A redescription of a Maastrichtian lobster Hoploparia antarctica Wilckens, 1907 (Crustacea: Decapoda), from Chubut, Argentina

1991 ◽  
Vol 65 (5) ◽  
pp. 795-800 ◽  
Author(s):  
M. B. Aguirre-Urreta ◽  
E. B. Olivero ◽  
F. A. Medina
Keyword(s):  
Geographic Distribution ◽  
Trace Fossils ◽  
Sedimentary Structures ◽  
New Findings ◽  
Southern Patagonia ◽  
Molluscan Fauna

The discovery of beautifully preserved specimens of a macruran decapod provides the basis for redescription of Hoploparia antarctica Wilckens, a hitherto poorly known species from the Campanian–Maastrichtian of the Austral basin of Southern Patagonia. Analyses of the associated molluscan fauna, trace fossils, and sedimentary structures indicate that the material is mostly preserved in calcareous sandstones and coquinas deposited in shallow, well-oxygenated environments. These new findings of H. antarctica in Maastrichtian deposits of the Lefipán Formation of Chubut expand the geographic distribution of the species and add a new element for the comparison of the Lefipán fauna with that of the austral Wedellian Province.

On a new Temnocephala (Platyhelminthes) from Southern Patagonia (Chile, Argentina), with a redescription of T. chilensis and some systematic and biogeographical insights

Zootaxa ◽  
2020 ◽  
Vol 4852 (3) ◽  
pp. 383-395
Author(s):  
RODRIGO PONCE DE LEÓN ◽  
ERICH H. RUDOLPH ◽  
ODILE VOLONTERIO
Keyword(s):  
New Species ◽  
Geographic Distribution ◽  
Southern Chile ◽  
Host Preferences ◽  
Southern Patagonia ◽  
Diagnostic Key ◽  
A New Species

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. 

scholarly journals The ghost of climatic change in the geographic distribution of Tillandsia aeranthos (Bromeliaceae)

Rodriguésia ◽  
2020 ◽  
Vol 71 ◽  
Author(s):  
Elián Leandro Guerrero
Keyword(s):  
South America ◽  
Climatic Change ◽  
Geographic Distribution ◽  
Buenos Aires ◽  
New Records ◽  
Southern Limit ◽  
New Findings ◽  
Southward Shift ◽  
Possible Cause ◽  
Color Variants

Abstract The geographic distribution of Tillandsia aeranthos is updated with new records. Its southern limit is extended 200 kilometers in a zone previously studied by many botanists and naturalists, but also in poorly explored areas. For this reason, the possibility that the change in distribution is recent is postulated and discussed. The coincidence of this change with the southward shift in the isohyets and the decrease of winter frost frequency are highlighted as a possible cause of the advance to the south. In addition, two petal color variants of this species are first mentioned for Argentina. The new findings display that it is necessary to further explore some dry forests of eastern Buenos Aires and study the possible consequences of the climatic change in the biota of South America.

Tubey or not tubey: Death beds of Ediacaran macrofossils or microbially induced sedimentary structures?

Geology ◽  
2019 ◽  
Vol 47 (10) ◽  
pp. 909-913
Author(s):  
Lyle L. Nelson ◽  
Emily F. Smith
Keyword(s):  
Environmental Conditions ◽  
Trace Fossils ◽  
Microbial Mat ◽  
Sedimentary Structures ◽  
Bedding Planes ◽  
Stratigraphic Interval

Abstract Within the upper Ediacaran Esmeralda Member of the Deep Spring Formation in southeastern California, USA, an ∼3 m stratigraphic interval contains multiple clastic bedding surfaces with enigmatic, three-dimensionally preserved corrugated tubes (<60 cm in length and 6 cm in width). When viewed as fragments and in situ on bedding planes, these resemble larger versions of annulated, tubular soft-bodied macrofossils that are common in late Ediacaran biotic assemblages regionally and globally. Despite superficial similarities to casts and molds of body fossils preserved in correlative strata, we suggest these tubes are instead previously undescribed organosedimentary structures that developed through differential compaction of rippled heterolithic interbeds bound by pyritized microbial mat layers. These distinctive structures formed within peritidal settings in the latest Ediacaran Period as the result of specific ecological and environmental conditions marked by flourishing microbial mat communities and dysoxic sediments. This interpretation may inform the biogenicity of other structures previously reported as macroscopic body or trace fossils.

On a new Temnocephala (Platyhelminthes) from Southern Patagonia (Chile, Argentina), with a redescription of T. chilensis and some systematic and biogeographical insights

Zootaxa ◽  
2020 ◽  
Vol 4852 (3) ◽  
pp. 383-395
Author(s):  
RODRIGO PONCE DE LEÓN ◽  
ERICH H. RUDOLPH ◽  
ODILE VOLONTERIO
Keyword(s):  
New Species ◽  
Geographic Distribution ◽  
Southern Chile ◽  
Host Preferences ◽  
Southern Patagonia ◽  
Diagnostic Key ◽  
A New Species

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. 

scholarly journals Barra de Tabatinga and Touros Formations: evidence of pleistocene hich sea-level stillstands of the Rio Grande do Norte coast

2001 ◽  
Vol 28 (2) ◽  
pp. 5 ◽  
Author(s):  
KENITIRO SUGUIO ◽  
ALCINA MAGNÓLIA FRANCA BARRETO ◽  
FRANCISCO HILÁRIO REGO BEZERRA
Keyword(s):  
Sea Level ◽  
Rio Grande ◽  
Trace Fossils ◽  
Coarse Grained ◽  
Marine Terrace ◽  
Upper Pleistocene ◽  
Sedimentary Structures ◽  
Partial Dissolution ◽  
Marine Terraces ◽  
Stratigraphic Nomenclature

The Barra de Tabatinga Formation corresponds to the previous informally named Barra de Tabatinga unit, after a homonymous beach name. These marine terrace deposits occur along the present shoreline in patches between Natal and Barra de Sagi (ca. 80km). The summit of those deposits is about 7.5m above m.s.l. at Natal. They are composed of very friable clayey sandstones and conglomerates, exhibiting more-or-less conspicuous hydrodynamic sedimentary structures. The Touros Formation, after a homonymous town name, corresponds to the previous Tertiary Guamaré Formation, found by Petrobras only in subsurface. These marine terrace deposits extend, frequently as steep sea-cliffs along the present shoreline, between São Bento and Zumbi (ca. 120 km). The summit of these deposits reaches to a maximum of 20m above m.s.l., 2km to the N of Zumbi. Deposits are made-up of medium to coarse-grained sanstones, frequently well-cemented due to partial dissolution of biodetrital components. Hydrodynamic sedimentary structures, and trace fossils of Ophiomorpha nodosa, are very conspicuous. Both marine terraces, recently dated by TL and/or OSL methods, indicated Upper Pleistocene ages, and overlie unconformably the Neogene Barreiras Formation. Finally, as they fulfill all the requirements of the Brazilian Stratigraphic Nomenclature Code, as demonstrated in this paper, two new formations are formally proposed here.  

Sign in / Sign up

Export Citation Format

Share Document