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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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This content will become publicly available on March 25, 2027
Sindora Leaflets from the Early Pleistocene Kon Tum Flora of Central Vietnam
Premise of research. Fabaceae fossil leaf records are abundant, but their identification within the family is challenging because of the lack of distinctive leaf architecture in many genera. Sindora (Fabaceae, Detarioideae, Detarieae) is a genus of paleotropical trees distributed mainly in Southeast Asia. Previous macrofossil records are limited to questionable leaves and woods. We report fossil leaflets with diagnostic characters of Sindora in a newly discovered early Pleistocene flora from Kon Tum, central Vietnam. Methodology. We collected 37 fossil fabaceous leaflets from the Kon Tum Formation at the Hung Phat site in Kon Tum City, Quang Ngai Province, Central Highlands region of Vietnam. Leaf architecture was compared with extant species by consulting digitized herbarium collections and the literature. Pivotal results. Diagnostic characters of the fossil leaflets include the pulvinulate petiolule, retuse to emarginate apex, wavy margin, convex to cuneate base, curved midvein, craspedodromous or semicraspedodromous secondary venation, and subapical midvein gland. The geologically recent age, morphological similarity, and overlapping extant and fossil distributions with extant S. siamensis all support assignment to Sindora cf. S. siamensis. Conclusions. The new specimens represent the first unequivocal macrofossil record for Sindora, confirming the genus’s presence in Indochinese forests by the early Pleistocene. As the first deciduous taxon recognized in the Kon Tum flora, the Sindora cf. S. siamensis occurrence supports a monsoonal regional climate, as found today. The contrast between the fossil abundance and current endangered status of S. siamensis in Vietnam provides paleobotanical insights for conservation planning.
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- Award ID(s):
- 1925755
- PAR ID:
- 10681069
- Publisher / Repository:
- University of Chicago Press
- Date Published:
- Journal Name:
- International Journal of Plant Sciences
- Volume:
- 187
- Issue:
- 3
- ISSN:
- 1058-5893
- Page Range / eLocation ID:
- 217-228
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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