Middle Pliocene vegetation: reconstructions, paleoclimatic inferences, and boundary conditions for climate modeling

The general characteristics of global vegetation during the middle Pliocene warm period can be reconstructed from fossil pollen and plant megafossil data. The largest differences between Pliocene vegetation and that of today occurred at high latitudes in both hemispheres, where warming was pronounced relative to today. In the Northern Hemisphere coniferous forests lived in the modern tundra and polar desert regions, whereas in the Southern Hemisphere southern beech apparently grew in coastal areas of Antarctica.Pliocene middle latitude vegetation differed less, although moister-than-modern conditions supported forest and woodland growth in some regions now covered by steppe or grassland. Pliocene tropical vegetation reflects essentially modem conditions in some regions and slightly cooler-than-or warmer-than- modern climates in other areas. Changes in topography induced by tectonics may be responsible for many of the climatic changes since the Pliocene in both middle and lower latitudes. However, the overall latitudinal progression of climatic conditions on land parallels that seen in the reconstruction of middle Pliocene sea-surface temperatures.Pliocene paleovegetational data was employed to construct a 2 ° × 2 ° global grid of estimated mid-Pliocene vegetational cover for use as boundary conditions for numerical General Circulation Model simulations of middle Pliocene climates. Continental outlines and topography were first modified to represent the Pliocene landscape on the 2 ° × 2 ° grid. A modern 1 ° × 1 ° vegetation grid was simplified and mapped on this Pliocene grid, and then modified following general geographic trends evident in the Pliocene paleovegetation data set.     

定量分析第三纪以来环境变化的新方法：—特有种气候分析法

1　全球气候变化研究新动向自 2 0世纪 80年代以来 ,全球气候变化研究至今仍方兴未艾。全球气温波动、大气中温室气体丰度变化、气候格局改变、气候带迁移和降水量增减 ,都影响到社会经济的发展和人类生活质量的提高。各国政府对全球气候变化的研究 ,如气候演变的过程、短期和长期气候变化的预测和自然灾害的防治都给予极大关注和财力支持[1] 。目前全球气候变化的研究正向两个方向发展。1.1　加大全球气候变化研究时间尺度 ,从研究当今气候发展到研究地质历史时期气候变化全球气候变化 ,如大气中ＣＯ2 浓度的变化、温度的升降和降水量的变…     

Climate Analysis of Endemic Species-A Novel Method for Quantitative Analysis of Global Climate Change Since Tertiary

There are many extant endemic plants in China, which were widely distributed in the North Hemisphere during Tertiary. The global cooling during the Tertiary caused a series of narrow distribution regions of the plants. Quaternary glaciation invaded most regions of North America and Eurasia where severe destruction was imposed onto vegetation. However, such destruction was lessened in China largely because of specific topographic and geographical and obviously, a number of other conditions accounted for an unusual refugee camp for the relics of plants in China, among which lots of endemic taxa exist. Recently, Chinese endemic species, such as Metaseqouia, Eucommia , have been employed to conduct multi-disciplinary comprehensive studies so as to analyze Tertiary climate changes quantitatively. Meanwhile, a rigorous method, i.e. climate analysis of endemic species (CAES) has come to maturation. This method is characteristic of some generality because it is supposed to be applicable to the endemic species in other regions of the world. CAES is involved in the following aspects: 1. Conduct multidisciplinary studies on living and fossil species of endemic plants and trace their evolutionary courses. 2. Compare fossil species with living one and clarify which is the nearest living relative (NLR) to fossil counterpart. 3. Fossils and their living counterparts (NLR) are supposed to have similar ecological requirements to meet their life cycles. 4. Investigate the geographic distribution of living and fossil plants within the same taxa and ascertain the dynamic changes of their distributions in geological age. 5. Analyze climate factors in the distribution of specific endemic taxa and obtain the data of climatic characters which are suitable for reconstruction of paleoclimate where fossil counterparts lived. 6. Further study the physio-ecology of living species and determinate paleoclimate where fossil counterparts lived. 7. Integrate analysis of the data from steps 4, 5 and 6, and quantitatively reconstruct the climate where fossil and living plants survive.     

定量分析第三纪以来环境变化的新方法——特有种气候分析法

There are many extant endemic plants in China, which were widelydistributed in the North Hemisphere during Tertiary. The global cooling during the Tertiary caused a series of narrow distribution regions of the plants. Quaternary glaciation invaded most regions of North America and Eurasia where severe destruction was imposed onto vegetation. However, such destruction was lessened in China largely because of specific topographic and geographical and obviously, a number of other conditions accounted for an unusual refugee camp for the relics of plants in China, among which lots of endemic taxa exist. Recently, Chinese endemic species, such as Metaseqouia, Eucommia, have been employed to conduct multi-disciplinary comprehensive studies so as to analyze Tertiary climate changes quantitatively. Meanwhile, a rigorous method, i.e. climate analysis of endemic species (CAES) has come to maturation. This method is characteristic of some generality because it is supposed to be applicable to the endemic species in other regions of the world. CAES is involved in the following aspects: 1. Conduct multidisciplinary studies on living and fossil species of endemic plants and trace their evolutionary courses. 2. Compare fossil species with living one and clarify which is the nearest living relative (NLR) to fossil counterpart. 3. Fossils and their living counterparts (NLR) are supposed to have similar ecological requirements to meet their life cycles. 4. Investigate the geographic distribution of living and fossil plants within the same taxa and ascertain the dynamic changes of their distributions in geological age. 5. Analyze climate factors in the distribution of specific endemic taxa and obtain the data of climatic characters which are suitable for reconstruction of paleoclimate where fossil counterparts lived. 6. Further study the physio-ecology of living species and determinate paleoclimate where fossil counterparts lived. 7. Integrate analysis of the data from steps 4, 5 and 6, and quantitatively reconstruct the climate where fossil and living plants survive.     

Red blood system in 10–12-year-old children of the Far North

Healthy children between the ages of 10 and 12 years (n=699) of the Far North (Taimyr peninsular) and Siberia (Krasnoyarsk city) were examined. The red blood system was investigated relative to the duration of residence in the polar region and the season of the year. The red blood cell (RBC) count and the hemoglobin level in children from the newly arrived population corresponded to the normal age values, and those of the aborigines were at the lower border of the normal value range. The qualitative composition of their red blood was changed—the level of the alkaline-resistant hemoglobin was elevated. In all the children who lived in the polar regions, the mean RBC volume was augmented, along with seasonal dynamics of blood electrolyte composition, changes in phospholipid spectrum of erythrocyte membranes, and certain activation of lipid peroxidation reactions. The oxygen-binding capacity of blood was changed in children from the polar regions, which led to alterations of hemoglobin affinity to O₂ in pO₂ in the direction of its increase in the lungs and decrease in tissues under conditions of existing pO₂. These deviations were the most common (from 5/6 to 2/3) in children during the first five years of their residence in polar regions; afterwards their frequency as compared to the control curve did not exceed 1/2, as in the aborigines.     

An ophiuroid trackway from the Lower Devonian Hunsrück Slate, Germany

A new trace fossil, Arcichnus saltatus , from the Lower Devonian Hunsrück Slate, Germany, is interpreted as the trackway of a protasterid ophiuroid, Taeniaster. The trackway consists of a series of horseshoe-shaped impressions, produced by a pair of arms, a feature characteristic of some ophiuroid trackways. This new trace fossil demonstrates that protasterids lived both infaunally and epifaunally.     

<Emphasis Type="Italic">Saccomorpha guttulata</Emphasis>: a new marine fungal microbioerosion trace fossil from cool- to cold-water settings

Euendolithic marine fungi are ubiquitous bioeroders of calcareous skeletal substrates, even under the extreme environmental conditions of the polar regions. The new bioerosion trace fossil Saccomorpha guttulata isp. nov. is presumably produced by a marine fungus that is interpreted to be well adapted to low temperatures, based on the provenance of the studied fossil and recent material. Its trace may thus serve as indicator for cool- to cold-water (palaeo) environments. The microboring is diagnosed by a radiating and ramifying system of club-shaped segments that gradually widen from a thin filament into a distal node. Below the initial point of entry, a stalked central cavity of slightly larger dimension and depth of penetration is developed, from which several segments emerge. The segments are interpreted to reflect a regular temporal sequence in the formation of hyphal filaments that widen into sporangial cavities. While all Saccomorpha ichnospecies share this composition of presumed sporangial cavities and hyphal filaments, with a varying degree of segmentation and gradation between these two elements, different strategies with regards to the temporal pattern in the formation of the different functional elements have evolved.     

Evidence of polar auxin flow in 375 million-year-old fossil wood

In living woody seed plants (conifers and dicotyledons), when various obstacles such as buds and branches disrupt the axial polar auxin flow, auxin whirlpools are formed that induce the differentiation of circular tracheary elements in the secondary xylem. Identical circular patterns also occur at the same positions in the wood of the 375 million-year-old Upper Devonian fossil progymnosperm Archaeopteris. We propose that this is the earliest clear fossil evidence of polar auxin flow. Such spiral patterns do not occur in the primary xylem of the ca. 390-385 million-year-old Lower Devonian fossil land plants, fossil progymnosperms, Psilotum nudum, living ferns, and current seed plants that we examined. This discovery reveals an exciting potential for plant fossils to provide structural evidence of evolutionarily diagnostic physiological and developmental mechanisms and for the use of a combination of fossil evidence and developmental biology to characterize evolutionary patterns in terms of genetic changes in growth regulation.     

Revision der fossilen Leguminosengattung Podogonium HEER (= Gleditsia Linné) aus dem europäischen Jungtertiär

The genus Podogonium HEER (extinct legume), known from many Tertiary localities in whole Europe, is rivised and newly combined: Gleditsia knorrii (HEER) GREGOR concerns the fructifications, Gleditsia lyelliana (HEER) HANTKE the leaves; the latter is divided into two formas: knorrii and lyelliana. A comparison with two one-seeded recent Gleditsia-species (G. aquatica MARSH. — USA and G. heterophylla BUNGE — China) yields following palecological setting for the fossil species: They lived under wet conditions (swamps, river banks, alluvial soils) — not in dry climate as believed formerly, together with deciduous trees. The stratigraphical range is from Lower Miocene to Pliocene, with the main occurence in Middle Miocene times (Upper Helvetian, Tortonian, Sarmatian-Karpatian, Badenian, Sarmatian). The fossil species are important plants in the Upper Freshwater Molasse in Bavaria and the adjacent regions.     

The oldest stegocephalian from the Iberian peninsula: evidence that temnospondyls were euryhaline.

The previous fossil record of limbed vertebrates of the Iberian peninsula started in the Triassic (245 Ma). The discovery of a new temnospondyl from the Late Carboniferous (Stephanian C, 290 Ma) extends the fossil record of stegocephalians in this region by at least 45 Ma. Early stegocephalians are usually thought to have been unable to live in salt water, but the new temnospondyl described below appears to have lived in a coastal region, presumably in salt water.     

First record of fossil angiosperm wood (Ulmoxylon,Ulmaceae) from the famous locality of Bı́lina (Czech Republic,Early Miocene)

A fossil angiosperm wood is described for the first time from the famous Early Miocene locality of Bı́lina. It represents a fossil elm wood, attributed to Ulmoxylon marchesonii Biondi. The fossil wood can be compared to extant North American soft elms, also to Ulmus macrocarpa Hance and U. parvifolia Jacq. from China or to the European common elm U. carpinifolia Gled. The wood together with fossil leaves/fruits of Ulmus pyramidalis Goeppert forms a single natural fossil species that lived in the Bı́lina area during the Early Miocene. The influence of two types of preservation, permineralised and xylitic, on the same wood species is also discussed. To cite this article: J. Sakala, C. R. Palevol 1 (2002) 161–166.     

云南保山上新统黄背栎Quercus Pannosa Hand.-Mazz.角质层特征及古环境意义

在滇西保山上新统首次发现了黄背栎(Quercuspannosa)压型化石,并分析了角质层构造。其特征主要为:上表皮无气孔器,表皮细胞为不规则形五边形,垂周壁微弯曲,脉络为网格状,无毛基;下表皮具环列型气孔器,表皮细胞为不规则形五边形,垂周壁微弯曲,脉络为五边形的网格状,具毛基,毛的根部由多细胞组成,毛基部的细胞特化成辐射状。利用现存最近亲缘种(NLRspecies)原理,并比较化石和现生Q.pannosa角质层特征,推断上新世Q.pannosa在羊邑生长的古环境比现生Q.pannosa生存的冷湿气候相对干旱,且化石Q.pannosa为近原地埋藏。     

上新世以采的中国自然地理环境和中国古人类的进化

本文通过把中国古人类的进化摆到中国这一特定的地理区域、特定的自然地理环境中去作联系的考察,提出如下几点看法:1.中国是世界上很早就为人类所居住的地区之一,受自然地理环境的影响和制约,中国古人类主要生存于自然条件较好的东部季风区域;2.古人类在中国境内主要是由南向北、进而向东北方向扩散和分布;3.中国最早的古人类可能是外来的,可能是从中国南部边境进入中国境内的。     

Diversity, endemism, and age distributions in macroevolutionary sources and sinks

Quantitative tests of historical hypotheses are necessary to advance our understanding of biogeographic patterns of species distributions, but direct tests are often hampered by incomplete fossil or historical records. Here we present an alternative approach in which we develop a dynamic model that allows us to test hypotheses about regional rates of taxon origination, extinction, and dispersal using information on ages and current distributions of taxa. With this model, we test two assumptions traditionally made in the context of identifying regions as "centers of origin"--that regions with high origination rates will have high diversity and high endemism. We find that these assumptions are not necessarily valid. We also develop expressions for the regional age distributions of extant taxa and show that these may yield better insight into regional evolutionary rates. We then apply our model to data on the biogeography and ages of extant genera of marine bivalves and conclude that diversity in polar regions predominantly reflects dispersal of taxa that evolved elsewhere rather than in situ origination-extinction dynamics.     

RHODOLITHS: BETWEEN ROCKS AND SOFT PLACES

Rhodoliths (maërl) are widely distributed in the worlds' oceans and have an excellent fossil record. Individuals are slow growing, may be long lived (>100 years), and are resilient to a variety of environmental disturbances. Their external morphology and internal growth bands are potential archives of environmental variation at scales of within years to tens of years. At high densities, these free-living non-geniculate coralline algae form rhodolith beds, communities of high diversity that can be severely impacted by resource extraction.     

Oxygen and carbon isotopic records of mollusks in the Kuokang Shell Bed, Taiwan: implications and applications

Oxygen and carbon isotopic compositions have been determined in fossil molluscan shells from the Kuokang Shell Bed and in modern shells from coastal areas around Taiwan. Fossil mollusks have been well preserved, based on X-ray diffraction, stable isotopic data and their occurrence in the field.

The stable isotopic data of fossil shells indicate that they lived in an open sea environment. Heavier oxygen and lighter carbon isotopic ratios of these fossils relative to modern counterparts around Taiwan indicate that these fossil mollusks grew in a glacial period, as supported by the ¹⁴C dating results. The calculated mean uplift rate for the Kuokang Shell Bed shows a lower rate compared to the eastern and southern parts of Taiwan and reflects a more stable, away-from-collision nature for western Taiwan.     

红杉属植物在中国云南中新世首次发现

化石标本采自中国云南省中部楚雄市吕合煤矿的石鼓村层 ,该层为灰色至浅灰色细砂岩至粗砂岩、粉砂质粘土层和褐煤层 ,地质时代属中新世 ① 。石鼓村层的孢粉组合以被子植物占绝对优势(90 % ) ,其中热带、亚热带植物成分类型较多 ,如金缕梅科、棕榈科等 ,温带植物成分类型较少 ,如榆科、桦木科等 ;裸子植物花粉占整个孢粉组合的 9% ,主要是松科和杉科花粉 ;蕨类植物孢子仅占整个孢粉组合的 1% ,以水龙骨单缝孢为主。本次发现的标本小枝长约 2 .8ｃｍ ,宽约 1.6ｃｍ ,小枝基部稍膨大。叶螺旋状排列 ,基部扭转 ,在同一平面排成 2列 ,以 30～ 70…     

Observations of the structural changes that occur during charcoalification: implications for identifying charcoal in the fossil record

All of our current understanding of fossil charcoal structure comes from observations of modern wood charcoal produced in furnaces. These charcoals consistently show cell wall homogenization after prolonged heating (>325°C) and this is therefore considered to be a key identifying feature of fossil charcoal. Yet furnaces are unable to replicate the full combustion processes that occur during a wildfire. Here, for the first time, we have studied the microscopic structural evolution of charcoal produced using calorimetry, wherein the wood is ignited under controlled conditions and the heat release rate and other parameters measured, and the resulting charcoal studied using reflected light microscopy. We show that homogenization of cell walls is actually only a short‐lived phase of charcoal formation that occurs during the early heating stages as the pyrolysis front traverses through the wood. Cell wall homogenization is then rapidly overprinted by the thinning, distortion and breakdown of cell walls, and a notable visual increase in reflectance. Our preliminary study therefore suggests that we need to first improve our understanding of charcoal formation in order to better understand the fossil record of wildfires.     

Fossil weevils (Coleoptera: Curculionidae) from latitude 85°S Antarctica

Two species of fossil listroderine weevils (Coleoptera: Curculionidae: Rhytirhinini: Listroderina) are reported from the Meyer Desert Formation at a locality on the Beardmore Glacier in the Transantarctic Mountains about 500 km from the South Pole. Associated fossils include wood, leaves and pollen of Nothofagus, stems and leaves of several species of mosses, achenes of Ranunculus, shells of freshwater molluscs and a fish tooth. The age of the fossiliferous strata is contentious but probably within the range of Pliocene to mid-Miocene. The fossils represent organisms that colonised the margins of a glacier at the head of a fjord during an interglaciation. The autecology of the listroderine species indicates that temperatures during summer months averaged 5°C. The mean annual temperature, with winter temperatures constrained by 6 months of darkness, is estimated to have been about −8°C compared to the −26°C estimated for sea level at latitude 85°S today. The closest evolutionary link of the fossil listroderines is with South American rather than Australian or New Zealand taxa. Divergence of the taxa, at least at the level of tribe, had most probably occurred on Gondwana before the continent broke apart. The fossil species are considered to be the descendants of Antarctic lineages which evolved on the continent in the Late Cretaceous or Palaeogene and survived until the Neogene. Extinction of the listroderines and most other Antarctic terrestrial biota occurred with the growth of the polar ice sheets and the change to the polar desert climate.