首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
A new genus is recognized on the basis of wind-dispersed fruits from the Eocene of western North America and Miocene of eastern Asia. The fruits consist of an accrescent hypogynous calyx of five obovate sepals and one or more globose fruit bodies. Although the fossils were formerly placed in the extant genera Porana (Convolvulaceae) and Astronium (Anacardiaceae), our investigation of numerous specimens from several floras in the western United States (e.g., Florissant, Green River, Clarno) and Canada (Whipsaw Creek, British Columbia) and the Yilan and Shanwang floras of China reveals unique characters that indicate that the fossils are a distinct genus, which we name Chaneya. Unlike Porana and Astronium, the fossil calyces have stomata that are longitudinally aligned, and early stages of fruit development show a gynoecium of five apocarpous carpels, of which only one or two usually enlarge at maturity. Precise systematic placement of the fossil genus is uncertain, but similarities to the extant Picrasma of the Simaroubaceae are suggestive of possible affinities. Two species are recognized: Chaneya tenuis (Lesq.) comb. nov., from the Eocene of western North America and northeastern China, and Chaneya kokangensis (Endo) comb. nov., from the Miocene of eastern Asia.  相似文献   

2.
? Premise of the study: Pueraria (Leguminosae, Papilionoideae) is native in East Asia, South Asia, Southeast Asia, and Oceania and is well known as a rampant invasive weed in the southeastern United States (P. montana; better known as kudzu), but relatively little is known about its early evolution and biogeographic origin. ? Methods: On the basis of comparative analyses of the fruit and leaflet architecture of closely related extant and fossil taxa, we studied the fossil history and biogeography of Pueraria. ? Key results: Fossil Pueraria is recognized on the basis of distinctive fruit and foliage from the Mio-Pliocene of middle latitudes in China, Japan, Abkhazia, and Croatia. Recognition of P. miothunbergiana from the Mio-Pliocene of China and Japan is reinforced by a trifoliolate leaf as well as isolated lateral and terminal leaflets. Pueraria shanwangensis sp. nov. represents the first recognition of fossil Pueraria fruits. This fruit species co-occurs with P. miothunbergiana in the Middle Miocene Shanwang flora and possibly represents the same population. Pueraria maxima (Unger) comb. nov., previously named as Dolichites maximus or Desmodium maximum, is recognized on the basis of leaflets from the Miocene of Croatia and Abkhazia. Other prior fossil reports of Pueraria and Dolichites are reevaluated. ? Conclusions: Pueraria had begun to diversify by at least the Middle Miocene and had spread into the Mio-Pliocene subtropical and temperate floras of the Balkan Peninsula, the Caucasus, and eastern Asia, which suggests the present diversity of this genus in tropical Asia and Oceania might have originated from the mid-latitudes of Eurasia.  相似文献   

3.
亚洲新生代藓类植物化石非常稀少,漳浦琥珀是目前已知的我国低纬度地区唯一含苔藓植物化石的新生代琥珀矿床。漳浦琥珀源自中中新世气候适宜期(~14-17 Ma)的龙脑香树脂,温暖潮湿的热带季雨林气候和广泛分布的龙脑香科植物,为藓类植物的生长、多样性演化和三维立体保存提供了条件。本研究共报道了漳浦县中中新世藓类植物化石3个属种,包括:白发藓属Leucobryum Hampe、牛舌藓属Anomodon Hook.et Taylor和扁枝藓属Homalia(Brid.)B.S.G.。首次利用三维X射线断层扫描技术(Micro-CT)研究了白发藓属化石,发现其与现生种短枝白发藓Leucobryum humillimum Cardot非常相似,因此将其命名为短枝白发藓(相似种)Leucobryum cf.humillimum。此外,当前牛舌藓属Anomodon和扁枝藓属Homalia化石是东亚地区的首例记录。漳浦琥珀中的藓类植物化石揭示了中中新世时期苔藓植物的多样性,丰富了东亚低纬度地区新生代苔藓植物的化石记录。  相似文献   

4.
A new species, Altingioxylon hainanensis, is described from the Eocene Changchang Formation of the Changchang Basin on Hainan Island, South China. It is the first record of a fossil wood assigned to Altingiaceae found in China, and the most ancient evidence of wood for this family in eastern Asia. The new species is similar to A. rhodoleioides, known since the Miocene in India and Java Island, and to Altingia hisauchii from the Miocene to Pliocene of Japan. The close resemblance between these species and Liquidambar sp., known from the Middle Miocene of western North America, provides additional evidence for the migration of their ancestors from Asia to North America across the Bering land bridge during the Miocene. Distinctions in ray sizes between the eastern Asian specimens and their contemporaries from Europe to Kazakhstan is suggested as a result of the divergence between the large eastern Asian clade and the North American–west Asian clade within Altingiaceae during the Eocene–Oligocene. The presence of crystals in ray cells may be considered an ancestral condition that persists in the eastern Asian lineages up to the extant Altingia and Semiliquidambar, but which was lost in other Altingiaceae in the course of evolution.  相似文献   

5.
刘武  吴秀杰  邢松 《人类学学报》2019,38(4):473-490
以往,在东亚大陆发现的更新世中期人类化石被分别归入直立人和古老型智人。这种分类的主要依据是化石形态特征以及年代。魏敦瑞对周口店第一地点人类化石研究描述的一些头骨、下颌骨和牙齿特征通常被作为判定直立人的标准。根据这些化石的年代分布,一般将30万年前的中更新世晚期作为划分直立人与古老型智人的大致年代界限。近20年来,在非洲、欧洲和东亚新发现了一些更新世中期人类化石,目前古人类学界对中国更新世中期人类化石特征及演化有了与以往不同的认识。最近对大荔、许家窑、盘县大洞、许昌、华龙洞等人类化石的研究显示,近30万年以来东亚大陆人类演化呈现复杂的多样性,将这一时期人类全部归入古老型智人难以准确反映更新世中期中国古人类演化模式及规律。本文结合近年中国更新世中期人类演化研究进展,选择部分具有演化及分类价值的形态特征,分析这些特征在更新世中期中国古人类化石的表现特点。在此基础上,对更新世中期中国古人类演化模式做了尝试性探讨。本研究发现,周口店、和县、沂源、南京等中更新世早期人类化石呈现有较多的区域性特征,形态特征表现相对稳定;而大荔、金牛山、许家窑、许昌、华龙洞、马坝、盘县大洞等中更新世晚期人类在化石形态特征表现复杂多样,变异范围大。此外,在这一时期人类化石上发现较多与生存活动、健康、环境适应有关的证据。根据这些发现,作者认为中国中更新世早期组人类演化以形态连续性为主;进入中更新世晚期,中国古人类演化区域性特征减弱,演化模式以多样性为主。一系列新的化石发现和研究证据提示中更新世晚期东亚大陆可能生存有不同的古人类成员。根据目前掌握的化石形态和年代证据,大约30万年前是中国更新世中期演化变化关键时间节点。  相似文献   

6.
Flying fishes are extraordinary aquatic vertebrates capable of gliding great distances over water by exploiting their enlarged pectoral fins and asymmetrical caudal fin. Some 50 species of extant flying fishes are classified in the Exocoetidae (Neopterygii: Teleostei), which have a fossil record no older than the Eocene. The Thoracopteridae is the only pre-Cenozoic group of non-teleosts that shows an array of features associated with the capability of over-water gliding. Until recently, however, the fossil record of the Thoracopteridae has been limited to the Upper Triassic of Austria and Italy. Here, we report the discovery of exceptionally well-preserved fossils of a new thoracopterid flying fish from the Middle Triassic of China, which represents the earliest evidence of an over-water gliding strategy in vertebrates. The results of a phylogenetic analysis resolve the Thoracopteridae as a stem-group of the Neopterygii that is more crown-ward than the Peltopleuriformes, yet more basal than the Luganoiiformes. As the first record of the Thoracopteride in Asia, this new discovery extends the geographical distribution of this group from the western to eastern rim of the Palaeotethys Ocean, providing new evidence to support the Triassic biological exchanges between Europe and southern China. Additionally, the Middle Triassic date of the new thoracopterid supports the hypothesis that the re-establishment of marine ecosystems after end-Permian mass extinction is more rapid than previously thought.  相似文献   

7.
丰富的化石记录显示中生代和新生代紫萁属在北半球广泛分布.本文描述了发现于福建中中新世佛昙群的紫萁属一新种:漳浦紫萁(Osmunda zhangpuensis Z.X.Wang and B.N.Sun,sp.nov.).化石小羽片保存完好,呈线状披针形,边缘具齿,羽状脉序.在该属现生种中,当前化石种与现生种Osmunda...  相似文献   

8.
Numerous fruits and seeds of Ruppia are reported from the Upper Pliocene (2.3–3.5 Myr ago) Zhangcun Formation in Yushe Basin, Shanxi, northern China. They are the first fossil Ruppia from China and demonstrate the importance of fruit and seed fossils in recording genera not represented by fossil leaves. These Ruppia are characterized by possessing a small oval endocarp, smooth endocarp surface, distinct elliptical external depressions, distinct apical mucro, slightly curved seed shape and conspicuous globose hilum. A new species, R. yushensis Zhao, Collinson and Li, is described from these endocarp and seed features. Comparison with the two European Miocene species, R. palaeomaritima Negru and R. maritime-miocenica Szafer, indicates the existence at that time of three different geographical and stratigraphical species. R. yushensis constitutes the first Pliocene record of Ruppia and extends the range of fossils of this genus from Europe to eastern Asia. R. yushensis is the only aquatic plant in the uppermost middle part of the Zhangcun Formation. This monotypic occurrence indicates a brackish, clear, tranquil and shallow lake in this region in the Late Pliocene. The smooth endocarp surface further suggests a warm temperate or temperate palaeoclimate.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 317–329.  相似文献   

9.
The subfamily Rosoideae Focke (Rosaceae) has a good fossil record in the Northern Hemisphere, but these fossil records are confined mainly to a few genera, whereas the majority, in particular those with herbaceous members, are still under‐represented. In this study, we describe new fruit fossils of Rosoideae, including Fragaria achenes and Rubus endocarps, from the late Pliocene of northwestern Yunnan, Southwest China. These fossils add new accounts to the fossil archive of Rosoideae and provide the first fossil record of Fragaria in East Asia. The new fossil findings provide a historical backdrop for the modern diversity and distribution of the subfamily in northwestern Yunnan, a topographically complex area accommodating a high diversity for many plant groups. Our Rubus fossils, in combination with other nearby coeval occurrences of the genus, suggest that Rubus was already establishing its modern diversity in northwestern Yunnan during the late Pliocene. This finding enriches our knowledge of the post‐Neogene diversification of flowering plants in northwestern Yunnan, which is thought to be largely driven by dramatic mountain uplifts and environmental complications associated with the southeastern extension of the Tibetan Plateau.  相似文献   

10.
硅藻鼠科是仅分布于亚洲的啮齿类类群,头骨具豪猪型咬肌结构,下颌则为松鼠型。该类群代表了一个从梳趾鼠类分化出的区域性支系,虽与豪猪次目相近,但并不是它的成员。最早的硅藻鼠化石记录发现于Baluchistan渐新世陆相地层中,稍晚的记录发现于南业晚渐新世。印度次大陆连续的地层为该科的演化历史提供了主要的化石依据。早中新世晚期至中中新世,硅藻科化石也发现了泰国、中国以及日本。其后的硅藻鼠种类少且鲜有化石记录。晚中新世早期在巴基斯坦有一个种,中国南部晚中新世也可能有一个种。尽管在最早的化石地点发现的标本较多,但其后的时段内除泰国李盆地外化石并不丰富,这指示了其特殊的生活习性或其生活区域化石保存的偏差。已知的化石记录并没有指示出该类群的多样性,也可能是缺少石化作用的结果。硅藻鼠类在水系外围区域延续生存与最近在老挝中部多岩石地带发现的现生Laonastes也是一个硅藻鼠的假设相一致。  相似文献   

11.
The fossil record evidences an old origin and diversification of Malvaceae in the Northern Hemisphere. The central Tibetan Plateau was at a low elevation with a monsoon influence during the Eocene, allowing the development of a subtropical flora containing Malvaceae. The taxonomic study of fossils from the Eocene of what is now the Tibetan Plateau is still ongoing. Malvaceae fossils from the Eocene Jianglang flora, are attributed to sub-families Tilioideae and Sterculioideae, and are compared with modern species. A new specimen of Firmiana is described based on a fruit valve with a pinnate venation, the secondary veins starting at the ventral suture and reaching the midvein, and the seeds attached at the proximal part of the ventral suture. This specimen represents the earliest known occurrence of the genus. A new occurrence of Craigia is also reported based on detached membranous valves of a fruit capsule with a prominent fusiform locular area and radiating venation. Based on the fossil record of Firmiana and its modern distribution, we infer that the genus may have originated in East Asia and subsequently diversified in South China and Southeast Asia. The new occurrence of Craigia indicates that the genus was distributed in humid areas in South, Southwest and North China during the Eocene. Both fossil records evidence the important role that the Tibetan region played in the diversification of plants in East and Southeast Asia.  相似文献   

12.
Abstract

Three species within the genus Calophyllum collected from middle Miocene Fotan Group sediments in Zhangpu County, Fujian, southeastern China are described in this paper. These fossils include Calophyllum zhangpuensis sp. nov., Calophyllum striatum, and Calophyllum suraikholaensis. The new fossil species C. zhangpuensis sp. nov. is oval, possesses entire leaves with closely spaced parallel secondary veins and has a round, or slightly retuse, apex. These specimens represent the first known fossil records of this relative wide leaf-type form of Calophyllum from China and have a length:width (L:W) ratio less than 3:1. In combination with the known modern geographic distribution and habitats of this wide leaf-type Calophyllum and other plants, data suggest that the middle Miocene Fotan flora is indicative of a warm climate. Thus, based on available fossil data, we speculate that this genus probably originated in India during the Paleocene before spreading from India to Bangladesh and into China, Sumatra, Malaysia, Indonesia, and Java during the Neogene, leading to its modern distribution. At least, the 3 fossil species in this region can explain floristic exchange between India, Fujian, and South China, which is consistent with previous studies; the occurrence of these 3 species indicates that Calophyllum began to diversity in China no later than the Miocene.  相似文献   

13.
Elucidating the spatio-temporal distributions of terrestrial plants is a key for interpreting the origin of distribution patterns and the tempo of intercontinental disjunction. Nordenskioeldia was distributed in eastern Asia and North America from the Late Cretaceous to the Miocene. Its fossil record provides important information on former patterns of disjunction and dispersal in the Northern Hemisphere. New specimens from the Paleocene of China allow us to further extend the history of the group and provide the impetus to review its distribution in space and time. The comparative morphological survey on fossil Nordenskioeldia found in the Paleocene sediments in both eastern Asia and North America confirms that they belonged to the same morpho-species, which indicates a close floristic continuity between both continents due to land connection available during that time. The spatio-temporal distributions of Nordenskioeldia indicate that the taxon probably expanded eastward from eastern Asia into North America by the end of Early/Middle Maastrichtian, subsequently colonized Greenland, northeastern North America and Spitsbergen in the Early Paleocene, and finally became extinct in the Miocene. The fluctuations in its northern limits took place in response to climate changes: warming from the Paleocene to the Eocene, cooling during the Eocene–Oligocene and amelioration during the Late Oligocene–Mid-Miocene.  相似文献   

14.
Determining whether the high-latitude Bering land bridge (BLB) was ecologically suitable for the migration of mesothermal plants is significant for Holarctic phytogeographic inferences. Paleobotanical studies provide a critical source of data on the latitudinal positions of different plant lineages at different times, permitting assessment of the efficacy of the BLB for migration. Here we report exceptionally preserved fossils of Firmiana and Tilia endochrysea from the middle Miocene of South Korea. This represents a new reliable record of Firmiana and the first discovery of the T. endochrysea lineage in the fossil record of Asia. The occurrence of these fossils in South Korea indicates that the two lineages had a distribution that extended much farther north during the middle Miocene, but they were still geographically remote from the BLB. In light of the broader fossil record of Asia, our study shows that, in the middle Miocene, some mesothermal plants apparently inhabited the territory adjacent to the BLB and thus they were possibly capable of utilizing the BLB as a migratory corridor. Some other mesothermal plants, such as Firmiana and the T. endochrysea lineages, however, are restricted to more southern regions relative to the BLB based on current fossil evidence. These lineages may have been ecologically unable to traverse the BLB, which raises questions about the efficacy of the BLB as a universal exchange route for mesothermal plants between Asia and North America during the middle Miocene.  相似文献   

15.
Itea is a genus of about 20 species of trees and shrubs that are today native to southeastern North America, eastern Asia, and eastern Africa. In this paper, I review the fossil record of Itea, which is based on four types of fossils: diporate, psilate pollen attributed to Itea or the dispersed pollen genus Iteapollis; carpofossils representing fruits and seeds attributed to Itea europaea; flowers preserved in amber and assigned to Adenanthemum iteoides; and leaf impressions attributed to Itea. The distributions of these fossils indicate that Itea was present in western North America from the early Eocene to Miocene, in eastern North America beginning no later than the early Miocene, and in western Eurasia from the late Eocene to Pliocene. Only one datapoint is known from eastern Asia; it is early Miocene in age. Based on the fossil record, it can be inferred that Itea crossed between continents over both the Bering Land Bridge and North American Land Bridge, and that it reached Africa from Europe via Anatolia. Thus, it is predicted that the sole extant North American species, I. virginica, may be most closely related to the sole extant African species, I. rhamnoides. The potential application of Itea fossils to calibrating phylogenetic trees generated from molecular sequence data is also discussed.  相似文献   

16.
The genus Burretiodendron Rehder is currently endemic to an area near the China–Vietnam border and the limestone mountains of Thailand and Myanmar. The fossil records of this genus were previously found only from the Miocene of Yunnan, Southwest China, and the Oligocene of Guangxi, South China. Here, we describe fossil fruits and associated leaves of Burretiodendron, which were discovered in the lower Oligocene Shangcun Formation of the Maoming Basin, Guangdong, South China. Morphological comparison with extant and fossil Burretiodendron taxa indicates that fruit fossils belong to the species Burretiodendron parvifructum J. Lebreton Anberrée & Z. K. Zhou. This is one of the earliest fossil records of the genus, providing additional evidence for the early biogeographic history of this genus and supporting the inference that the genus originated in South China. According to the habitat conditions of modern species, we speculate that there were limestone mountains around the Maoming Basin in the early Oligocene.  相似文献   

17.
A number of cupressaceous fossil leaves are described in this paper that come from the lower Miocene of Inner Mongolia, northern China. These new examples of fossil leaves are compressed, have their branchlets arranged in a plane, either spreading or ascending, and are flat. These specimens also possess scale-like leaves that are dimorphic, preserved facial leaves that are rhomboidal and have obtuse apices, and lateral leaves that are boat-shaped and have slightly incurved apices. The epidermal cells of these fossils are quadrangular, rectangular, or narrowly rectangular, while the leaves are amphistomatic, and stomata are elliptical or oblong, and monocyclic. In comparison with both living and related fossil taxa, we identify the new fossils as Platycladus preorientalis sp. nov. Taken in combination with a molecular phylogenetic analysis, the new fossils suggest that the genus Platycladus originated in the Oligocene in mid and high Asian latitudes. Thus, the ancient Platycladus lineage probably migrated from Europe to Asia following the closure of the Turgai strait during the Oligocene.  相似文献   

18.
Recently discovered fossil bamboo leaves and pollen are described from the Neogene of Poland. Morphological analysis of fossil leaves from the Late Miocene deposits of the Bełchatów Lignite Mine, Central Poland have allowed them to be determined as “Bambusa” lugdunensis Saporta. It is the first record of this species in the Cenozoic of Poland. The fossils have been compared with other records of bamboos from the Cenozoic of Europe. Pollen grains from the Middle Miocene (Badenian) deposits from the Legnica brown coal deposit (Lower Silesia) provide additional evidence of bamboos. These are assigned to Graminidites bambusoides Stuchlik, and are similar to those of recent Arundinaria. We infer that plant (plants?) that produced the pollen of G. bambusoides could have grown in swamp forests and/or reed marshes. This report provides a general survey of the occurrence of bamboos in the European Neogene, from which the leaves and pollen documented here present important data on the distribution of this group of monocots in Poland and eastern Europe.  相似文献   

19.
刘武  吴秀杰 《人类学学报》2022,41(4):563-575
近年对许家窑、许昌、华龙洞、澎湖、夏河、哈尔滨等人类化石开展的系统研究,引发了学界对中更新世晚期人类演化及分类的不同认识。基于对相关中国人类化石形态特征的分析,作者提出这一时期中国人类化石形态特征表现为四种类型:1)以中更新世晚期人类共有特征为主;2)以原始特征为主;3)以现代特征为主;4)独特形态组合。多数化石形态特征表现为前三种类型,而许昌和许家窑这种以硕大的头骨和巨大颅容量构成的独特形态组合在其他同时期化石还没有发现。化石形态的多样性提示,不同类型的中更新世晚期中国古人类对现代人的形成贡献不同。作者认为在该时期的人类化石形态多样性规律还未阐明的情况下,将具有混合或镶嵌特征的相关人类化石归入分类地位不确定的人群较为合适。  相似文献   

20.
本文描述的较完整的花鳅 Cobitis 化石在我国尚属首次发现.花鳅属是花鳅亚科(Cobitinae)中较进步的鱼类,广布于欧洲、亚洲和非洲,已知化石则产自欧洲和亚洲的第三系.长胸鳍花鳅 Cobitis longipectoralis sp. nov. 的发现为探讨鳅科起源及其地理分布提供了新的资料.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号