association should be considered as well as others factors when evaluating the causes of the extinction of the ground sloths. © SAREM, 2012. Source

Mesquite fruits Prosopis spp. are an important food resource for both humans and animals due to their high nutritional value, but key dietary components are unevenly distributed within the fruit. While carbohydrates occur in the soft, outer mesocarpo, proteins are found in the much harder seeds. This raises the potential for differences in processing costs, and may explain variation in the use of mesquite seeds described ethnographically. Here we report the results of a series of processing experiments that evaluate the nutritional value and time costs associated with increasing levels of mesquite processing (gathering and grounding) using traditional manos and metates. We show that while additional processing does lead to more protein in mesquite flour as seeds are broken down, differences in nutritional value are minimal, overall energetic value remains the same, and the high additional processing costs reduce energetic return rates. These results suggest that under most circumstances mesquite processed using these technologies would be done mostly to extract the carbohydrates. A comparison of residual plant parts from these experiments with similar plant macrofossils from regional archaeological sites suggest similar patterns of processing in the past, with an anthropogenic rather than natural origin for the recovered remains. Copyright © Facultad de Ciencias Sociales - UNCPBA - Argentina. Source

De La Fuente M.S.,Museo de Historia Natural de San Rafael | Fernandez M.S.,Museo de La Plata

Here, we report an unusual pattern in the manus and pes morphology of the Tithonian marine turtle Neusticemys neuquina. We analyse the forelimbs of two previously known specimens and describe the hind limbs of two previously undescribed specimens. Neusticemys neuquina is characterized by a relative elongation of both the forelimb and hind limb, compared with stem Chelonoidea, as well as an elongation of the pedal digit V, achieved through the elongation of the bones, as well as a moderate hyperphalangy. The elongation of pedal digit V is the most striking feature of N. neuquina, a feature unknown in other turtles. □Limb morphology, Neusticemys neuquina, Tithonian turtle. © 2010 The Authors, Journal compilation © 2010 The Lethaia Foundation. Source

Otaola C.,Museo de Historia Natural de San Rafael
Ethnobiology Letters

Many cultural and natural processes form the archaeological record. Taphonomy, the study of the transition of organic matter from living contexts (the biosphere) to geological contexts (the lithosphere), aids in understanding how agents and processes affect skeletal remains in the archaeological record. In this paper the results of an actualistic taphonomic study on deposition of bones in open-air and cave contexts in the high elevation Andes Mountains are presented. Results indicate that within the first three months after deposition many bones are displaced or removed from sites and that the agents that act in each context are different. Horizontal displacement of bones from their deposited locations is limited in the cave context but is dominant in the open air site. Carnivores appear to be responsible for moving bones in open-air contexts, and rodents appear to displace bones vertically in the cave context. Such naturalistic experiments are important in particular areas of the world in which local taphonomic processes vary. © 2014 Society of Ethnobiology Source

Sterli J.,Museo Paleontologico Egidio Feruglio | Sterli J.,CONICET | De La Fuente M.S.,Museo de Historia Natural de San Rafael | De La Fuente M.S.,CONICET | And 2 more authors.

A new species of meiolaniform turtle, Trapalcochelys sulcata gen. nov. sp. nov. is described, based on material from the late Campanian-early Maastrichtian Allen Formation, Patagonia (Argentina). The postcranial remains recovered are described macroscopically (e.g. external morphology) and microscopically (e.g., histological sections of the shell). Trapalcochelys sulcata gen. nov. sp. nov. shares with other meiolaniforms the presence of sulci strongly curved anteriorly among marginal scales, and dermal bones ornamented with small foramina. This new species differs from the other Late Cretaceous meiolaniform from Patagonia -Patagoniaemys gasparinae- in the general size and in the shape of neural 1. The shell-bone histology is characterized by a diploe structure, in which well developed internal and external compact bone layers frame an area of cancellous bone. Compact bone is mostly composed by interwoven structural fiber bundles. The abundance of structural fibers in the internal cortex and the presence of large pipe-like vascular spaces in the cancellous bone are the most distinctive histological features observed for T. sulcata. All meiolaniform turtle remains of the Upper Cretaceous of South America are exhaustively revised. The known South American record of Upper Cretaceous meiolaniforms is restricted to Argentina and in this revision six localities with outcrops bearing these fossils have been identified. Meiolaniforms are confirmed as a component of the late Campanian-early Maastrichtian South American Allenian tetrapod assemblage. Source

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