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1.
《Comptes Rendus Palevol》2008,7(8):557-569
New observations on the Late Miocene and Earliest Pliocene mustelids from the Middle Awash of Ethiopia are presented. The Middle Awash study area samples the last six million years of African vertebrate evolutionary history. Its Latest Miocene (Asa Koma Member of the Adu-Asa Formation, 5.54–5.77 Ma) and Earliest Pliocene (Kuseralee and Gawto Members of the Sagantole Formation, 5.2 and 4.85 Ma, respectively) deposits sample a number of large and small carnivore taxa among which mustelids are numerically abundant. Among the known Late Miocene and Early Pliocene mustelid genera, the Middle Awash Late Miocene documents the earliest Mellivora in eastern Africa and its likely first appearance in Africa, a new species of Plesiogulo, and a species of Vishnuonyx. The latter possibly represents the last appearance of this genus in Africa. Torolutra ougandensis is known from both the Late Miocene and Early Pliocene deposits of the Middle Awash. The genus Sivaonyx is represented by at least two species: S. ekecaman and S. aff. S. soriae. Most of the lutrine genera documented in the Middle Awash Late Miocene/Early Pliocene are also documented in contemporaneous sites of eastern Africa. The new observations presented here show that mustelids were more diverse in the Middle Awash Late Miocene and Early Pliocene than previously documented.  相似文献   

2.
A complete taxonomic review of Neogene birds of continental Asia is provided. To date, avifauna from the latter half of the Miocene and Pliocene of Central Asia (Mongolia and adjacent regions of Inner Asia) are most thoroughly investigated. Available data enable a reconstruction of successive replacement of Early and Middle Miocene avifaunas by communities of the Recent type. Middle Miocene avifaunas of Mongolia include a great number of extinct genera and species, many of which were widespread in Eurasia. Extant genera became dominant in the Late Miocene and taxa close to living species appear in the Late Pliocene fossil record. Late Pliocene communities of birds of Central Asia were complex in genesis, composed of Miocene relicts (Struthio), immigrants from the European regions of the Palearctic (phasianid Plioperdix), North American immigrants (Calcarius), and also autochthonous elements, the origin of which is apparently connected with the arid belt of Central Asia (diverse passerines).  相似文献   

3.
Late Neogene stable isotope stratigraphy and planktonic foraminiferal biostratigraphy have been examined in a high sedimentation rate core (E67-135, Shell Oil Co.) drilled at 725 m water depth in the De Soto Canyon, Gulf of Mexico. The 305 m core contains sections that are Late Miocene, Early Pliocene, Late Pliocene, and Quaternary in age, and is rich in well-preserved assemblages of planktonic foraminifera.A biostratigraphy has been established based on the ranges of 34 selected species of foraminifera. The core 3orrelates with sections from the Gulf of Mexico, the Caribbean Sea, and the subtropical North and South Atlantic Oceans using, as datums, the evolutionary appearances of Globorotalia miocenica Palmer and Globorotalia margaritae evoluta Cita, the extinction of Globorotalia miocenica and the first appearance of Globorotalia truncatulinoides (d'Orbigny).Oxygen and carbon isotope stratigraphy is based on analysis of the benthonic foraminifer, Uvigerina d'Orbigny. Isotopic trends are similar to those observed in the Pacific and Atlantic Oceans. From Early Pliocene to Late Pleistocene time, average δ18O values increase (2.42‰ to 3.36‰) and exhibit a wider range of values (0.71‰ in Early Pliocene compared to 1.65‰ in Late Pleistocene sediments), probably reflecting Late Neogene climatic deterioration. The ratio 13C12C decreases significantly by ?0.21‰ from the Late Miocene to the Early Pliocene. A decrease in δ13C is observed in other cores and is probably related to changing oceanic circulation patterns in Late Miocene time.  相似文献   

4.
The phasianid genera Perdix, Plioperdix, and Bantamyx from the Neogene of Mongolia and Transbaikalia are reviewed. Based on published data and new material, the diagnoses of Late Pliocene Perdix margaritae Kurochkin and Plioperdix ponticus (Tugarinov) and Late Miocene Bantamyx georgicus Kurochkin are emended. It is shown that a tarsometatarsus from the Upper Miocene of the Pavlodar locality belongs to the genus Palaeoperdix rather than Palaeortyx, as was proposed in the previous studies. Small Neogene Asian phasianids are compared in detail with Neogene taxa from Europe and extant genera.  相似文献   

5.
The analysis of planktic foraminiferal assemblages from Site 1090 (ODP Leg 177), located in the central part of the Subantarctic Zone south of South Africa, provided a geochronology of a 330-m-thick sequence spanning the Middle Eocene to Early Pliocene. A sequence of discrete bioevents enables the calibration of the Antarctic Paleogene (AP) Zonation with lower latitude biozonal schemes for the Middle–Late Eocene interval. In spite of the poor recovery of planktic foraminiferal assemblages, a correlation with the lower latitude standard planktic foraminiferal zonations has been attempted for the whole surveyed interval. Identified bioevents have been tentatively calibrated to the geomagnetic polarity time scale following the biochronology of Berggren et al. (1995). Besides planktic foraminiferal bioevents, the disappearance of the benthic foraminifera Nuttallides truempyi has been used to approximate the Middle/Late Eocene boundary. A hiatus of at least 11.7 Myr occurs between 78 and 71 m composite depth extending from the Early Miocene to the latest Miocene–Early Pliocene. Middle Eocene assemblages exhibit a temperate affinity, while the loss of several planktic foraminiferal species by late Middle to early Late Eocene time reflects cooling. During the Late Eocene–Oligocene intense dissolution caused impoverishment of planktic foraminiferal assemblages possibly following the emplacement of cold, corrosive bottom waters. Two warming peaks are, however, observed: the late Middle Eocene is marked by the invasion of the warmer water Acarinina spinuloinflata and Hantkenina alabamensis at 40.5 Ma, while the middle Late Eocene experienced the immigration of some globigerinathekids including Globigerinatheka luterbacheri and Globigerinatheka cf. semiinvoluta at 34.3 Ma. A more continuous record is observed for the Early Miocene and the Late Miocene–Early Pliocene where planktic foraminiferal assemblages show a distinct affinity with southern mid- to high-latitude faunas.  相似文献   

6.
7.
Anthracotheres of late Middle Miocene and Late Miocene age have been described from several localities in northern Africa, all of them currently assigned to the genus Libycosaurus Bonarelli, although in several previous works they were assigned to Merycopotamus Falconer and Cautley, a considerably younger and specialised form from the Indian subcontinent which has quite different dental and cranial morphology. Three species of Libycosaurus have been named, but there has been some doubt about the morphometric variation within the various species, with some authors such as Gaziry (1987) placing the fossils from Sahabi (Latest Miocene, Libya) and Beglia (end Middle Miocene to basal Late Miocene, Tunisia) into the same species despite marked size differences, and others (Ducrocq et al., 2001) creating a species for a restricted sample of small specimens from Nementcha (Late Middle Miocene, Algeria), but which overlaps with the range of size variation of Beglia fossils. The aim of this paper is to examine the available samples in greater depth in order to understand the morphometric variation in these anthracotheres. It is confirmed that the Beglia sample is quite variable (Black, 1972), both morphologically and metrically, but it is concluded that it nevertheless belongs to a single species, because specimens from some of the localities within the Beglia Formation (e.g. Loc. 17 in the lower levels at Beglia) span the entire range of variation (Pickford, 1994). The sample from Nementcha cannot be distinguished from the Beglia sample on any consistent metric or morphological basis, but in general the specimens fall at the low end of the range of variation of the Beglia sample. It is thus likely that L. algeriensis is a synonym of L. anisae. The Sahabi and Chad samples (L. petrocchii), in contrast, fall above the known range of variation of the Beglia material in almost all metric features, but are close to it morphologically, and they are considered to represent a species distinct from the Beglia sample.  相似文献   

8.
中国陆相新第三系的初步划分与对比   总被引:72,自引:25,他引:47  
本文着重介绍了欧洲地中海区新第三纪研究的进展、分期和对比,并提出我国新第三纪哺乳动物群的分期及与世界对比的初步设想。文中着重阐明将蓬蒂期(Pontian(s. s. )相当于我国保德三趾马红土)置于中新世的根据,并建议把新第三纪/第四纪的界限放在1.8百万年(相当奥杜威事件)。对中新世,作者建议划分为五个不同的期:早中新世,谢家期;中中新世早期,山旺期;中中新世晚期,通古尔期;晚中新世,坝河期和最晚中新世,保德期。对上新世的划分目前尚有困难,建议暂时保留静乐期,代表上新世早期,大体相当欧洲的路西南期(Ruscinian, MN14—MN15)。借用游河期代表上新世晚期,约相当于欧洲的维兰尼期(Villanyian,MN16—MN17)。  相似文献   

9.
Palynological analyses of two wells (Haema-1 and Kachi-1) located in two sub-basins of the Northern South Yellow Sea Basin have been carried out in order to establish a palynostratigraphic breakdown of the sedimentary succession and to determine environments of deposition. Seven assemblage zones and two assemblage subzones have been erected on the basis of frequency variations in, and occurrences of, biostratigraphically significant palynomorphs as follows: Classopollis-Ephedripites Assemblage Zone (AZ): Barremian-Albian; Alisporites-Aquilapollenites-Penetetrapites AZ, which is subdivided into an Alisporites-Rugubivesiculites Assemblage Subzone: Cenomanian-Lower Maastrichtian, and an Aquilapollenites-Penetetrapites Assemblage Subzone: Upper Maastrichtian; Momipites-Coryluspollenites AZ: Paleocene; Caryapollenites-Inaperturopollenites AZ: Lower-Middle Eocene; Quercoidites-Pinuspollenites AZ: Upper Eocene; Liquidambarpollenites-Fupingopollenites-Magnastriatites AZ: Lower-Middle Miocene; Graminidites-Persicarioipollis AZ: Pliocene. The depositional environments represented by the well sections are considered to have been generally fluvio-lacustrine, and the climate to have varied between semi-arid and wet, and subtropical and warm temperate, except during the Late Eocene and Pliocene when a cool-temperate climate prevailed. Six stages in the development of the sub-basins are recognised. These are: (1) initial stage of rift or pull-apart basin-formation during the Late Jurassic?-Cretaceous; (2) subsidence from the Paleocene to Middle Eocene; (3) alternation of uplift and subsidence in the Late Eocene; (4) synrift inversion and erosion through the Oligocene; (5) uplift during the Early Miocene; and (6) widespread subsidence from the Middle Miocene onwards apart from during the Early Pliocene when the region was subjected to uplift once more.  相似文献   

10.
In Pliocene and Quaternary deep-sea sediments of DSDP Site 284 (temperate South Pacific), a significant positive correlation exists between test porosity and the percentage of forms with reticulate surface ultrastructure in samples of the planktonic foraminifer Neogloboquadrina pachyderma (Ehrenberg). Surface ultrastructural characteristics have previously been shown to be related to paleoceanographic oscillations. No relation exists between porosity and surface ultrastructure in either the Late Miocene or earliest Pliocene samples measured.  相似文献   

11.
临夏盆地的新生代地层及其哺乳动物化石证据   总被引:20,自引:9,他引:20  
临夏盆地的新生代地层相当发育 ,保存了从渐新世至全新世的连续沉积序列。更为重要的是 ,这些沉积物中含有丰富的哺乳动物化石 ,为划分和对比临夏盆地的新生代地层提供了可靠的证据。然而 ,此前关于这个盆地地层层序和时代的认识有许多矛盾之处 ,地层命名繁复 ,化石证据混乱。近年来我们对临夏盆地的野外考察已理清了沉积序列 ,并在充分的哺乳动物化石证据的基础上重新厘定了各个岩石地层单位所对应的地质时代。临夏盆地的新生代哺乳动物化石以晚渐新世的巨犀动物群、中中新世的铲齿象动物群、晚中新世的三趾马动物群和早更新世的真马动物群最为丰富。  相似文献   

12.
《Palaeoworld》2020,29(4):761-768
Newly discovered Miocene hyaenid specimens, recently collected from the Siwalik Group, are described and discussed. A careful comparison with the known material reveals that these specimens belong to the early hyaenid species Thalassictis cf. T. proava, Ictitherine indet. and Lepthyaena sivalensis. The stratigraphic range of T. proava extended up to the Dhok Pathan Formation (Middle Miocene to Early Pliocene). The stratigraphic range of T. proava comprises the Middle to Late Miocene, with the youngest record in Hasnot, Potwar Plateau in the Siwalik Group. The material is of great interest because Siwalik carnivoran material is rare.  相似文献   

13.
A stratigraphical chart of marine ostracoda from Lower Miocene to Recent is established. Selected species (approximatively 220) are those morphologicaly well characterized and known from different parts of the Mediterranean area. It appears that: • lower Miocene ostracodes are still poorly known; • specific diversity is high during the Tortonian and the Lower Messinian before the complete disappearance of marine Mediterranean species during the Upper Messinian évaporitic episodes; • during the early Pliocene, about half of the Upper Miocene marine species are reintroduced with the Atlantic waters; other species migrate for the first time in the Mediterranean Sea by the same way; • at the end of the Pliocene or at the beginning of the Pleistocene several species known in Mediterranean since the Middle Miocene or before, such as Cytherella sp. gr. transversa and Ruggieria tetraptera, as well some “nordic guests” such as Hemicythere villosa and Cythere lutea, appear. This work is an opportunity to confirme a Late Miocene age for the Neogene of Skyros (Aegean Sea), to assign the “Upper Pliocene” of Terquem to the Lower Pleistocene and to refute the existence of a pliocene psychrosphere.  相似文献   

14.
Although the divergence of the Panthera clade from other Felidae might be as old as the earliest middle Miocene, its fossil record before the Pliocene is virtually non-existent. Here we reassess the affinities of a felid from the early upper Miocene of Turkey, known by well-preserved associated upper and lower dentitions. We conclude that it belongs to the same genus (Miopanthera Kretzoi, 1938) as the middle Miocene ‘Styriofelis’ lorteti (Gaillard, 1899), and that this genus is close to, if not part of, the Panthera clade.  相似文献   

15.
《Comptes Rendus Palevol》2007,6(5):335-343
Recent expeditions in the northeastern Qinghai-Tibetan Plateau have produced additional mammalian fossils from the Lower Baodean (equivalent to Vallesian, Late Miocene), and, significantly, a new large and the earliest muntjac, Muntiacus noringenensis sp. nov. It is phylogenetically closer to the Late Pliocene M. fenghoensis and extant M. vuqangensis than the other fossil and extant muntjacs are. The existence of this muntjac and other folivores in the Late Miocene Qaidam Basin suggests a forested period in the basin and the evolution from a forested and humid environment to a desert one today. Such a dramatic evolution in environments is an evidence of the effect of the uplift of the Qinghai-Tibetan Plateau and of its influence on continental climates.  相似文献   

16.
The oxygen- and carbon-isotope compositions of planktic and benthic foraminifera and calcareous nannofossils from Middle Oligocene-Early Miocene Equatorial Atlantic sediments (DSDP Site 354) indicate two important paleoceanographic changes, in the Late Oligocene (foraminiferal Zone P.21) and in the Early Miocene (foraminiferal Zone N.5). The first change, reflected by a δ18O increase of 1.45‰ inGlobigerina venezuelana, affected only intermediate pelagic and not surface, deep or bottom waters. The second change affected surface and intermediate waters, whereas deep and bottom waters showed only minor fluctuations. In the case of the former the isotope effect of the moderate ice accumulation on the Antarctic continent is amplified in the Equatorial Atlantic by changes in the circulation pattern. The latter paleoceanographic change, reflected by a significant increase in18O in both planktic and benthic forms (about 1.0‰ and 0.5‰, respectively), may have been caused by ice volume increase and temperature decrease. Both oxygen- and carbon-isotope compositions indicate a marked depth-habitat stratification for planktic foraminifera and calcareous nannofossils. Three different dwelling groups are recognized: shallowGlobigerinoides, Globoquadrina dehiscens, Globorotalia mayeri and nannofossils; intermediateGlobigerina venezuelana; and deepCatapsydrax dissimilis. The comparison of foraminifera and calcareous nannofossils suggests that the isotopic compositions of nannofossils are generally controlled by the same parameters which control the isotopic composition of shallow-dwelling foraminifera, but the former are more enriched in18O.  相似文献   

17.
《Marine Micropaleontology》1988,13(3):193-212
Foraminifera and diatoms have been analyzed from an upper Miocene through Pleistocene(?) sequence of marine sediments exposed on Maria Madre Island, largest of the Trés Marias Islands off the Pacific coast of Mexico. The Neogene stratigraphic sequence exposed on Maria Madre Island includes a mid-Miocene(?) non-marine and/or shallow marine sandstone unconformably overlain by a lower upper Miocene to uppermost Miocene upper to middle bathyal laminated and massive diatomite, mudstone, and siltstone unit. This unit is unconformably overlain by lower Pliocene middle to lower bathyal sandstones and siltstones which, in turn, are unconformably overlain by upper Pliocene through Pleistocene(?) upper bathyal to upper middle bathyal foraminiferal limestones and siltstones. These beds are unconformably capped by Pleistocene terrace deposits. Basement rocks on the island include Cretaceous granite and granodiorite, and Tertiary(?) andesites and rhyolites. The upper Miocene diatomaceous unit contains a low diversity foraminiferal fauna dominated by species of Bolivina indicating low oxygen conditions in the proto-Gulf Maria Madre basin. The diatomaceous unit grades into a mudstone that contains a latest Miocene upper to middle bathyal biofacies characterized by Baggina californica and Uvigerina hootsi along with displaced neritic taxa. An angular unconformity separates the upper Miocene middle bathyal sediments from overlying lower Pliocene siltstones and mudstones that contain a middle to lower bathyal biofacies and abundant planktonic species including Neogloboquadrina acostaensis and Pulleniatina primalis indicating an early Pliocene age. Significantly, this Pliocene unit contains common occurrences of benthic species restricted to Miocene sediments in California including Bulimina uvigerinaformis. Pliocene to Pleistocene(?) foraminiferal limestones and siltstones characterize submarine bank accumulations formed during uplift of the Trés Marias Island area, and include abundant planktonic foraminifera such as Pulleniatina obliquiloculata and Neogloboquadrina duterteri. Common benthic foraminifera in this unit are indicative of upper bathyal water depths. The Neogene depositional history recorded on Maria Madre Island involves an early late Miocene subsidence event marking formation of the Trés Marias Basin with relatively undiluted diatomaceous sediment deposited in a low oxygen setting. Subsidence and deepening of the basin continued into the early Pliocene along with rapid deposition of terrigenous clastics. Uplift of the basinal sequence began in late Pliocene time accompanied by deposition of upper Pliocene-Pleistocene foraminiferal limestones on a rising submarine bank. Continued episodic uplift of the Neogene deposits brought the island above sea level by late Pleistocene time.  相似文献   

18.
In the W-Aures (Algeria), the El Kantara pass displays about 50 m of Red Marls overlying the Maastrichtian limestones with Laffitteina. The Red Marls are, in their turn, overlain by the Thanetian marly limestones of the river El Haï. The micropaleontological inventory of these Red Marls establishes the co-occurrence of subaerian (Microcodium = Paronipora), fresh-water (Charophyta) and marine microfossils (Foraminifers). The stratigraphical significance of these microfossils is discussed. The upper part of the Red Marls, yielding abundant Valvulina and scarce Glomalveolina, is of Thanetian age. The age of the lower part is less established, but the occurrence of Microcodium suggests a Thanetian age too. Located at the margin of the northern opening of the trans-Saharan epeiric sea, the El Kantara section establishes a Thanetian age for the beginning of the Paleocene transgression. Danian deposits are missing, in spite of the absence of an obvious hiatus on the field. After general emersion during the early Paleocene, the Thanetian transgression starts with the set up of lakes at the depositional area of the Red Marls. Marine influences, limited at first, become gradually prevailing, and end with the deposition of neritic marly limestones of river El Haï.  相似文献   

19.
The ochotonid faunas of Eurasia and North America from the Oligocene to the present time are reviewed. The pika family (Ochotonidae Thomas 1897) belongs to the order Lagomorpha, which includes five families: Ochotonidae, Mimotonidae Li 1978, Leporidae Fischer 1817 (hares), Palaeolagidae Dice 1929, and Prolagidae Gureev 1960. The family Ochotonidae consists of two subfamilies: Sinolagomyinae Gureev, 1960 and Ochotoninae Thomas, 1897 and comprises a total of 17 genera. Originating in Central Asia at the beginning of the Late Oligocene, pikas flourished during the Late Oligocene. The highest taxonomic diversity of pikas can be found in the Miocene and Pliocene; towards the Pleistocene, the ochotonid fauna declined. Only one genus, Ochotona, remained extant by the end of the Pleistocene. The genus includes a total of 38 known extinct taxa and 28 extant species.  相似文献   

20.
Turtle remains are common in the Miocene-Holocene deposits of Greece, and are a key focus of the growing research interest in Neogene herpetofaunas from the Aegean region. Some of the most important finds include one of Europe's stratigraphically youngest pleurodiran taxa, Nostimochelone lampra, from the Early Miocene of Macedonia, together with arguably the richest record of fossil tortoises from the Eastern Mediterranean. This incorporates the presently oldest definitive representatives of the quintessential genus Testudo sensu stricto from the Late Miocene of Attica and Macedonia, and numerous specimens of the colossal (carapace ∼2 m-length) testudinid Cheirogaster from Late Miocene-Late Pliocene sediments in southern and northern Greece, as well as on the eastern Aegean islands of Samos and Lesvos. Tantalising, but as yet unconfirmed Miocene accounts of the geoemydid Mauremys in Macedonia, and indeterminate emydid-like remains from Euboea, also provide potentially significant range extensions. Although hampered by a historically sparse documentation, the fossil turtles of Greece are a significant resource that record both assemblage changes and the origin of modern lineages.  相似文献   

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