| 1. |
- Adroit, Benjamin, et al.
(författare)
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Are morphological characteristics of Parrotia (Hamamelidaceae) pollen species diagnostic?
- 2022
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Ingår i: Review of Palaeobotany and Palynology. - Amsterdam : Elsevier BV. - 0034-6667 .- 1879-0615. ; 307, s. 104776-104776
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Tidskriftsartikel (refereegranskat)abstract
- Parrotia persica is one of the most notable endemic relict tree species growing in the Hyrcanian forest at the southern Caspian Sea. The recent discovery of sibling species Parrotia subaequalis, occurring in the temperate forests of south-eastern China, offers the opportunity to compare their morphology and ecological preferences and to dig deeper into the paleophytogeographic history of the genus from a perspective. Since pollen morphology of these species would be essential to unravel the origin and evolution of these Arcto-Tertiary species, the present study aimed to investigate whether it is possible to segregate pollen from these two species. Therefore, a detailed combined light- and scanning electron microscopy-based pollen-analysis of each taxon was conducted, the pollen was described, measured, and compared using statistical approaches and principal component analyses to establish unbiased results. The correlation-based principal component analysis achieved for each species shows an overall good superposition of pollen grains measured in equatorial and polar views in the first principal plane, revealing that the P. persica pollen is morphometrically as homogeneous as that of P. subaequalis. Then, the significant difference, mainly driven by lumen density, has been highlighted between the two species. Ultimately, the cross-validation of the resulting two-species linear discriminants classifier shows that based upon this reference dataset, (sub)fossil pollen grain can now be confidently assigned to either of the two species with an 85.8% correct-assignment rate. This opens new doors in the affiliation of fossil Parrotia pollen and suggests that previous pollen records need to be revised.
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| 2. |
- Bouchal, Johannes M., 1979-, et al.
(författare)
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Miocene palynofloras of the Tınaz lignite mine, Muğla, southwest Anatolia: taxonomy, palaeoecology and local vegetation change
- 2017
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Ingår i: Review of Palaeobotany and Palynology. - Amsterdam : Elsevier. - 0034-6667 .- 1879-0615. ; 243, s. 1-36
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Tidskriftsartikel (refereegranskat)abstract
- Middle Miocene deposits exposed at the Tınaz lignite mine, Yatağan Basin, Muğla, southwestern Turkey, were palynologically investigated. The Tınaz lignite mine section belongs to the Eskihisar Formation. The lignite seam at the base of the section represents the uppermost part of the Turgut Member. Above, c. 65 m of clayey siltstone, limestone, and marls represent the Sekköy Member. Nine spores, zygospores and cysts of fungi and algae, seven moss and fern spores, 12 gymnosperm pollen types, and more than 80 angiosperm pollen taxa were recovered from the Tınaz lignite mine section. Three pollen zones were recognized, of which pollen zone 1 corresponds to the formation of the main lignite seam and reflects the change from a fluviatile to a lacustrine depositional setting. Pollen zones 2 and 3 and a transitional zone 2-3 reflect different stages of lake development and a shift in local vegetation from forested (pollen zones 1 and 2) to more open (transitional zone 2-3, zone 3). Interpreting changes in regional vegetation from pollen zones 1 to 3 is not straightforward as changes in the pollen spectra may be affected by changing contributions of airborne and water transported pollen and spores to the observed palynoassemblages. Age inference for the Tınaz lignite mine section has been complicated by the absence of datable ash layers, associated mammal faunas, or marine sediments. However, pollen zone 3 shares key features with the pollen spectrum recovered from the nearby mammal site Yenieskihisar (upper part of Sekköy Member) for which an age of 12.5-11.2 Ma has been suggested, and to the youngest pollen zone recovered from the mammal locality Çatakbağyaka, 10 km south of Tınaz, that probably represents mammal zone MN7/8 instead of MN5 or MN6 as previously suggested. In contrast, pollen zones 1 and 2 are fairly similar to the basal parts of the Çatakbağyaka pollen flora (uppermost parts of Turgut Member, basalmost parts of Sekköy Member). Furthermore, new mammal data from the Yatağan basin suggest that the layers below pollen zone 1 are MN4/5, and that carnivores cooccuring with pollen zone 1 in the main lignite seam of Eskihisar probably belong to MN6. Hence, a Langhian to Serravallian age can be inferred for pollen zones 1 and 2 of the Tınaz lignite mine section, and a late Serravallian age for pollen zone 3. Palaeobiogeographic relationships of the palynofloras are generally northern hemispheric, with many north temperate tree taxa showing modern disjunctions East Asia- NorthAmerica (Tsuga, Carya), East Asia- western Eurasia (Zelkova), East Asia- North America- western Eurasia (Liquidambar), or restricted to East Asia (Cathaya, Eucommia) or North America (Decodon). A few taxa belong to extinct lineages that have complex biogeographic patterns (Engelhardioideae, Cedrelospermum). The presence of Picrasma (Simaroubaceae) in the lower lignite layers of pollen zone 1 is remarkable, as the botanical affinities with the enigmatic flower Chaneya present in early to middle Miocene deposits of Turkey and Central Europe have recently been shown to be with Picrasma.
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| 3. |
- Geier, Christian, et al.
(författare)
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Paleovegetation and paleoclimate inferences of the early late Sarmatian palynoflora from the Gleisdorf Fm. at Gratkorn, Styria, Austria
- 2022
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Ingår i: Review of Palaeobotany and Palynology. - Amsterdam : Elsevier. - 0034-6667 .- 1879-0615. ; 307, s. 1-65
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Tidskriftsartikel (refereegranskat)abstract
- The Gleisdorf Formation (Fm.) deposits in the clay pit at Gratkorn, Styria, Austria, are dated to 12.2–12 Ma,and are of late Middle Miocene age (late Serravallian or Sarmatian). To reconstruct the paleovegetation and estimate the paleoclimate at this important vertebrate site, the palynoflora close to the boundary between the vertebrate-bearing layers of the Gratkorn Fm. and the overlying limnic clay deposits of the Gleisdorf Fm. was investigated. Using the single-grain method, 140 palynomorphs were identified. The palynoflora suggests that the paleovegetation was characterised by well-drained lowland and upland forests, riparian forest, and swamp forests. Depending on the dominating tree species, lowland and upland forests might have had closed or more open canopies. Open habitats included wet meadows and shrublands. In addition, conifers were present in theswampy lowlands and the forested uplands. The most prominent paleoclimatic signatures of the palynoflora indicate a fully humid warm temperate climate, with hot to warm summers and cool winters (Cfa-, Cfb-climate), and a seasonal climate with cool and drier winters and hot to warm and wetter summers (Cwa-, Cwb-climate). Our results align with existing studies bordering the Styrian Basin and support the presence of subtropical to warm-temperate vegetation around Gratkorn during the Sarmatian.
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| 4. |
- Grímsson, Fridgeir, et al.
(författare)
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Cenozoic vegetation and phytogeography of the sub-arctic North Atlantic
- 2021
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Ingår i: Biogeography in the Sub-Arctic: The Past and Future of the North Atlantic Biotas. - : John Wiley & Sons. - 9781118561478 ; , s. 29-49
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Bokkapitel (refereegranskat)abstract
- This chapter provides a review of Cenozoic plant assemblages from the sub-arctic North Atlantic region and their biogeographic implications. Previous work is reviewed and new data are presented that considerably change our understanding of the role of the northern North Atlantic for plant dispersal and evolution of plant lineages during the Paleogene and Neogene. Paleogene plant fossils in this region are known from West and East Greenland, the Faroe Islands and Scotland. In contrast to the widely held view that most Paleogene plant taxa of Greenland belong to extinct lineages, we provide evidence for the presence of several extant genera in these floras (e.g. Fagus, Quercus). Thus, Engler’s hypothesis about the ‘Arcto-Tertiary element’ remains a fundamental hypothesis about the origin of northern temperate tree genera. In general, a remarkable diversity of extinct and modern lineages of Fagaceae is documented for Palaeocene and Eocene floras. Neogene fossils are found in Iceland and provide records of climate evolution in the sub-arctic North Atlantic and of the duration of a functioning land bridge for plant migration between North America and Europe. Counter to the traditional view suggesting a functioning land bridge only during the Paleogene, there isnow convincing evidence that this link was available for plants until the latest Miocene. This has important implications for understanding low genetic differentiation documented in extant plant groups having a disjunct distribution in northern temperate regions of Europe, North America and East Asia. Relatively warm conditions persisted in the sub-arctic North Atlantic until the end of the Zanclean (early Pliocene) based on plant fossil evidence from Iceland. The shift to modern tundra conditions occurred during the Piacenzian (late Pliocene) and is documented in the Pliocene and Pleistocene fossil plant assemblages of Iceland.
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| 5. |
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| 6. |
- Malaikanok, Paranchai, et al.
(författare)
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Community assembly of tropical Fagaceae-dominated forests in Thailand dates back at least to the Late Palaeogene
- 2023
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press. - 0024-4074 .- 1095-8339. ; 202:1, s. 1-22
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Tidskriftsartikel (refereegranskat)abstract
- The Late Oligocene to Early Miocene flora of the Ban Pa Kha Subbasin (Li Basin, northern Thailand) provides a record of montane dry tropical oak-pine forests. The rich ensemble of Fagaceae typical of these forests might have existed in the wider region of Southeast Asia since Eocene times and various fossil plant assemblages represented both lowland (Fagaceae, Dipterocarpaceae) and upland (Fagaceae, Pinaceae) tropical forests. These findings are in conflict with previous interpretations of vegetation development in northern Thailand, which stressed that stratigraphically older (possibly Late Oligocene) spore and pollen assemblages in northern Thailand were markedly different from the modern tropical flora and had a distinct northern temperate character. A major change in climate would have caused a dramatic shift to tropical conditions since the Mid-Miocene. Considering palaeobotanical data from adjacent regions in Southeast Asia, we suggest that differences in spore and pollen assemblages in intermontane basins in northern Thailand are more likely to represent different facies and lowland/upland settings. Assembly of these forest ecosystems, typically comprising Quercus sections Cyclobalanopsis, Ilex and Quercus, pollen of Castaneoideae with affinities to Castanopsis and Lithocarpus, and extinct fagaceous genera such as Eotrigonobalanus, most probably dates back to the Eocene. The absence of oaks of Quercus section Cerris in the spore and pollen assemblage of the Ban Pa Kha Subbasin, despite this group being part of the modern vegetation, might reflect the late arrival (secondary radiation) of this chiefly temperate group in tropical Southeast Asia.
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| 7. |
- Vieira, Manuel, et al.
(författare)
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Niche evolution versus niche conservatism and habitat loss determine persistence and extirpation in late Neogene European Fagaceae
- 2023
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 300, s. 107896-107896
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Tidskriftsartikel (refereegranskat)abstract
- An increasing body of palaeobotanical data demonstrates a series of Pliocene and Pleistocene extirpationsand extinctions of plant lineages in western Eurasia, which are believed to have been determinedby the climatic properties of their related East Asian and North American sister lineages.We investigatedthe diversity of a widespread northern hemispheric plant family, Fagaceae, during the Late Pliocene ofPortugal. We found a high diversity of Fagaceae comprising extant and extinct lineages. Dispersed pollenof Castanopsis and Quercus sect. Cyclobalanopsis represent the youngest records of these Himalayan-Southeast Asian groups in western Eurasia. Likewise, fossil-species of Quercus sect. Lobatae and theNorth American clade of sect. Quercus are the youngest records of these modern New World groups inwestern Eurasia. For the extinct Trigonobalanopsis, the pollen record of Portugal is the youngest known ofthis genus. Climate data of modern representatives demonstrate that a deterministic model can explainonly a part of the Pliocene and Pleistocene extirpations. Modern cold month mean temperatures ofCastanopsis and Quercus sect. Cyclobalanopsis and their last occurrences in western Eurasia in the Pliocenefit with a deterministic model (niche conservatism). In contrast, survival or extirpation of groupswith high cold tolerance appear to have been more complex. Here, niche evolution, abundance anddiversity of a lineage during pre-Pleistocene times, and habitat availability/loss determined the fate ofFagaceae lineages in western Eurasia.
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