INVESTIGADORES
ESCAPA Ignacio Hernan
congresos y reuniones científicas
Título:
Triassic Floras of Antarctica: Paleobiology and paleoecology of polar latitude communities
Autor/es:
ESCAPA, IGNACIO; DECOMBEIX, ANNE-LAURE; RYBERG, PATRICIA; SCHWENDEMANN, ANDREW; SERBET, RUDOLPH; TAYLOR, EDITH L.; TAYLOR, THOMAS N.
Lugar:
Portland, USA
Reunión:
Congreso; Geological Society of America Annual Meeting; 2009
Institución organizadora:
Geological Society of America
Resumen:
We present a synthesis of research conducted during the last 20
years on fossils collected in MiddleLate Triassic formations of the
Beardmore Glacier area, Central Transantarctic Mountains, Antarctica.
The presence of both compressed/impressed and permineralized specimens
allows the detailed description of individual organs (e.g., leaves,
seeds, roots, etc.) as well as the reconstruction of a whole organism
concept for several Antarctic taxa. This last concept represents an
essential tool for a deeper understanding of the paleobiology of
high-latitude plants, the paleoecology of the ecosystems, and the
phylogenetic relationships of Triassic plants.
In general terms,
the highly diverse floras include lycopsids, sphenopsids, ferns, and
gymnosperms. The ferns are particularly diverse, including the families
Gleicheniaceae, Matoniaceae, Osmundaceae, Marattiaceae, Cyatheaceae
(?), and other enigmatic forms. The gymnosperms also show an
interesting diversity and are represented by cycads, seed ferns, and
conifers. Recent data show the presence of ginkgoaleans, a group
previously unknown in early Mesozoic Antarctic communities, a new type
of enigmatic ovule, and a voltzian pollen cone with in situ pollen. In
addition, anatomically preserved material, including trunks, leaves,
roots, and pollen cones, has provided one of the most complete
reconstructions of a fossil cycad in the world. The possibility of
reconstructing complete organisms represents a considerable advancement
in the resolution of evolutionary relationships in Triassic plants, and
provides important data on the adaptations of these plants to polar
latitudes.Anatomically preserved specimens found in
permineralized peat provide exceptional data on the ecology of these
plants, including their interactions with microorganisms and
arthropods, and ephemeral stages of the life history of some of the
seed plants, such as embryo development. These remarkably
well-preserved and diverse taphofloras, including well-preserved fossil
tree rings, provide a unique opportunity to understand the functioning
of ecosystems in a strongly seasonal, high-latitude environment that
has no modern equivalent.