Abstract Detail

Paleobotanical Section

Salinas, Fabiola Estrada [1], Calvillo-Canadell, Laura [2], Cevallos-Ferriz, Sergio [3].

Phyllanthaceae and Euphorbia (Euphorbiaceae) leaves from the Oligocene Los Ahuehuetes locality, Tepexi de Rodríguez, Puebla, Mexico.

The study of fossil plants collected in Mexico has added confidence to the hypothesis discussing the origin of its vegetation. Leaf architecture has been an unsustituble tool to identify of the fossil leaf material. In the Oligocene Los Ahuehuetes locality, Tepexi of Rodriguez, Puebla, members of Anacardiaceae, Berberidaceae, Leguminosae, Rosaceae and Salicaceae, among others, have been discussed. Here we add the description and identification of two impression/compressions fossil leaf types. Characteristics of the fossil material were compared with previuosly described leaves of Euphorbiaceae, cleared material facilitated by MEXU, and the digital herbaria of Kew Royal Botanic Gardens and Aluka. Terminology follows the Manual of Leaf Architecture. The first one has a microphyllous asymmetric leaf with ovate lamina and entire margin, convex apex, truncated and concave-convex base, petiole with marginal attachment, pinnate first order venation, broquidodromous second order venation, mixed percurrent third order venation, opposite percurrente fourth order venation, and regular reticulated fifth-order venation. Other characteristics include a pair of basal veins, and simple agrophic veins. All these features are found in Phyllanthaceae. The second leaf type is microphyllous and symmetrical lamina, has toothed margin in the distal region, and tooth are straight/concave or concave/concave, venation is parallel, and at ca.50% of the lamina length a primary vein changes its course towards the teeth. Leaf morphology and venation pattern resembles that of Euphorbia epiphylloides. Leaf architecture of the second fossil plant suggest that extant member of Euphorbia restricted today to India who had in the Paleogene a greater distribution area.

Broader Impacts:

1 - Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Copilco El Alto, Coyoacan, México D.F, 04510, México
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

Keywords:
Phyllanthaceae
Euphorbiaceae
Oligocene
Tepexi de Rodríguez, Puebla
Leaves.

Presentation Type: Oral Paper:Papers for Sections
Session: 3
Location: Melrose/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 10:30 AM
Number: 3009
Abstract ID:699
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award