亚洲早古近纪哺乳动物生物年代学与生物地理学的新认识(英文)

近期的研究极大地丰富了亚洲古新世和早始新世哺乳动物群信息,因此有必要对现存亚洲生物年代学和生物地理学框架做出调整。在定量和定性分析的基础上,将生物年代界线与主要的动物群更替事件对应起来,改进了古新世和早始新世亚洲陆相哺乳动物分期年代对比及生物地理学的认识。以往知之甚少的上湖期以原始啮形类和钝脚类为主,其后的浓山期则呈现出亚洲哺乳动物的地方性分异。随着新的基干啮形类以及真正的啮型类的出现,啮形类开始辐射。上湖期-浓山期的界线与北美Torrejonian-Tiffanian界线相当,并且动物群更替很可能是由全球变冷阶段的开始引发的。格沙头期哺乳动物进一步分化,亚洲土著类群急剧减少,以多瘤齿兽类、夜鼩类(nyctitheriids)、克莫土兽类(cimolestids)和食果猴为代表的北美迁入物种开始出现。而在北美,亚洲哺乳动物(包括北柱兽类和原恐角兽类)的第一次入侵发生于Tiffanian-5a期初期,第二次入侵发生于Clarkforkian初期,包含了啮齿类、裂齿类及冠齿兽类。因此格沙头期的开始可与北美Tiffanian-5a的开始相对比。伯姆巴期的开始以偶蹄类、奇蹄类和真灵长类的首次出现为标志,与古新世-始新世界线相当。这些类群在亚洲的出现与它们在北美和欧洲出现于始新世之初的情况类似。与格沙头期初期的动物群扩散不同,伯姆巴期的动物群扩散似乎持续了更长时间,并且也有可能直接发生在亚洲和欧洲之间。     

美国怀俄明州大角盆地北部Polecat台地古新世动物群演化（英文）

怀俄明州大角盆地北部的Polecat台地和麦卡洛峰的重要发现对了解北美古新世哺乳动物生物地层以及古新世-始新世极热事件中陆生动物群更替模式和原因具有重要意义。1910年,普林斯顿大学和美国自然历史博物馆的古生物学者指出,古新世的哺乳动物与始新世的明显不同,这使得古新世是一个不同于始新世的时期的观点很快被接受。80年之后,密歇根大学和卡耐基研究院的古生物学者指出,陆相古新统-始新统界线可以用动物群的快速更替和小型化作为标志,并伴随着一次重要的碳同位素漂移,这使得古新世-始新世极热事件(PETM)作为真正的全球性温室升温事件得到了公认。1950年,投身古生物事业的年轻学者周明镇被介绍到怀俄明参加古新世哺乳动物野外工作。在那里,他积累了专业知识和经验,并促成了对中国古新统进行的类似考察。现在的挑战是如何将北美和亚洲大陆相似的古新世历史拼合在一起。     

安徽潜山盆地古新世地层和脊椎动物概述（英文）

潜山盆地中、新生代红层由一套单斜的碎屑岩组成,划分为上白垩统高河埠组、古新统望虎墩组(分为上、中、下三段)和痘姆组(分上、下两段)。1970年以来,在潜山盆地的持续调查发现了大量脊椎动物化石。迄今为止,潜山盆地古新统共报道了45属61种(含9个未命名的种)脊椎动物,包括爬行类、鸟类和哺乳类。其中哺乳动物最为丰富,共有33属46种(含7个未命名种),分属10个目16个科。根据化石产出的层位,可以在潜山古新统中识别出7个化石层位。基于哺乳动物生物地层学证据,望虎墩组下段至上段下部可以大致与广东南雄盆地上湖组和江西池江盆地狮子口组对比,对应于亚洲陆相哺乳动物分期的上湖期;望虎墩组上段上部和痘姆组可以与南雄盆地浓山组以及池江盆地的池江组对比,与浓山期相对应。综合我国几个古新世盆地的古地磁研究结果显示,上湖期可以大致与北美陆相哺乳动物分期的Puercan和Torreionian对比,浓山期则与Tiffanian早中期(Ti1-Ti4a)相当。上湖期和浓山期还可以进一步与国际地质年表中的丹尼期(Danian)和塞兰特期(Selandian)对比。因此,潜山盆地发现的脊椎动物化石的时代属于早、中古新世。     

内蒙古苏崩地点的古新世软食中兽(哺乳纲,中兽目):古新世-始新世界线附近“东方伊甸园”扩散模式的新证据(英文)

记述了发现于内蒙古苏崩晚古新世格沙头期的中兽类软食中兽Hapalodectes属的一个新种。这是软食中兽在中国古新世地层中的首次发现,也是亚洲格沙头期的第二种软食中兽。已有的系统学和生物地层学证据支持软食中兽属和软食中兽科(Hapalodectidae)亚洲起源的观点。软食中兽显然是在古新世-始新世极热事件(PETM)期间通过白令陆桥扩散到北美大陆的,因而符合"东方伊甸园"学说中的生物地理格局。软食中兽有限的(即非欧洲的)地理分布使得我们可以重建该属生物地理学历史。如同软食中兽一样的"东方伊甸园"式的扩散模式,可以看作是大的环境变化事件导致多个支系产生相似的系统学和生物地理学分布格局的生物地理扩散机制。严格地检查了所谓的在古新世-始新世界线上或其附近的与"东方伊甸园"模式相矛盾的大陆间哺乳动物扩散事例,结果发现这些例子都是不可靠的。"东方伊甸园"生物地理学说充分解释了PETM时期哺乳动物群更替以及劳亚古陆哺乳动物地理分布格局的成因。     

从异地迁入的动物类群是北美西部内陆地区古新世最早期哺乳动物群的重要组成部分吗?(英文)

K/T界线绝灭事件后残存类群的迁入和地方性辐射在北美西部内陆地区的古新世最早期(Puercan期)哺乳动物群的进化中所起的作用存在争议。持续的野外工作和室内研究极大地扩展和提升了我们对北美地区的白垩纪最晚期(北美陆相哺乳动物分期的Lancian期)和Puercan1期(Pu1)的地方动物群组成的认识,也揭示了这些地方动物群生物年代学对比的局限。总的来说,北美西部内陆地区北部的Pu1地方动物群主要由多瘤齿兽类和真兽类组成,而Lancian期存在的有袋类各类群绝灭。大多数的Pu1哺乳动物是由其他地区迁移而来,其中许多类群在K/T界线后不久就迁徙到这个地区。北美洲古纬度高的地区和亚洲太平洋沿岸地区的白垩纪最晚期或者古新世最早期哺乳动物群的缺乏,妨碍了对异地迁移到北美的哺乳动物起源于亚洲这一假说的验证。另一个假说认为,大多数迁入北美西部内陆地区北部的Pu1哺乳动物可能来自北美大陆的其他地区。这一假说得到了越来越多的支持,并且没有证据表明是错误的。     

广东南雄晚古新世的中兽类

广东南雄盆地早第三纪红层罗佛寨群分上、下两部分:下部上湖组含有比较丰富的哺乳动物化石,时代确定为中古新世;而上部浓山组长期以来由于缺乏哺乳动物化石,时代一直未确定。1973年冬,中国科学院古脊椎动物与古人类研究所的一个野外队,在浓山组地层中发现了一些哺乳动物化石,为确定浓山组的时代提供了重要的依据。在这些材料中有两块中兽化石,虽然材料都很破碎,但对于了解该动物群的性质和确定该地层时代仍有一定意义。     

湖南衡阳盆地岭茶地区古近纪介形类动物群北大核心

描述衡阳盆地东北部岭茶地区介形类化石9属23种。岭茶地区古近纪介形类动物群以Cypris和Li mnocythere两属最繁盛,可划分为两个化石组合:栗木坪组为Cypris henanensis-Cyprois reniformis-Li mno-cythere honggangensis组合,岭茶组为Li mnocythereirregularis-Cypris favosa-Ilyocypris gaoyouensis组合。岭茶地区栗木坪组与珠江三角洲地区宝月组的介形类动物群相同,岭茶组与华涌组的介形类面貌也基本相同,因此栗木坪组和岭茶组的时代应属晚古新世和早始新世,这与栗木坪组和岭茶组中哺乳动物、古地磁和碳氧同位素的研究结果相一致。     

湖南衡阳盆地岭茶地区古近纪介形类动物群

描述衡阳盆地东北部岭茶地区介形类化石9属23种。岭茶地区古近纪介形类动物群以Cypris和Li mnocythere两属最繁盛,可划分为两个化石组合:栗木坪组为Cypris henanensis-Cyprois reniformis-Li mno-cythere honggangensis组合,岭茶组为Li mnocythereirregularis-Cypris favosa-Ilyocypris gaoyouensis组合。岭茶地区栗木坪组与珠江三角洲地区宝月组的介形类动物群相同,岭茶组与华涌组的介形类面貌也基本相同,因此栗木坪组和岭茶组的时代应属晚古新世和早始新世,这与栗木坪组和岭茶组中哺乳动物、古地磁和碳氧同位素的研究结果相一致。     

广东南雄盆地上湖组介形类动物群及白垩-第三系界线

南雄盆地上湖组介形类可划分为2个性质不同的动物群及4个化石带:下部为 Porpocypris 动物群,是以中生代属种为主,中、新生代属种混生的过渡性动物群,时代为晚白垩世最晚期;上部为 Cypris 动物群,以 Cypris 属占优势, Sinocypris 属开始出现, Cypridea 等古老属种绝灭为主要特征,时代为早—中古新世.根据介形类演化发展阶段和白垩纪末生物绝灭事件,南雄盆地白垩系与第三系的界线应划在 Porpocypris 与 Cypris 动物群之间,即上湖组坪岭段与下惠段之间.     

北美西部古新世-始新世极热事件(PETM)期间的哺乳动物群序列(英文)

跟随一队研究哺乳动物群在古新世-始新世变化的生物地层学和古地理学的学者,已故周明镇教授开始了他的古脊椎动物学事业。这是化石记录中偶蹄类、奇蹄类和灵长类(APP类群)首次出现的时期。随着北美西部Polecat Bench新的最晚古新世Clarkforkian哺乳动物群的发现,古新世作为一个独立于始新世的分期从1911年开始被接受。后来,研究证明古新世-始新世界线包括了一段时间,这期间发育了矮小型哺乳动物支系。古新世-始新世碳同位素漂移(CIE)与哺乳动物矮小化以及APP类群的首次出现是同时的。据此可以对CIE进行全球性总结,结果表明它与古新世-始新世极热事件(PETM)相关。PETM这一全球温室变暖事件不仅对地球气候和生物群有短暂的影响,而且对生物群同样具有深远持续的影响。我们所知的哺乳动物与CIE和PETM之间关系的大部分内容是通过对Polecat Bench周边剖面独特地层记录的高分辨率研究得到的。周教授早年曾在那里工作过,如今他的骨灰也撒在那里。     

河南潭头、卢氏和灵宝盆地上白垩统一下第三系的划分

在这篇短文中,根据脊椎动物化石的发现,进一步叙述和讨论了豫西潭头、灵宝和卢氏三个盆地的中、新生代地层的划分问题。在这三个盆地的中、新生代堆积物中,属于晚白垩世的有潭头盆地秋扒组和灵宝盆地的南朝组,后一个盆地还可能存在着时代更早的白垩纪地层。在潭头盆地的高峪沟组和大章组中分别找到中古新世的阶齿兽、中兽科和晚古新世的牧兽科、假古猬科化石;在潭头组中发现原恐角兽类和古脊齿兽类化石,时代为早始新世。在灵宝盆地的项城群中尚未找到哺乳类化石,可能包括古新世和始新世早中期的堆积。卢氏盆地的卢氏组和锄钩峪组以及灵宝盆地的川口组和浑水河组的时代为晚始新世。卢氏组下部和川口组或许可延至中始新世。     

The long‐term history of dispersal among lizards in the early Eocene: new evidence from a microvertebrate assemblage in the Bighorn Basin of Wyoming,USA

Abstract: Early Eocene mammal faunas of North America were transformed by intercontinental dispersal at the Paleocene–Eocene boundary, but lizard faunas from the earliest Eocene of the same area were dominated by immigrants from within the continent. A new lizard assemblage from the middle early Eocene of Wyoming sheds light on the longer‐term history of dispersal in relation to climate change. The assemblage consists of three iguanid species (including two new species possibly closely related to living Anolis), Scincoideus, ‘Palaeoxantusia’, four anguids, two species of an undescribed new anguimorph clade, Provaranosaurus and a varanoid (cf. Saniwa). Most North American glyptosaurin glyptosaurines are now referred to Glyptosaurus, and Glyptosaurus hillsi is given a new diagnosis. Scincoideus is otherwise known only from the mid‐Paleocene of Belgium, and the specimens described here are the first to document intercontinental dispersal to North America among lizards in the early Eocene. Like in mammals, some immigrant lizard lineages first appearing in the Bighorn Basin in the earliest Eocene persisted in the area long after the Paleocene–Eocene thermal maximum, but other immigrants appear to have been restricted to the Paleocene–Eocene thermal maximum.     

Evolution of Paleocene to Early Eocene larger benthic foraminifer assemblages of the Indus Basin,Pakistan

Afzal, J., Williams, M., Leng, M.J., Aldridge, R.J. & Stephenson, M.H. 2011: Evolution of Paleocene to Early Eocene larger benthic foraminifer assemblages of the Indus Basin, Pakistan. Lethaia, Vol. 44, pp. 299–320. The Paleocene–Early Eocene carbonate successions of the Indus Basin in Pakistan formed on the northwestern continental shelf margin of the Indian Plate in the eastern Tethys Ocean. Based on larger benthic foraminifera (LBF), eight Tethyan foraminiferal biozones (SBZ1–SBZ8) spanning the Paleocene to Early Eocene interval are identified. The base of the Eocene is identified by the first appearance of Alveolina sp. Other stratigraphically important LBFs that are characteristic of the earliest Eocene are Ranikothalia nuttalli, Discocyclina dispansa and Assilina dandotica. Stable isotope analysis through the Paleocene–Eocene (P–E) boundary interval identifies more positive δ¹³C values for the Late Paleocene (+3.4‰ to +3.0‰) and lower values (+2.7‰ to +1.6‰) for the earliest Eocene. However, there is insufficient sampling resolution to identify the maximum negative δ¹³C excursion of the Paleocene–Eocene Thermal Maximum. During Late Paleocene times LBF assemblages in the Indus Basin were taxonomically close to those of west Tethys, facilitating biostratigraphic correlation. However, this faunal continuity is lost at the P–E boundary and the earliest Eocene succession lacks typical west Tethys Nummulites, while Alveolina are rare; LBFs such as Miscellanea and Ranikothalia continue to dominate in the Indus Basin. The absence of Nummulites from the earliest Eocene of Pakistan and rarity of Alveolina, elsewhere used as the prime marker for the base of the Eocene, may imply biogeographical barriers between east and west Tethys, perhaps caused by the initial stages of India‐Asia collision. Later, at the level of the Eocene SBZ8 Biozone, faunal links were re‐established and many foraminifera with west Tethys affinities appeared in east Tethys, suggesting the barriers to migration ceased. □Biostratigraphy, Eocene, India‐Asia collision, larger benthic foraminifera, palaeoecology, Paleocene.     

Diversity of Menispermaceae from the Paleocene and Eocene of South China

We present here the earliest known Asian fossil records of the Menispermaceae based on fossil fruits from Paleocene and Eocene localities in South China. A new genus and species, Paleoorbicarpum parvum sp. nov., and two new species of Stephania Loureiro, S. ornamenta sp. nov. and S. geniculata sp. nov., are recognized from Paleocene deposits of the Sanshui Basin, Guangdong, and a new occurrence of the widespread Eocene species Stephania auriformis (Hollick) Han & Manchester is recognized from the Maoming Basin, Guangdong. The Paleocene Stephania specimens described here represent the earliest fossil endocarp record of the Menispermaceae in eastern Asia. This discovery shows that the moonseed family had arrived in tropical and humid South China by at least the middle Paleocene, which provides important evidence for the origin and phytogeographic history of the family.     

苏北盆地高邮凹陷D1井白垩纪-古近纪微体古生物地层及沉积环境

高邮凹陷D1井富含介形虫、轮藻和孢粉等化石。通过系统的微体古生物分析,首次对该地区白垩纪一古近纪微体古生物地层进行了精确划分,从下到上共建立11个化石组合：其中介形虫4个,轮藻4个,孢粉3个。文中还简要探讨了沉积环境演变,为该地区油气勘探提供有力的生物地层依据。     

Mammalian turnover and community structure in the Paleocene of North America

The effects of faunal turnover on mammalian community structure are evaluated for 17 faunal zones of the North American Paleocene through early Eocene land mammal ages (Puercan through early Wasatchian). Generic disappearances were significantly high at the end of the Puercan, Torrejonian, and Tiffanian land mammal ages, but appearances were significantly high only during the early Puercan. Generic richness rose rapidly in the early Puercan, remained stable throughout most of the Paleocene, and increased from the late Paleocene into the early Eocene. The null hypothesis that generic turnover clustered preferentially according to dentally defined trophic or body size categories could be rejected or attributed to sampling problems for all but the early (Pu0) and late Paleocene (Ti5‐Cf2). Early Paleocene change in community structure most probably represented endemic radiation of mammals into previously unoccupied niches. Community restructuring in the late Paleocene reflected a complex of causes, including climatic wanning, intercontinental dispersal, and competition.     

广东南雄古新世一新的裂齿类

记述了广东南雄盆地早～中古新世上湖组上部发现的裂齿目一新属新种──杨氏华南兽（Ｈｕａｎａｎｉｕｓ ｙｏｕｎｇｉ ｇｅｎ． ｅｔ ｓｐ． ｎｏｖ．）。新属在上、下前日齿不臼齿化,上臼齿无次尖,下臼齿三角座和跟座均呈Ｖ形等方面显得原始。但在颊齿单面高冠,上臼齿原尖前、后脊分别与前、后附尖相连,小尖发育,具初始的次尖架,下臼齿略呈双曲拱柱状,具下后附尖等方面显示了向典型的裂齿类方向发展。     

Palaeogene marine stratigraphy in China

Palaeogene deposits are widespread in China and are potential sequences for locating stage boundaries. Most strata are non‐marine origin, but marine sediments are well exposed in Tibet, the Tarim Basin of Xinjiang, and the continental margin of East China Sea. Among them, the Tibetan Tethys can be recognized as a dominant marine area, including the Indian‐margin strata of the northern Tethys Himalaya and Asian‐margin strata of the Gangdese forearc basin. Continuous sequences are preserved in the Gamba–Tingri Basin of the north margin of the Indian Plate, where the Palaeogene sequence is divided into the Jidula, Zongpu, Zhepure and Zongpubei formations. Here, the marine sequence ranges from Danian to middle Priabonian (66–35 ma), and the stage boundaries are identified mostly by larger foraminiferal assemblages. The Paleocene/Eocene boundary is found between the Zongpu and Zhepure formations. The uppermost marine beds are from the top of the Zongpubei Formation (~35 ma), marking the end of Indian and Asian collision. In addition, the marine beds crop out along both sides of the Yarlong Zangbo Suture, where they show a deeper marine facies, yielding rich radiolarian fossils of Paleocene and Eocene. The Tarim Basin of Xinjiang is another important area of marine deposition. Here, marine Palaeogene strata are well exposed in the Southwest Tarim Depression and Kuqa Depression. They comprise mostly neritic and coastal lagoon facies of the Tethyan realm. Palaeontological evidence suggests that the Paleocene/Eocene boundary here is in middle of the Qimugen Formation. The Tarim Basin was largely drained by Late Oligocene. To the east, the marine offshore Palaeogene strata are widespread in the North Taiwan and East Zhejiang depressions of the continental shelf basin of East China Sea. Abundant fossils including foraminifera, calcareous nannofossils, ostracods, pollen and bivalves occur in the marine environment. Biostratigraphically, the sequence is well correlated with the international planktonic foraminiferal and nannofossil zonations.     

Facies,paleoenvironment, carbonate platform and facies changes across Paleocene Eocene of the Taleh Zang Formation in the Zagros Basin,SW-Iran

The Paleocene–Eocene Taleh Zang Formation of the Zagros Basin is a sequence of shallow-water carbonates. We have studied carbonate platform, sedimentary environments and its changes based on the facies analysis with particular emphasis on the biogenic assemblages of the Late Paleocene Sarkan and Early Eocene Maleh kuh sections. In the Late Paleocene, nine microfacies types were distinguished, dominated by algal taxa and corals at the lower part and larger foraminifera at the upper part. The Lower Eocene section is characterised by 10 microfacies types, which are dominated by diverse larger foraminifera such as alveolinids, orbitolitids and nummulitids. The Taleh Zang Formation at the Sarkan and Maleh kuh sections represents sedimentation on a carbonate ramp.

The deepening trends show a gradual increase in perforate foraminifera, the deepest environment is marked by the maximum occurrence of perforate foraminifers (Nummulites), while the shallowing trends are composed mainly of imperforate foraminifera and also characterised by lack of fossils in tidal flat facies.

Based on the facies changes and platform evolution, three stages are assumed in platform development: I; algal and coralgal colonies (coralgal platform), II; coralgal reefs giving way to larger foraminifera, III; dominance of diverse and newly developing larger foraminifera lineages in oligotrophic conditions.