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Premise of research. The Neogene collision of the Australian tectonic plate (Sahul) with Southeast Asia (Sunda) restructured the vegetation of both regions. The rarity of plant macrofossils from Sunda has limited the understanding of precollision vegetation and plants that migrated from Sunda to Sahul. Despite the importance of legumes in the living flora, no Malesian reproductive or pre-Neogene fossils of the Fabaceae are known. Methodology. We collected 47 plant macrofossils from the Tambak Member of the Tanjung Formation (middle-late Eocene) while surveying the Wahana Baratama coal mine near Satui, South Kalimantan, Indonesian Borneo. These fossils represent Southeast Asian forests before the Sahul-Sunda collision. We studied three isolated large (up to 72 mm in length) seeds from the upper Tambak Member, along with 43 fossil leaves and two palynological samples from the lower Tambak Member. Pivotal results. We describe the extinct legume Jantungspermum gunnellii gen. et sp. nov. The J. gunnellii seeds are flattened on one side, bilobed, and heart shaped with a long hilum (~60 mm) overlain on the suture, closely resembling Castanospermum , the Australian black bean tree. The leaves represent seven morphotypes, which include Fabaceae but are otherwise unidentifiable. One specimen preserves in situ cuticle. The palynoflora includes diverse ferns and palms, Typhaceae, Onagraceae, and forest taxa, including Podocarpaceae, Sapindaceae, and Fabaceae, indicating a largely freshwater coastal swamp environment in the lower Tambak Member. Conclusions. The Jantungspermum seeds are double the length of Castanospermum seeds, representing a closely related but extinct papilionoid taxon. The discovery suggests a Sundan precollision history, a much later Sunda-Sahul migration, and an eventual Asian extinction for the Castanospermum lineage, which today inhabits coastal rainforests of northern Australasia. The seeds represent the only known fossil relative of Castanospermum , the oldest legume fossils from Malesia, and one of the largest fossil angiosperm seeds. The new seeds, leaves, and palynomorphs provide a window into Eocene Malesian vegetation and rare macrofossil evidence of Sundan history for a living Australasian lineage. [ABSTRACT FROM AUTHOR]

Premise of research. Winteraceae, a family within the Canellales, is composed of tropical trees and shrubs broadly distributed in the Southern Hemisphere. The family is found today in eastern Australia, New Zealand, Malesia, Oceania, Madagascar, and the Neotropics across a range of dry to wet tropical to temperate climate regions. The fossil record of woods related to the Winteraceae in the Southern Hemisphere is limited to the Late Cretaceous of the Antarctic Peninsula. Here, we present a detailed anatomical description of the secondary xylem of a well-preserved trunk from the early Eocene Laguna del Hunco site, Huitrera Formation, Patagonia (Chubut Province, Argentina), that is referable to a new species of the genus Winteroxylon (Gottwald) Poole and Francis. Methodology. The wood is preserved as a siliceous permineralization; it was sectioned using standard petrographic techniques and observed under both light and scanning electron microscopy. The anatomy was compared with that of extant and fossil species of Winteraceae. Pivotal results. The diagnostic anatomical features of Winteraceae preserved in the fossil include an absence of growth rings, a lack of vessels, tracheids that are rectangular in cross section with circular bordered pits, diffuse axial parenchyma, rays showing two distinct size ranges (uniseriate-biseriate or multiseriate, 3–15 cells wide), and the presence of heterocellular rays containing sclerotic nests, cells with dark contents, and oil cells. The new fossil species most resembles extant genera within the Zygogynum s.l. clade from Australasian and Malesian rain forests; its anatomy is very similar to that of the extant genus Bubbia. The new Patagonian Winteraceae fossil wood is characterized by the presence of sclerotic nests and oil cells in the rays, which differ from those of previously described species of Winteroxylon. Conclusions. On the basis of the distinctive characters preserved, we erect Winteroxylon oleiferum sp. nov. The new fossil is the first reliable macrofossil record of Winteraceae from South America, supporting the abundant palynological record of the family from the continent, and it is the oldest record of the Zygogynum s.l. clade, adding to the long list of southern biogeographic connections between South America and Australasia via Antarctica during the warm early Cenozoic. [ABSTRACT FROM AUTHOR]

Premise of research. The early Eocene Laguna del Hunco (LH) fossil site, northwestern Chubut Province, Argentina, holds one of the best-preserved and most diverse paleofloras worldwide. The paleoflora comprises ferns, gymnosperms, and flowering plants. Despite the rapidly growing knowledge of its macrofossil record, little is known about the site's palynological content. Herein, we present the first dispersed spore-pollen assemblages recovered from LH. Methodology. Palynological samples were collected from seven stratigraphic levels of the Tufolitas de LH (Huitrera Formation), of which six yielded palynomorphs. We determine the botanical affinities of fossil morphotypes and provide systematic descriptions of some taxa. In addition, we establish similarities between LH and other Patagonian Eocene localities, and we compare palynological and prior megafloral records from LH. Pivotal results. We identify 56 spore and pollen species and 28 plant families, of which eight (Cyatheaceae, Schizaeaceae, Polypodiaceae, Asteraceae, Chloranthaceae, Nothofagaceae, Rubiaceae, and Ulmaceae) are reliably reported from the site for the first time. Among other Eocene Patagonian palynofloras, the LH assemblage is similar to Pampa de Jones/Nahuel Huapi Este and Confluencia. Conclusions. The LH spore-pollen assemblages augment the plant fossil record for this significant Eocene locality by incorporating new taxa (e.g., Asteraceae, with one morphotype that represents the oldest record of the family in Patagonia). The new data also reinforce the presence of plant families previously reported from macrofossils, such as Juglandaceae, with pollen grains similar to those of the Engelhardia-Alfaroa group, and Fagaceae (Castaneoideae), complementing the macrofossil record of leaves and reproductive structures. [ABSTRACT FROM AUTHOR]