DIFFUSE TERMITINAE NESTS SHED LIGHT ON THE AFFINITIES OF LAETOLICHNUS KWEKAI (KRAUSICHNIDAE)

Palaios ◽  
2021 ◽  
Vol 36 (3) ◽  
pp. 122-127
Author(s):  
LILIANA F. CANTIL ◽  
JORGE F. GENISE ◽  
JUAN L. FARINA ◽  
SEBASTIÁN LUPO ◽  
DARÍO PORRINI ◽  
...  

ABSTRACT The insect trace fossil Laetolichnus kwekai, which is composed of a small chamber extending to slender cylinders at each end, was tentatively included in the ichnofamily Krausichnidae as termite nests. New evidence presented here provides information to validate these inferences. A more complex structure formed by interconnected Laetolichnus was recently found in the same Pliocene deposits (Laetoli, Tanzania) as the isolated specimens reported previously. Our study confirms inclusion of Laetolichnus in Krausichnidae and supports the inference that it represents a nest of a social insect. Neoichnological field studies in the coastal dunes of Buenos Aires Province, Argentina, were undertaken to refine further the nature of these affinities. Survey of the dune surface revealed abundant loose fragments of termite nests of a size and shape comparable to that of L. kwekai. The fragile nests constructed by Onkotermes brevicorniger, which are described here in detail for the first time, enable us to interpret the fossil structures. They consist of connected chambers similar to the interconnected Laetolichnus. These were frequently exposed and broken by wind action resulting in loose fragments similar to the isolated Laetolichnus. The Celliforma ichnofacies represented at Laetoli, which contains L. kwekai, indicates arid or semiarid shrublands and woodlands. The distribution of O. brevicorniger also corresponds to arid and semiarid shrublands and dry woodlands of Argentina. Although the African termite producer of L. kwekai and the South American Onkotermes would be phylogenetically unrelated, the analogous structures probably reflect convergent nesting behaviors as an adaptation to similar arid to semiarid environmental conditions.

2019 ◽  
Vol 294 (3) ◽  
pp. 285-305
Author(s):  
José L. Prado ◽  
Ricardo Bonini ◽  
Cristian Favier-Dubois ◽  
Gustavo N. Gómez ◽  
Pamela Steffan ◽  
...  

A comparative study was made with the known record of equids species in South America, identifying the remains as Equus neogeus, Hippidion devillei, and Hippidion principale. These data increase the record of Equidae in South America and provide new evidence about the chronological and geographical distribution. The sedimentary deposits of the Lujan Formation outcropping at Tapalqué creek (4 to 120 ky) were accumulated through fluvial processes. This Formation comprises a rich vertebrate fauna corresponding to the Lujanian South American Land Mammal Age, which includes numerous and diverse vertebrate remains. The taphonomic analysis indicates that the faunistic assemblage was formed and was subject to diagenetic processes without distinction of its action in the fossiliferous levels, that can be recognized as fluvial deposits.


2020 ◽  
pp. 128-138
Author(s):  
A. S. Bik-Bulatov

The article uses little known letters of M. Gorky, many of which were published for the first time in 1997, as well as findings of Samara-based experts in local history to shed light on the writer’s work as editor-in-chief of the Samarskaya Gazeta newspaper in 1895. The researcher introduces hitherto unstudied reminiscences of the journalist D. Linyov (Dalin) about this period, which reference a letter by Gorky, now lost. The paper details a newly discovered episode of Gorky’s professional biography as a journalist: it concerns his campaign against a Samara ‘she-wolf,’ the madam of a local brothel A. Neucheva. Linyov’s reminiscences turn out to be an important and interesting source, offering an insight into the daily grind of the young editor Gorky, providing new evidence of his excellent organizational skills, and describing his moral and social stance. The author presents his work in the context of a recently initiated broader discussion about the need to map out all Russian periodicals for the period until 1917, as well as all research devoted to individual publications.


Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1769
Author(s):  
Maria Macarena Arrien ◽  
Maite M. Aldaya ◽  
Corina Iris Rodriguez

Agriculture is the largest fresh water consuming sector, and maize is the most produced and consumed crop worldwide. The water footprint (WF) methodology quantifies and evaluates the water volumes consumed and polluted by a given crop, as well as its impacts. In this work, we quantified for the first time the green WF (soil water from precipitation that is evapotranspired) and the green virtual water exports of maize from Buenos Aires province, Argentina, during 2016–2017, due to the relevance of this region in the world maize trade. Furthermore, at local level, we quantified the green, blue (evapotranspired irrigation), and grey (volume of water needed to assimilate a pollution load) WF of maize in a pilot basin. The green WF of maize in the province of Buenos Aires ranged between 170 and 730 m3/ton, with the highest values in the south following a pattern of yields. The contribution of this province in terms of green virtual water to the international maize trade reached 2213 hm3/year, allowing some water-scarce nations to ensure water and water-dependent food security and avoid further environmental impacts related to water. At the Napaleofú basin scale, the total WF of rainfed maize was 358 m3/ton (89% green and 11% grey) and 388 m3/ton (58% green, 25% blue, and 17% grey) for the irrigated crop, showing that there is not only a green WF behind the exported maize, but also a Nitrogen-related grey WF.


1995 ◽  
Vol 69 (1) ◽  
pp. 135-159 ◽  
Author(s):  
Alberto L. Cione ◽  
Eduardo P. Tonni

The concept of “land-mammal age” as developed in South America is examined. The “Uquian Land-mammal age” is used as a study case. “Land-mammal age” parataxonomy is here considered methodologically but not conceptually different from chronostratigraphic taxonomy. “Land-mammal ages” in South America are based on stages. However, we consider that accurate biostratigraphic studies must be done in South America for establishing the biostratigraphy and precise boundary stratotypes of most stages-ages. The Uquia outcrops are here considered inadequate as a stratotype. A new South American continental stage-age is proposed. This stage is based on a biostratigraphic scheme. The stratotypes of the stage and biozones are located in the fossiliferous southeastern Buenos Aires Province marine cliffs. The lower boundary stratotype is proposed. The stage-age is probably correlated with the Gauss Chron and the lower Matuyama Chron. Additionally, some major units of Ameghino are validated and a different timing for the arrival of North American mammals to southern South America is presented.


2020 ◽  
Author(s):  
N.C. Caruso ◽  
E.M. Luengos Vidal ◽  
M.C. Manfredi ◽  
M.S. Araujo ◽  
M. Lucherini ◽  
...  

AbstractLand-sea interface is an ecotone where the intersection of marine and terrestrial ecosystems create unique ecological conditions for terrestrial mobile species and freshwater-adapted organisms to exploit marine-derived food resources. Mammalian carnivores play an important role in almost any ecosystem where they live due to their top-down (or trophic cascade) effects on prey species and primary producers, thus structuring ecosystems along varied food-web pathways. We use camera trapping to study the patterns of coexistence, habitat use and activity pattern of carnivores species in a coastal area in southern Buenos Aires province, Argentina. We were able to detect five of the seven species of Mammalian carnivores being the Pampas fox Lycalopex gymnocercus and Geoffroy’s cat Leopardus geoffroyi the two most common. Geoffroy’s cat seems to use more intensively those areas close to the shoreline, while we found little support of it for Pampas fox; which seems to use more inland areas. Congruently, we found evidence of a lack of spatial and, to a lower extent, temporal avoidance between the two most common carnivore species of our study area. Our findings support those previous studies indicating that the coastal dunes have an important role in the conservation of the biodiversity of Buenos Aires province. Wildlife conservation is compatible with carefully-designed ecotourism and limited infrastructure development and this may be a unique chance for the areas of Buenos Aires coast that have not been affected yet by poorly planned, conservation-unfriendly urbanization.


Check List ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1942 ◽  
Author(s):  
Noelia S. Ferrando ◽  
María C. Claps

We provide here a checklist of species of Monogononta rotifers from lentic and lotic environments in Argentina, 25 years after the initial catalogue compiled by Susana B. José de Paggi. This new inventory now includes the reports on rotifers documented in 93 studies produced after 1990. The majority of the investigations were carried out in three of the 24 Argentine provinces. In addition, the presence of 13 species in samples from three water bodies within Buenos Aires province are now cited here for the first time in Argentina. In this updated checklist, a total of 351 species are catalogued, the majority being representatives of the Lecanidae, Brachionidae, and Lepadellidae.


2010 ◽  
Vol 30 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Germán Cantón ◽  
Carlos Campero ◽  
Matías Villa ◽  
Ernesto Odriozola

Phalaris angusta is a South American natural grass that produces poisoning in sheep and cattle in Argentina and Brazil. Phalaris spp. can produce unrelated forms of poisoning in ruminants, acute and chronic syndromes. The objective of this paper was to describe an outbreak of acute and chronic Phalaris nervous syndrome in 53 of 980 fattening steers and heifers in a farm of Buenos Aires province. On September of 2006 the animals developed nervous signs and died after 3-5 days. The herd was removed to a phalarisfree pasture. Three months later (on December) 15 new clinical cases developed in the herd. Necropsy performed in one affected calf showed neither grossly nor microscopic changes. Microscopically, there were no major alterations in tissues. Nervous signs had been described in some field cases where neither pigment deposition nor axonal degeneration could be detected. Clinical findings displayed by affected cattle after consumption of Phalaris angusta pastures resemble those observed by other authors in Phalaris staggers. This is the first report in Argentina where both syndromes were seen in the same herd.


1992 ◽  
Vol 6 ◽  
pp. 56-56
Author(s):  
Alberto L. Cione ◽  
Eduardo P. Tonni

Former workers developed in South America a chronostratigraphic system not essentially different to that of European stage/age system. However, the authors of this paper believe that accurate biostratigraphic studies have to be done in southern South America for establishing the precise boundary stratotypes of most stage/ages. A new South American Upper Cenozoic continental stage/age is recognized. The stratotype is located in the fossiliferous southeastern Buenos Aires Province marine cliffs between Mar del Plata and Miramar. The outcrops in the area are the best continental representation of Plio-Pleistocene times in South America. It is younger than Chapadmalalan and older than Ensenadan and replaces the “Uquian”. We consider that the “Uquian” actually emcopasses Chapadmalalan and Ensenadan times. The Uquía outcrops are here considered inadequate as stratotype especially by the dearth of micromanmals, the relatively poor fossil record and the comparatively inadequate geographic location. The new stage would be correlated with the Gauss Chron and possibly with the lower Matuyama Chron. The lower boundary is tentatively stated. For so doing, a biostratigraphic scheme is proposed. This lower boundary approximately corresponds to the base of the Barranca de los Lobos “Formation” of Kraglievich (1952) and a new (unpublished) unconformity bounded unit (Zárate, 1989). Some taxa that apparently ranges from the base are candidates to define it after a detailed biostratigraphic study.Additionally, a different timing for the arrival of North American mammals to southern South America is given.


2014 ◽  
Vol 86 (1) ◽  
pp. 311-331 ◽  
Author(s):  
RICHARD A. FARIÑA ◽  
ADA CZERWONOGORA ◽  
MARIANA DI GIACOMO

The South American Pleistocene mammal fauna includes great-sized animals that have intrigued scientists for over two centuries. Here we intend to update the knowledge on its palaeoecology and provide new evidence regarding two approaches: energetics and population density and relative abundance of fossils per taxa. To determine whether an imbalance exists, population density models were applied to several South American fossil faunas and the results compared to those that best describe the palaeoecology of African faunas. The results on the abundance study for Uruguay and the province of Buenos Aires during the Lujanian stage/age reveal that bulk-feeding ground sloths (Lestodon and Glossotherium) were more represented in the first territory, while the more selective Scelidotherium and Megatherium were more abundant in the second. Although the obtained values were corrected to avoid size-related taphonomic biases, linear regressions of abundance vs. body mass plots did not fit the expected either for first or second consumers. South American Pleistocene faunas behave differently from what models suggest they should. Changes in sea level and available area could account for these differences; the possibility of a floodplain in the area then emerged could explain seasonal changes, which would modify the calculations of energetics and abundance.


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