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Leaves are the most abundant and visible plant organ, both in the modern world and the fossil record. Identifying foliage to the correct plant family based on leaf architecture is a fundamental botanical skill that is also critical for isolated fossil leaves, which often, especially in the Cenozoic, represent extinct genera and species from extant families. Resources focused on leaf identification are remarkably scarce; however, the situation has improved due to the recent proliferation of digitized herbarium material, live-plant identification applications, and online collections of cleared and fossil leaf images. Nevertheless, the need remains for a specialized image dataset for comparative leaf architecture. We address this gap by assembling an open-access database of 30,252 images of vouchered leaf specimens vetted to family level, primarily of angiosperms, including 26,176 images of cleared and x-rayed leaves representing 354 families and 4,076 of fossil leaves from 48 families. The images maintain original resolution, have user-friendly filenames, and are vetted using APG and modern paleobotanical standards. The cleared and x-rayed leaves include the Jack A. Wolfe and Leo J. Hickey contributions to the National Cleared Leaf Collection and a collection of high-resolution scanned x-ray negatives, housed in the Division of Paleobotany, Department of Paleobiology, Smithsonian National Museum of Natural History, Washington D.C.; and the Daniel I. Axelrod Cleared Leaf Collection, housed at the University of California Museum of Paleontology, Berkeley. The fossil images include a sampling of Late Cretaceous to Eocene paleobotanical sites from the Western Hemisphere held at numerous institutions, especially from Florissant Fossil Beds National Monument (late Eocene, Colorado), as well as several other localities from the Late Cretaceous to Eocene of the Western USA and the early Paleogene of Colombia and southern Argentina. The dataset facilitates new research and education opportunities in paleobotany, comparative leaf architecture, systematics, and machine learning.
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Putative Celtis Leaves from Eocene Patagonia are Allied with Asian Anacardiaceae
The most common macrofossils in the highly diverse flora from Laguna del Hunco (early Eocene of Chubut, Argentina) are “Celtis” ameghinoi leaves, whose true affinities have remained enigmatic for a century. The species accounts for 14% of all plant fossils in unbiased field counts and bears diverse insect-feeding damage, suggesting high biomass and paleoecological importance. The leaves have well-preserved architecture but lack cuticles or reproductive attachments. We find that the fossils only superficially resemble Celtis and comparable taxa in Cannabaceae, Ulmaceae, Rhamnaceae, Malvaceae, and many other families. However, the distinctive foliar morphology conforms in detail to Dobinea (Anacardiaceae), a genus with two species of shrubs and large herbs ranging from India’s Far East and Tibet to Myanmar and central China, and we propose Dobineaites ameghinoi (E.W. Berry) gen et. comb. nov. for the fossils. This discovery strengthens the extensive biogeographic links between Eocene Patagonia and mainland Asia, provides the first fossil record related to Dobinea, and represents a rare Gondwanan macrofossil occurrence of Anacardiaceae, which was widespread and diversified in the Northern Hemisphere at the time. The diverse leaf architecture of Anacardiaceae includes several patterns usually associated with other taxa, and many other leaf fossils in this family may remain misidentified.
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- PAR ID:
- 10508956
- Publisher / Repository:
- Asociación Paleontológica Argentina
- Date Published:
- Journal Name:
- Ameghiniana
- Volume:
- 61
- Issue:
- 2
- ISSN:
- 0002-7014
- Page Range / eLocation ID:
- 73-92
- Subject(s) / Keyword(s):
- Anacardiaceae Argentina Chinese flora Dobinea Gondwana Herbivory Laguna del Hunco Leaf architecture
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5710/AMGH.21.02.2024.3586
