Eotrigonobalanus Furcinervis Research Articles

New fossil flora from Palaeogene sediments near Bersin village (SW Bulgaria)

Data for new local palaeoflora near the village of Bersin (SW Bulgaria) are presented. Eight species of fossil plants have been identified. Eotrigonobalanus furcinervis is dominant over other species. The flora-bearing layers originate from the lower part of the Nevestino Formation, which is formed by alternating sandstone and mudstone sediments. Based on the established fossil macroflora, it can be assumed that the age of the flora-bearing sediments is late Eocene.

The First Record of Eotrigonobalanus Furcinervis (Fagaceae) from the Oligocene of the Thrace Basin, Western Turkey

Eotrigonobalanus furcinervis was recorded for the first time from the Oligocene sediments of the Thrace Basin. The species was discovered in the upper part of the Danişmen Formation from the Marmaraereglisi Area, southeastern the Basin. Eotrigonobalanus furcinervis appeared in large numbers early during the early Paleocene–late Oligocene localities in Europe; especially in Thrace of Greece, Bulgaria, Germany, Czech Republic, Hungary and Romania. Therefore, this data is valuable as the first recording for Thrace Basin.

Reconstructing leaf area from fragments: testing three methods using a fossil paleogene species.

Fossil leaf traits can enable reconstruction of ancient environments and climates. Among these, leaf size has been particularly studied because it reflects several climatic forcings (e.g., precipitation and surface temperature) and, potentially, environment characteristics (e.g., nutrient availability, local topography, and openness of vegetation). However, imperfect preservation and fragmentation can corrupt its utilization. We provide improved methodology to estimate leaf size from fossil fragments. We apply three methods: (1) visually reconstructing leaf area based on taxon-specific gross morphology; (2) estimating intact leaf area from vein density based on a vein scaling relationship; and (3) a novel complementary method, determining intact leaf length based on the tapering of the midvein in the fragment. We test the three methods for fossils of extinct Eotrigonobalanus furcinervis (Fagaceae) from two lignite horizons of the middle and late Eocene of central Germany respectively (~45/46 and 35/36 Ma). The three methods, including the new one, yield consistent leaf size reconstructions. The vein scaling method showed a shift to larger leaf size, from the middle to the late Eocene. These methods constitute a toolbox with different solutions to reconstruct leaf size from fossil fragments depending on fossil preservation. Fossil leaf size reconstruction has great potential to improve physiognomy-based paleoenvironmental reconstructions and the interpretation of the fossil record.

A new Oligocene flora from Ludvíkovice near Děčín (České středohoří Mts., the Czech Republic)

A recently recovered site of plant macrofossils, Ludvíkovice, in the České středohoří Mts. is situated on Sokolí vrch hill, belonging to the Děčín Formation (radiometrically dated to 30.8–24.7 Ma), according to regional stratigraphy. The flora has yielded a fern, Rumohra recentior, and several angiosperms, but no conifers. The prevailing foliage is preserved without cuticles. Noteworthy are records of Daphnogene cinnamomifolia, Laurophyllum cf. acutimontanum, Platanus neptuni, Sloanea artocarpites, Carya fragiliformis / C. quadrangula, Alnus rhenana, Trigonobalanopsis rhamnoides, Eotrigonobalanus furcinervis and cf. Quercus sp. Several foliage specimens of dicots could not be identified to species level, i.e., Leguminophyllum sp., Pungiphyllum cf. cruciatum and Dicotylophyllum sp. div. The fossil plant assemblage of Ludvíkovice corresponds to zonal mesophytic vegetation accompanied by riparian elements. This is corroborated by the Integrated Plant Record vegetation analysis, which reconstructs a zonal broad-leaved evergreen forest similar to the living broad-leaved evergreen sclerophyllous forest from Southern Hunan and Northern Guangxi in SE China. The vegetation thrived under a humid climate characterized by average values of MAT (14.6–24.1 °C), WMMT (24.7–28.3 °C), CMMT (2.2–18.8 °C) and MAP (979–1724 mm). The fossil flora of Ludvíkovice is similar in composition to the floras of Markvartice, Veselíčko, also from the Oligocene Děčín Formation of the České středohoří Mts. and the Hrazený hill.

Revision of a late Oligocene florule from the south-western edge of the Lower Rhine Basin (western Germany)

AbstractThe late Oligocene flora from the Nirmer Tunnel at the south-western edge of the Lower Rhine Basin was first described by Menzel (1913). A revision of Menzel’s original material indicates that most taxa are from the vegetation of riparian forests (Magnolia burseracea, Ocotea rhenana, Rhodoleia bifollicularis, Eotrigonobalanus furcinervis, Trigonobalanopsis rhamnoides, Sparganium sp. vel Typha sp.) and mesophytic forests (Carpolithes dactyliformis, Sapotacites minor). Some specimens cannot be identified, so they are named Dicotylophyllum div. spp. here. The fossil species Carpolithes dactyliformis (sandstone imprints and endocasts) belongs to Cornaceae subfamily Mastixioideae and is lectotypified here. The floral assemblage is compared with some similar floras from the Oligocene of Central Europe.

Late Oligocene macrofloras from fluviatile siliciclastic facies of the Köln Formation at the south-eastern border of the Lower Rhine Embayment (North Rhine-Westphalia, Germany)

Abstract The leaf remains described herein came from the oldest sites of the Cainozoic deposits in the Lower Rhine Embayment, located in the Siebengebirge Volcanic Field at the south-eastern border of this basin, in the area of Siebengebirge and vicinity. These revisited floras are bound to pre-volcanic siliciclastic facies of the Siebengebirge Mts., interpreted as marginal facies of the Köln Formation. Chronostratigraphically they are assigned to the late Oligocene (Chattian). The described leaf remains are partially compressions with preserved epidermal anatomy, and therefore highly useful for systematic determination of leaf impressions recovered from other localities of siliciclastic facies. On account of the epidermal characteristics of leaf compressions varying in gross morphology, the previously determined taxa Quercus goepperti, Laurus phoeboides, and Persea speciosa all fall into the abundantly represented Eotrigonobalanus furcinervis. The siliciclastic deposits originated in coastal and flood plain areas within fluviatile environments of variable deposition energy. Remains of Taxodium dubium, Eotrigonobalanus furcinervis, Populus germanica, and Daphnogene cinnamomifolia dominate among the recovered fossils. The general aspects of this plant assemblage correspond, together with their sedimentary settings, to riparian forest vegetation with mesophytic elements.

Fossil plant stomata indicate decreasing atmospheric CO<sub>2</sub> prior to the Eocene–Oligocene boundary

Abstract. A unique stratigraphic sequence of fossil leaves of Eotrigonobalanus furcinervis (extinct trees of the beech family, Fagaceae) from central Germany has been used to derive an atmospheric pCO2 record with multiple data points spanning the late middle to late Eocene, two sampling levels which may be earliest Oligocene, and two samples from later in the Oligocene. Using the inverse relationship between the density of stomata and pCO2, we show that pCO2 decreased continuously from the late middle to late Eocene, reaching a relatively stable low value before the end of the Eocene. Based on the subsequent records, pCO2 in parts of the Oligocene was similar to latest Eocene values. These results suggest that a decrease in pCO2 preceded the large shift in marine oxygen isotope records that characterizes the Eocene–Oligocene transition and that when a certain threshold of pCO2 change was crossed, the cumulative effects of this and other factors resulted in rapid temperature decline, ice build up on Antarctica and hence a change of climate mode.

Atmospheric CO2 from the late Oligocene to early Miocene based on photosynthesis data and fossil leaf characteristics

The late Oligocene represents a comparatively cool phase followed by a warming event, the so-called Late Oligocene Warming that predates the Mi-1 glacial event at the Oligocene–Miocene transition. There is evidence that these climate events were linked to level changes in atmospheric CO2. In this study, atmospheric CO2 from the late Oligocene to the early Miocene is reconstructed by a terrestrial proxy, stomatal parameters of angiosperm leaves. Fossil leaves of six plant species were considered: Laurophyllum pseudoprinceps, L. acutimontanum (both Lauraceae), Platanus neptuni (Platanaceae), Eotrigonobalanus furcinervis, Quercus rhenana and Q. praerhenana (all Fagaceae). The plant material originates from various sites in Germany (late Oligocene to the early Miocene) and Austria (early Miocene). A mechanistic-theoretical approach based on stomatal data, photosynthesis and gas exchange control was used. Since this approach also requires climate data as input parameters for calculating assimilation and transpiration rates, palaeoclimate of these sites were also derived in detail. Considerable differences were found between results obtained by the two Lauraceae taxa and all other taxa, with the Lauraceae indicating a high CO2 level. If Lauraceae are included, a CO2 level of about 700ppm for the late and latest Oligocene is obtained and about 500ppm for the early Miocene. All non-Lauraceae taxa belonging to different families indicate a consistently lower level of CO2 of about 400ppm for all considered sites and time slices. A value of 400ppm is also consistent with other proxy data that are available for that time period. A steady level of 400ppm would indicate a decoupling of CO2 and cooling/warming events from the late Oligocene to the early Miocene. More data provided by different proxies are desirable to unravel the interactions between atmosphere and climate for the late Oligocene and the early Miocene.

Stomatal pore length change in leaves of Eotrigonobalanus furcinervis (Fagaceae) from the Late Eocene to the Latest Oligocene and its impact on gas exchange and CO2 reconstruction

It has repeatedly been reported that stomatal pore length changes with changing atmospheric CO2 concentration. Since stomatal pore length affects stomatal conductance, the question arises of how pore length change interacts with the application of stomatal density as a CO2 proxy. In this study, stomatal density, pore length and maximum stomatal conductance are evaluated for Eotrigonobalanus furcinervis (Fagaceae) from the late Eocene, late Oligocene and latest Oligocene. Then a model that simulates plant gas exchange by treating transpiration and photosynthesis as coupled processes and allows also for CO2 reconstruction was applied to the data of E. furcinervis. The model is based on an optimization approach which calculates plant gas exchange as providing a maximum amount of photosynthesis rate under given climate conditions. Stomatal density increases from the late Eocene onwards in E. furcinervis and stomatal pore length decreases. Maximum stomatal conductance which results from both stomatal pore length and density is highest for the late Eocene and lowest for the latest Oligocene. Since both stomatal conductance and stomatal density are usually negatively correlated with CO2, the stomatal data of E. furcinervis appear to be in conflict with a CO2 decrease over that period, as inferred from other evidence. The model results indicate that the stomatal data of E. furcinervis are in fact linked to a decrease of CO2 from the late Eocene to the Oligocene, in accordance with other proxy data although the late Eocene CO2values of this study are lower than usually found for this time period (range between 259 and 640ppm for the late Eocene, 213–581 ppm for the late Oligocene and 258–611 ppm for the latest Oligocene). The seemingly inconsistency between changes of stomatal density, stomatal pore length and stomatal conductance as found in this study is due to the effect on gas exchange exerted by other climate parameters than CO2. The results of this study strongly suggest that any interpretation of stomatal parameters as indicators of CO2 should consider the influence of climate on stomatal conductance and gas exchange.

THE EARLY OLIGOCENE FLORA OF SANTA GIUSTINA (LIGURIA, ITALY) - REVISION AND COMPARISON WITH THE FLORA OF THE TARD CLAY FORMATION

Based on palaeobotanical material preserved at the University of Genoa, Italy (DIP.TE.RIS.), a revision of the Early Oligocene flora of Santa Giustina, as well as the 1916 monograph of Principi, was undertaken. It is shown that apart from members of the Lauraceae family, Eotrigonobalanus furcinervis and Sloanea olmediaefolia were dominant in the flora, which was mainly composed of warmth-demanding species. The site is primarily characterized by remnants of the vegetation developed under warm and moist climate and abundant water supply. A few additional plants from the neighboring zonal vegetation are also present. The flora is quite reminiscent of that of the Tard Clay Formation, part of the Inner Carpathian Region, providing a proven link to the floristic relationships of these areas. Up to the Pre-Neogene, the Inner Carpathian Region and the surrounding Alpine-Carpathian-Dinaric Region was composed of a composite terrane that 1) existed independently from Stable Europe, and, 2) had a much more southerly position than today. This terrane collage was sharply bordered from all directions except west, as is supported by new evidences of the floristic affinities with the Santa Giustina flora.

Unidirectional shift in leaf morphology of coexisting species — a possible indicator of palaeoclimatic differences

The pre-Neogene basement of the Pannonian domain is built up by a collage of terranes deriving from different parts of the Tethys, which finally accreted in the Late Oligocene–Early Miocene times. Combined stratigraphical, sedimentological, palaeomagnetic and tectonic investigations have revealed the palaeogeographic position of the Palaeogene Basin, including the Buda and Bükk tectonic units However, despite floristic similarities, the Buda and Bükk regions also show important physiognomic differences. In the vicinity of Budapest (Buda unit), the large size and width of leaves are conspicuous, whereas in Eger-Kiseged (Bükk unit), leaves are definitely smaller and narrower. In order to define the differences quantitatively, morphometrical measurements were adopted. The shape and size of leaf fossils were compared by means of a circular grid ( Hill, 1980). Leaves of 4 dominant species ( Sloanea elliptica (Andreánszky) Z. Kvaček & Hably, Engelhardia orsbergensis (Wessel & Weber) Jähnichen, Mai & Walther, Eotrigonobalanus furcinervis (Rossmässler) Walther & Kvaček, and Zizyphus zizyphoides (Unger) Weyland were the target of our study. The average leaf area is 1.4–2.3 times larger in the Buda tectonic unit (Budapest locality) than in the Bükk tectonic unit (Eger-Kiseged locality). Statistical tests proved highly significant differences between these values. Regarding the asymmetry of the leaf lamina, the four species differed considerably. Nevertheless, a significant difference between the two localities was shown only in one of them ( Sloanea elliptica). Consequently, a significant alteration of measures of asymmetry as a function of habitat conditions was not indicated. Smaller leaf area and significantly narrower leaf blade are possible indicators of drier climatic conditions in the Bükk unit.

Changes in atmospheric CO 2 concentrations and climate from the Late Eocene to Early Miocene: palaeobotanical reconstruction based on fossil floras from Saxony, Germany

In the present study, proxy data concerning changes in atmospheric CO 2 and climatic conditions from the Late Eocene to the Early Miocene were acquired by applying palaeobotanical methods. Fossil floras from 10 well-documented locations in Saxony, Germany, were investigated with respect to (1) stomatal density/index of fossil leaves from three different taxa ( Eotrigonobalanus furcinervis, Laurophyllum pseudoprinceps and Laurophyllum acutimontanum), (2) the coexistence approach (CA) based on nearest living relatives (NLR) and (3) leaf margin analysis (LMA). Whereas the results of approach (1) indicate changes in atmospheric CO 2 concentration, approaches (2) and (3) provide climate data. The results of the analysis of stomatal parameters indicate that the atmospheric CO 2 concentration was higher during the Late Eocene than during the Early Oligocene and increased towards the Late Oligocene. A lower atmospheric pCO 2 level after the Late Eocene is also suggested by an increase in marine palaeoproductivity at this time. From the Late Oligocene onwards, no changes in atmospheric CO 2 concentration can be detected with the present data. For the considered sites, the results of the coexistence approach and of the leaf margin analysis document a significant cooling event from the Late Eocene to the Early Oligocene. The pCO 2 decrease from the Late Eocene to the Early Oligocene indicated by the stomatal data raised in this study was thus coupled to a temperature decrease which is reflected by the present datasets. From the Early Oligocene onwards, however, no further fundamental climate change can be inferred for the considered locations. The pCO 2 increase from the Early Oligocene to the Late Oligocene, which is indicated by the present data, is thus not accompanied by a climate change at the considered sites. A warming event during the Late Oligocene is, however, recorded by marine climate archives. According to the present data, no change in pCO 2 occurred during the cooling event at the Oligocene/Miocene boundary, which is also indicated by marine data. The quality and validity of stomatal parameters as sensors for atmospheric CO 2 concentration are discussed.

The Palaeogene flora of Hochstetten‐Dhaun (Nahe‐area, Rhineland‐Palatinate, SW‐Germany)

AbstractA flora from the Palaeogene of Hochstetten‐Dhaun (Nahe‐area, Rhineland‐Palatinate, SW‐Germany) is described. Leaf remains of the intermediate Fagaceae species Eotrigonobalanus furcinervis (Rossmaessler) Walther & Kvaček represent the dominant element. Moreover, Equisetum sp., Tetraclinis salicornioides (Unger) Kvaček, Daphnogene cinnamomifolia (Brongniart) Unger forma lanceolata sensu Kvaček & Walther, Daphnogene cinnamomifolia (Brongniart) Unger forma cinnamomifolia sensu Kvaček & Walther, Daphnogene sp., cf. Quercus sp. vel Castaneophyllum sp., Eotrigonobalanus furcinervis (Rossmaessler) Walther & Kvaček, cf. subsp. haselbachensis Kvaček & Walther, cf. Trigonobalanopsis rhamnoides (Rossmaessler) Kvaček & Walther, and Populus cf. germanica (Menzel) Walther occur in this flora. In addition, three leaf‐morphotypes are characterized and several undeterminable leaf remains are listed. We interpret the source vegetation as a mixed mesophytic forest. Based on the composition and overall morphological and physiognomical character, we conclude that the flora is of lowermost Oligocene age.