安徽潜山盆地早第三纪叶肢介化石

笔者于1981年6月与安徽省地质局327地质队李继超工程师前往江苏六合冶山,观察寒武系剖面时,在冶山东部下寒武统深灰色薄层灰岩中,找到金臂虫、三叶虫(Redlichia,Pa-raprotolenella 等)(图版Ⅰ)、无铰纲腕足类以及软舌螺类等化石。金臂虫化石系在本区寒武系第一次发现,也是江苏省境内首次发现。该标本经笔者研究为一新属——Yeshanella。这不仅丰富了金臂虫类化石资料,而且为研究我国东部金臂虫类化石提供重要线索。     

南黄海盆地的叶肢介化石

文中描述采自南黄海7井叶肢介化石,分别是Yunmenglimnadia huanghaiensis(sp.nov.),Y.subrhombica(sp.nov.),Y.brevis(sp.nov.)和Perilimnadia?cf.P.taizhouensis Chen。其地层时代为早古新世。     

安徽含山上泥盆统叶肢介化石

国内晚泥盆世的叶肢介,曾在湖南长沙岳麓山上泥盆统岳麓组上部产Lioestheria yuelu-shanensis Zhang,在南京附近龙潭擂鼓台上泥盆统五通组顶部也发现一层叶肢介化石,仅有Lioestheria longtanensis Zhang一种,总的来说,晚泥盆世叶肢介化石发现较少。本文所描述的材料,是含山县清溪煤矿井口矸石堆的黑色含炭质粉砂质页岩中采集的。为查明其确切的层位,实测了主井井壁剖面,现     

安徽含山侏罗纪叶肢介

安徽侏罗纪叶肢介,曾发现于舒城晓天附近,层位为上侏罗统毛坦厂组,计有2属、7种(陈丕基等,1982,第24—26页)。中、下侏罗统的叶肢介,一直未见报道。本文所描述的叶肢介是安徽区测队三分队陆伍云等同志于1980年进行区域地质调查时在巢湖东约10公里的含山县彭庄村边发现的,1981年5月,我所曹正尧、林启彬、黎文本及笔者与陆伍云等同志一起,观察了侏罗系剖面,重新采集化石。化石产于中侏罗统含山组下部厚约9米的灰黑色(风化后呈灰白色)泥岩。该地含山组假整合覆于中下侏罗统象山群之上。与叶肢介共生的尚有植物Equisetites sp. (cf. E.     

从叶肢介化石看大陆漂移

今天,人类已可以向太空发射火箭进行各种考察,但对于我们居住和生活的这个星球内在规律的了解,还远远不够。关于地球内在运动规律的认识,不久前在科学界也还被形而上学束缚着。许多人认为:大陆从一开始形成,位置就固定不变了,只在其周     

江西清江盆地早第三纪新余组腹足类化石

一、前言江西清江盆地早第三纪地层发育良好,产有丰富的腹足类化石,已报道的有清江组和临江组的非海相腹足类化石(余汶,1977,1983).本文记述的是清江盆地西部边缘新余县马洪乡新余组中的陆生腹足类化石,共计6属、8种,隶属4科,其中包括1新属和5新种.同时,对这一腹足类化石组合的性质及其时代特征,新余组的沉积环境及时代归属等问题进行了探讨.本文是在余汶老师悉心指导下完成的.承     

新疆中二叠世叶肢介化石

描述新疆阜康三工河剖面芦草沟组的叶肢介石２科３属４种（其中２新种）和鄯善照壁山剖面“照壁山组“的叶肢介化石２科４属５种,时代均为中二叠世。     

一块珍贵的叶肢介卵化石

淡黄油亮“几丁丸”,深埋红层几亿年。历尽沧桑貌更美,珍贵化石甲世间。登在本期封三的有一张早三迭世产的带卵的叶肢介化石,一侧是此叶肢介卵化石放大76倍时的情景。你看它多么象鱼肝油丸。这是目前我们所能见到的世界上保存得最好的叶肢介卵化石。保存得如此完美的距今约2亿2千万年的叶肢介卵化石,读者一定会认为它的沉积环境是特别好的,谁又会料到它竟然会产在过去长期曾被认为是哑地层的石千峰群中上部的红层中呢?现在让我介绍一下这张举世珍贵的叶肢介卵化石的一些情况吧。     

广东东莞盆地早第三纪介形类动物群

一、前言东莞盆地位于珠江三角洲东部广州市的东南(图1),为北东南西向展布的狭长沉积盆地,长90公里,宽20公里,面积约1800平方公里。盆地内地势平坦,河网发育,全为第四系覆盖,盆地边缘出露下古生界、侏罗-白垩系及下第三     

闽西南早、中侏罗世叶肢介

福建中生代含煤地层分布广泛。1930年,王恒升、李春昱在闽北建瓯上樟垅创立“梨山煤系”用以代表福建中生代含煤地层,定其时代为早侏罗世。1933年,斯行健研究了长汀珠山该地层内所产植物化石,定其时代为里阿斯世。这样,梨山煤系的地质时代就从古植物方面得到了肯定,并长期为省内外地质工作者所引用。303地质队于1963年在漳平大坑井田对这套含煤地层进行了详细划分,下部划分出大坑组和文宾山组,所含植物化石经徐仁研究定其时代为晚三叠世考依波—瑞替克期;上部改称为梨山组,属早侏罗世。稍后,省区测队在梨山组上部杂色碎屑岩中采获一些淡水瓣鳃类化石,定其时代为中侏罗世,故将其分出,称漳平群,后     

新疆准噶尔盆地北缘新近系顶山盐池组及相关地层问题

在新疆准噶尔盆地北缘乌伦古河流域建立了一个新近纪岩石地层单位:顶山盐池组。该组平行不整合于哈拉玛盖组之上,是一套以红色泥质粉砂岩为主体的细碎屑岩堆积,厚约50 m,含有上下两个化石带。上化石带时代为中新世晚期或上新世;下化石带为中中新世中晚期,与通古尔期默尔根小哺乳动物群大体相当。根据岩性和化石组合,推测顶山盐池组含有风成沉积物,或主要为风成堆积。其下部地层与流域中可可买登组为同期异相沉积。通过下伏的哈拉玛盖组,顶山盐池组可以和附近地区的铁尔斯哈巴合剖面衔接,构成乌伦古河流域一个从晚渐新世到中新世晚期或上新世大体连续的地层序列。这个序列有可能包含了塔本布鲁克期至保德期的沉积物和动物群。我们将这个序列与中国以及欧洲的相同时段生物年代序列进行了初步的对比,并讨论了有关的生物年代和年代地层问题。以哈拉玛盖动物群为代表的中中新世动物群的繁盛与它们的地理分布和中中新世全球气候最佳期的温暖气候可能相关。     

忍冬科(狭义)植物地理及其对认识东亚植物区系的意义

本文所谓狭义的忍冬科,包含4族、12属即忍冬族(忍冬属、鬼吹箫属),北极花族(毛核属,糯米条属、六道木属、北极花属、双盾木属、猬实属、七子花属),锦带花族(德维花属、锦带花属)和莛子？族(莛子？属)。基于它们的分布、化石资料和以木本为主的特性,忍冬科可认为是一个古老的科,可能起源于晚白垩纪或早第三纪。又基于以下事实：在东亚糯米条属、莛子？属和锦带花属中,可见到一系列的系统发育列;东亚特有的七子花属,是联系忍冬族和北极花族的一个中间纽带;东亚不但有较高比例的古特有属,还有一些新特有属;由此,我们认为东亚是该科的多样化中心。在化石和细胞学资料不充分的情况下,我们仅根据三个主要特征,如属的系统位置是否孤立,与近缘属的分布区是否间断及属内的分化类型的多寡和种间的区别是否明显,试图将6个东亚特有属归为三类：七子花属、双盾木属和猬实属作为古特有属,锦带花属作为活化了的古特有属,六道木属和鬼吹箫属作为新特有属。     

A MODEL FOR THE EVOLUTION OF ASYMMETRICAL MALE HYBRID STERILITY AND ITS IMPLICATIONS FOR SPECIATION

Chromosomal analysis of several cases of asymmetrical male hybrid sterility in Drosophila has implicated the X- or the Y-chromosome and one or more autosomes. Here, I develop a model for the evolution of this phenomenon. An autosomal locus is assumed to affect viability and to interact with a Y-linked or an X-linked locus to determine male fertility. In a new environment, selection for viability favors a new allele at the autosomal locus, but incompatibility of this new allele with the sex-chromosome-linked gene generates male sterility. The incompatibility can be resolved if a new allele at the sex-linked locus invades the population. This results in nonreciprocal male hybrid sterility, the direction of the nonreciprocity being determined by the dominance or recessiveness of the new autosomal gene in its effect on fertility. It is shown that stable polymorphism for the autosomal locus is possible and that, if the equilibrium frequency of the new allele is above a critical value, the population will be constantly at the verge of speciation, “waiting” for the sex-linked mutation to occur. The appearance of this mutation causes a runaway process leading to rapid fixation of the new autosomal and sex-linked alleles. If the equilibrium frequency of the new autosomal allele is less than the critical value, deterministic speciation is impossible, but random drift may increase the frequency above the critical value and predispose the population to the invasion of the new sex-linked allele. Thus, both deterministic and stochastic modes of speciation are possible. Because deterministic speciation requires large selection coefficients, which impose a severe genetic load on the population, and because stochastic speciation requires repeated population bottlenecks, it is concluded that relative to the number of successful speciation events there will be many more events of deme extinction.     

PHOTOSYNTHETIC PIGMENTS OF PSEUDOSCOURFIELDIA MARINA AND SELECT GREEN FLAGELLATES AND COCCOID ULTRAPHYTOPLANKTON: IMPLICATIONS FOR THE SYSTEMATICS OF THE MICROMONADOPHYCEAE (CHLOROPHYTA)1

Photosynthetic pigments of the green flagellate Pseudoscourfieldia marina (Throndsen) Manton (Micromonadophyceae) are similar to those of the coccoid Pycnococcus provasolii Guillard; prasinoxanthin is the predominant carotenoid. Other organisms that possess prasinoxanthin also possess additional pigments not found in either P. marina or P. provasolii. Uriolide, a xanthophyll previously described from the coccoid done URI 266G, was also found in Mantoniella squamata (Manton et Parke) Desikachary, Micromonas pusilla Manton et Parke and Mamiella gilva (Parks et Rayns) Moestrup, all flagellate members of the Mamiellales, and the coccoid clone IV E5G. Other unidentified carotenoids were also present in M. squamata, M. pusilla, and M. gilva. These results suggest that P. marina and the coccoid organisms URI 266G and IV E5G may be related to the Mamiellales, and that P. provasolii may be more closely related to P. marina than to M. squamata, M. pusilla, and M. gilva.     

THE MORPHOLOGY OF HYOLITHIDS AND ITS FUNCTIONAL IMPLICATIONS

Abstract:  The exceptionally preserved hyolithids Gompholites striatulus , Maxilites robustus , Maxilites snajdri and Maxilites sp. are described with particular emphasis on helen and muscle scar morphology. These two aspects of hyolithid morphology have remained controversial. In life position, each helen curved ventrally. When the operculum closed the aperture of the conch, each helen was locked at the commissure slit with its dorsal edge tilted forward. Inside the conch, it was held in the dorsal apertural plane and clear of the inner surface of the operculum. Previously unidentified muscle scars are described from both the operculum and the conch. Dorsal scars on the conch aperture held muscles directed to the operculum. Comparative study of the muscle insertion pattern indicates that hyolithids did not have serially arranged muscles and that all hyolithids may have had a common skeleto-muscular system. The arrangement of the muscle scars with respect to the helens suggests that the latter were capable of relatively complex movements and could have been used to propel the organism over the substrate. The general morphology and orientation of the helens suggests that in addition they functioned to stabilize the organism on the sea-floor.     

翅果形态及其在槭树科分类与演化上的意义

槭树科（Ａｃｅｒａｃｅａｅ）是北温带分布的科,含２属,全世界约２００种,中国是槭树科植物的现代分布中心。对槭树科翅果的专门研究尚未见报道。本文１、引用一套槭属翅果形态学术语;２、观察并描述７５种械属植物的翅果;３、研究槭属１６个组的翅果的１７个可比性状,根据分枝系统分析法得出槭属各组的演化关系及趋势,这趋势与依据其花、叶等性状得出的演化关系基本上是一致的。     

ARCHAEOPTERIS MACILENTA,ANATOMY AND MORPHOLOGY OF ITS FROND

The stem, rachides, and pinnae of Archaeopteris macilenta, formerly considered to be a fern of Devonian age, comprise a branch system in which the ultimate divisions heretofore referred to as pinnules are the leaves. The primary vascular system of the “frond” is a lobed siphonostele from which leaf traces arise in a spiral sequence. The anatomy of the “rachis” and of the “pinnae” is shown to be similar to that of the stem, Callixylon, which bore these “fronds.” Branching, epidermal pattern and stomates are described for the spirally arranged leaves (fertile pinnules). Attachment and dehiscence of sporangia as well as their stomates are reported. Archaeopteris is retained in the Class Progymnospermopsida which includes plants with gymnospermous anatomy and pteridophytic reproduction. It is suggested that Actinopodium, Svalbardia and Siderella are related closely to Archaeopteris and that this group of genera shows evolutionary stages in webbing of leaves and planation of branch systems. The opportunities for ontogenetic studies of the arborescent genus Archaeopteris are pointed out.