Three early plant taphonomy experiments (1833-1836)

Between 1833 and 1836 in England, then in Prussia and finally in France, young botanists experimented with making plant fossils to understand better how such fossils could be formed and how to interpret fossil assemblages. These experiments are described and discussed. Despite these promising beginnings, plant taphonomy was not really developed as a science until much later.

From Patagonia to Indonesia: plant fossils highlight West Gondwanan legacy in the Malesian flora

Rainforests with the chinquapin Castanopsis and the yellowwood conifer Dacrycarpus occur today throughout Indonesia and the larger Malesian ecoregion, but they represent, in part, a history of survival stretching tens of millions of years and thousands of kilometers to the palaeo-Antarctic. Unlike New World and African tropical rainforests, the Malesian flora’s history is closely tied to tectonic introductions from exotic terranes, and thus, much palaeobotanical data about the origins of the Malesian rainforest comes from those terranes. For example, South America, Antarctica, and Australia remained adjacent until the Eocene final separation of Gondwana, and warm climates promoted high-latitude dispersals among those landmasses. Australia’s subsequent northward movement led to the late Oligocene Sahul-Sunda collision and the uplift of New Guinea, allowing the introductions into Malesia of survivor taxa that were once widespread in mesic Gondwanan rainforests. In Patagonian Argentina, the prolific Laguna del Hunco (52.2 Ma) site preserves abundant and well-preserved fossils of an unexpectedly large number of lineages whose living relatives characteristically associate in perhumid, lower montane “oak-laurel” rainforests of Malesia, especially in New Guinea. These taxa include the angiosperms Castanopsis (Fagaceae), Gymnostoma (rhu, Casuarinaceae), Alatonucula (extinct engelhardioid Juglandaceae), Eucalyptus (gums, Myrtaceae), Ceratopetalum (coachwood, Cunoniaceae), Lauraceae (laurel family), and Ripogonum (supplejack, Ripogonaceae); conifers in Cupressaceae (cypress family: Papuacedrus), Araucariaceae (dammars and relatives: Agathis and Araucaria Section Eutacta), and Podocarpaceae (yellowwoods: Dacrycarpus, Podocarpus, and a species similar to Phyllocladus); and the fern Todea (king fern, Osmundaceae). Many of these records are the only occurrences of the respective taxa in South America, living or fossil, vastly extending their past ranges and thus the biogeographic history of part of the Malesian mountain flora. The living-fossil taxa inhabit, and several dominate, critical watershed areas of high endemism and biodiversity in Malesia’s endangered tropical-montane rainforests. In Malesia itself, there have been very few Cenozoic palaeobotanical investigations for about a century or more. To remedy this situation and improve understanding of the evolution of the Malesian flora in situ, we have begun palaeobotanical fieldwork in collaboration with Professor Yahdi Zaim and ITB, along with international colleagues. So far, we have discovered several promising new fossil sites in the Eocene-Oligocene of West Sumatra (Sangkarewang and Sawahlunto formations) and South Kalimantan (Tanjung Formation), and I will report preliminary observations.

A Jurassic flower bud from the Jurassic of China

Angiosperms may be distinguished from their gymnosperm peers by their flowers, and thus a flower is a good proxy of fossil angiosperms. However, flowers and their parts are usually too frail to be preserved in the fossil record. This makes the origin of angiosperms and their flowers the foci of controversy in botany. Eliminating such botanical controversies can only be achieved by studying related plant fossils. Applying routine SEM, LM, and MicroCT technologies, we document a fossil flower bud, Florigerminis jurassica gen. et sp. nov., from the Jurassic of Inner Mongolia, China. This fossil includes not only a leafy shoot but also physically connected fruit and flower bud. The developmentally interpolated existence of a blooming flower between the flower bud and mature fruit in Florigerminis suggests that angiosperm flowers were present in the Jurassic, in agreement with recent botanical progress. Florigerminis jurassica underscores the presence of angiosperms in the Jurassic and demands a re-thinking on angiosperm evolution.

First Fossil Fokienia (Cupressaceae) in South China and Its Palaeogeographic and Palaeoecological Implications

Fokienia A. Henry & H. H. Thomas is a monotypic genus of the Cupressoideae Rich. ex Sweet (Cupressaceae), native to subtropical evergreen mesophytic forests in South China, northern Laos and Vietnam. The fossil record of Fokienia is very scanty, with only one known occurrence of foliage in the Oligocene of Longjing, Jilin, China. Here we report the fossil foliage of Fokienia discovered in the Miocene Erzitang Formation of the Guiping Basin, South China, which is similar to that of the only extant species Fokienia hodginsii in both macromorphological and epidermal features. This species is the earliest fossil record within the modern distribution area of Fokienia and the only fossil species for which morphology and anatomy have been studied in detail. Fossil evidence suggests that the genus Fokienia was present at middle latitudes of the Northern Hemisphere in the Oligocene and spread to South China during the Miocene. Due to physiological adaptations to warm-wet environments and weak cold tolerance, Fokienia migrated southward, as global climate cooling gradually drove it to extinction in the mid-latitudes. The ecological niche of the extant species, and co-existing plant fossils, suggest that the fossil assemblage represents the remains of an evergreen broad-leaved and conifer mixed forest growing under humid and warm Miocene climate.

The opposite poles of a debate - lapides figurati and the Accademia dei Lincei

The essay analyses the research carried out by some members of the Accademia dei Lincei on lapides figurati, namely by Fabio Colonna on animal fossils, and by Federico Cesi and Francesco Stelluti on plant fossils; the aim is to show the role played by the Accademia dei Lincei in establishing during the second half of the seventeenth century the opposite poles of the debate on the lapides figurati, on the one hand as chronological indices of a past world and, on the other, as sudden outcome of the vis vegetativa.

First record of late Campanian paleoceanographic and paleoclimatic changes, Arabian Platform, Mazidag-Mardin area, SE Turkey

The sedimentology, geochemistry and paleontology of the pelagic upper Campanian Maastrichtian Bozova Formation in the "Mazidag" (Mazıdağı) - Mardin area, SE Turkey, reveal paleoceanographic and paleoecological changes for the first time. A 119.25 m-thick composite stratigraphic section is characterized by alternating marls, clayey limestones, shales, and black shales; no coarse siliciclastic admixture or turbidite intercalations were recorded in the section. Biostratigraphic data indicate the presence of the Radotruncana calcarata Zone, and the UC15de/UC16 nannofossil zones. Stable isotope and elemental geochemical analyses have been carried out in the studied section. The isotope curves display similar patterns compared to reference curves from European and Chinese basins in the same interval. The prominent negative carbon isotope excursion determined in the upper interval can be correlated with the Late Campanian Event. Proxy elements display generally two relative rising trends in productivity from the lower part and the middle part of the succession. The lower part of the section records relatively more dysoxic/anoxic conditions and coincides with common black shale beds. The presence of both diverse planktonic foraminifera and calcareous nannofossils in the studied interval indicates a fully marine, warm-water, low-latitude Tethysian oceanic environment. In addition, the plant fossils derived from the nearby land mass indicate that a tropical humid climate was similar to that in northeast Australia. Therefore, warm water, tropical humid atmospheric conditions developed in the studied area causing the rise in productivity, precipitation and transportation of plant debris into offshore environments.

Paleoaltitudinal histories for the northern and southern margins of the Tibetan Plateau during the Late Cenozoic: revealed by GDGTs

<p>As an important driver of global climate change during the Cenozoic, the uplift of the Tibetan Plateau (TP) has strongly influenced the origination and evolution of the Asian monsoon system, and therefore the aridification of central Asia. Over the last two decades, the application of stable isotope paleoaltimeters and the discoveries of mammal and plant fossils have greatly promoted the understanding of the uplift history of the TP. However, paleoaltitudinal reconstructions based on different paleoaltimeters have suggested differing outcomes and therefore remain controversial. Novel paleoaltimeters have therefore needed to be developed and applied to constrain the uplift history of the TP more accurately and effectively by comparing and verifying multi-proxies. Paleothermometers based on glyceryl dialkyl glycerol tetraethers (GDGTs) are widely used in terrestrial and ocean temperature reconstructions. In this study, GDGT-based paleothermometers were tentatively applied to the Gyirong Basin on the southern TP, and the Xining Basins on the northern TP, in an attempt to quantitatively reconstruct their paleoaltitudes.</p><p>Both soil and aquatic-typed branched GDGTs have been identified from Late Miocene to Mid-Pliocene (7.0-3.2 Ma) samples taken from the Gyirong Basin; their reconstructed paleotemperatures were 7.5±3.3°C and 14.2±4.5°C, respectively. The former temperature may represent the mean temperature of the terrestrial organic matter input area, while the latter may represent the lake surface temperature. The results would suggest that the lake surface of the Gyirong Basin during the Late Miocene to Mid-Pliocene was 2.5±0.8 km and that the surrounding mountains exceeded 3.6±0.6 km, implying that the central Himalayas underwent a rapid uplift of ~1.5 km after the Mid-Pliocene.</p><p>GDGT-based paleotemperature reconstructions using MBT'<sub>5ME</sub> values show that the Xining Basin dropped in temperature by ~10°C during the ~10.5-8 Ma period, exceeding that in sea surface temperatures and low-altitude terrestrial temperatures during these periods. By combining these results with contemporaneous tectonic and sedimentary records, we infer that these cooling events signaled the regional uplift with the amplitude of ~1 km of the Xining basins. Our results support that the TP was still growing and uplifting substantially since the Late Miocene, which may provide new evidence for understanding the growth, expansion and uplift patterns of the TP.</p>

Naming of parts: the use of fossil-taxa in palaeobotany

Fossil plants are extinct plants whose remains (referred to as plant fossils) are found preserved in sedimentary deposits. Plant fossils are classified using fossil-taxa as defined in the International Code of Nomenclature. Fossil-taxa differ conceptually from taxa of living plants in that they often do not refer to whole organisms, but to the remains of one or more parts of the parent organism, in one or more preservational states. There can be complications when two parts of a plant are shown to be connected, or when two preservational states are correlated, and to avoid disrupting the wider palaeobotanical taxonomy it is often best to keep the fossil-taxa separate. Extinct fossil plants reconstructed by piecing together the plant fossils are best not given formal Linnean taxonomic names. There can also be problems using living plant taxa for fossils, even when there is a close morphological similarity of particular plant parts. Fossil-taxa for different plant parts can reflect different taxonomic ranks of the parent plants so care must be taken when using such taxa in floristic or phylogenetic studies. Because of taphonomic factors, a number of “artificial” fossil-taxa have proved useful, despite that they do not fully reflect the systematic positions of the parent plants.