scholarly journals Paleoclimate estimates for the Paleogene-Neogene in southern South America using fossil leaves as proxies

2021 ◽  
Author(s):  
Bárbara VENTO ◽  
Gabriela G. PUEBLA ◽  
Diego PINZÓN ◽  
Mercedes PRÁMPARO
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Multivariate Methods ◽  
Leaf Margin ◽  
Plant Composition ◽  
Southern South America ◽  
Temperature And Precipitation ◽  
Fossil Leaves ◽  
Cool Temperate ◽  
Paleoclimate Reconstructions

It is widely recognized that fossil leaves are good proxies for paleoclimate estimates, and leaf physiognomy analysis is a traditional technique used to make climate estimates. There are only a few paleoclimate reconstructions for the southern part of South America based on this technique. Here we report climate parameters using fossil leaves from the Río Turbio (Eocene-Oligocene) and Río Guillermo (Oligocene-early Miocene?) formations in southern South America, Cuenca Austral, Argentina. We used univariate (leaf margin and leaf foliar area analysis) and multivariate methods (CLAMP, DiLP) on two datasets from South America, in the Southern Hemisphere. Lower and upper members of the Río Turbio Formation show a mixed paleoflora represented by paratropical as well as cool-temperate taxa such as Nothofagus, with a similar percentage of untoothed fossil leaves. Climate estimates indicate warm and humid conditions for both Río Turbio Formation members. The Río Guillermo Formation is represented by mostly cool-temperate elements, mainly Nothofagus, and most with toothed margins. The paleoclimate analysis indicates a decrease in temperature and precipitation when comparing the two studied formations. Today, temperate forests in southern Argentina have a plant composition and climate more similar to the estimates made for the Río Guillermo Formation.

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.

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.

Amylostereum areolatum.

2021 ◽  
Author(s):  
Keyword(s):  
South Africa ◽  
New Zealand ◽  
South America ◽  
Southern Hemisphere ◽  
North Africa ◽  
White Rot ◽  
Symbiotic Association ◽  
Southern South America ◽  
Western Asia ◽  
The Usa

Abstract A. areolatum is a basidiomycete that causes a white rot of a broad range of conifers. Its invasiveness arises from a symbiotic association with woodwasps of the genus Sirex. The species Sirexnoctilio is listed as "highly invasive" on the ISSG/IUCN website (ISSG, 2008) and is a Regulated Pest for the USA (APHIS, 2009a). The wasp and the fungus are native to Europe, North Africa and western Asia where their damage is considered secondary (Spradbery and Kirk, 1978). Introduced to areas of the Southern Hemisphere where exotic pine species are grown in plantations, these organisms have caused major losses. The insect invaded New Zealand by at least 1900, but did not cause serious concern until the 1940s (Talbot, 1977). It later spread to Tasmania and the southern parts of Australia and the wasp/fungus association was introduced into southern South America, beginning in Uruguay in 1980 (Ciesla, 2003). Invasion of South Africa occurred in 1994 (Tribe, 1995). Woodwasps are repeatedly detected in material imported to the USA, but were successfully excluded until 2004 (Wilson et al., 2009). The wasp and fungus were later found in nearby Canada (Ontario), although apparently due to a separate introduction (Bergeron et al., 2008; Wilson et al., 2009). Recent surveys found the wasp in four states of the USA (Evans-Goldner and Bunce, 2009) and 25 counties of Ontario in Canada (Shields, 2009). Schiff (2008) summarizes differences in complexity of the ecological situations in the Southern Hemisphere countries and North America that could affect spread and impact of the fungus and wasp.

Biogeographic congruence in the South Pacific

1991 ◽  
Vol 4 (1) ◽  
pp. 127 ◽  
Author(s):  
O Seberg
Keyword(s):  
New Zealand ◽  
South America ◽  
Southern Hemisphere ◽  
Classical Problem ◽  
Distribution Patterns ◽  
General Area ◽  
Southern South America ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

Ever since J. D. Hooker's famous 'Introductory Essay' to Flora NOVE-Zelandise, a classical problem in biogeography has been to give a casual explanation of southern hemisphere distribution patterns. An attempt is made to see whether the cladograms for the circum-Pacific areas (South America, New Zealand, Tasmania and Australia) are congruent. The area cladograms are derived from Nothofagus (Fagacae), Embothriinae (Protaceae), Oreobolus (Cyperaceae), Cyttaria (Helotiales) and Eriococcidae (Homoptera). The resulting general area cladogram showing southern South America as the sister-area to New Zealand, south-eastern Australia and Tasmania, and Tasmania plus south-eastern Australia as sister-areas to New Zealand are compared with different geological hypotheses for the area. The biological area cladogram is shown to be congruent with widely different geological hypotheses.

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.

Sign in / Sign up

Export Citation Format

Share Document