Biology Reference
In-Depth Information
Figure 5.6
Reconstruction of Weddellia during the Cretaceous and Paleogene. Stippled area
represents continuous coastal environment surrounded by shallow seas. From Hill and Dett-
mann 1996 (see also references therein). Used with permission from Yale University Press,
New Haven, CT.
southern beech). There were emergent lands in the Guiana and Brazilian
shields, the Mato Grosso Plateau, and at scattered sites along the axis of the
proto-Andes Mountains. The rest of South America was mostly swamp-
land periodically inundated by marine incursions through the Maracaibo
and Paraná inlets. High atmospheric CO
2
, warm temperatures, moderate to
high rainfall with little seasonality, continental climates (especially in the
drier interior northern parts), and broad biotic distributions characterized
the continent.
The Cretaceous vegetation of northern South America consisted of
gymnosperm-prominent communities. There are macrofossils of the Arau-
cariaceae, Podocarpaceae, cycadophytes, and
Brachyphyllum
, and microfos-
sils similar to
Ephedra
(Mormon tea) representing plants probably growing
