Late middle Eocene epoch of Libya yields earliest known radiation of African anthropoids

Reconstructing the early evolutionary history of anthropoid primates is hindered by a lack of consensus on both the timing and biogeography of anthropoid origins. Some prefer an ancient (Cretaceous) origin for anthropoids in Africa or some other Gondwanan landmass, whereas others advocate a more recent (early Cenozoic) origin for anthropoids in Asia, with subsequent dispersal of one or more early anthropoid taxa to Africa. The oldest undoubted African anthropoid primates described so far are three species of the parapithecid Biretia from the late middle Eocene Bir El Ater locality of Algeria and the late Eocene BQ-2 site in the Fayum region of northern Egypt. Here we report the discovery of the oldest known diverse assemblage of African anthropoids from the late middle Eocene Dur At-Talah escarpment in central Libya. The primate assemblage from Dur At-Talah includes diminutive species pertaining to three higher-level anthropoid clades (Afrotarsiidae, Parapithecidae and Oligopithecidae) as well as a small species of the early strepsirhine primate Karanisia. The high taxonomic diversity of anthropoids at Dur At-Talah indicates either a much longer interval of anthropoid evolution in Africa than is currently documented in the fossil record or the nearly synchronous colonization of Africa by multiple anthropoid clades at some time during the middle Eocene epoch.     

First skulls of the early Eocene primate Shoshonius cooperi and the anthropoid-tarsier dichotomy

The phylogenetic relationships of living tarsiers and extinct omomyid primates are critical for deciphering the origin and relationships of primate higher taxa, particularly anthropoids. Three competing phylogenetic hypotheses are: (1) tarsiers are most closely related to early Cenozoic Omomyidae, particularly genera such as Necrolemur from the late Eocene of Europe; (2) tarsiers share a more recent common ancestry with anthropoids than they do with any known omomyid; (3) tarsiers and/or omomyids are most closely related to strepsirhines. The anatomy of four skulls of the early Eocene omomyid Shoshonius cooperi--the first cranial material recovered for this genus--strongly suggests that Shoshonius shares a more recent common ancestry with Tarsius than do either anthropoids or other Eocene omomyids for which cranial anatomy is known. If the primate suborder Haplorhini (anthropoids, omomyids, tarsiids) is monophyletic, the phylogenetic position of Shoshonius requires that anthropoids and Tarsius diverged by at least the early Eocene, some 15 million years before the first appearance of anthropoids in the fossil record.     

A fossil owl monkey from La Venta, Colombia

Knowledge of the evolutionary history of living New World anthropoids is limited by a relatively poor fossil record. The discovery in 1986 of a new fossil monkey from the middle Miocene deposits of La Venta, Colombia, 12-15 million years ago (Myr BP), is the first example of a living New World monkey genus appearing in Tertiary rocks. Including anatomical evidence of the dentition and facial skull, it provides an unambiguous link between a Neogene fossil and the owl monkey, Aotus, the only modern crepuscular-nocturnal anthropoid primate. This new form brings to three the number of La Venta fossil monkeys which preserve excellent dentitions sharing extensive similarities with modern genera. All of these species are potentially ancestral to their extant relatives. The La Ventan Aotus is additional support for the idea that the modern platyrrhine radiation includes long-lived genera or generic lineages, some of which may be traceable to the early Miocene, 20 Myr BP.     

Indraloris and Sivaladapis: Miocene adapid primates from the Siwaliks of India and Pakistan

THE primate family Adapidae underwent a major radiation during the Eocene in Europe(1,2) and North America(3,4). Asian and African Eocene mammalian faunas are still poorly known, but there is sufficient evidence to indicate at least a modest radiation of Eocene adapids in Asia(5,6) and probably also in Africa(2). Apart from possible lemuriform and anthropoid primate derivatives, the family Adapidae was thought to have become extinct at the end of the Eocene (middle Tongrian, approximately 37 Myr (refs 2, 7, 8)). We present here new evidence which indicates that at least two genera of adapid primates, Indraloris and Sivaladapis (gen. nov.), survived into the late Miocene of India and Pakistan. These genera are little advanced over Eocene Adapidae in terms of dental adaptations and are apparently south Asian relicts of a much earlier radiation.     

Interrelationships among primate higher taxa

One of the most controversial issues in primate palaeontology concerns the phylogenetic position of the extinct primate infraorder Adapiformes. During the Eocene, this group of primates of modern aspect possessed a holarctic distribution, and may have been present in the poorly known Palaeogene of Africa. Mainly on the basis of craniodental morphology, at least four hypotheses have been proposed concerning the phylogenetic interrelationships among adapiforms and other primate higher taxa: (1) that adapiforms are ancestral to both lemuriforms (including Lorisoidea) and anthropoids; (2) that adapiforms cannot be shown to possess a special phylogenetic relationship with either lemuriforms or anthropoids; (3) that adapiforms are the sister taxon of lemuriforms; and (4) that Adapiformes is not a natural, monophyletic group, but rather consists of nested clades within the radiation of lemuriforms. Here, we describe features of the ankle and wrist joints of several adapiform taxa that provide an independent test of the preceding hypotheses. These traits suggest that lemuriforms are monophyletic with respect to known adapiforms, but that adapiforms nevertheless are their stem lineage (sensu Ax).     

Late Eocene of Burma yields earliest anthropoid primate, Pondaungia cotteri.

In April 1978, a fragment of a primate lower jaw containing the second and third molar teeth was found in late Eocene exposures of the Pondaung Hills about 1 mile north-west of Mogaung village in northwestern Central Burma. This approximately 40-Myr-old specimen is the first fossil primate found in Burma since the fragmentary remains of the controversial earliest anthropoids Pondaungia cotteri Pilgrim and Amphipithecus mogaungensis Colbert were recovered more than 50 yr ago. The jaw described here is believed to represent further evidence of P. cotteri. Its recovery from undoubled late Eocene exposures coupled with its salient higher primate characters and excellent state of preservation provides the opportunity to substantiate further that the Pondaung primates of Burma are the earliest known record of the Anthropoidea.     

Fossil evidence for an ancient divergence of lorises and galagos

Morphological, molecular, and biogeographic data bearing on early primate evolution suggest that the clade containing extant (or 'crown') strepsirrhine primates (lemurs, lorises and galagos) arose in Afro-Arabia during the early Palaeogene, but over a century of palaeontological exploration on that landmass has failed to uncover any conclusive support for that hypothesis. Here we describe the first demonstrable crown strepsirrhines from the Afro-Arabian Palaeogene--a galagid and a possible lorisid from the late middle Eocene of Egypt, the latter of which provides the earliest fossil evidence for the distinctive strepsirrhine toothcomb. These discoveries approximately double the previous temporal range of undoubted lorisiforms and lend the first strong palaeontological support to the hypothesis of an ancient Afro-Arabian origin for crown Strepsirrhini and an Eocene divergence of extant lorisiform families.     

The first discovery ofEucommia fruit fossil in China

A fruit of Eucommia has been recovered from the Eocene of Fushun, Liaoning Province. This represents the only confirmed occurrence of fruits of this genus in the paleobotanical record of China. Although Eucommia is endemic to central China today, the genus was more widespread in the Northern Hemisphere during the Tertiary. The fossil specimen from Fushun corresponds closely to the fruits of E. montana Brown from the Eocene of western North America and is easily distinguished from fruits of the living E. ulmoides Oliv. and the Japanese Eocene species, E. kobayashii Huzioka by its smaller size.     

Evidence for echolocation in the oldest known bats

The earliest-known bats are represented by excellent fossil material, including virtually complete skeletons of Icaronycteris index from the early Eocene (50 Myr BP) of western Wyoming and Palaeochiropteryx tupaiodon from the middle Eocene (45 Myr BP) 'Grube Messel' of western Germany. These taxa have been closely allied with Recent Microchiroptera, a suborder of diverse bats noted for their powers of ultrasonic echolocation. A problem with this relationship is the alleged absence in the Eocene forms of specializations in the auditory region and other aspects of the skeletal system. It has been proposed, therefore, that the oldest bats are members of a group more primitive and possibly ancestral to the Microchiroptera and the visually oriented Megachiroptera. Previously undescribed specimens now show, however, that Icaronycteris and Palaeochiropteryx share special basicranial features with microchiropterans which suggest comparable refinement of ultrasonic echolocation. These results support the theory that a sophisticated sonar system was present in the earliest records of microchiropteran history.     

Stepwise evolution of stable sociality in primates

Although much attention has been focused on explaining and describing the diversity of social grouping patterns among primates, less effort has been devoted to understanding the evolutionary history of social living. This is partly because social behaviours do not fossilize, making it difficult to infer changes over evolutionary time. However, primate social behaviour shows strong evidence for phylogenetic inertia, permitting the use of Bayesian comparative methods to infer changes in social behaviour through time, thereby allowing us to evaluate alternative models of social evolution. Here we present a model of primate social evolution, whereby sociality progresses from solitary foraging individuals directly to large multi-male/multi-female aggregations (approximately 52 million years (Myr) ago), with pair-living (approximately 16?Myr ago) or single-male harem systems (approximately 16?Myr ago) derivative from this second stage. This model fits the data significantly better than the two widely accepted alternatives (an unstructured model implied by the socioecological hypothesis or a model that allows linear stepwise changes in social complexity through time). We also find strong support for the co-evolution of social living with a change from nocturnal to diurnal activity patterns, but not with sex-biased dispersal. This supports suggestions that social living may arise because of increased predation risk associated with diurnal activity. Sociality based on loose aggregation is followed by a second shift to stable or bonded groups. This structuring facilitates the evolution of cooperative behaviours and may provide the scaffold for other distinctive anthropoid traits including coalition formation, cooperative resource defence and large brains.     

河南灵长类动物地史分布初探

本文对河南省灵长类动物的地史分布以及影响灵长类动物分布的主要因素进行了初步探讨,并对现生灵长类资源的保护提出了建设性意见。     

A basal tyrannosauroid dinosaur from the Late Jurassic of China

The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest known tyrannosauroid and shows several unexpectedly primitive pelvic features. Nevertheless, the limbs of G. wucaii share several features with derived coelurosaurs, and it possesses features shared by other coelurosaurian clades. This unusual combination of character states provides an insight into the poorly known early radiation of the Coelurosauria. Notably, the presumed predatory Guanlong has a large, fragile and highly pneumatic cranial crest that is among the most elaborate known in any non-avian dinosaur and could be comparable to some classical exaggerated ornamental traits among vertebrates.     

Magnetostratigraphy and pavleo-environmental record of Tertiary deposits of Lanzhou Basin

The Tertiary deposits of the Yongdeng section, the Lanzhou Basin were studied by means of magnetostrati-graphy. The magnetostratigraphic sequences from Paleocene to Miocene were established, and the time scale for the corresponding stratigraphy and mammalian faunas was also established by referring to their correlation to the GPTS of BKSA95 (The geomagnetic polarity time scale which was thoroughly revised and updated by Berggreen et al. in 1995). In the end the paleoenvironmental records and their relationship with the uplifting of the Tibetan Plateau were discussed. The results are as follows. The top boundary of the Xiliugou Formation is dated to be 51 Ma, i.e. Eocene. TheYehucheng Formation covers the time span of 51-31.5 Ma, i.e. from late Early Eocene to early Early Oligocene. The Xianshuihe Formation covers the time span of 31.5-15 Ma, i.e. from Early Oligocene to Middle Miocene. The lower member of the Xianshuihe Formation spans from 31.5 to 20.0 Ma, i.e. from Early Oligocene to early Early Miocene. The middle member is from 20.0 to 16.5 Ma, i.e. in the middle Early Miocene.     

比较不同旅游管理模式对短尾猴(Macaca thibetana)分群的影响

灵长类旅游业近年来呈日益增长的发展趋势,然而关于旅游业对灵长类种群的影响还知之甚少.我国有丰富的现生灵长类资源,近20年来,部分旅游景点不同程度地进行了野生灵长类的旅游开发.为了解旅游开发对短尾猴种群的影响,比较了黄山野生猴谷、峨眉山清音阁生态猴区两处的猴群大小和分群记录,研究发现:由于两地对游客的管理方式不同,两地2007年猴群的大小和分群的记录存在差异.建议旅游开发管理者禁止游客对短尾猴的投喂,恢复其自然的生存状态.     

Episodic fresh surface waters in the Eocene Arctic Ocean

It has been suggested, on the basis of modern hydrology and fully coupled palaeoclimate simulations, that the warm greenhouse conditions that characterized the early Palaeogene period (55-45 Myr ago) probably induced an intensified hydrological cycle with precipitation exceeding evaporation at high latitudes. Little field evidence, however, has been available to constrain oceanic conditions in the Arctic during this period. Here we analyse Palaeogene sediments obtained during the Arctic Coring Expedition, showing that large quantities of the free-floating fern Azolla grew and reproduced in the Arctic Ocean by the onset of the middle Eocene epoch (approximately 50 Myr ago). The Azolla and accompanying abundant freshwater organic and siliceous microfossils indicate an episodic freshening of Arctic surface waters during an approximately 800,000-year interval. The abundant remains of Azolla that characterize basal middle Eocene marine deposits of all Nordic seas probably represent transported assemblages resulting from freshwater spills from the Arctic Ocean that reached as far south as the North Sea. The termination of the Azolla phase in the Arctic coincides with a local sea surface temperature rise from approximately 10 degrees C to 13 degrees C, pointing to simultaneous increases in salt and heat supply owing to the influx of waters from adjacent oceans. We suggest that onset and termination of the Azolla phase depended on the degree of oceanic exchange between Arctic Ocean and adjacent seas.     

A primitive sarcopterygian fish with an eyestalk

The discovery of two Early Devonian osteichthyan (bony fish) fossils has challenged established ideas about the origin of osteichthyans and their divergence into actinopterygians (teleosts and their relatives) and sarcopterygians (tetrapods, coelacanths, lungfishes and related groups). Psarolepis from China and an unnamed braincase from Australia combine derived sarcopterygian and actinopterygian characters with primitive features previously restricted to non-osteichthyans, suggesting that early osteichthyan evolution may have involved substantial parallellism between sarcopterygians and actinopterygians. But interpretation of these fossils has been hampered by poor phylogenetic resolution. Here we describe a basal sarcopterygian fish, Achoania gen, et sp. nov., that fills the morphological gap between Psarolepis and higher sarcoptergyians. We also report the presence of eyestalk attachments in both Achoania and Psarolepis, showing that this supposedly non-osteichthyan feature occurs in basal sarcopterygians as well as the actinoptergyian-like Australian braincase.     

中产阶级:中国语境中的概念功能分析

中产阶级这一话题已成为学界关注的中心话题之一。学者们对中产阶级尤其是中国中产阶级的理解与认识彼此之间存在分歧,就划分中产阶级的经济指标以及中产阶级占总人口比例而言,看法不一。本文拟从中产阶级这一概念入手,追溯这一概念的来源,考察这一概念在中国提出的社会条件,描述中产阶级概念在社会观念的建构中所起的重要作用,分析中产阶级在当下中国语境之中具有的丰富意涵,揭示其意识形态特征以及其所掩盖的诸种社会问题,与此同时,论述中产阶级概念在塑造未来社会形态方面所具有的积极意义和建设性价值。     

The Cenozoic palaeoenvironment of the Arctic Ocean

The history of the Arctic Ocean during the Cenozoic era (0-65 million years ago) is largely unknown from direct evidence. Here we present a Cenozoic palaeoceanographic record constructed from >400 m of sediment core from a recent drilling expedition to the Lomonosov ridge in the Arctic Ocean. Our record shows a palaeoenvironmental transition from a warm 'greenhouse' world, during the late Palaeocene and early Eocene epochs, to a colder 'icehouse' world influenced by sea ice and icebergs from the middle Eocene epoch to the present. For the most recent approximately 14 Myr, we find sedimentation rates of 1-2 cm per thousand years, in stark contrast to the substantially lower rates proposed in earlier studies; this record of the Neogene reveals cooling of the Arctic that was synchronous with the expansion of Greenland ice (approximately 3.2 Myr ago) and East Antarctic ice (approximately 14 Myr ago). We find evidence for the first occurrence of ice-rafted debris in the middle Eocene epoch (approximately 45 Myr ago), some 35 Myr earlier than previously thought; fresh surface waters were present at approximately 49 Myr ago, before the onset of ice-rafted debris. Also, the temperatures of surface waters during the Palaeocene/Eocene thermal maximum (approximately 55 Myr ago) appear to have been substantially warmer than previously estimated. The revised timing of the earliest Arctic cooling events coincides with those from Antarctica, supporting arguments for bipolar symmetry in climate change.     

源下油气成藏主控因素与成藏模式——以北部湾盆地乌石凹陷乌石17X下始新统流沙港组三段油藏为例

北部湾盆地乌石凹陷下始新统流沙港组三段发育源下断块油藏,其原油来自上覆流沙港组二段超压成熟烃源岩,其成藏受"源储压差"、沉积相和有效断块圈闭三因素控制。"源储压差"控制了油气运移方向,油气由流沙港组二段源内超压区向下部、侧向流沙港组三段常压区运移,在断裂圈闭带中聚集。流沙港组二段超压还起到了封盖油气作用。流沙港组三段近岸水下扇扇中辫状水道微相储层物性较好,是"甜点"储层。下始新统流沙港组三段具有"高压源、源封盖、源储接触"的源下油气成藏模式。乌石凹陷东部流沙港组三段始新世裂陷幕断裂圈闭带是"源下"油气富集的区带。     

中国梅花鹿地理分布的变迁

在综合化石记录、历史文献和野外资料的基础上对我国梅花鹿地理分布的变迁进行了探讨.早更新世,梅花鹿分布于华北区和台湾;中更新世至全新世,向北扩展到蒙新区的东部、东北区以及朝鲜、苏联西伯利亚东南部,向南经华中区的东部分布到广西和越南北部,另有一支经东部滨海平原迁移到了日本.川西高原的四川亚种是由华北区向西南延伸的一支演化而来.梅花鹿是适应性很强的林缘动物,其分布区急剧地缩减与晚更新世至全新世青藏高原的强烈抬升有关,更主要地是受冰期后人为活动的影响.