Jurassic intraplate contraction of southern Patagonia: The El Tranquilo Anticline area, Deseado Massif

2019 ◽  
Vol 94 ◽  
pp. 102224 ◽  
Author(s):  
César Navarrete ◽  
Guido Gianni ◽  
Rodolfo Christiansen ◽  
Yanko Kamerbeek ◽  
Santiago Periale ◽  
...  
2008 ◽  
Vol 82 (2) ◽  
pp. 372-376 ◽  
Author(s):  
Ana Maria Báez ◽  
Laura Nicoli

Notobatrachus degiustoi is the most completely known Jurassic frog and has been recorded in many outcrops of the La Matilde Formation of the Deseado Massif area in southern Patagonia. Herein, we erect a new species of the genus based on partially articulated remains collected from the Callovian Las Chacritas Member of the Cañadón Asfalto Formation, about 500 km northwest of the northern limit of the known geographical distribution of N. degiustoi. The new species differs from the latter in having a maxilla with a distinct pterygoid process and lacking teeth at least along the posterior two-thirds of its length, and a complete maxillary arch. We also provide an expanded diagnosis of Notobatrachus. This finding adds to our understanding of the early diversification of frogs.


2008 ◽  
Vol 460 (1-4) ◽  
pp. 178-185 ◽  
Author(s):  
Rubén Somoza ◽  
Haroldo Vizán ◽  
Graeme K. Taylor

Zootaxa ◽  
2020 ◽  
Vol 4852 (3) ◽  
pp. 383-395
Author(s):  
RODRIGO PONCE DE LEÓN ◽  
ERICH H. RUDOLPH ◽  
ODILE VOLONTERIO

To date, only one species of Temnocephala is known from Chile, Temnocephala chilensis, and three from southern Argentina (Patagonia), namely T. chilensis, Temnocephala dionii, and Temnocephala mexicana. Here we describe a new species of Temnocephala and provide an updated description of T. chilensis based on material found on an anomuran crab (Aeglidae) from southern Chile. Additional hosts and localities are reported for both species in southern Argentina and Chile, and a diagnostic key for all species of Temnocephala hosted on Aegla and Parastacidae is included as well. In southern Chile, both T. chilensis and the new species were found on the crayfish Samastacus spinifrons and on the anomuran crabs Aegla abtao and Aegla alacalufi; in addition, the new species was found on Aegla manni, and T. chilensis on Aegla rostrata. In southern Argentina, T. chilensis and the new species were found on Aegla riolimayana and S. spinifrons. Based on their shared traits (morphology of the penial stylet, host preferences and geographic distribution), the temnocephalans hosted in Aegla are tentatively gathered into two clusters, the Chilensis and Axenos groups. 


The Holocene ◽  
2021 ◽  
pp. 095968362110259
Author(s):  
Bruno Mosquera ◽  
María V Mancini

Paleoenvironmental data from wet-meadow environments in the arid-semiarid region of Patagonia are still incipient and the paleoenvironmental records came from pollen sequences of caves and rockshelters. The main reasons to study wetland records are their undisturbed (by humans) sedimentologic continuity, in contrast to deposits in rock shelters and caves; and their regional presentation of environmental changes that can be compared to archeological data. The aim of this paper is to evaluate the past hydrological dynamic of a wet-meadow from Deseado Massif and its relationship with the human occupation. For this purpose, we present the results of the sediment and pollen analysis of Mallín La Primavera wet-meadow that provide a sequence starting in the mid-Holocene. The results indicate a lower water table in the mallín prior to 6900 cal yr BP. Sediment analysis indicates low energy sedimentation environment with flood events and very low energy streams. Human occupational data show chronological discontinuities in mid-Holocene in several regions of Patagonia and the southern cone. In the studied region, two chronological hiatuses (7828–6434 cal yr BP and 3005–2710 cal yr BP) where recognized that appear to correlate with shrub steppes, indicating dry conditions. These conditions may explain the lack of archeological radiocarbon dates in the area during this period. The integration of sediment and pollen results from the Deseado Massif indicates dry and windy conditions for the middle Holocene. The lack of archeological radiocarbon dates would have been influenced by the loss of moisture in water sources such as springs and their associated wet meadows ( mallines).


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yamina Micaela Rosas ◽  
Pablo L. Peri ◽  
María Vanessa Lencinas ◽  
Romina Lasagno ◽  
Guillermo J. Martínez Pastur

Abstract Background Biodiversity supports multiple ecosystem services, whereas species loss endangers the provision of many services and affects ecosystem resilience and resistance capacity. The increase of remote sensing techniques allows to estimate biodiversity and ecosystem services supply at the landscape level in areas with low available data (e.g. Southern Patagonia). This paper evaluates the potential biodiversity and how it links with ecosystem services, based on vascular plant species across eight ecological areas. We also evaluated the habitat plant requirements and their relation with natural gradients. A total of 977 plots were used to develop habitat suitability maps based on an environmental niche factor analysis of 15 more important indicator species for each ecological area (n = 53 species) using 40 explanatory variables. Finally, these maps were combined into a single potential biodiversity map, which was linked with environmental variables and ecosystem services supply. For comparisons, data were extracted and compared through analyses of variance. Results The plant habitat requirements varied greatly among the different ecological areas, and it was possible to define groups according to its specialization and marginality indexes. The potential biodiversity map allowed us to detect coldspots in the western mountains and hotspots in southern and eastern areas. Higher biodiversity was associated to higher temperatures and normalized difference vegetation index, while lower biodiversity was related to elevation and rainfall. Potential biodiversity was closely associated with supporting and provisioning ecosystem services in shrublands and grasslands in the humid steppe, while the lowest values were related to cultural ecosystem services in Nothofagus forests. Conclusions The present study showed that plant species present remarkable differences in spatial distributions and ecological requirements, being a useful proxy for potential biodiversity modelling. Potential biodiversity values change across ecological areas allowing to identify hotspots and coldspots, a useful tool for landscape management and conservation strategies. In addition, links with ecosystem services detect potential synergies and trade-offs, where areas with the lowest potential biodiversity are related to cultural ecosystem services (e.g. aesthetic values) and areas with the greatest potential biodiversity showed threats related to productive activities (e.g. livestock).


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Damián A. Fernández ◽  
Luis Palazzesi ◽  
M. Sol González Estebenet ◽  
M. Cristina Tellería ◽  
Viviana D. Barreda

AbstractA major climate shift took place about 40 Myr ago—the Middle Eocene Climatic Optimum or MECO—triggered by a significant rise of atmospheric CO2 concentrations. The biotic response to this MECO is well documented in the marine realm, but poorly explored in adjacent landmasses. Here, we quantify the response of the floras from America’s southernmost latitudes based on the analysis of terrestrially derived spores and pollen grains from the mid-late Eocene (~46–34 Myr) of southern Patagonia. Robust nonparametric estimators indicate that floras in southern Patagonia were in average ~40% more diverse during the MECO than pre-MECO and post-MECO intervals. The high atmospheric CO2 and increasing temperatures may have favored the combination of neotropical migrants with Gondwanan species, explaining in part the high diversity that we observed during the MECO. Our reconstructed biota reflects a greenhouse world and offers a climatic and ecological deep time scenario of an ice-free sub-Antarctic realm.


2009 ◽  
Vol 19 (2) ◽  
pp. 297-308 ◽  
Author(s):  
A. Tessone ◽  
A. F. Zangrando ◽  
G. Barrientos ◽  
R. Goñi ◽  
H. Panarello ◽  
...  

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