ORIGINAL ARTICLE
The fossil localities of the Piedra Chamana Fossil Forest (Eocene, Peru): a prospectus for research and conservation
1
Marsh Institute of Clark University, Worcester, MA 01610, USA
2
Department of Biology, Penn State Altoona, Altoona, PA 16601, USA
3
Department of Earth and Environmental Science, Temple University, Philadelphia, PA 19122, USA
4
Center for Tropical Paleontology and Archeology (CTPA), Smithsonian Tropical Research Institute (STRI),
Ancon, Panama City, Panama
5
nstitute of Geosciences, University of São Paulo, Brazil
6
Departamento Académico de suelos, Facultad de Agronomía, Universidad Nacional Pedro Ruiz Gallo,
Lambayeque, Peru
7
Instituto Geológico Minero y Metalúrgico, INGEMMET, Lima, Peru
8
Museo de Historia Natural, Universidad Nacional Mayor San Marcos, Peru
9
National Park Service, Florissant Fossil Beds National Monument (Emeritus volunteer), Florissant,
CO 80816, USA
Submission date: 2025-11-21
Acceptance date: 2025-12-08
Online publication date: 2026-03-06
Publication date: 2026-03-06
HIGHLIGHTS
- The Eocene paleovegetation shows affinities with today’s Amazon forests
- The woods, leaves, and paleosols indicate very warm and highly seasonal conditions
- Multiple fossil sites include in situ forests of exceptional scientific importance
- The in situ trees remain in vertical position after >2000 m of surface uplift
- Conservation of these important fossil localities is urgently needed
KEYWORDS
fossil woods and leavesin situ forestT0 assemblagepaleosolspaleoenvironmentlowland tropical forestfossilforest conservation
ABSTRACT
The fossil plants of the Piedra Chamana Fossil Forest in northern Peru occur in volcaniclastic
rocks of the Huambos Formation dated at 39 Ma (late Middle Eocene). Studies to date have focused on the fossil
leaves and woods in ashfall and overlying ashflow tuffs near the town of Sexi. Additional fossiliferous strata
occur in tuffs and sedimentary deposits over a large area near Sexi and the adjacent community of Cunyac.
These largely unstudied fossil exposures include locations with in situ vertical trees in growth position associated
with paleosols. The paleoflora, dominated by taxa related to lowland Amazonian clades and including a few
Asian components and a mangrove, suggests a seasonally flooded lowland tropical forest and more dry-adapted
interfluvial vegetation growing under warm conditions. Associated paleosols also suggest distinct wet-dry cycles
as they are highly weathered with mottling and show evidence of freshwater influence, landscape heterogeneity,
and intense weathering. At present, the integrity of the fossil sites is compromised by mining, illegal collecting,
and inadequate site protections, all of which have contributed to a significant loss of fossil material. Conservation
and protection of these important paleontological sites and their development as a resource for education
and tourism will benefit both science and the local community.
FUNDING
This work was supported by funding
from the American Philosophical Society (grant to
DWW), the National Science Foundation (grant number
0403510 to DWW and HWM), the National Geographic
Society (grant CP-103R-17 to DWW), a Penn
State Altoona Research Development Grant (to SEA)
and a Francis Velay undergraduate research grant
from Temple University (to JY).
CONFLICT OF INTEREST
The authors
have declared that no competing interests exist.
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