Museo de Historia Natural de San Rafael

San Salvador de Jujuy, Argentina

Museo de Historia Natural de San Rafael

San Salvador de Jujuy, Argentina
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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.

Perez-Garcia A.,Complutense University of Madrid | De La Fuente M.S.,Museo de Historia Natural de San Rafael | Ortega F.,Spanish University for Distance Education (UNED)
Acta Palaeontologica Polonica | Year: 2012

A freshwater turtle from the lithographic limestone of Las Hoyas (Barremian of Cuenca, Spain) is described as a new genus and species of Eucryptodira, Hoyasemys jimenezi. The holotype consists of the skull, lower jaw, carapace, plastron, vertebral column, pectoral and pelvic girdle remains, and fore- and hindlimbs. Hoyasemys jimenezi gen. et sp. nov. is characterized by three pairs of blind oblique depressions on the ventral surface of the basisphenoid, and a character combination composed, among others, of the articulation between the fourth and fifth cervical vertebrae through a cotyle in the fourth and a condyle in the fifth, amphicoelous caudal centra, and most digits of manus and pes with three elongated phalanges. This study allows clarification of the systematic position of a species of uncertain affinity often identified as "chelydroid" in appearance. A phylogenetic analysis shows Hoyasemys jimenezi gen. et sp. nov. forms a monophyletic group with Judithemys sukhanovi, Dracochelys bicuspis, Sinemys lens, and Ordosemys leios, collectively the sister group of crown Cryptodira.

Llano C.,Museo de Historia Natural de San Rafael | Ugan A.,Smithsonian Tropical Research Institute | Guerci A.,National University of Cuyo | Otaola C.,Museo de Historia Natural de San Rafael
Intersecciones en Antropologia | Year: 2012

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.

Tassi L.V.,CONICET | Monti M.,Museo de Historia Natural de San Rafael | Gallego O.F.,CONICET | Gallego O.F.,Northeast National University | And 2 more authors.
Alcheringa | Year: 2013

Tassi, L.V., Monti, M., Gallego, O.F., Zavattieri, A.M. & Lara, M.B., 2013. The first spinicaudatan (Crustacea:Diplostraca) from Permo-Triassic continental sequences in South America and its palaeoecological context. Alcheringa 37, 187-199. ISSN 0311-5518. Cornia martinsnetoi sp. nov., the first spinicaudatan from Permian-Triassic continental sequences of southern South America, is described. The new species has characters diagnostic of the typical late Palaeozoic-Early Triassic subfamily Vertexiinae from Gondwana. This new taxon was found in tuffaceous siltstones in the upper part of the Quebrada de los Fósiles Formation (Puesto Viejo Group), which may span the Permo-Triassic boundary in Argentina. The lower and coarser-grained interval of the Quebrada de los Fósiles Formation was deposited in distal alluvial fans and low- to high-sinuosity rivers. The upper fine-grained interval of this formation, which hosts the spinicaudatans and associated fossils (ostracods, megaspores, fish scales), was deposited in shallow floodplain lakes. Intense volcanic activity influenced the sedimentary evolution of this succession and was accompanied by aridification and some climatic seasonality that likely generated stressful conditions for the biota. Previous biostratigraphic studies support an Early Triassic age for the beds containing Cornia martinsnetoi sp. nov. © 2013 Copyright Taylor and Francis Limited.

De la Fuente M.S.,Museo de Historia Natural de San Rafael | De la Fuente M.S.,CONICET | Umazano A.M.,CONICET | Umazano A.M.,National University of La Pampa | And 2 more authors.
Cretaceous Research | Year: 2011

A new chelid species (Prochelidella cerrobarcinae nov. sp.) are described from the Aptian-Albian? Puesto La Paloma Member, Cerro Barcino Formation, northern of Chubut Province, Argentina. The basal section of this member, which bears the turtle remains, is composed of tuffaceous mudstones with plane parallel lamination, asymmetrical ripples and a chert intercalation suggesting sub-aqueous deposition in a relatively shallow lacustrine environment. Pr. cerrobarcinae nov. sp. is represented by post-cranial remains of several specimens that not only represents the oldest pleurodiran chelid record in the world but, together with the chelid remains of Albian Lightning Ridge, New South Wales, Australia, indicates that chelid diversification began well before the final fragmentation of southern Gondwana. © 2011 Elsevier Ltd.

Otaola C.,Museo de Historia Natural de San Rafael
Ethnobiology Letters | Year: 2014

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

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 | Year: 2012

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.

Hassan G.S.,CONICET | De Francesco C.G.,CONICET | Dieguez S.,Museo de Historia Natural de San Rafael
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

The objectives of this study were to (a) analyze the distribution pattern of diatom assemblages in freshwater systems from central-western Argentina, (b) investigate the key climatic and limnological factors affecting the species distributions, and (c) evaluate the extent and limitations of diatoms as Quaternary paleoenvironmental indicators in the area. Diatoms were sampled and physical and chemical variables were quantified in a total of 45 lotic and lentic sites. Altitude, annual precipitation, and summer (January) temperature data were obtained from a world climate database. Previously published data from an adjacent region was incorporated into the modern dataset. Environmental variables significantly influencing diatom assemblage composition were identified through partial canonical correspondence analyses (CCAs). In order to assess the degree of analogy between modern and fossil assemblages, the modern analog technique (MAT) was applied. Diatom taxa showed distinct abundance patterns in relation to altitude, with a shift from communities dominated by periphitic and benthic taxa in lower sites to communities dominated by small benthic-tychoplanktonic taxa in high elevated waterbodies. The pH was the strongest variable explaining the variance within the diatom dataset, followed by log-conductivity and summer air temperature. The comparison of modern diatom assemblages with fossil sequences allowed reconstruction of the evolution of shallow, lentic and vegetated habitats. A good analogy between modern and Pleistocene diatom assemblages was found. The strong relationship between diatoms and climate-driven environmental variables, such as pH, conductivity and summer temperature, enhances the importance of the diatom floras as paleoclimatic indicators in the area and encourages future development of quantitative inference models for the region. © 2012 Elsevier B.V.

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.
Ameghiniana | Year: 2013

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.

Forasiepi A.M.,Museo de Historia Natural de San Rafael | Carlini A.A.,Museo de La Plata
Zootaxa | Year: 2010

A new genus and species, Patagosmilus goini, of the family Thylacosmilidae (Mammalia, Metatheria, Sparassodonta) is described here. The new taxon is based on a single specimen collected from the west margin of the Río Chico, in Río Negro Province, Argentina, from the middle Miocene Colloncuran SALMA. Until now, two formally recognized species were encompassed in the family Thylacosmilidae: Thylacosmilus atrox, from the late Miocene-late Pliocene Huayquerian to Chapadmalalan SALMAof Argentina and probably Uruguay; and Anachlysictis gracilis, from the middle Miocene Laventan SALMA of Colombia. Recognition of the Patagonian taxon, Patagosmilus, provides new anatomical data, likely to be included in future phylogenetic analyses. The overall morphology of Patagosmilus suggests that it has a more generalized anatomy than Thylacosmilus. The dental morphology suggests the new Patagonian taxon was probably closer to Thylacosmilus than Anachlysictis. Saber-tooth thylacosmilids have several autapomorphic features in the skull that differentiate them from other sparassodonts, including the delayed replacement or non-replacement of the deciduous last premolar. Copyright © 2010.

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