广西柳城巨猿洞早更新世爪兽化石(奇蹄目,哺乳动物纲)

广西柳城巨猿洞是迄今我国所发现的含爪兽化石最丰富的第四纪化石点。该化石点的爪兽上颊齿原尖强壮,呈圆锥状;次尖发育,呈新月形;原脊完全退失;m3齿带更发育;可归入我国第四纪较常见的中国黄昏爪兽(Hesperotherium sinense)。但柳城巨猿洞的标本明显比我国其他第四纪地点的爪兽较小,尤其是比早更新世晚期的代表小很多。在形态特征方面,柳城巨猿洞的爪兽与重庆巫山的最为接近,而与安徽繁昌及湖北建始的差异较大;但在牙齿的宽／长比值方面,却与安徽繁昌的最为接近。我国已发现的爪兽化石以单个牙齿为主,在分类鉴定方面存在诸多问题,通过牙齿测量的点散布图,可以有效地检验对零散爪兽牙齿齿序的鉴别是否正确。     

甘肃平凉第三纪晚期爪兽类一新属

1970年,中国科学院古脊椎动物与古人类研究所韩康信和王令红两同志在上海收集到一批哺乳动物化石,其中有三颗就是这里记述的一种第三纪晚期的爪兽牙齿。化石产地和层位不清,据了解,化石来自甘肃平凉。我国过去发现的第三纪晚期的爪兽不多,仅在内蒙古通古尔及河北磁县找到过的短吻巨爪兽(Macrotherium brevirostris),在山西霍县找到过安乐黄河兽(Huanghotherium anlungense)。平凉的新发现不仅代表一个新的种类,而且对了解我国爪兽化石的地理分布也有一定价值。     

老第三纪哺乳类化石在滇西首次发現

1964年地质部地质科学研究院赵国光等同志在滇西工作时,于丽江发现了相当多的哺乳动物化石。这批化石中最多的是原始真犀类(主要是Prohyracodon)的牙齿;也有一些两栖犀和原始貘类的牙齿;此外,有少量的牙齿碎片表明,该地还有雷兽、石炭兽及爪兽等化石。     

河南卢氏始新世灵长类一新属

河南卢氏上始新统卢氏组下部含脊椎动物化石层中,曾发现过好几种在第三纪早期哺乳类进化上很有意义的化石,例如:古齿兽科的副等尖齿兽(Paratriisodon),古剑齿虎(Eusmilus),始犬(Miacis),双锥兽(Dichobune)等。最近,在同一批材料中,又发现了一种新的跗猴类的灵长类化石,虽然只有一个不太完整的标本,但因我国已知的古老灵长类化石的材料很少,所以还是一个较有意义的发现。     

吐鲁番盆地古新世哺乳类化石的发现及新疆新生代哺乳类化石层提要

最近,玉门矿务局吐鲁番勘探大队吴忠兴同志,在吐鲁番盆地老第三系中,采集了几个哺乳类的牙齿。很清楚的是一种原始的恐角兽类(Dinocerata)的化石,属于过去发现于蒙古人民共和国上古新统格沙头组(Gashato)中的原恐角兽属(Prodinoceras)。这个发现在地层及古生物上有很大意义。因为这是我国境内首次发现的古新世哺乳类化石;因此,也是我国目前唯一知道的古新统脊椎动物化石层位。在古生物方面,恐角兽类化石,过去我国仅在内蒙二连伊尔丁曼纳层中,发现过一种时代较晚(晚始新世),和相当特化的戈壁兽(Gobiatherium),吐鲁番盆地原始类型的发现是这方面知识上一个重要的进展。     

东北中生代哺乳类动物化石的发现及其意义*

中生代哺乳动物的研究,在了解哺乳类的起源与进化上非常重要。过去美国中亚攷察(?)曾在蒙古人民共和国上白垩纪Djadochta 层内发现了保存完整的食虫类(Insectivora)化石,但在我国的中生代地层内,过去尚无哺乳类动物的化石发现。日本侵占我国东北期间,矢部长克及鹿间时夫曾发表在辽东省南部所采的侏罗纪哺乳类化石一种,定名为满洲兽(Manchurodon)(矢部,鹿间1938);后来鹿间时夫又发表了在东北阜新煤田所采的,时代亦可能为侏罗纪的食虫类化石一种,     

临夏盆地晚中新世爪兽亚科(奇蹄目,哺乳纲)一新种

爪兽在我国新近纪地层中发现的数量和种类都相当稀少。本文根据产自甘肃省临夏盆地晚中新世柳树组的一批化石材料建立的一个爪兽化石新种临夏奈王爪兽(Nestoritherium linxiaense sp.nov.)是此属目前所发现的最原始的种类。新种以鼻骨与泪骨相接触、上臼齿原小尖萎缩、原脊不太发育、下颌粗壮、齿隙短、下犬齿可能存在但发育较弱以及p4下内尖孤立而区别于其他各种。根据新发现的化石,确立了Nestoritherium属名的有效性,并将修订后的Nestoritherium wuduense(Xue&Coombs,1985)归入其中,认为此属是Hesperotherium的祖先类型。     

原始索齿兽类化石在美国发现

<正> 在纽约美国自然历史博物馆工作的我国古生物工作者齐陶从有关方面获悉,美国古脊椎动物学家克累顿(Clayton),麦肯纳(McKenna M.C.)和道宁(DomningD.P.)不久前在美国华盛顿州和俄勒冈州发现中渐新世的海生哺乳类索齿兽目(Desmostylia)化石.化石地点位于太平洋的西海岸.此次发现的这类化石,共有两个属两个种,均为首次发现.其中一个属、种为一     

A NEW SPECIES OF CHALICOTHERIINAE (PERISSODACTYLA,MAMMALIA) FROM THE LATE MIOCENE IN THE LINXIA BASIN OF GANSU, CHINA

爪兽在我国新近纪地层中发现的数量和种类都相当稀少.本文根据产自甘肃省临夏盆地晚中新世柳树组的一批化石材料建立的一个爪兽化石新种临夏奈王爪兽(Nestoritherium linxiaense sp.nov.)是此属目前所发现的最原始的种类.新种以鼻骨与泪骨相接触、上臼齿原小尖萎缩、原脊不太发育、下颌粗壮、齿隙短、下犬齿可能存在但发育较弱以及p4下内尖孤立而区别于其他各种.根据新发现的化石,确立了Nestoritherium属名的有效性,并将修订后的Nestoritherium wuduense (Xue&Coombs,1985)归入其中,认为此属是Hesperotherium的祖先类型.     

云南禄丰三列齿科—新属

1938年,楊锺健、卞美年在祿丰上三迭系中发現了卞氏兽(Bienotherium)的化石。这是在近廿年来世界古生物学上最重要的发現之一。这个发現的重要性在于:卞氏兽及其他几种与牠相近的属于三列齿科(Tritylodontidae)的动物,是作为从爬行类到哺乳类的过渡类型的“似哺乳类爬行动物”中最接近于哺乳类的一种。     

甘肃灵台雷家河剖面中的日进鼠(Chardinomys)

甘肃灵台雷家河剖面产出的日进鼠化石包括了该属从老到新的所有种类 :中新世末—上新世初的C .primitivussp .nov.、早上新世的C .lingtaiensissp .nov .、早上新世—晚上新世初的C .yusheensis和早上新世—晚上新世的C .nihowanicus。系统描述了上述各种 ,对种间的演化过程及该属与Occitanomys和Orientalomys的关系进行了比较和讨论。     

APPEARANCE, DISTRIBUTION, AND GENETIC DISTINCTIVENESS OF LONGMAN'S BEAKED WHALE, INDOPACETUS PACIFICUS

Longman's beaked whale, Indopacetus pacificus , was known previously from only two skulls. Here we describe four new specimens of this species from strandings in the western and central Indian Ocean. Two juveniles, previously misidentified from external morphology as Hyperoodon planifrons , were identified as I. pacificus through diagnostic characteristics of mitochondrial (mt) DNA sequences derived from the holotype of this species. Images of the external appearance and teeth of the species are presented for the first time. Comparison of the color pattern of these new specimens with that of "tropical bottlenose whales" sighted in the tropical Indian and Pacific oceans confirm that those unidentified whales represent I. pacificus. Moore (1968) erected a new genus, Indopacetus , for this species (described initially as Mesoplodon pacificus ) based primarily on cranial morphology. Phylogenetic analyses of short mtDNA fragments available from the specimens known to date were unable to resolve the validity of this genus. However, the diagnostic osteological features highlighted by Moore (1968) for Indopacetus were also observed in the new specimens. Rib count and number of fused cervical vertebrae may also be diagnostic. Rostrum depth at mid-length and melon shape further distinguish this species from Mesoplodon beaked whales. As such, we see no reason on morphological grounds to overturn Moore's (1968) proposal that Longman's beaked whale is sufficiently distinct to be afforded its own genus.     

Nile perch,Lates niloticus,predation on the freshwater prawn,Caridina nilotica,in the Nyanza Gulf,Lake Victoria,East Africa

Synopsis The percentage of Nile perch, Lates niloticus, containing the prawn, Caridina nilotica, declined from 60–85%, for fish between 5 and 40 cm total length, to less than 10% for fish larger than 80 cm in length. The maximum number of prawns eaten by a Nile perch increased steadily, from 10 prawns for a fish in the 5–9.9 cm length group, to 913 prawns in a fish in the 60–69.9 cm length group, and then fell sharply for larger fish. The mean number of Caridina eaten by fish that were foraging on this animal followed a similar trend. Gill raker spacing increased in direct proportion to fish length and this may prevent fish larger than 70 cm in length from being effective prawn predators.     

Allostery: An Overview of Its History,Concepts, Methods,and Applications

The concept of allostery has evolved in the past century. In this Editorial, we briefly overview the history of allostery, from the pre-allostery nomenclature era starting with the Bohr effect (1904) to the birth of allostery by Monod and Jacob (1961). We describe the evolution of the allostery concept, from a conformational change in a two-state model (1965, 1966) to dynamic allostery in the ensemble model (1999); from multi-subunit (1965) proteins to all proteins (2004). We highlight the current available methods to study allostery and their applications in studies of conformational mechanisms, disease, and allosteric drug discovery. We outline the challenges and future directions that we foresee. Altogether, this Editorial narrates the history of this fundamental concept in the life sciences, its significance, methodologies to detect and predict it, and its application in a broad range of living systems.     

The melanomas: a synthesis of epidemiological, clinical, histopathological, genetic, and biological aspects, supporting distinct subtypes, causal pathways, and cells of origin

Converging lines of evidence from varied scientific disciplines suggest that cutaneous melanomas comprise biologically distinct subtypes that arise through multiple causal pathways. Understanding the respective relationships of each subtype with etiologic factors such as UV radiation and constitutional factors is the first necessary step toward developing refined prevention strategies for the specific forms of melanoma. Furthermore, classifying this disease precisely into biologically distinct subtypes is the key to developing mechanism-based treatments, as highlighted by recent discoveries. In this review, we outline the historical developments that underpin our understanding of melanoma heterogeneity, and we do this from the perspectives of clinical presentation, histopathology, epidemiology, molecular genetics, and developmental biology. We integrate the evidence from these separate trajectories to catalog the emerging major categories of melanomas and conclude with important unanswered questions relating to the development of melanoma and its cells of origin.     

广西合浦盆地古新世上洋组孢粉组合及其地层意义

广西合浦盆地上洋组在亚1井中有很好的揭示,明显表现为三分特征。作者通过对该井上洋组微体植物化石的研究,建立了三个孢粉、藻类组合,由下而上分别为:Boehlensipollis-Tricolporo-pollenites-Tricolpites-Ulmoideipites组合;Boehlensipollis qingjiangensis-Ulmoideipites-Nuxpollen-ites-Pentapollenites组合和Pinaceae-Ulmaceae-Liqudambarpollenites-Conicoidium组合。前两个组合可与北部湾长流组及广东南雄盆地上湖组等地古新世孢粉组合进行对比。第三个组合以松科花粉含量突然增加为特征,在我国许多地区晚古新世孢粉组合中都有反映。 上洋组植被在古新世早、中期以阔叶植物为特征,指示一种热带—亚热带型气候,早期干旱,中期略有缓和,晚期植被以针叶阔叶混交林为特征,表明气候变温凉。     

准噶尔盆地克拉美丽地区的蜥脚类

本文是对1983年,中国科学院古脊椎动物与古人类研究所新疆古生物考察队在准噶尔盆地克拉美丽地区工作时采得蜥脚类化石进行简报。化石得自中一晚侏罗世五彩湾组、石树沟组,计有苏氏巧龙(Bellusaurus sui gen. et sp. nov.)和天山龙(未定种)(Tienshanosaurus sp.)。     

Demography of Propithecus verreauxi at Beza Mahafaly,Madagascar: Sex ratio,survival, and fertility, 1984–1988

Eighty-five sifakas (Propithecus verreauxi) have been captured, marked, released, and monitored between September 1984 and August 1988 at the Beza Mahafaly Special Reserve in southwest Madagascar. Estimates are presented of the age and sex structure of this population and of age-specific fertility and survival. Using data from this and other studies, it is shown that sifaka tertiary sex ratios do not depart significantly from 50:50, but that they do differ significantly from those of haplorhine primates, which have strongly female-biased tertiary sex ratios. Two demographic mechanisms that could give rise to this distinction are considered: 1) intermittently male-biased birth cohorts among sifakas and 2) different patterns of survivorship in haplorhines and sifakas.     

Ademosynoides asiaticus Martynov, 1936, the earliest known member of an extant beetle family (Insecta, Coleoptera, Trachypachidae)

Fossil beetles are described from Kedrovka beds of the locality Babii Kamen’, Kuznetsk Basin, Siberia. According to different authors, this locality is dated to the terminal Permian or basal Triassic. SEM studies have shown that Ademosynoides asiaticus Martynov, 1936, described from this locality, should be placed in the family Trachypachidae, which makes it the earliest known extant family of beetles. In addition to the re-studied holotype, further material is described for this species; a new species of the same genus and a new genus and species of the same family are also described. As a result, almost 10% of the 78 beetle fossils known from this locality are identified as belonging to Trachypachidae. Unfortunately, the study of these beetles is complicated by the rather poor preservation quality and very small size of the majority of the fossils, which usually cannot be properly studied without using SEM. However, even in this case there is no full certainty that the results are absolutely reliable.     

Membranes,viruses, detergents,and endosomes

The fluid mosaic model for biological membranes was formulated 40 years ago. Ten years later endosomes were discovered as important prelysosomal organelles. At the outset of my research career, I was fortunate to witness both these turning points in biochemistry and cell biology from close up, and to participate in some of the studies. In this short essay, I will describe how this came about, and also try to provide some background as to the general starting situation in those not so distant pioneering years of membrane biology.