Age of Neoproterozoic bilatarian body and trace fossils, White Sea, Russia: implications for metazoan evolution

A uranium-lead zircon age for a volcanic ash interstratified with fossil-bearing, shallow marine siliciclastic rocks in the Zimnie Gory section of the White Sea region indicates that a diverse assemblage of body and trace fossils occurred before 555.3 +/- 0.3 million years ago. This age is a minimum for the oldest well-documented triploblastic bilaterian Kimberella. It also makes co-occurring trace fossils the oldest that are reliably dated. This determination of age implies that there is no simple relation between Ediacaran diversity and the carbon isotopic composition of Neoproterozoic seawater.     

Modular construction of early Ediacaran complex life forms

Newly discovered, exceptionally preserved, soft-bodied fossils near Spaniard's Bay in eastern Newfoundland exhibit features not previously described from Ediacaran (terminal Neoproterozoic) fossils. All of the Spaniard's Bay taxa were composed of similar architectural elements-centimeter-scale frondlets exhibiting three orders of fracticality in branching. Frondlets were combined as modules atop semi-rigid organic skeletons to form a wide array of larger constructions, including frondose and plumose structures. This architecture and construction define the "rangeomorphs," a biological clade that dominated the Mistaken Point assemblage (575 to 560 million years ago) but does not appear to be ancestral to any Phanerozoic or modern organisms.     

Old World fossil record of modern-type hummingbirds

I report on tiny skeletons of stem-group hummingbirds from the early Oligocene of Germany that are of essentially modern appearance and exhibit morphological specializations toward nectarivory and hovering flight. These are the oldest fossils of modern-type hummingbirds, which had not previously been reported from the Old World. The findings demonstrate that early hummingbird evolution was not restricted to the New World. They further suggest that bird-flower coevolution dates back to the early Oligocene and open another view on the origin of ornithophily in Old World plants.     

The ediacarian period and syste: metazoa inherit the Earth

The Ediacarian, here defined as the initial period and system of the Phanerozoic Eon, is characterized by the oldest known multicellular animal life. The distinctive biotal assemblage comprises naked Metazoa, represented in the type region by 26 species in 18 genera and 4 or more phyla, plus simple metazoan surface tracks. Elements of this unique biota appeared worldwide at low paleolatitudes, following terminal Proterozoic glaciation. Ediacarian history lasted from about 670 million to 550 million years ago. This interval, plus Early Cambrian, was the time during which metazoan life diversified into nearly all of the major phyla and most of the invertebrate classes and orders subsequently known.     

"Inordinate Fondness" explained: why are there So many beetles?

The phylogeny of the Phytophaga, the largest and oldest radiation of herbivorous beetles, was reconstructed from 115 complete DNA sequences for the 18S nuclear ribosomal subunit and from 212 morphological characters. The results of these analyses were used to interpret the role of angiosperms in beetle diversification. Jurassic fossils represent basal lineages that are still associated with conifers and cycads. Repeated origins of angiosperm-feeding beetle lineages are associated with enhanced rates of beetle diversification, indicating a series of adaptive radiations. Collectively, these radiations represent nearly half of the species in the order Coleoptera and a similar proportion of herbivorous insect species.     

Synchronous aggregate growth in an abundant new Ediacaran tubular organism

The most abundant taxon of the Neoproterozoic soft-bodied biota near Ediacara, South Australia, occurs as clusters of similarly sized individuals, which suggests synchronous aggregate growth by spatfall. Tubes of Funisia dorothea gen. et sp. nov. were anchored within the shallow, sandy sea bed and lived in dense, typically monospecific concentrations. Tubes were composed of modular, serially repeating elements. Individuals grew by adding serial elements to the tubular body and by branching of tubes. Their construction and close-packed association imply likely affinity within the Porifera or Cnidaria. These data suggest that several of the most successful marine invertebrate ecological strategies known today were in place in Earth's oldest known metazoan ecosystems before the advent of skeletonization and widespread predation.     

6个不同类型山药品种引种鉴定及特色品种筛选

6个不同类型山药品种的引种鉴定及特色品种筛选结果表明:短块茎山药(紫山药、白山药)可以作为特色山药品种进行示范推广;较短块茎山药(无架双胞、麻山药)以及较长块茎的大和长芋(块茎长度为0.9～1.2 m)可作为优良品种加以利用,丰富山药品种结构。产量高低依次为水山药>大和长芋>麻山药>无架双胞>紫山药>白山药;水山药产量最高,为63.75 t/hm2。生育期最长的为紫山药和白山药;水山药和无架双胞出苗最快,紫山药和白山药出苗较慢。     

Australopithecus sediba at 1.977 Ma and implications for the origins of the genus Homo

Newly exposed cave sediments at the Malapa site include a flowstone layer capping the sedimentary unit containing the Australopithecus sediba fossils. Uranium-lead dating of the flowstone, combined with paleomagnetic and stratigraphic analysis of the flowstone and underlying sediments, provides a tightly constrained date of 1.977 ± 0.002 million years ago (Ma) for these fossils. This refined dating suggests that Au. sediba from Malapa predates the earliest uncontested evidence for Homo in Africa.     

Iguanid lizard from the upper cretaceous of Brazil

Pristiguana brasiliensis, new genus and species, from the Upper Cretaceous Baurú Formation of Brazil, is the oldest fossil referable to the living lizard family Iguanidae. It resembles living primitive South American iguanids in some features, but also shows similarity to members of the related family Teiidae. Iguanid fossils do not appear in North America until the early Eocene, probably by waif dispersal from South America during the late Paleocene or early Eocene. A southern continental (Gondwanan) origin of iguanids is more plausible than the northern one often suggested.     

An upper eocene frog from the dominican republic and its implication for Caribbean biogeography

A frog of the leptodactylid genus Eleutherodactylus is reported from Eocene amber found in the Dominican Republic. It is the first described amphibian fossil in amber, and the oldest complete lissamphibian fossil from Mesoamerica (Central America and Mexico). Dating of the amber matrix indicates that by the end of the Eocene a diverse fauna was present in the Antilles, much earlier than has generally been proposed. The presence of this and other amber fossils from this same age suggests that Tertiary patterns of landmass movements were significant in determining the present distribution of species.     

两个人工选择奥利亚罗非鱼群体系统发育 及其遗传多样性分析

[目的]了解人工选择偏好对奥利亚罗非鱼遗传多样性的影响,为今后人工选育及生产提供参考依据.[方法]对两个奥利亚罗非鱼群体(那马群体和武鸣群体)各70尾个体的线粒体DNA的D-loop区序列、CoI基因和Cytb基因进行测序及系统进化研究,并选用20对微卫星标记对其遗传多样性进行分析.[结果]基于D-loop区序列两个群体共检测出32个单倍型,其中共享单倍型6个;基于CoI基因共检测出23个单倍型,其中共享单倍型16个;基于Cytb基因共检测出14个单倍型,其中共享单倍型10个.基于D-loop区序列、CoI基因和Cytb基因单倍型分别构建的系统发育进化树显示,武鸣群体和那马群体的个体交错在一起,地理差异不明显,且采用NJ法和ME法构建系统发育进化树的进化拓扑结构基本相似.20对微卫星引物均能在奥利亚罗非鱼中获得稳定有效的扩增条带,其中有18个微卫星位点呈多态性;那马、武鸣群体的平均等位基因数(Na)分别为6.5000和7.9444,平均有效等位基因数(Ne)分别是3.9857和4.7268,平均观测杂合度(Ho)分别为0.7123和0.7752,平均期望杂合度(He)分别为0.9614和0.9711、平均Nei期望杂合度分别为0.7017和0.7636,均表现为武鸣群体略高于那马群体.两个群体的遗传分化系数(Fst)在不同微卫星位点间差异明显,其变化范围为0.0173(GM241)~0.2318(UNH868),平均0.0997;从单群体近交系数(Fis)和总群体近交系数(Fit)来看,所有微卫星位点的数值均为负值.[结论]经短期人工选择的武鸣群体奥利亚罗非鱼遗传多样性较被长期人工选择的那马群体遗传多样性丰富,即短期内的不同人工选择偏好对线粒体DNA的遗传影响较小.     

Discovery of the oldest known anthropoidean skull from the paleogene of Egypt

A group of primate fossils newly discovered in the Fayum badlands of Egypt is probably of Eocene age. The site is much older than the localities of previously known Egyptian early Tertiary primates. These finds include a crushed cranium that is the oldest skull found to date of a higher primate. This skull shows four characteristics of higher primates: a catarrhine dental formula, an ectotympanic at the rim of the auditory bulla, a fused frontal bone, and postorbital closure. Details of tooth structure (premolars and molars) and a possibly unfused mandibular symphysis resemble these parts in certain Eocene prosimians.     

Isotopic evidence for massive oxidation of organic matter following the great oxidation event

The stable isotope record of marine carbon indicates that the Proterozoic Eon began and ended with extreme fluctuations in the carbon cycle. In both the Paleoproterozoic [2500 to 1600 million years ago (Ma)] and Neoproterozoic (1000 to 542 Ma), extended intervals of anomalously high carbon isotope ratios (δ(13)C) indicate high rates of organic matter burial and release of oxygen to the atmosphere; in the Neoproterozoic, the high δ(13)C interval was punctuated by abrupt swings to low δ(13)C, indicating massive oxidation of organic matter. We report a Paleoproterozoic negative δ(13)C excursion that is similar in magnitude and apparent duration to the Neoproterozoic anomaly. This Shunga-Francevillian anomaly may reflect intense oxidative weathering of rocks as the result of the initial establishment of an oxygen-rich atmosphere.     

11个鸭种(群)遗传变异的微卫星标记分析

利用9个微卫星标记对高邮鸭、金定鸭、荆江麻鸭、山麻鸭、白羽番鸭、黑羽番鸭（纯黑）、黑羽番鸭（白头）、苏牧麻鸭、苏牧白羽鸭、苏牧黑鸭及龙白鸭11个鸭种（群）的平均基因杂合度、平均多态信息含量进行了分析。结果表明：11个鸭种（群）在9个微卫星座位上的基因频率存在一定差异．其平均基因杂合度为0．6599.平均多态信息含量为0．5966。其中．黑羽番鸭（白头）平均基因杂合度最高．为0．6948．遗传多样性最丰富;荆江麻鸭平均遗传杂合度最低,为0．5757。     

A nearly modern amphibious bird from the Early Cretaceous of northwestern China

Three-dimensional specimens of the volant fossil bird Gansus yumenensis from the Early Cretaceous Xiagou Formation of northwestern China demonstrate that this taxon possesses advanced anatomical features previously known only in Late Cretaceous and Cenozoic ornithuran birds. Phylogenetic analysis recovers Gansus within the Ornithurae, making it the oldest known member of the clade. The Xiagou Formation preserves the oldest known ornithuromorph-dominated avian assemblage. The anatomy of Gansus, like that of other non-neornithean (nonmodern) ornithuran birds, indicates specialization for an amphibious life-style, supporting the hypothesis that modern birds originated in aquatic or littoral niches.     

Small mid-Pleistocene hominin associated with East African Acheulean technology

Hominin fossils from the African mid-Pleistocene are rare despite abundant Acheulean tools in Africa and apparently African-derived hominins in Eurasia between 1.0 and 0.5 million years ago (Ma). Here we describe an African fossil cranium constrained by 40Ar/39Ar analyses, magnetostratigraphy, and sedimentary features to 0.97 to 0.90 Ma, and stratigraphically associated with Acheulean handaxes. Although the cranium represents possibly the smallest adult or near-adult known between 1.7 and 0.5 Ma, it retains features observed in larger Homo erectus individuals, yet shows a distinct suite of traits indicative of wide population variation in the hominins of this period.     

Early human cultural and skeletal remains from guitarrero cave, northern peru

An early man site in highland Peru yielded a rich cultural assemblage in stratigraphic association with faunal remains, botanical remains, and campfire remnants that furnished secure radiocarbon dates. A human mandible and teeth, showing interesting patterns of occlusal wear, were found in a stratum dated by a charcoal sample to 10,610 B.C., the oldest such date in South America.     

Natal homing and connectivity in Atlantic bluefin tuna populations

Atlantic bluefin tuna populations are in steep decline, and an improved understanding of connectivity between individuals from eastern (Mediterranean Sea) and western (Gulf of Mexico) spawning areas is needed to manage remaining fisheries. Chemical signatures in the otoliths of yearlings from regional nurseries were distinct and served as natural tags to assess natal homing and mixing. Adults showed high rates of natal homing to both eastern and western spawning areas. Trans-Atlantic movement (east to west) was significant and size-dependent, with individuals of Mediterranean origin mixing with the western population in the U.S. Atlantic. The largest (oldest) bluefin tuna collected near the northern extent of their range in North American waters were almost exclusively of western origin, indicating that this region represents critical habitat for the western population.     

Archeological traces of early hominid activities, East of lake Rudolf, kenya

Excavations have demonstrated that stone artifacts occur stratified within beds of Lower Pleistocene (or end Pliocene) age. At one site a low-density scatter of worked stone objects occurs together with small but significant quantities of broken-up bones. Potassium-argon dates indicate an age greater than 2 million years; thus, this may be the oldest known hominid occupation site. More than 20 hominid fossils have been recovered from various sedimentary formations in the area.     

东海中南部外海虾类组成特征分析

依据2006年5月（春）、8月（夏）、11月（秋）和2007年2月（冬）在东海中南部外海（26°00′-28°30′N,126°00′E以西）海域虾类资源调查资料,对该海域虾类的种类组成季节变化和空间格局特征作了分析。结果表明：东海中南部外海虾类季节间相似性指数较低,各季节贡献率较大的有长角赤虾、戴氏赤虾、东海红虾和假长缝拟对虾等种类。东海中南部外海虾类种类组成可分为A、B两个组群,A组群主要分布在126°00′E以西100 m等深线附近海域,主要以戴氏赤虾、长角赤虾、假长缝拟对虾、高脊管鞭虾和东海红虾为主;B组群主要分布在126°00′E以东100 m等深线附近海域,主要以脊单肢虾、日本异指虾和九齿扇虾为主。两个群聚类型的空间分布没有明显的群聚边界,但密集区有所不同。