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1.
本文重新研究了产自新疆西准噶尔晚泥盆世法门期洪古勒楞组和铁列克提组的苔藓虫动物群, 重点关注其形态学特征和古生态学意义。该苔藓虫动物群由隐口目(Cryptostomata)、窗格苔藓虫目(Fenestrata), 变口目 (Trepostomata)和泡孔目(Cystoporata)组成。优势类群隐口目苔藓虫是具有中轴或中板的细枝状和双叶状群体。 它们的虫室具有加厚的外区体壁, 弯曲强烈的自虫室, 数量众多的大虫室(metazooecia)或隐蔽虫室(tectizooecia), 以及径向刺突和/或棘状刺突。多样化的异虫室、刺突、自虫室等结构, 以及不同生长环境中的不同生态组合是新疆西准噶尔法门期苔藓虫成功演化的基础。洪古勒楞组下段和铁列克提组下部的苔藓虫动物群可以划分为三类生态组合(即: No. 1, No. 2和No. 3), 代表前滨—近岸—远岸的沉积环境。其中, 近岸环境的枝状—双叶状—网状苔藓虫组合的属种丰度、分异度最高。  相似文献   

2.
新疆西准噶尔上泥盆统洪古勒楞组产出丰富的介形类化石,本文对乌兰柯顺和布龙果尔两条剖面的洪古勒楞组介形类开展生物地层学研究。首次在活动板块边缘地区建立底栖介形类生物带,为研究区的地层划分和对比提供新的依据。洪古勒楞组下段介形类可划分为两个带和两个亚带:Hollinella valentinae-Samarella coumiacensis带和Microcheilinella hoxtolgaiensis-Praepilatina adamczaki带,后者以Microcheilinella bulongourensis的消失为界可分为上、下亚带。在两个研究剖面上洪古勒楞组底部出现典型的弗拉期介形类分子,由此证明西准噶尔上泥盆统可能存在弗拉阶-法门阶(F-F)界线。  相似文献   

3.
寒武纪没有化石苔藓动物的任何记录.最老的、毫无疑问的、真正的苔藓动物,发现于我国峡东地区的下奥陶统特马豆克阶地层中.这类苔藓动物以丰富但多样性低的变口目和少量的隐口目为代表.弗洛期的一些苔藓动物,在北美,英国和波罗的海地区(俄罗斯西北部)已相继发现,这时以Ceramopora?unapensis为代表的泡孔目苔藓动物开始出现,有一定的多样性.中奥陶世初期,苔藓动物迅速崛起,古生代狭唇纲的四个目--变口目、隐口目、泡孔目和管孔目(=环口目)苔藓动物都已经有了代表.由于奥陶纪是苔藓动物发生、演化发展和辐射的重要时期,因此,奥陶纪,特别是早奥陶世苔藓动物的任何新的发现,都有重要的意义.本文描述和解释的一个新的苔藓动物群,发现于安徽滁州琅琊山弗洛阶的红花园组上部.这个苔藓动物群由变口目爱沙尼亚苔虫亚目的两个种:Dianulites hexaporites(Pander),Orbiramus grandis sp.nov.和隐口目翼网苔虫亚目的一个种:Prophyllodi-ctya putilovensis Lavrentjeva组成.尽管这个苔藓动物群在局部地区可能还是低多样性的,但就整个世界范围而言,有一定的多样性,类似于同样以变口目苔藓动物占优势的比林根苔藓动物群,后一苔藓动物群产于波罗的海以东地区(俄罗斯西北部)同时代的地层中.  相似文献   

4.
苔藓动物是一类多为海生、滤食性的群体生物。奥陶纪是苔藓动物发生、演化辐射和灭绝的重要时期,也是苔虫礁形成的最早时期。已知最老的化石苔藓动物发现于中国特马豆克晚期。构成苔藓动物基本分类框架的狭唇纲(包括变口目、隐口目、泡孔目和管孔目)和宽唇纲(包括窗孔目和栉口目)也都是在奥陶纪时期逐步形成的,其中,变口目出现于特马豆克期Tr2时间段,在弗洛期和大坪期,多样性较低,但从达瑞威尔期开始,经桑比期至凯迪期,多样性不断增高,并出现辐射。隐口目(特别是"双叶类隐口目苔虫")也经历了与变口目相类似的发展过程,但它首次出现的时间要相对略迟于变口目。这两个目在整个奥陶纪苔藓动物群中一直占据主导地位。泡孔目、管孔目和窗孔目,先后首次出现在弗洛期Fl2时间段、大坪期Dp1和Dp2时间段,但它们在整个奥陶纪期间一直处于低多样性态势。至于栉口目,它首次出现的时间可能更迟,在凯迪期Ka4时间段,犹如昙花一现。苔藓动物的演化在接近奥陶纪末时呈两幕式灭绝,一次发生在凯迪期Ka2时间段(可能相当于塔凯和安斯蒂的"拉夫塞伊灭绝"),另一次发生在赫南特期Hi2时间段(可能相当于塔凯和安斯蒂的"赫南特灭绝")。分子生物学和形态学证据表明,苔藓动物属原口动物,而不是以前长期认为的后口动物,或介于原口动物和后口动物之间的过渡类型;而且,苔藓动物与腕足动物、帚形动物之间没有直接的亲缘关系。苔藓动物可能起源于一种叫原内肛动物的生物,它们的目一级分类单元之间的系统发育关系目前尚未形成共识,本文绘制的谱系图还有待于化石记录的不断补充和分子生物学研究的逐步介入以使其日趋完善。  相似文献   

5.
小嘴贝类腕足动物Planovatirostrum形态奇特,在我国,目前仅在新疆北部和布克赛尔蒙古族自治县和什托洛盖镇北10余公里处七里沟剖面洪古勒楞组中段底部层位中发现,化石大致呈簇状密集或花斑状分布。经过对产Planovatirostrum planoovale岩性、岩相和生物相的综合分析得知,这段地层是一套深水相沉积,P.pla-noovale生活在水体宁静、海水较深的软质基底上。  相似文献   

6.
王复振 《四川动物》1991,10(3):25-26
国家自然科学研究基金项目中,在进行浙江舟山群岛嵊泗列岛污损生物时注意三角藤壶、海葵等外,以苔藓虫类很显著,属外肛动物门(Ectoprocta)裸唇纲(Gymnolaemata),有40种,其中4种是中国新纪录,今将4种的形态特征、采集地及地理分布并附图记述之。1角形单节苔虫Crisidia cornuta geniculata Milne-Edwards(图,1)1.1形态特征群体树枝状,长在岩石等上,每一节间部只一个虫。个虫细管形,长0.27—0.36毫米,宽0.03毫米。初长一个虫,继生左右二个虫,再同式繁生。室口圆形,与个虫同宽。个虫表面散布细孔。该种属于节苔虫科(Crisiidae)。1.2采集地浙…  相似文献   

7.
记录了最近在中国记载的侵染双翅目昆虫的虫霉目两个新种,毛蚊虫疠霉(Pandora bibionis)发现于浙江庆元的毛蚊(Bibio sp),其初生分生孢子拟卵形,多对称144~20.5×7.2~11.5μm(平均16.5~174×8.4~10.4μm), L/D 1.4~2.3(平均1.7~2.0);假根2倍粗于分生孢子梗,末端膨大为吸盘状固着器;休眠孢子外壁刺毛状,19.1~23.4μm。食蚜蝇干尸霉(Tarichium syrphis)发现于陕西镇坪县的斑翅狭口食蚜蝇上,其休眠孢子外被圆锥形长刺,长2.2~5.0μm,直径21.2~28.1μm。在毛蠓上发现中国新记录胶孢虫疠霉,并根据本文所采用的Humber(1989)系统,将其组合为胶孢虫瘴霉(Furia gloeosora comb. Nov.);此外,还将北虫疫霉(Erynia borea)组合为北虫疠霉(Pandoraborea comb. Nov.),并同时给予修订。  相似文献   

8.
新疆塔里木盆地奥陶系良里塔格组礁滩相非常发育,部分地区泡孔目、隐口目和窗孔目苔虫化石非常丰富,本文首次系统描述了塔里木盆地巴楚-塔中和塔北碳酸盐台地部分取心井上奥陶统良里塔格组的泡孔目、隐口目和窗孔目苔虫7科11属13种,包括1个新种和6个未定种,分别为Lunaferamita nevadensis Utgaard,L. vesicu-larissp.nov.,L.sp.,Graptodictya meneghinii(Vinassa de Regny),Chazydictya sp.,Rhinidictya nicholsoni Ulrich,Metadictyacf.crassa(Hall),Trigonodictya acuta(Hall),Stictoporella sp.,Chasmatopora spatiosa Ariun-chimeg,Ralfinellasp.,Moyerella sp.,Moorephylloporina sp.。其中,隐口目细枝状的Rhinidictya和网状的Chasmatopora,Moorephylloporina在塔中和巴楚地区横向及纵向地层中分布非常广泛。  相似文献   

9.
新疆北部准噶尔盆地周边石炭系广泛出露, 其中上石炭统发育海相火山—沉积序列, 包括西准噶尔地区的哈拉阿拉特组、阿腊德依克赛组, 东准噶尔地区的石钱滩组以及盆地南部的祁家沟组、奥尔吐组等。本文研究在上述各地层的灰岩层或夹层、碎屑岩中获得的四射珊瑚9属17种和床板珊瑚2属3种, 对石钱滩组中的3个新种进行了详细的系统古生物学描述。上述珊瑚化石的地质时代主要为巴什基尔期至莫斯科期。在珊瑚动物群的组成上, 哈拉阿拉特组中新发现Caninophyllum属分子, 结合盆地东、西部共同产出的床板珊瑚Cystodendropora 属分子, 说明整个准噶尔盆地周边的动物群面貌大致类似, 而西准噶尔地区的化石丰度、分异度显著低于盆地东部和东南部。综合前人资料, 目前在准噶尔盆地周边发现的珊瑚化石有约一半为地方性分子。本文认为研究区珊瑚化石的分布和组成特征与晚石炭世准噶尔洋走向封闭或半封闭的演化趋势密切相关。  相似文献   

10.
报道中国粪隐翅虫属的3个种,记述1新种,新疆粪隐翅虫Coprophilus(Zonyptilus)xinjiangensis sp.nov.,首次记录分布中国大陆的2个种,奇异粪隐翅虫C.(Z.)difformis Smetana和台湾粪隐翅虫C.(Coprophilus)formosanus Shibata.编制了该属的中国种检索表.模式标本保存在西华师范大学生命科学学院.新疆粪隐翅虫,新种Coprophilus(Zonyptilus)xinjiangensis sp.nov.(图1~10)本种与来自塔吉克斯坦和哈萨克斯坦的双斑粪隐翅虫C.(Z.)bimaculatus Luze很相似,但通过它的鞘翅黄色至黄色显红、无端斑,以及雄性外生殖器侧叶的不同形态可以区分.新种与来自中国台湾的奇异粪隐翅虫C.(Z.)difformisSmetana也相似,但它的身体较小,前胸无性二型,雄性腹部第8腹板后缘中部近弓形突出,以及雄性外生殖器的不同形态,与之有别.正模♂,中国新疆,1995-08,新疆八一农学院采.副模2♀♀,采集记录同正模.词源:新种种名源自模式产地地名.  相似文献   

11.
Modern hermit crabs form associations with many organisms which encrust, bore into, or cohabit the living chambers of gastropod shells occupied by the crabs. Among these hermit crab symbionts are bryozoan species which develop massive, commonly multilayered, colonies encrusting hermit crab shells. These colonies extend the living chamber of the crab through a characteristic process of helicospiral tubular growth originating from the shell aperture. The scant information available on the ecology of Recent bryozoan‐hermit crab symbioses is reviewed. Symbioses have been recorded from intertidal to upper slope environments, and from tropical to cold temperate zones. None of the hermit crab species are obligatory symbionts of bryozoans, and the majority of the modern bryozoan species involved are also not obligatory symbionts. Fossil examples always lack the hermit crabs, which have a poor fossilization potential; however, the distinctive tubular growth pattern and other features of the bryozoans enable recognition of ancient examples of the symbiosis. The earliest inferred associations between bryozoans and hermit crabs date from the Mid Jurassic, but associations remained uncommon until the Neogene. A remarkably wide taxonomic diversity of Recent and fossil bryozoans are known or inferred symbionts of hermit crabs. The broad evolutionary pattern of the association demonstrates multiple originations of the symbiosis by bryozoans belonging to at least 5 cyclostome and 12 cheilostome families. Only the Miocene‐Recent cheilostome family Hippoporidridae has an evolutionary history closely tied to symbiosis with hermit crabs. There is no evidence for coevolution.  相似文献   

12.
Laboratory-reared colonies of the bryozoans Fredericella sultana and Plumatella fungosa were placed upstream of 2 fish farms endemic for salmonid proliferative kidney disease (PKD) to assess rates of infection of bryozoans by Tetracapsuloides bryosalmonae, the causative agent of PKD. Colonies were deployed in the field for 8 trial periods of 2 wk each throughout the summer of 2001. Following each trial, bryozoan colonies were maintained in laboratory culture for 28 d and were regularly monitored for infection by searching for sac stages of T. bryosalmonae. Infections were never identified by observations of sac stages, however positive PCR results and sequencing of cultured material confirmed that cryptic infections were present in colonies of both species deployed at one site. The possibility that PCR results reflected contamination of surfaces of bryozoans can be excluded, given the short period of spore viability of T. bryosalmonae. Highest rates of infection occurred when 4 of 23 colonies of F. sultana and 1 of 12 colonies of P. fungosa were infected during the period 10 to 24 July. No infections were detected from mid-August to late October at this site. None of the colonies at the other site became infected throughout the period of study. Our data provide the first estimates of infection rates of bryozoans by T. bryosalmonae. Additionally, they provide evidence that a cryptic stage can be maintained within bryozoan hosts for a period of 4 to 6 wk.  相似文献   

13.
Sixty specimens of the giant marine isopod Glyptonotus antarcticus Eights, collected from Borge Bay, Signy Island, Antarctica were examined for epizoans. Ten species of cheilostomatid bryozoans were found on the isopods. The purpose of the study was to quantify the prevalence, intensity, abundance, and spatial distribution of the bryozoans on the isopods. The proportion of isopods colonized was 42%. The larger isopods had both significantly more epizoic bryozoan colonies and species. The greatest density of bryozoans was on the fused pleon and telson. There was no significant difference between the dorsal and ventral abundance of bryozoan colonies. The diversity of epizoic bryozoans on the isopods is higher than on other host organisms from more stable environments. This may be because of active selection by settling larvae. The frequency of local substrata being scoured by ice is high around Signy Island, so there may be a selective advantage in colonizing a motile host. Accepted: 20 June 1998  相似文献   

14.
Two Lower Bajocian new localities, with many silicified bryozoans and brachiopods have been discovered in Causses (France): Saint-Rome-de-Cernon (Aveyron) and Mende (Lozère). The study of the faunas allows to increase the anterior knowledges supplied by the study of localities in the South of Causses (neighbourhood of Alzon and Sumène = North of the Seuil sud-caussenard).The interest is, at first, the distance between the localities: Mende in the North, Saint-Rome-de-Cernon in the West. Moreover, in the second, well-preserved faunas were fossilized without transport. Bryozoans and brachiopods are very numerous. Large and complete bryozoan colonies have been get out by action of HCl. Fine internal structures like rhynchonellid Nannirhynchia or like thecidean transversarium and hemispondylium have been studied. At last, observations and paleoecological hypothesis are drawn, likewise comparison between three localities or locality-groups known in the Causses basin.The fauna from Saint-Rome-de-Cernon is biocoenosis, the substratum was soft, the hydrodynamism low and the depth, according to lamellibranchs, about 200 meters. The beds with bryozoans and small brachiopods contain a fauna with two predominant bryozoan species: Ceriocava straminea and Mesenteripora wrighti. These two species could built large colonies, in spite of fine granulometry of the sedimentary bottom. These colonies provided supports to less adapted bryozoans, to thecidids and to lamellibranch Lopha. The beds with terebratulids and bryozoans contain lesser bryozoans and thecidids. Terebratulids are the main group and are fixed with their peduncle to organic support above the irregular deposits. Beside these benthic animals, the rhynchonellid Nannirhynchia campestriensis is epibiontic on gorgonids or epiphytic on floating sea-weeds.On the contrary, all fossils from Mende have been more or less carried, excepted large sponges perhaps. The most numerous bryozoans (Ceriocava straminea, Mesenteripora wrighti) and numerous Lenticulines (Foraminifera) lived on hard bottom with moving water in community with crinoids. It is possible that a smaller part of bryozoans, requiring lower hydrodynamism, lived, either in sheltered parts of the crinoid community or closer to the sedimentation zone. Thecidids were fixed either on bryozoans in crinoid communities or on shelly remains and on bryozoans nearer to the sedimentation zone. Like in Saint-Rome-de-Cernon, Nannirhynchia campestriensis was epibiontic, or epiphytic, or both.In comparison with the whole localities from the Seuil sud-caussenard, we notice the simplicity of Saint-Rome-de-Cernon and Mende. The localities from the Seuil sud-caussenard were assemblages proceeding from 2 or 3 biotops. On the contrary, at Saint-Rome-de-Cernon we have a biocoenosis and at Mende a thanatocoenosis supplied by one biotop almost.  相似文献   

15.
Abstract. This paper reports the second occurrence of a sand‐grain encrusting interstitial epifauna dominated by bryozoans and polychaetes at a site thousands of kilometers from the first described occurrence of such a fauna 20 years ago. Such faunas seem to have gone almost unrecorded in the marine ecological literature, but they are potentially geographically widespread and ecologically significant, deserving recognition and further study by benthic ecologists. Although rooted‐erect and free‐living lunulitiform bryozoans can be abundant in soft‐bottom habitats, the presence of encrusting forms was, until recently, considered to be limited to patches of hard substrata. In 1985 and 1988, a new and seemingly unique habitat for encrusting bryozoans and other organisms on single grains of shell or sand was reported from the coastal waters of Florida, USA. Here we report a second discovery of an interstitial encrusting fauna from the continental shelf off the state of São Paulo, Brazil. In addition to the cupuladriid Discoporella umbellata, several species of bryozoans (9 cheilostomes, 3 ctenostomes, and 1 cyclostome) were found encrusting on or boring into sand grains from the 4 stations examined. Four species were found exclusively on sand to gravel size grains. The most abundant colonies, with ~1300–1500 colonies m?2, belonged to a new species of Cleidochasma. New species of Trypostega and Reginella, each with up to 200–300 colonies m?2, were also discovered. The grain‐encrusting bryozoans were characterized by their small size, and by the fact that sexual reproduction was initiated very early in colony growth; brood chambers (for the development of embryos into larvae) occurred in colonies having only a few zooids. Colonies of boring ctenostome and cheilostome bryozoans were even more abundant than those of grain encrusting forms, being present in almost every piece of shell (~5000–5500 colonies m?2). The fauna also included representatives of other groups of encrusting organisms, especially tubeworms (11,000–13,000 tubes m?2). Planned work on samples from additional stations on the São Paulo shelf will no doubt yield a larger number of species from various taxa and perhaps show some overlap in sand fauna species between the Brazilian and Floridian sites. In addition to the unique species of single grain encrusters, colonies of bryozoan species characteristic of larger subtidal hard substrata were also found on sand or gravel size grains, indicating that an interstitial refuge may be available to some epifaunal taxa and suggesting that this interstitial refuge, which remains almost completely unknown to benthic ecologists, may play a large role in determining distributions of those taxa.  相似文献   

16.
The presence of the stoloniferous hydroid Obelia geniculata (L.) had no effect on the pigment concentration or nitrogen status of underlying blade tissue of the giant kelp Macrocystis pyrifera (L.) C. Agardh. The sheet-like colonies of the bryozoan Membranipora membranacea (L.) markedly reduced the pigment concentration of colonized blade tissue, but only during winter. Reductions in pigment concentration are most likely a result of damage to underlying tissue due to some factor related to the presence of bryozoan colonies on blade surfaces. Blade tissue colonized by M. membranacea also had higher δ15N signatures than surrounding bryozoan-free tissue, possibly indicating the provision of nitrogen to M. pyrifera by bryozoan colonies. Results show that seasonal changes in nitrogen and colony size can strongly modify the effect of epifauna on macroalgae they colonize. Unlike bryozoans, hydroid colonies provided no barrier to nitrogen uptake by colonized M. pyrifera tissue and enhanced ammonium uptake was observed for tissue colonized by O. geniculata during nitrogen limitation. Epifauna with stoloniferous growth forms such as hydroids are more likely to have benign or even mutualistic relationships with macroalgae they colonize than the sheet-like colonies of bryozoans.  相似文献   

17.
A new cryptostome bryozoan, Prophyllodictya simplex sp. nov., is described from the Nantzinkuan Formation (Lower Ordovician, lower Tremadoc) of Liujiachang, central China. This antedates the previously oldest known bryozoan by several million years. Colony morphology and the phylogenetic position of Prophyllodictya within Cryptostomata are explored. Phylogenetic analysis suggests that Cryptostomata (except Prophyllodictya) can be divided into two major groups, and that Prophyllodictya occupies a basal position in the cryptostome tree, which accords with its simple morphology and antiquity. A close relationship is evident between bryozoans from the South China palaeoplate and those from Baltica.  相似文献   

18.
Summary In this paper, a preliminary concept on the interplay of local, regional and global control factors of bryozoan diversity and distribution pattern is introduced. Recent bryozoans from the Philippines, New Zealand and the Gulf of Aqaba are compared to the selected fossil specimens from the Oxfordian and Santonian. Reef bryozoan skeletons are studied in order to separate local control within the substrate-water interface from regional control. The latter originate mainly from the transport function of the water column (e.g. sediment load, wave energy, vagile predators). This is true especially for erect (tree-like) and massive (multilaminar) bryozoans which are subjected to the dynamics of the water body in the littoral area. This regional control, affects simultaneously several structural and substrate zones of a reef. Early life history of vertically growing reef bryozoans reflect local control, while older zoarial structures reflect the signals of regional influence. Three types of multiserial nodular bryozoans are cited: self-overgrowing sheets (‘S-Nodule’, derived from ‘S-Sheet’), circumlaterally budding colonies (‘C-Nodules’), and fungiform bryozoans. Bryozoan growth form selection allows the separation of two types of regional controls, long range control which favours the selection of specialized sheets, and slow rate control documented in the growth form modification of sheets changing into nodules. In the domain of local control epibiontic microorganisms, microbial mats and biofilms on hard substrata represent probably the most important elements, aside from the limited substrate space. Symbiotic and/or competitive bryozoan-microorganism interrelationships result in the distinct adaptations of bryozoan growth. It is apparent that bryozoan modifications of substrate micro-topography influence the character of epibiontic microbial settlement. The peak occurrence of microbial settlement on prominent external bryozoan skeleton parts is discussed as an effect of feeding currents. In contrast, smooth and unelevated exoskeletons are less favourable for micro-epibiontic colonization. Due to the high level of order in the spatial zonation patterns of epibionts on calcifying bryozoans, the term ‘bryozoan-microreef’ is introduced. Bryozoan-microreefs are locally controlled reefs. They are e.g. characterized by higher competitive abilities than bryozoans without ‘reefdwellers’. Local control has a fast rate of change and is reflected in morphologies of individual zooids and/or single zooid generations. Regional control has a slower rate but a higher range. It is important for growth modifications of the whole zoaria. The very slow rate of global control cannot be recorded within the life span of bryozoan zoaria unless it is expressed through regional control (such as monsoons). Nevertheless, global control is paleoecologically important because it is traceable in bryozoan (paleo-)biogeography. For practical purpose, we suggest to define those control factors of bryozoans as global which affect simultaneously at least one tropical and one non-tropical bryozoan community. This reportis dedicated to the memory of our friend and research colleague Mr. Joselito G. Santiago of the University of San Carlos, Marine Biology Section. Tiago (as we fondly call him) has started within the scope of the Philippine Bryozoan Project an applied research on fish abundance and productivity around a new artificial reef model. This prototype model was conceptualized with him. His promising study remained unfinished; he died May 13, 1993, while sampling inside the reef cave off Marigondon.  相似文献   

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