Create your own conference schedule! Click here for full instructions

The Virtual Conference is located at

Abstract Detail


Allen, Sarah E. [1], Martin, Kelly D. [2], Meyer, Herbert W. [3], Woodcock, Deborah [4].

An Eocene leaf flora from the northern Peruvian Andes.

The village of Sexi in the Cajamarca region of northern Peru is footsteps away from an impressive fossil forest known as El Bosque Petrificado Piedra Chamana. The mineralized forest was deposited in a lahar or pyroclastic flow, and ashfall deposits, 39 million years ago (late Middle Eocene). It has been under study for the past two decades and includes both dicotyledonous angiosperms and palms. To date, over 30 species have been described from the fossil wood which is densely embedded in rock outcrops, scattered across the ground, and occasionally found in situ. Anatomical characteristics of the woods suggest a wet, seasonal lowland forest with a dry period.
In addition to the dendroflora, a small collection of angiosperm fossil leaves was recovered from the ashfall deposit in 2005 and 2007. These remained in their field wrappings until they were curated in 2019 at the Museo de Historia Natural in Lima, Peru. This was coupled with high resolution photographs of each specimen to facilitate more comprehensive remote study. Previously, the majority of the specimens were only documented with low resolution field photographs.  
The leaves are being reexamined and described in detail using standard leaf architecture terminology to build off earlier analyses using the field photographs. Preliminary investigation has revealed approximately 20 dicotyledonous leaf morphotypes. Most of the leaves are incomplete, but when the margin is preserved, it is untoothed. The lack of teeth indicates a warm, tropical climate. The presence of around 20 species suggests high diversity based on having only ~210 dicotyledonous leaf specimens. The leaf collection also includes ~10 monocot specimens. Although the number of specimens is low, the diversity will be examined and compared to other floras using rarefaction.
The leaves can also be used to estimate temperature and precipitation using leaf physiognomic approaches. Finally, leaf morphotypes with tentative taxonomic identifications can be compared to the wood flora in the future even though correlation of leaf taxa with wood taxa is problematic. Wood of Avicennia (a mangrove in Acanthaceae) has been reported, and the most common leaf morphotype has characters that are consistent with that genus.

Log in to add this item to your schedule

1 - Penn State Altoona, Biology, 206 Hawthorn, 3000 Ivyside Park, Altoona, PA, 16601, USA
2 - Penn State Altoona, 3000 Ivyside Park, Altoona, PA, 16601, USA
3 - U.S. National Park Service, Florissant Fossil Beds National Monument, PO Box 185, Florissant, CO, 80816, USA
4 - Clark University , George Perkins Marsh Institute, 950 Main Street, Worchester, MA, 01610, USA

Leaf Architecture
Fossil Leaves

Presentation Type: Poster
Session: P3, Paleobotany Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3PB005
Abstract ID:852
Candidate for Awards:None

Copyright © 2000-2021, Botanical Society of America. All rights reserved