Hernández Villalva, Denise Viridiana , Calvillo-Canadell, Laura , Cevallos-Ferriz, Sergio , López-Gómez, Victor .
Paleoclimatic inference of the Miocene Ixtapa Formation, Chiapas, through leaf physiognomy.
The relationship between modern vegetation and climate is a good paleoclimatic proxy based on biological actualism. Different plant organs have a specific morphology that represent responses to environmental requirements. In plants, the leaf is one of the most susceptible organs responding to the environment requirements. Recent studies indicate a strong correlation between climate, genes and phenotype, reflected in the lamina physiognomy, and variously represented in the Miocene flora of Ixtapa, Chiapas. The aim of this study is to determine environmental parameter sunder which this flora developed as defined on the analysis of 120 different morphotypes. These were analyzed and studied with the CLAMP program methodology, and were compared to the flora of 173 sites mainly located in the North Hemisphere. The study suggests that Ixtapa,Chiapas, during the Middle Miocene (12.5 to 15.2 million years ago) had a semi-cold wet weather. Comparing this result with current climates described for Mexico, one would expect that a cloud forest vegetation grew in the region.Among the 120 morphotypes recognized, two types have been related to Burseraceae and Sapindaceae, which may be part of part of the cloud forest vegetation. However, the predominant characteristics of fossil leaves, yet unidentified,includes features such as mesophyll size, entire margin, unlobed lamina, and acute apex, which suggests they represent a seasonal tropical vegetation type,with alternating wet and dry periods. The apparent controversy of the climate analysis vs. ecomorphological observations represent an opportunity to expand ideas on the relationship of the sceneries as vegetation selectors, suggesting that the floristic diversity of Chiapas is the result of climatic variations related to heterogeneous physiography in the state, both, now and in the past.
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1 - Universidad Autónoma De México, Paleobotany, Ciudad Universitaria, México, D. F, Distrito Federal, N/A, 04510, Mexico
2 - Instituto De Geología, UNAM, Circuito De La Investigación, Ciudad Universitaria, Coyoacan, N/A, 04510, Mexico
3 - Instituto De Geología, UNAM, Department Of Palentology, Ciudad Univwersitaria, Coyoacan, MEXICO D.F., N/A, 01900, Mexico
4 - Facultad de Ciencias, UNAM, Biología, Ciudad Universitaria, Coyoacan, México D.F., 04510
Presentation Type: Oral Paper:Papers for Sections
Location: Union A/Hyatt
Date: Tuesday, July 10th, 2012
Time: 10:30 AM