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| Caffapanax canessae Wilf, 2025 |
Abstract
Premise: Araliaceae comprise a moderately diverse, predominantly tropical angiosperm family with a limited fossil record. Gondwanan history of Araliaceae is hypothesized in the literature, but no fossils have previously been reported from the former supercontinent.
Methods: I describe large (to macrophyll size), palmately compound-lobed leaf fossils and an isolated umbellate infructescence from the early Eocene (52 Ma), late-Gondwanan paleorainforest flora at Laguna del Hunco in Argentine Patagonia.
Results: The leaf fossils are assigned to Caffapanax canessae gen. et sp. nov. (Araliaceae). Comparable living species belong to five genera that are primarily distributed from Malesia to South China. The most similar genus is Osmoxylon, which is centered in east Malesia and includes numerous threatened species. The infructescence is assigned to Davidsaralia christophae gen. et sp. nov. (Araliaceae) and is also comparable to Osmoxylon.
Conclusions: The Caffapanax leaves and Davidsaralia infructescence, potentially representing the same source taxon, are the oldest araliaceous macrofossils and provide direct evidence of Gondwanan history in the family. The new fossils and their large leaves enrich the well-established biogeographic and climatic affinities of the fossil assemblage with imperiled Indo-Pacific, everwet tropical rainforests. The fossils most likely represent shrubs or small trees, adding to the rich record of understory vegetation recovered from Laguna del Hunco.
Keywords: Araliaceae, biogeography, fossil rainforests, Laguna del Hunco, leaf architecture, Malesia, Osmoxylon, paleoconservation, Patagonia
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| Caffapanax canessae gen. et sp. nov., holotype, MPEF-Pb 10171a (see Figure 2A for counterpart). Specimen has five primary lobes, including a pair of reflexed basal lobes, a pair of lateral lobes each with one sublobe, and an expanded medial lobe with paired sublobes. Scale bar: 10 cm. |
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| Caffapanax canessae gen. et sp. nov., holotype. (A) MPEF-Pb 10171b (counterpart, see Figure 1 for part). Scale bar: 10 cm. (B) Discovery photo with part and counterpart, Laguna del Hunco quarry LH04, 21 November 2006. |
Family—Araliaceae Juss.
Genus— Caffapanax Wilf gen. nov.
Caffapanax canessae Wilf sp. nov.
Diagnosis—Petiole insertion marginal; base cordate. Blade size microphyll to macrophyll; length:width (L:W) ratio near or below 1:1. Primary veins basally actinodromous, regular, robust. Blade palmately lobed with three or five wide, convex primary lobes; lobe size increases markedly distally. When blade is five-lobed, the basal lobes reflexed, the next lateral lobe pair undivided or with one sublobe per lobe, and the medial lobe much larger than the laterals, with a prominent pair of pinnate sublobes. Margin serrate; teeth short, narrow, non-glandular. Major and minor secondary veins craspedodromous, terminating as tooth principal veins; fimbrial vein present. Higher-order venation well organized; areolation impressed in tiny quadrangular to pentagonal fields; freely ending veinlets absent.
Etymology—The new generic and specific epithets honor Técnicos Mariano Caffa and Leandro Canessa, respectively, of the MEF for their admirable record over more than two decades of fieldwork and fossil discovery in Patagonia. They continue to make significant contributions to paleontology, including the holotype of the new species (Figures 1, 2) unearthed by Téc. Caffa.
Genus—Davidsaralia Wilf gen. nov.
Davidsaralia christophae Wilf sp. nov.
Peter Wilf. 2025. Osmoxylon-like Fossils from early Eocene South America: West Gondwana–Malesia Connections in Araliaceae. American Journal of Botany. 112(6); e70045. DOI: doi.org/10.1002/ajb2.70045 [19 May 2025]
