South America

KF - The Political Economy of South America’s Global South Relations

by Kevin Funk

Cordylancistrus santarosensis (Siluriformes: Loricariidae), a new species with unique snout deplatation from the Río Santa Rosa, Ecuador

by Milton Tan

Cordylancistrus santarosensis is described based on five specimens from the Río Santa Rosa, Ecuador. This species can... more Cordylancistrus santarosensis is described based on five specimens from the Río Santa Rosa, Ecuador. This species can be distinguished from all other members of the Chaetostoma group by having plates on the tip of the snout (except for a central region at the extreme anterior edge), but lacking plates laterally on the head. This snout plating condition is inter- mediate between the fully plated snout of other Cordylancistrus and the unplated snout of Chaetostoma.

The southernmost bear: Pararctotherium (Carnivora, Ursidae, Tremarctinae) in the latest Pleistocene of Southern Patagonia, Chile.

by Leopoldo Soibelzon

The broken Zig-Zag: Late Cenozoic large mammal and turtle extinction in South America.

by Leopoldo Soibelzon

During the latest Pleistocene-earliest Holocene, South American terrestrial vertebrate faunas suffered one of the... more During the latest Pleistocene-earliest Holocene, South American terrestrial vertebrate faunas suffered one of the largest (and probably the youngest) extinction in the world for this lapse. No megamammal and most of the large mammals survived in the continent, and several complete ecological guilds and their predators were erased. A giant terrestrial turtle also went extinct. The mammal extinction had been attributed mainly to overkill, climatic change or a combination of both. We propose human overhunting as the main cause of the extinction in South America. However, according to our interpretation, the slaughtering of mammals had to have been accomplished in a particular frame. During most of the middle and late Pleistocene, dry and cold climate and open areas predominated in South America. Nearly all of those megamammals and large mammals that became extinct were adapted to this kind of environments. The periodic, though relatively short, interglacial increase in temperature and humidity had provoked the dramatic shrinking of open areas and extreme reduction of the biomass (not diversity) of mammals adapted to open habitats. Many populations were surely close to a minimum level of population viability. During the longer glacial periods, mammals populations recovered. This alternation of low and high biomass of mammals from open and closed areas is what we refer to as the Zig-Zag. During the present interglacial, humans entered South America and broke the Zig-Zag when killed all the megamammals and almost all the large mammals during their less favourable periodic lapse.

Deciduous teeth morphology of some tremarctines (Ursidae, Tremarctinae). Descriptions, comparissons and possible phylogenetic implications.

by Leopoldo Soibelzon

The morphology of some deciduous teeth of Arctotherium tarijense and A. latidens (Ursidae: Tremarctinae) is here... more The morphology of some deciduous teeth of Arctotherium tarijense and A. latidens (Ursidae: Tremarctinae) is here described and compared for the first time. The crown morphology of dP4 and dp4 is similar to that of M1 and m1. The general morphology of dP/dp4 in A. tarijense and Ursinae is similar, but their permanent morphology dentition is different. The dP/dp4 of A. tarijense seems to bear a generalized set of characters (i.e. crown outline, the protocone and parastyle of dP4, the metaconid and hypoconid of dp4); unfortunately these teeth cannot be compared with their homologues in other tremarctines. Consequently, we are unable to include these characters in the phylogenetic analysis of the Tremarctinae subfamily in order to know whether the phylogenetic relationships are affected or not. It is noteworthy, that if these characters were present in M/m1 of A. tarijense, at least, some of them could be undoubtedly regarded as plesiomorphic features. In this respect, is the deciduous teeth morphology more conservative than that of permanent teeth?

Systematic review of fossil Tremarctinae (Carnivora, Ursidae) from South America

by Leopoldo Soibelzon

In this paper the systematics, and the geographic and stratigraphic distribution of the South American fossil taxa of... more In this paper the systematics, and the geographic and stratigraphic distribution of the South American fossil taxa of Tremarctinae (Carnivora, Ursidae) are reviewed and discussed. New diagnostic characters are proposed, in order to support each taxon. Only one genus (Arctotherium), of the Pleistocene and Lower Holocene of South America, is recognized, with five species: A. vetustum, A. wingei, A. angustidens, A. bonariense and A. tarijense. Arctotherium is recorded from the Ensenadan (Upper Pliocene to Middle Pleistocene) to the Lujanian (Upper Pleistocene to Lower Holocene) in Venezuela, Brazil, Bolivia, Uruguay, Argentina, and Chile. A. vetustum is recorded in the Bonaerian (Middle Pleistocene) in Argentina; A. wingei in the Lujanian in Venezuela, Bolivia and Brazil; A. angustidens in the Ensenadan of Bolivia and Argentina; A. bonariense in the Bonaerian and Lujanian of Argentina and A. tarijense in the Bonaerian and Lujanian of Uruguay, Argentina, and Chile. Arctotherium is characterized by ten features: the post palatine margin slightly overpasses the distal end of M2, P1-3 compressed in a triangular arrangement, protocone reduced or absent in P4, length between canine and P4 less than P4 mesio-distal length, metastyle reduced or absent in M1, M2 wider than in other ursids, p4 crown ellipsoidal shaped, m1 trigonid wider than in other ursids, m2 crown kidney shaped, m3 crown sub circulate shaped.

The fossil record of the South American Short-faced bears (Ursidae, Tremarctinae).

by Leopoldo Soibelzon

The present study includes a review of the geographic and stratigraphic distribution of short-faced bears (Ursidae,... more The present study includes a review of the geographic and stratigraphic distribution of short-faced bears (Ursidae, Tremarctinae) in South America. In addition, the authors discuss biogeographic hypotheses regarding the origin of South American tremarctines. The Tremarctinae subfamily is distributed exclusively in America, from Alaska to southern Patagonia. Its biochron comprises the temporal lapse between Late Miocene and recent times; the first record of Tremarctinae in North America corresponds to the Hemphillian and the last to the Rancholabrean. In South America, the first record corresponds to the Ensenadan. In the present day, it corresponds to the only living tremarctine, the “Andean Bear,” but short-faced bears became extinct during the early Holocene. The extinction of short-faced bears in North and South America appears to have been approximately synchronous. Finally, the fossil record in South America indicates species turnover between the Ensenadan and Bonaerian, during which time the giant species Arctotherium angustidens was replaced by A. tarijense, A. bonaeriense, and A. vetustum (and probably A. wingei).

Faunistic analisys of vertebrates from “las toscas del Río de La Plata” (Buenos Aires, Argentina): a palaeontological site in disappearance

by Leopoldo Soibelzon

At the coast of the río de la Plata in the Buenos
Aires city lies a classic paleontological site, known as... more At the coast of the río de la Plata in the Buenos
Aires city lies a classic paleontological site, known as “toscas del Río de La Plata” or simple as “las toscas”. It has
been studied for over 120 years and, although it has been widely spread, today is only possible to observe it
during low tide. For this reason, most of the available materials are those collected during the first half of the
XXth century, and that so far have only been incorporated into scarce taxonomic reviews. Among the fossils
collected in “las toscas” highlights Glyptodon munizi Ameghino, Neosclerocalyptus pseudornatus Ameghino,
Mesotherium cristatum Serrés, Arctotherium angustidens Gervais y Ameghino and Theriodictis platensis
(Mercerat); all are exclusive species from the Ensenadan Stage (early to -middle Pleistocene). The sediments of
“las toscas” were deposited during times of normal polarity, more precisely during the “Jaramillo” event (Chron
C1r1n, ca. de 1 Ma). Faunistic evidences (e.g. Tolypeutes, Catagonus) allow to interpret “las toscas” as an open
environment with dry conditions and probably colder than the present.

Largest opossum (Mammalia: Marsupialia: Didelphidae), from the Late Tertiary of the Pampean Region.

by Leopoldo Soibelzon

We describe Thylophorops lorenzinii sp. nov. (Marsupialia, Didelphidae), the largest known didelphid opossum, living... more We describe Thylophorops lorenzinii sp. nov. (Marsupialia, Didelphidae), the largest known didelphid opossum, living or extinct. Its type specimen comes from Late Pliocene levels at Punta San Andrés, southeastern Buenos Aires Province, Argentina. With an estimated body mass between 4.8 and 7.4 kg, it obviously surpasses that of the (up to now) largest didelphid, the living Didelphis virginiana Kerr. In addition to its larger size, the new species differs from T. chapalmalensis Ameghino and T. perplanus Ameghino in that its lower molars have more labially salient hypoconids and proportionally large hypoconulids which are not antero-posteriorly compressed.

The fossil record of the short-faced bears (Ursidae, Tremarctinae) from Venezuela. Systematic, biogeographic, and paleoecological implications.

by Leopoldo Soibelzon

The first record of a Tremarctinae bear in Venezuela was made by Royo and Gómez in 1960. Since then, three new... more The first record of a Tremarctinae bear in Venezuela was made by Royo and Gómez in 1960. Since then, three new specimens from two localities have been collected but not reported. The purpose of this contribution is to discuss the taxonomy, bioestratigraphy, and biogeographic implications of these records. The bear genera included in the subfamily Tremarctinae are distributed exclusively in America. In South America only one fossil genus is recorded, Arctotherium, comprising five species: A. angustidens, restricted to the Ensenadan (early–middle Pleistocene) of Argentina and Bolivia; A. vetustum, recorded only in the Bonaerian (middle Pleistocene) of Brazil and Argentina; two Bonaerian and Lujanian (middle Pleistocene–early Holocene) species, A. bonariense (recorded only in Argentina), and A. tarijense (distributed in Argentina, Bolivia, Uruguay and Chile); and A. wingei, recorded with certainty only in the Lujanian (later Pleistocene-early Holocene). After the present study we conclude that (1) the only species recorded in Venezuela is A. wingei, and (2) all known specimens come from the Lujanian. Outside of Venezuela, this species is recorded in Bolivia and Brazil but without accurate stratigraphic provenances. Although A. wingei is one of the most plesiomorphic species of Arctotherium, it has not been recorded in sediments older than later Pleistocene. That could be interpreted as the species’ preference for low latitude tropical or subtropical environments, which are poorly represented in early Pleistocene continental sediments.

Estimación de la masa corporal de las especies de osos fósiles y actuales (Ursidae, Tremarctinae) de América del Sur.

by Leopoldo Soibelzon

Precise estimates of body mass in fossil taxa are elementary to paleobiological reconstruction. Using demonstrated... more Precise estimates of body mass in fossil taxa are elementary to paleobiological reconstruction. Using demonstrated relationships between body mass and anatomical measurements in modern mammals, several authors proposed prediction equations to estimate the body mass of fossil taxa. We calculate the body mass of extant and fossil South American bears (Tremarctos ornatus and Arctotherium respectively) applying 61 selected allometric equations to 19 cranial, dental and postcranial measurements. We also estimate the body mass ranges of the five Arctotherium species by simple size comparison to size and weight of extant bears. Extrapolating on the basis of geometric similitude with T. ornatus we further estimated the body mass of Arctotherium in order to know if our estimations, bias published equations, were feasible. Also we test the prediction equations results with a specimen of Tremarctos ornatus of known body mass. We found that the best prediction equations for all Arctotherium species are based on femoral (8 equations) and cranial (one equation) measurements. In turn the best prediction equations for T. ornatus are based on cranial (one equation), first lower molar (one equation), femoral (two equations) and humeral measurements (three equations).

The khipu of Chupachu: the organization of labor, calendar and population.

by Alejandro Skromnitsky

The study of a social and economic relations in the Inca Empire (XV-XVI century) was carried out by many scientists;... more The study of a social and economic relations in the Inca Empire (XV-XVI century) was carried out by many scientists; many research papers devoted to the issue of the organization of labor and labor service. However, detailed and thorough analysis was conducted only by some scholars (J. Murra, Gary Urton). However, this analysis was combined with an analysis of state fiscal policy and the Inca calendar that would allow more carefully trace the relationship of elements of social-economic structure, such as establishing a population of some provinces according to the types of labor service, and distribution of obligations in time. In this context, an important new analysis of labor in the Inca Empire. So the purpose of the proposed research is to identify fundamental principles of fiscal policy of the Incas. For this we consider the economic structure of the empire.

Early Pleistocene glaciations in Argentina (South America) and the response of the mammals: the case of the Pampean Region

by Esteban Soibelzon

Soibelzon E, Tonni, EP

Geographic Narratives in the South American Travelogues of Harry A. Franck: 1917-1943

by Steven Driever

published in Journal of Latin American Geography, 2011

El registro de maderas fósiles de Leguminosae de Sudamérica

by Leandro C. A. Martínez

The fossil wood record of Leguminosae from South America. the Leguminosae has an extensive fossil wood record... more The fossil wood record of Leguminosae from South America. the Leguminosae has an extensive fossil wood record worldwide. In South America 56 records with affinity to Leguminosae were counted. Each record is analyzed and unpublished data is also included. the Leguminosae is the most palaeoxylological diverse family of South America. It has an extensive temporal record, from the Palaeocene to the Pleistocene, and a broad geographical span, from Patagonia to north Colombia.

Resumen: La familia Leguminosae posee un extenso registro de maderas fósiles en todo el mundo. En Sudamérica se reconocen 56 registros afines a la familia. Se enlistan todos los registros conocidos y se incluyen algunos datos inéditos. La familia Leguminosae es la de mayor diversidad paleoxilológica de Sudamérica. La misma posee un extenso registro paleoxilológico temporal, desde el Paleoceno hasta el Pleistoceno, y geográfico, desde Patagonia hasta el norte de Colombia.

The extinction of Equidae and Proboscidea in South America. A test using Carbon isotope data.

by José Luis Prado

Prado J.L., M.T. Alberdi, B. Sánchez & G. Gómez. 2011. The extinction of Equidae and Proboscidea in South America. A test using Carbon isotope data. Estudios Geológicos [online], doi: 10.3989/egeol.40422

Carbon isotopes, preserved in 166 samples of fossil teeth and bone, provide key data for understanding the ecology of... more Carbon isotopes, preserved in 166 samples of fossil teeth and bone, provide key data for understanding the ecology of extinct horses and gomphotheres during the Plio-Pleistocene in South America. To analyze the patterns of dietary partitioning throughout this time we divided the samples into 19 groups,
taking into account the genus and the age of the corresponding localities. In this study, the diets of both groups are assessed to test extinction hypotheses. The strong resource partitioning among herbivores assumed under Co-evolutionary disequilibrium hypothesis is supported by isotopic data of horses from latest Pleistocene. Hippidon and Equus had very different diets. In contrast, species of gomphotheres from late Pleistocene in South America seem to have had less specialized diets containing a broad mix of both C3 and C4 plants, which is in line with the dietary assumptions of the mosaic-nutrient hypothesis, but does not support the assumptions of Co-evolutionary disequilibrium hypothesis.

Chapter 18: A new mammal fauna at the top of the Gran Barranca sequence and its biochronological significance

by Martin Ciancio

Alejandro G. Kramarz, María Guiomar Vucetich, Alfredo A. Carlini, Martín R. Ciancio, María Alejandra Abello, Cecilia M. Deschamps, and Javier N. Gelfo.
2010
Published in: The Paleontology of Gran Barranca: Evolution and Environmental
Change through the Middle Cenozoic of Patagonia, eds. R.H. Madden,
A. A. Carlini,M.G. Vucetich, and R. F. Kay. Published by Cambridge
University Press.#Cambridge University Press 2010.

The top of the stratigraphic sequence of the fossil-bearing Sarmiento Formation at Gran Barranca has yielded a... more The top of the stratigraphic sequence of the fossil-bearing Sarmiento Formation at Gran Barranca has yielded a distinctive
assemblage of mammalian taxa. Fossils occur in strata located 25m above the uppermost level bearing typical Colhuehuapian mammals. This association is represented by fragmentary remains of small to middle-sized mammals belonging to paucituberculatan marsupials, dasypodids, glyptodonts, tardigrades, hegetotheres, interatheres, proterotheriids, and hystricognath rodents. Although this fauna contains at least two new rodent species not recorded in other faunas, it is more similar to that recorded at the lower and middle sections of the Pinturas Formation in northwest Santa Cruz Province (the Ameghinos’ Astrapothericulan fauna) than to any other known fossil mammal assemblage. The strata yielding this fauna (Upper Fossil Zone, UFZ) is estimated to be in Chron C6n (19.7 to 18.7Ma), but the taxic similarity with the younger astrapothericulan fauna (dated between 17.5 and 16.5 Ma) suggests that the UFZ is placed at the youngest extreme of the
Chron C6n. The Astrapothericulan and the UFZ assemblages
would correspond to a single post-Colhuehuapian – pre-Santacrucian biochronological unit (the “Pinturan”) which would span from
18.75 to
16.5Ma. This is the youngest faunal unit within the standard sequence of the middle Cenozoic SALMAs at Gran Barranca. The assignment to this unit of other earlyMiocene faunas elsewhere in South America (at present poorly o partially known) depends on further descriptions and future findings.

LOS XENARTHRA DE GRAN BARRANCA: MAS DE 20 MA DE HISTORIA

by Martin Ciancio

Carlini, A.A., Ciancio, M. y Scillato-Yane G.
2005
ACTAS DEL XVI CONGRESO GEOLOGICO ARGENTINO. LA PLATA.
Pp: 419-424.

Cerro Bombero: registro de Hippidion saldiasi Roth, 1899 (Equidae, Perissodactyla) en el Holoceno temprano de Patagonia (Santa Cruz, Argentina).

by José Luis Prado

Paunero, R.S.; Rosales, G.; Prado, J.L.; Alberdi, M.T. 2008. Cerro Bombero: registro de Hippidion saldiasi Roth, 1899 (Equidae, Perissodactyla) en el Holoceno temprano de Patagonia (Santa Cruz, Argentina). Estudios Geológicos, 64 (1): 89-98.

A new record of Hippidion saldiasi with new radiocarbon data referred to early Holocene (8,850 ± 80 year C-14 B.P) of... more A new record of Hippidion saldiasi with new radiocarbon data referred to early Holocene (8,850 ± 80 year C-14 B.P) of Patagonia is reported. Both its peculiar geographic location in a scarcely prospected zone and its radiocarbon age, provide new elements to discuss the previous hypotheses about the
extinction of the horses and its relations with the human beings that inhabited the different environments of South America.

Stegomastodon platensis (Proboscidea, Gomphotheriidae) en el Pleistoceno de Santiago del Estero, Argentina

by José Luis Prado

Alberdi, M.T., E. Cerdeño y J.L. Prado. 2008. Stegomastodon platensis (Proboscidea, Gomphotheriidae) en el Pleistoceno de Santiago del Estero, Argentina. Ameghiniana, 45 (2): 257-271.

Mammal fossil remains from Santiago del Estero Province (Argentina) are very poorly known. In this paper, best... more Mammal fossil remains from Santiago del Estero Province (Argentina) are very poorly known. In this paper, best preserved specimens of Gomphotheriidae (Mammalia, Proboscidea) are
presented. They come from Quaternary beds outcropping along the Río Dulce, near of the city of Santiago del Estero. The comparative study with other South American gomphotheres remains, mainly from Argentina and Brazil, allow their identification as Stegomastodon platensis, being among the largest forms of this species. Previous studies referred this locality to the late Pleistocene. Enamel tooth sample was dated
to 19.900 ± 120 BP by AMS 14C, supporting that age for this fauna. Carbon and oxygen isotopic composition of the tooth enamel has been analyzed to get new data on the paleodiet and habitat preference of South American gomphotheres. Carbon isotopic values indicate an adaptation to an exclusively C4 diet.
The oxygen isotopic analysis indicates cooler climatic conditions than present.