Fossil Leaves of Meliosma (Sabiaceae) With Associated Pollen and a Eupodid Mite From the Eocene of Maoming Basin, South China

A first occurrence of the genus Meliosma (Sabiaceae) is reported from the upper Eocene of the Maoming Basin of South China. This fossil is one of the oldest reliable records of the genus within its modern center of diversity. Fossil leaves are assigned to a new species, Meliosma eosinica sp. nov. based on leaf morphology and epidermal characters. The leaf epidermal anatomy of fossil Meliosma is illustrated for the first time. We also provide the first SEM observation of pollen grains associated with Meliosma. This study also documents an occurrence of mites within the leaf domatia previously unknown from the fossil record. We presume that the studied mite belongs to the superfamily Eupodoidea (Arthropoda), and probably the family Eupodidae, which comprises very small soft-bodied cosmopolitan mites occupying a wide range of terrestrial habitats. Additionally, we analyze the damage types on the fossil leaves of Meliosma. They exhibit exclusively external foliage feeding damage caused by arthropods and traces of probable fungal infection. A review of currently known fossil occurrences of leaves, fruits, and wood of Meliosma provides evidence for the geological and geographical distribution of the genus.

An image dataset of cleared, x-rayed, and fossil leaves vetted to plant family for human and machine learning

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.

Studies in New Zealand Oligocene and Miocene Plant Macrofossils

<p>Assemblages of fossil leaves ranging in age from Upper Oligocene to Upper Miocene or Lower Pliocene have been examined from localities in Southland, Central Otago, the Dunedin area, the Buller region and Great Barrier Island. Nearly 200 form taxa have been recognized so far; of these 52 are figured and described and the remainder are included in an illustrated catalogue. Conifers, Casuarinaceae and Nothofagus spp. are discussed in detail. Thirteen new species are named and described: Gleichenia southlandica, Hypolepis maruiensis, Blechnum maruiense, Dacrydium (Lagarostrobos) franklinoides, Microcachrys imbricata, Phyllocladus strictus, Libocedrus compressa, Nothofagus southlandica, Gymnostoma stellata, Gymnostoma crassa, Casuarina avenacea, Metrosideros diffusoides and ? Eucalyptus roxburghiensis. Six new species are described but not named as more detailed study is still proceeding. A further ten new form taxa are identified to genus level only. The fossil flora from the Kaikorai Valley, Dunedin, originally described by Oliver (1936) is revised and Blechnum proceroides, Nothofagus pinnata, N. australis, N. kaikoraiensis and Ripogonum latipetiolatum are new names arising from this revision. The fossil assemblages from Southland and Central Otago are derived from heath, swamp and forest communities developed on an early to mid Tertiary peneplain. In contrast the fossil floras of the Buller region reflect predominantly forest vegetation developed on young soils of a prograding coastal floodplain backed by rapidly rising fault block ranges, while the fossil floras of Dunedin and Great Barrier Island reflect vegetation periodically affected by volcanic activity. Late Oligocene and Miocene climates throughout New Zealand appear to have been humid and at least as warn as Auckland today, although conditions on the east coast of the South Island may have been cooler and drier than on the west. The sediment containing the Landslip Hill fossil flora is interpreted as a silcrete and resembles similar deposits in Australia. The uncompressed state of the fossils and the preservation of turgid cell structures indicates early silica cementation in a surface or near-surface environment, probably as a result of direct precipitation of silica from ground water. The present-day New Zealand flora appears to be derived in part from the late Cretaceous flora of coastal eastern Gondwanaland. Other south-west Pacific floras may stare a similar origin, and may also have contributed to the New Zealand flora following fragmentation of the continental margin. The distribution of New Zealand Tertiary plants, as far as it is known, is consistent with my inferred paleogeography.</p>

Studies in New Zealand Oligocene and Miocene Plant Macrofossils

<p>Assemblages of fossil leaves ranging in age from Upper Oligocene to Upper Miocene or Lower Pliocene have been examined from localities in Southland, Central Otago, the Dunedin area, the Buller region and Great Barrier Island. Nearly 200 form taxa have been recognized so far; of these 52 are figured and described and the remainder are included in an illustrated catalogue. Conifers, Casuarinaceae and Nothofagus spp. are discussed in detail. Thirteen new species are named and described: Gleichenia southlandica, Hypolepis maruiensis, Blechnum maruiense, Dacrydium (Lagarostrobos) franklinoides, Microcachrys imbricata, Phyllocladus strictus, Libocedrus compressa, Nothofagus southlandica, Gymnostoma stellata, Gymnostoma crassa, Casuarina avenacea, Metrosideros diffusoides and ? Eucalyptus roxburghiensis. Six new species are described but not named as more detailed study is still proceeding. A further ten new form taxa are identified to genus level only. The fossil flora from the Kaikorai Valley, Dunedin, originally described by Oliver (1936) is revised and Blechnum proceroides, Nothofagus pinnata, N. australis, N. kaikoraiensis and Ripogonum latipetiolatum are new names arising from this revision. The fossil assemblages from Southland and Central Otago are derived from heath, swamp and forest communities developed on an early to mid Tertiary peneplain. In contrast the fossil floras of the Buller region reflect predominantly forest vegetation developed on young soils of a prograding coastal floodplain backed by rapidly rising fault block ranges, while the fossil floras of Dunedin and Great Barrier Island reflect vegetation periodically affected by volcanic activity. Late Oligocene and Miocene climates throughout New Zealand appear to have been humid and at least as warn as Auckland today, although conditions on the east coast of the South Island may have been cooler and drier than on the west. The sediment containing the Landslip Hill fossil flora is interpreted as a silcrete and resembles similar deposits in Australia. The uncompressed state of the fossils and the preservation of turgid cell structures indicates early silica cementation in a surface or near-surface environment, probably as a result of direct precipitation of silica from ground water. The present-day New Zealand flora appears to be derived in part from the late Cretaceous flora of coastal eastern Gondwanaland. Other south-west Pacific floras may stare a similar origin, and may also have contributed to the New Zealand flora following fragmentation of the continental margin. The distribution of New Zealand Tertiary plants, as far as it is known, is consistent with my inferred paleogeography.</p>

Fossil Alloceltidoxylon, Allonymphaea, Arecocaryon, Paralnoxylon and Paranyssa and extant Komaroviopsis, Marcanodendron, and Papyrocactus (Magnoliophyta), new replacement generic names

Eight new generic replacement names were validated. The new fossil wood generic name Alloceltidoxylon is validated to replace later homonym, Scottoxylon Wheeler & Manchester (non Scotoxylon Vogellehner). The new fossil generic name Allonymphaea is proposed to replace later homonym, Thiebaudia M. Chandler (non Thiebautia Colla nec Thibaudia Ruiz et Pavon ex Jaume St.-Hilaire), based on leaf remains. The new fossil generic name Arecocaryon, based on fruit remains, is proposed to replace the later homonym Friedemannia M.E. Collinson, Manchester& V. Wilde (non Friedmannia Chantanachat & Bold, Algae). The new fossil wood generic name Paralnoxylon is validated to replace later homonym, Cantia Stopes (non Kantia Pia). The new fossil generic name Paranyssa, based on fossil leaves, is validated to replace later homonym, Browniea Manchester & Hickey (non Brownea Jacquin). Three new generic names for extant flowering plants were validated: Komaroviopsis replaces Komarovia Korovin (non Komaroffia O. Kuntze) and Komaroviopsideae trib. nov. replaced invalid Komarovieae, Marcanodendron instead of Uladendron Marcano-Berti (non fossil Ulodendron Lindley & Hutton) and Papyrocactus replaces Toumeya Britton & Rose (non Tuomeya W.H. Harvey, Algae). The new combinations Alloceltidoxylon eocenicum, Allonymphaea rayaniensis, Arecocaryon messelense, Paralnoxylon arborescens, Paranyssa serrata, Komaroviopsis anisosperma, Marcanodendron codesuri, and Papyrocactus papyracanthus are proposed. Alloceltidoxylon, Allonymphaea, Arecocaryon, Komaroviopsis, Marcanodendron, Paralnoxylon, Paranyssa, Papyrocactus, new replacement generic names, Komaroviopsideae trib. nov.

Geometric and topological approaches to shape variation in Ginkgo leaves

Leaf shape is a key plant trait that varies enormously. The range of applications for data on this trait requires frequent methodological development so that researchers have an up-to-date toolkit with which to quantify leaf shape. We generated a dataset of 468 leaves produced by Ginkgo biloba , and 24 fossil leaves produced by evolutionary relatives of extant Ginkgo . We quantified the shape of each leaf by developing a geometric method based on elastic curves and a topological method based on persistent homology. Our geometric method indicates that shape variation in modern leaves is dominated by leaf size, furrow depth and the angle of the two lobes at the leaf base that is also related to leaf width. Our topological method indicates that shape variation in modern leaves is dominated by leaf size and furrow depth. We have applied both methods to modern and fossil material: the methods are complementary, identifying similar primary patterns of variation, but also revealing different aspects of morphological variation. Our topological approach distinguishes long-shoot leaves from short-shoot leaves, both methods indicate that leaf shape influences or is at least related to leaf area, and both could be applied in palaeoclimatic and evolutionary studies of leaf shape.