The migration and evolution of floras in the southern hemisphere

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 325-328 ◽  
Author(s):  
P. H. Raven
Keyword(s):  
North America ◽  
South America ◽  
Southern Hemisphere ◽  
Relative Position ◽  
Southern South America ◽  
The Past ◽  
Main Pathway ◽  
Set Up ◽  
Warm Temperate ◽  
Northern And Southern Hemispheres

As modern groups of angiosperms have appeared over a period of more than 80 million years, the relative position of the southern continents has changed. For the First 20 m.y. of this period, opportunities for migration were good between Africa and Europe, and this constituted the main pathway for migration between the northern and southern hemispheres. South America progressively moved away from Africa and towards North America over the past 90 m.y. Southern South America and Australasia shared a rich, warm temperate rainforest flora until about 40 m.y. ago. The development of modern climates during the past 10 m.y. has set up modern patterns of vegetation.

scholarly journals Late Holocene summer temperatures in the central Andes reconstructed from the sediments of high-elevation Laguna Chepical, Chile (32° S)

2013 ◽  
Vol 9 (3) ◽  
pp. 2277-2308
Author(s):  
R. de Jong ◽  
L. von Gunten ◽  
A. Maldonado ◽  
M. Grosjean
Keyword(s):  
Climate Change ◽  
South America ◽  
Temperature Reconstruction ◽  
High Elevation ◽  
Ice Age ◽  
Central Chile ◽  
Southern South America ◽  
Calibration Period ◽  
The Past ◽  
Insight Into

Abstract. High-resolution reconstructions of climate variability that cover the past millennia are necessary to improve the understanding of natural and anthropogenic climate change across the globe. Although numerous records are available for the mid- and high-latitudes of the Northern Hemisphere, global assessments are still compromised by the scarcity of data from the Southern Hemisphere. This is particularly the case for the tropical and subtropical areas. In addition, high elevation sites in the South American Andes may provide insight into the vertical structure of climate change in the mid-troposphere. This study presents a 3000 yr long austral summer (November to February) temperature reconstruction derived from the 210Pb and 14C dated organic sediments of Laguna Chepical (32°16' S/70°30' W, 3050 m a.s.l.), a high-elevation glacial lake in the subtropical Andes of central Chile. Scanning reflectance spectroscopy in the visible light range provided the spectral index R570/R630, which reflects the clay mineral content in lake sediments. For the calibration period (AD 1901–2006), the R570/R630 data were regressed against monthly meteorological reanalysis data, showing that this proxy was strongly and significantly correlated with mean summer (NDJF) temperatures (R3yr = −0.63, padj = 0.01). This calibration model was used to make a quantitative temperature reconstruction back to 1000 BC. The reconstruction (with a model error RMSEPboot of 0.33 °C) shows that the warmest decades of the past 3000 yr occurred during the calibration period. The 19th century (end of the Little Ice Age (LIA)) was cool. The prominent warmth reconstructed for the 18th century, which was also observed in other records from this area, seems systematic for subtropical and southern South America but remains difficult to explain. Except for this warm period, the LIA was generally characterized by cool summers. Back to AD 1400, the results from this study compare remarkably well to low altitude records from the Chilean Central Valley and Southern South America. However, the reconstruction from Laguna Chepical does not show a warm Medieval Climate Anomaly during the 12–13th century, which is consistent with records from tropical South America. The Chepical record also indicates substantial cooling prior to 800 BC. This coincides with well-known regional as well as global glacier advances which have been attributed to a grand solar minimum. This study thus provides insight into the climatic drivers and temperature patterns in a region for which currently very few data are available. It also shows that since ca AD 1400, long term temperature patterns were generally similar at low and high altitudes in central Chile.

scholarly journals Salvia reflexa (Lamiaceae): a new record for Pakistan

2019 ◽  
Vol 6 (1) ◽  
pp. 17-21
Author(s):  
Wahid Hussain ◽  
Lal Badshah ◽  
Sayed Afzal Shah ◽  
Farrukh Hussain ◽  
Asghar Ali ◽  
...  
Keyword(s):  
South Africa ◽  
New Zealand ◽  
North America ◽  
South America ◽  
Range Expansion ◽  
New Record ◽  
New World ◽  
Southern South America ◽  
Tribal Areas

Salvia reflexa Hornem., a member of the New World subgenus Calosphace, ranges from North America to southern South America, Australia, New Zealand, South Africa and Afghanistan in Asia, and still continues to expand its range. Here we report further range expansion for S. reflexa into the tribal areas of Pakistan and hypothesize that it has been introduced from Afghanistan. This represents a new record for the flora of Pakistan.

Gondwana and Pangea

2004 ◽  
Author(s):  
John J. W. Rogers ◽  
M. Santosh
Keyword(s):  
North America ◽  
South America ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Late Paleozoic ◽  
Northern Asia ◽  
Pan African ◽  
History Of ◽  
Single Block ◽  
Orogenic Belts

Pangea, the most recent supercontinent, attained its condition of maximum packing at ~250 Ma. At this time, it consisted of a northern part, Laurasia, and a southern part, Gondwana. Gondwana contained the southern continents—South America, Africa, India, Madagascar, Australia, and Antarctica. It had become a coherent supercontinent at ~500 Ma and accreted to Pangea largely as a single block. Laurasia consisted of the northern continents—North America, Greenland, Europe, and northern Asia. It accreted during the Late Paleozoic and became a supercontinent when fusion of these continental blocks with Gondwana occurred near the end of the Paleozoic. The configuration of Pangea, including Gondwana, can be determined accurately by tracing the patterns of magnetic stripes in the oceans that opened within it (chapters 1 and 9). The history of accretion of Laurasia is also well known, but the development of Gondwana is highly controversial. Gondwana was clearly a single supercontinent by ~500 Ma, but whether it formed by fusion of a few large blocks or the assembly of numerous small blocks is uncertain. Figure 8.1 shows Gondwana divided into East and West parts, but the boundary between them is highly controversial (see below). We start this chapter by investigating the history of Gondwana, using appendix SI to describe detailed histories of orogenic belts of Pan-African age (600–500-Ma). Then we continue with the development of Pangea, including the Paleozoic orogenic belts that led to its development. The next section summarizes the paleomagnetically determined movement of blocks from the accretion of Gondwana until the assembly of Pangea, and the last section discusses the differences between Gondwana and Laurasia in Pangea. The patterns of dispersal and development of modern oceans are left to chapter 9, and the histories of continents following dispersal to chapter 10. By the later part of the 1800s, geologists working in the southern hemisphere realized that the Paleozoic fossils that occurred there were very different from those in the northern hemisphere. They found similar fossils in South America, Africa, Madagascar, India, and Australia, and in 1913 they added Antarctica when identical specimens were found by the Scott expedition.

Temperate Forests of the Southern Andean Region

2007 ◽  
Author(s):  
Thomas T. Veblen
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Boreal Forests ◽  
Temperate Forests ◽  
High Latitudes ◽  
Andean Region ◽  
Southern South America ◽  
The Andes ◽  
Evergreen Conifers

Although most of the continent of South America is characterized by tropical vegetation, south of the tropic of Capricorn there is a full range of temperate-latitude vegetation types including Mediterranean-type sclerophyll shrublands, grasslands, steppe, xeric woodlands, deciduous forests, and temperate rain forests. Southward along the west coast of South America the vast Atacama desert gives way to the Mediterranean-type shrublands and woodlands of central Chile, and then to increasingly wet forests all the way to Tierra del Fuego at 55°S. To the east of the Andes, these forests are bordered by the vast Patagonian steppe of bunch grasses and short shrubs. The focus of this chapter is on the region of temperate forests occurring along the western side of the southernmost part of South America, south of 33°S. The forests of the southern Andean region, including the coastal mountains as well as the Andes, are presently surrounded by physiognomically and taxonomically distinct vegetation types and have long been isolated from other forest regions. Although small in comparison with the extent of temperate forests of the Northern Hemisphere, this region is one of the largest areas of temperate forest in the Southern Hemisphere and is rich in endemic species. For readers familiar with temperate forests of the Northern Hemisphere, it is difficult to place the temper temperate forests of southern South America into a comparable ecological framework owing both to important differences in the histories of the biotas and to contrasts between the broad climatic patterns of the two hemispheres. There is no forest biome in the Southern Hemisphere that is comparable to the boreal forests of the high latitudes of the Northern Hemisphere. The boreal forests of the latter are dominated by evergreen conifers of needle-leaved trees, mostly in the Pinaceae family, and occur in an extremely continental climate. In contrast, at high latitudes in southern South America, forests are dominated mostly by broadleaved trees such as the southern beech genus (Nothofagus). Evergreen conifers with needle or scaleleaves (from families other than the Pinaceae) are a relatively minor component of these forests.

Certeau, Michel de (1925–86)

2018 ◽  
Author(s):  
Tom Conley
Keyword(s):  
North America ◽  
South America ◽  
Social Practice ◽  
The Other ◽  
General Philosophy ◽  
Late Medieval ◽  
The Past ◽  
Michel De Certeau ◽  
History Of ◽  
Strategic Policies

Michel de Certeau, a French philosopher trained in history and ethnography, was a peripatetic teacher in Europe, South America and North America. His thought has inflected four areas of philosophy. He studied how mysticism informs late-medieval epistemology and social practice. With the advent of the Scientific Revolution, the affinities the mystic shares with nature and the cosmos become, like religion itself, repressed or concealed. An adjunct discipline, heterology, thus constitutes an anthropology of alterity, studying the ‘other’ and the destiny of religion since the sixteenth century. De Certeau opens the hidden agendas that make representations of the past a function of social pressures, so that sometime histories are rearticulated in mirrored or subversive forms. This subversion makes accessible a general philosophy of invention that works within and against the strategic policies of official institutions. De Certeau’s writings also belong to activism, the history of ideological structures, psychoanalysis, and post-1968 theories of writing (écriture) as defined by Deleuze, Derrida, Foucault and Lyotard.

scholarly journals International increase in Salmonella enteritidis: A new pandemic?

1990 ◽  
Vol 105 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D. C. Rodrigue ◽  
R. V. Tauxe ◽  
B. Rowe
Keyword(s):  
North America ◽  
South America ◽  
Atlantic Ocean ◽  
Salmonella Enteritidis ◽  
European Countries ◽  
The Past ◽  
America South ◽  
Global Increase ◽  
Salmonella Serotype ◽  
Reported Data

SUMMARYOver the past 5 years Salmonella enteritidis infections in humans have increased on both sides of the Atlantic ocean. The WHO salmonella surveillance data for 1979–87 were reviewed and show that S. enteritidis appears to be increasing on at least the continents of North America, South America, and Europe, and may include Africa. S. enteritidis isolates increased in 24 (69%) of 35 countries between 1979 and 1987. In 1979, only 2 (10%) of 21 countries with reported data reported S. enteritidis as their most common salmonella serotype; in 1987, 9 (43%) of 21 countries reported S. enteritidis as their most common serotype; 8 (89 %) of 9 were European countries. Although the reason for the global increase is not yet clear, investigations in individual countries suggest it is related to consumption of eggs and poultry which harbour the organism.

The biology of Cryptolestes pusilloides (Steel & Howe) (Coleoptera, Cucujidae), a pest of stored cereals in the Southern Hemisphere

1964 ◽  
Vol 54 (4) ◽  
pp. 649-656 ◽  
Author(s):  
L. P. Lefkovitch
Keyword(s):  
South Africa ◽  
Life Cycle ◽  
Sexual Dimorphism ◽  
North America ◽  
South America ◽  
East Africa ◽  
Southern Hemisphere ◽  
Developmental Period ◽  
Biological Information ◽  
Dry Conditions

Cryptolestes pusilloides (Steel & Howe) has, since 1944, become a regularly occurring pest of stored cereals in South America, Australia, South Africa, and to a lesser extent, East Africa, and apparently occurs also in North America as well as in Portugal (where it has recently been found on stored almonds), but has not established itself in flour mills in the U.K., notwithstanding its frequent introduction. Prior to that time it appears to have been very rare. Its life-cycle resembles that of C. ugandae Steel & Howe, and in common with that species and with C. turcicus (Grouv.), it is unable to breed successfully at relative humidities below 50 per cent. Its temperature range is 15–35°C., the optimum for development and fecundity being at about 30°C. at 90 per cent. R.H. Survival was greatest at 27·5°C. and newly formed adults weighed most at 22·5°C. In general, males weighed more than females and their developmental period under any one set of conditions was slightly longer than that of females. The biological information now available shows that C. ferrugineus (Steph.) and C. capensis (Waltl), which are taxonomieally associated by exhibiting sexual dimorphism in the structure of the mandibles, are species that can withstand dry conditions, whereas C. ugandae, C. turcicus, C. pusillus (Schönh.) and C. pusilloides, all of which show sexual dimorphism in the antennae, are unable to breed at relative humidities much below 50 per cent.

A Panorpoid (Insecta: Mecoptera) from the Lower Eocene of Patagonia, Argentina

2009 ◽  
Vol 83 (6) ◽  
pp. 994-997 ◽  
Author(s):  
Julián F. Petrulevičius
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Lower Cretaceous ◽  
Fossil Record ◽  
Uneven Distribution ◽  
Fossil Insects ◽  
Lower Eocene ◽  
Southern South America ◽  
Stem Group ◽  
Recent Species

The order Mecoptera is represented on all continents, albeit with an uneven distribution. Mecoptera includes about 34 families (Labandeira, 1994, p. 34), only four of them, until now, represented in South America: Permochoristidae Tillyard, 1917 (†) (Pinto, 1972); Bittacidae Handlirsch, 1906 [and stem-group “Neorthophlebinae” (†)] (Petrulevičius, 2001a, 2003, 2007); Nannochoristidae Tillyard, 1917; and Eomeropidae Cockerell, 1909. The two latter families have a present relict distribution in southern South America but without fossil record, obviously an artifact due to few studies of fossil insects in the subcontinent. The diversity of recent Bittacidae is high in South America with respect to other continents. Thirty-five percent of recent genera of Bittacidae come from South America, and 80% of these genera are endemic (extracted from Penny, 1997). Bittacidae is well represented in the fossil record, with species from the Jurassic of Patagonia (Petrulevičius, 2007), Lower Cretaceous of Brazil (Petrulevičius and Martins-Neto, 2001), to the late Paleocene of Argentina (Petrulevičius, 1998, 1999, 2001b, 2003). This contribution reports a specimen belonging to the Panorpoidea, a group with no recent species in South America and very few species in the entire Southern Hemisphere.

Kooiichthys jono n. gen. n. sp., a primitive catfish (Teleostei, Siluriformes) from the marine Miocene of southern South America

2015 ◽  
Vol 89 (5) ◽  
pp. 791-801 ◽  
Author(s):  
María de las Mercedes Azpelicueta ◽  
Alberto Luis Cione ◽  
Mario Alberto Cozzuol ◽  
Juan Marcos Mirande
Keyword(s):  
South America ◽  
Southern Coast ◽  
Sea Lion ◽  
The West ◽  
Southern South America ◽  
Posterior Limb ◽  
Weberian Apparatus ◽  
Almost All ◽  
Warm Temperate ◽  
Colony Area

AbstractA specimen of a remarkable new catfish genus and species was collected in middle/late Miocene marine beds of the Puerto Madryn Formation at the base of the marine cliff of the sea lion colony area near Puerto Pirámide, southern coast of Península Valdés, northeastern Patagonia, Argentina. Siluriforms (catfishes) constitute a most important monophyletic ostariophysan group of mainly freshwater fishes that occurs in almost all continents but it is especially diverse in South America. Catfishes are presently distributed in tropical to temperate areas and a small number of species are marine or amphibiotic. The new catfish shows many primitive features for catfishes in the maxilla, autopalatine, hyal elements, and Weberian apparatus. The genus is clearly distinguished by four autapomorphies: sand clock–shaped autopalatine, posterior limb of autopalatine widening strongly, post-articular arm of autopalatine longer, and a metapterygoid longer than broad. One tree was obtained both under equal and implied weighting with the following topology: a basal polytomy in the Siluriformes formed by Diplomystidae, Bachmanniidae, Kooiichthys and the Siluroidei. The new species appears to have been a marine or amphibiotic taxon: it was collected in beds considered to represent the Maximum Flooding Horizon of the transgression that deposited the Puerto Madryn Formation. The coast at this moment was at approximately 90 km to the west. According to faunistic evidence, the sea was warm temperate.

Sign in / Sign up

Export Citation Format

Share Document