scholarly journals An avian femur from the Late Cretaceous of Vega Island, Antarctic Peninsula: removing the record of cursorial landbirds from the Mesozoic of Antarctica

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7231 ◽  
Author(s):  
Abagael R. West ◽  
Christopher R. Torres ◽  
Judd A. Case ◽  
Julia A. Clarke ◽  
Patrick M. O'Connor ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Femoral Shaft ◽  
South American ◽  
South American Species ◽  
Taxonomic Assignment ◽  
South Dakota School ◽  
Flat Shape ◽  
The Subject ◽  
The Antarctic ◽  
Important Character

In 2006, a partial avian femur (South Dakota School of Mines and Technology (SDSM) 78247) from the Upper Cretaceous (Maastrichtian) Sandwich Bluff Member of the López de Bertodano Formation of Sandwich Bluff on Vega Island of the northern Antarctic Peninsula was briefly reported as that of a cariamiform—a clade that includes extant and volant South American species and many extinct flightless and cursorial species. Although other authors have since rejected this taxonomic assignment, SDSM 78247 had never been the subject of a detailed description, hindering a definitive assessment of its affinities. Here we provide the first comprehensive description, illustration, and comparative study of this specimen. Comparison of characters that may be assessed in this femur with those of avian taxa scored in published character matrices refutes the inclusion of SDSM 78247 within Cariamiformes, instead supporting its assignment to a new, as-yet unnamed large-bodied species within the genus Vegavis, and therefore its referral to a clade of semiaquatic anseriforms. Important character states diagnostic of Vegavis + Polarornis include strong craniocaudal bowing of the femoral shaft, the presence of a distinct fossa just proximal to the fibular trochlea, and the broad and flat shape of the patellar sulcus. Referral to Vegavis is based on the presence of a distinctive proximocaudal fossa and distolateral scar. This genus was previously known only from Vegavis iaai, a smaller-bodied taxon from the same locality and stratigraphic unit. Our reassignment of SDSM 78247 to Vegavis sp. removes the record of cariamiform landbirds from the Antarctic Cretaceous.

The youngest record of fossil land mammals from Antarctica; its significance on the evolution of the terrestrial environment of the Antarctic Peninsula during the late Eocene

1997 ◽  
Vol 71 (2) ◽  
pp. 348-350 ◽  
Author(s):  
S. F. Vizcaino ◽  
M. Bond ◽  
M. A. Reguero ◽  
R. Pascual
Keyword(s):  
Antarctic Peninsula ◽  
Present Note ◽  
Late Eocene ◽  
South American ◽  
Terrestrial Environment ◽  
Shallow Marine ◽  
Early Oligocene ◽  
La Meseta Formation ◽  
The Antarctic ◽  
Seymour Island

The record of fossil land mammals from Antarctica has been restricted previously to the middle levels of the Eocene-?early Oligocene La Meseta Formation in Seymour Island, Antarctic Peninsula. This mostly shallow-marine sequence was divided informally into seven subunits (Tertiary Eocene La Meseta or TELM 1 to 7) by Sadler (1988). Land mammals, representing South American lineages of marsupials, edentates, and ungulates were recovered from TELM 3, 4, and 5 (Marenssi et al., 1994; Vizcaíno et al., 1994). The purpose of the present note is to report the discovery of a well-preserved ungulate tooth from the uppermost level of the La Meseta Formation (TELM 7) and to discuss its paleoenvironmental implications.

Zoogeography of the Antarctic ascidian fauna in relation to the sub-Antarctic and South America

2007 ◽  
Vol 19 (3) ◽  
pp. 321-336 ◽  
Author(s):  
Carmen Primo ◽  
Elsa Vázquez
Keyword(s):  
South America ◽  
Saint Paul ◽  
South American ◽  
South American Species ◽  
Species Classification ◽  
Antarctic Region ◽  
Antarctic Species ◽  
Tristan Da Cunha ◽  
Centre Of Origin ◽  
The Antarctic

AbstractThis study of the relationships between the Antarctic, sub-Antarctic and South America biogeographical regions used both existing and new data. We constructed a presence/absence matrix of 237 species for 27 biogeographical divisions which included the Amsterdam-Saint Paul and Tristan da Cunha islands. Species and areas were classified using cluster analysis combined with MDS ordination. Six main groups were obtained from the species classification: 1) Amsterdam-Saint Paul, and 2) Tristan da Cunha species, 3) species from the Macquarie Province, 4) species from the sub-Antarctic Region, 5) Antarctic species and species distributed in the cold regions, 6) South American species. The biogeographical components were dominated by the endemic (although it is not as high as in other groups), Antarctic-South America and Southern Hemisphere elements. Except for Amsterdam-Saint Paul, Tristan da Cunha and Bouvet, the areas considered were grouped together with Macquarie being rather related to New Zealand regions. We speculate that the Antarctic Region may have acted as an “evolutionary incubator”, providing a centre of origin for sub-Antarctic and South American ascidians.

The santonian through paleogene record of Proteaceae in the southern South America - Antarctic peninsula region

1998 ◽  
Vol 11 (4) ◽  
pp. 373 ◽  
Author(s):  
Rosemary A. Askin ◽  
Alicia M. Baldoni
Keyword(s):  
South America ◽  
Antarctic Peninsula ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Type Species ◽  
Pollen Record ◽  
South American ◽  
Southern South America ◽  
Nothofagus Forest ◽  
The Antarctic

Proteaceous plants were an important component of the high-latitude Late Cretaceous–Paleogene podocarpaceous conifer and Nothofagus forest vegetation growing in high-rainfall temperate conditions. In the southern South America–Antarctic Peninsula region the fossil record of the Proteaceae comprises pollen, leaves, fruits and wood with affinities to the extant subfamilies Grevilleoideae, Proteoideae, and possibly Carnarvonioideae and Persoonioideae. The oldest reported occurrences of Proteaceae in this region are in the middle–late Santonian of the Antarctic Peninsula and include pollen of Proteacidites subscabratus Couper, with the addition in the Campanian of other species of Proteacidites and Propylipollis, Cranwellipollis spp. and Peninsulapollis spp. Diversity of proteaceous pollen increased through the Campanian and Maastrichtian, reflecting the spread of Proteaceae along the Antarctic Peninsula and into South America. Both endemic species and species derived from the Australian region are represented. Compared to coeval Australian assemblages, however, proteaceous diversity remained relatively low. Interestingly, Beauprea-type species (Beaupreaidites spp., Peninsulapollis spp.) are common and varied in the Antarctic Peninsula from Campanian into the Eocene, yet the South American pollen record does not include these forms, except for rare Peninsulapollis gillii. Possibly drier conditions may have discouraged northward migration of this group. South American fossil proteaceous taxa are primarily related to Grevilleoideae, a trend that continues into the modern flora on that continent.

A new ‘South American ungulate’ (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula

2006 ◽  
Vol 258 (1) ◽  
pp. 163-176 ◽  
Author(s):  
M. Bond ◽  
M. A. Reguero ◽  
S. F. Vizcaíno ◽  
S. A. Marenssi
Keyword(s):  
Antarctic Peninsula ◽  
New South ◽  
South American ◽  
The Antarctic

Icy relations: the emergence of South American Antarctica during the Second World War

Polar Record ◽  
2006 ◽  
Vol 42 (2) ◽  
pp. 153-165 ◽  
Author(s):  
Adrian Howkins
Keyword(s):  
Antarctic Peninsula ◽  
Subsequent Development ◽  
Second World War ◽  
South American ◽  
World War ◽  
The United Kingdom ◽  
History Of ◽  
Economic Imperialism ◽  
The Antarctic ◽  
Second World

During the Second World War, both Chile and Argentina advanced sovereignty claims to the Antarctic Peninsula and surrounding sub-Antarctic islands that overlapped substantially with claims that the United Kingdom had made in 1908 and 1917. This article explores the emergence of the concept of a South American Antarctica during this period. Although, at one level, the two South American countries attempted to create a united front against the British, they actually decided to press their claims to Antarctica for different and sometimes conflicting reasons. In Argentina, nationalists connected the question of sovereignty in Antarctica with their claims to the Malvinas and with a broader struggle against a supposed British economic imperialism. In Chile, patriotic officials were less concerned with British claims to the Antarctic Peninsula and more worried about Argentina's growing interest in the region. The article concludes that a better understanding of the complex and contradictory history of the emergence of the idea of South American Antarctica during the Second World War leads to an enhanced appreciation of the subsequent development of the so-called ‘Antarctic Problem’ as it developed over the next 15 years. In order to avoid the artificiality of the term ‘Falklands (Malvinas)’, the British terms ‘Falklands’ and ‘Falkland Islands’ have been used when discussing the United Kingdom's position, and the Argentine term ‘Malvinas’ when discussing that of Argentina.

An additional record of a placental mammal (Order Astrapotheria) from the Eocene of West Antarctica

1992 ◽  
Vol 4 (1) ◽  
pp. 107-108 ◽  
Author(s):  
J.J. Hooker
Keyword(s):  
Antarctic Peninsula ◽  
Present Note ◽  
Late Eocene ◽  
The Other ◽  
West Antarctica ◽  
La Meseta Formation ◽  
James Ross Island ◽  
The Subject ◽  
The Antarctic ◽  
Seymour Island

Recently, fossil land mammals have been recorded in the James Ross Island area, east of the Antarctic Peninsula, from the marine middle-late Eocene strata of Seymour Island. These include two endemic species of polydolopid marsupial: Antarctodolops dailyi Woodburne & Zinsmeister 1984, and Eurydolops seymourensis Case, Woodburne & Chaney 1988, and three partly determinate placentals identified as a tardigrade edentate, a sparnotheriodontid litoptern and a trigonostylopid astrapothere (Bond et al. 1989). The marsupials are represented by fragmentary jaw and complete dental material, the litoptern and astrapothere only by tooth fragments. All are recorded from Unit TELM 5 of the La Meseta Formation (Sadler 1988), the two ungulates at a lower level than the rest. The subject of the present note is a second tooth fragment from Seymour Island identified as an astrapothere. It is worth recording because such mammal remains are rare and it is from TELM 4, the unit below that yielding the other land mammals.

scholarly journals A New Method for Identifying the Pacific–South American Pattern and Its Influence on Regional Climate Variability

2016 ◽  
Vol 29 (17) ◽  
pp. 6109-6125 ◽  
Author(s):  
Damien Irving ◽  
Ian Simmonds
Keyword(s):  
Climate Variability ◽  
Antarctic Peninsula ◽  
Southern Oscillation ◽  
Global Coordinate System ◽  
Identification Algorithm ◽  
South American ◽  
West Antarctica ◽  
Southwest Atlantic ◽  
The Pacific ◽  
The Antarctic

Abstract The Pacific–South American (PSA) pattern is an important mode of climate variability in the mid-to-high southern latitudes. It is widely recognized as the primary mechanism by which El Niño–Southern Oscillation (ENSO) influences the southeast Pacific and southwest Atlantic and in recent years has also been suggested as a mechanism by which longer-term tropical sea surface temperature trends can influence the Antarctic climate. This study presents a novel methodology for objectively identifying the PSA pattern. By rotating the global coordinate system such that the equator (a great circle) traces the approximate path of the pattern, the identification algorithm utilizes Fourier analysis as opposed to a traditional empirical orthogonal function approach. The climatology arising from the application of this method to ERA-Interim reanalysis data reveals that the PSA pattern has a strong influence on temperature and precipitation variability over West Antarctica and the Antarctic Peninsula and on sea ice variability in the adjacent Amundsen, Bellingshausen, and Weddell Seas. Identified seasonal trends toward the negative phase of the PSA pattern are consistent with warming observed over the Antarctic Peninsula during autumn, but are inconsistent with observed winter warming over West Antarctica. Only a weak relationship is identified between the PSA pattern and ENSO, which suggests that the pattern might be better conceptualized as a preferred regional atmospheric response to various external (and internal) forcings.

222Rn in the Antarctic Peninsula During 1986

1988 ◽  
Vol 24 (1-4) ◽  
pp. 85-88 ◽  
Author(s):  
E.B. Pereira ◽  
A.W. Setzer ◽  
I.F.A. Cavalcanti
Keyword(s):  
Seasonal Variation ◽  
Antarctic Peninsula ◽  
Radon Concentration ◽  
Positive Association ◽  
Atmospheric Temperature ◽  
South American ◽  
The South ◽  
Short Term ◽  
Strong Positive Association ◽  
The Antarctic

Abstract 222Rn was continuously measured at the Brazilian Antarctic Station (62 oS, 58 oW) during the year of 1986. Baseline radon concentration averaged 0.02 Bq.m-3 with surges peaking at 0.4 Bq.m-3. The data exhibited a characteristic periodicity of about 25 days and a strong positive association with short term fluctuations of atmospheric temperature. No seasonal variation of radon were observed. Interpretation of the radon surges with reference to synoptic charts and weather satellite pictures showed that the continental influence of radon at the Antarctic Peninsula is very small and comes only from the tip of the South American cone.

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