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From the Buschmann-Klippe-Formation, mainly considered as Late Precambrian in age until now, the ArchaeocyathaBuschmannia roeringi, n. gen., n. sp. is described. Based on this discovery, an Early Cambrian age for the Nama-group is assumed.  相似文献   

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We propose Tinamutrema as a new genus for Brachylaima centrodes (Braun, 1901) Dollfus, 1935 and for T. canoae, as a new species inhabiting tinamus in the Area de Conservación Guanacaste, Costa Rica. Specimens from Costa Rica resemble B. centrodes in having an elongate body, pretesticular genital pore and terminal genitalia, intercecal uterine loops occupying all available space between the anterior testis and the intestinal bifurcation, an oral sucker width:pharynx width ratio of approximately 1:0.55, an oral sucker:ventral sucker width ratio of approximately 1:1, and vitelline follicles extending into the forebody closer to the pharynx than to the anterior margin of the ventral sucker and by living in the cloaca. They differ from B. centrodes in having vitelline follicles that do not extend as far anteriorly as those in B. centrodes, which extend anteriorly to the level of the anteriormost extent of the cecal "shoulders," dense tegumental spination as opposed to sparse or no spination, relatively smaller cirrus with fewer spines, longer and more sinous pars prostatica, and forebody averaging 36% of total body length (TBL) as opposed to 42% TBL. Both species differ from other members of the Brachylaimidae in possessing a spinose cirrus and a cirrus sac containing both the cirrus and the pars prostatica. Preliminary phylogenetic assessment suggests that these traits are plesiomorphic, and thus the species are basal to the rest of the Brachylaimidae, whose diagnosis we emend accordingly.  相似文献   

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Divisispiculimermis mirus n. gen., n. sp., a mermithid parasitizing larvae of Chironomus sp. in the Cajón o Grande Stream, Córdoba, Argentina, is described. The new genus differs from all other mermithid genera in having paired spicules which are separated and divided into proximal and distal sectors. The other diagnostic characters of the genus are medium size, nematodes with the cuticle appearing smooth (lacking cross fibers under the light microscope); head separated from the rest of the body by a slight constriction at the level of the amphids, six cephalic papillae, mouth papillae absent, mouth opening posterior to level of cephalic papillae; six hypodermal chords at midbody; weakly S-shaped vagina; postparasitic juvenile with a tail appendage.  相似文献   

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描述了贵州水城大河边煤矿晚二叠世龙潭组的植物茎干化石Guizhouoxylon dahebianense gen. et sp. nov., 茎具清楚生长轮,髓部较大,初生木质部内始式,原生木质部由环纹管胞、稀螺纹管胞组成,后生木质部包括有密螺纹管胞和密螺纹至梯纹增厚的导管组成,导管近端部的穿孔板椭圆形,梯纹至网纹增厚。次生木质部密材型,射线单列,一般低矮,管胞自内向外由梯状纹孔变为不规则拥挤分布的具缘纹孔,偶而可见木薄壁细胞。根据后生木质部中导管的穿孔板类型与低等被子植物Platanus acerifolia Willd相似,也讨论了被子植物的起源问题。  相似文献   

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Sagittopteris  belemnopteroides gen.et sp.nov.在山西的发现   总被引:1,自引:1,他引:0  
山西晚古生代植物自赫勒(Halle,1927)研究以来向为世人瞩目。解放后,李星学(1963)又对华北广大地区月门沟群的化石进行了详细研究,补充了前人的不足。近年来,山西省区域地质调查队在1/20万区域地质调查和一系列的专题研究中,采集了大量化石标本。笔者在鉴定中发现不少有意义的分子,本文报道的即系其中之一。化石为作者之一肖素珍于1976年在晋东南参加剖面测制时采集的。本种在山西其他地区亦有出现。如太原西山、沁水杏峪、柳林、沁  相似文献   

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Summary Four new species of hystrignathid nematodes are described from the midgut caeca of Passalus unicornus (Coleoptera: Passalidae) from St. Lucia, West Indies. Artigasia horridospina n.sp. is differentiated from A. dispar van Waerebeke, 1973 by virtue of fewer rows of spines in the oesophageal region and in possessing lateral alae, and from A. insignia Travassos & Kloss, 1958 in the extent of the oesophageal spiens and in having the lateral alae commence more anteriorly. The first annule is also much shallower than that of A. insignia. Longior semialata n.sp. is differentiated from L. longicollis Travassos & Kloss, 1958 on body length, b ratio, egg size and the starting point of the lateral alae. Mentecle magnifica n.sp. differs from M. parvus Travassos & Kloss, 1958 in having the spines of the oesophageal region extending much further down the body and in having ridged eggs. It is also longer and relatively thinner. Paraxyo ensicrinatus n.sp. differs from P. monodelpho Travassos & Kloss, 1958 in having a proportionately longer tail. The spines in the oesophageal region also extend considerably further posteriorly than in P. monodelpho.Two types of male associated with the above nematodes are described and illustrated, but not assigned to females. Pulchrocephala? pulchrocephala Travassos, 1925 is redescribed from the gut of the mole-cricket Scapteriscus vicinus.Scanning electron micrographs of four of the described species are given and briefly discussed. ac]19801024  相似文献   

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J. Chazeau 《BioControl》1983,28(4):373-378
Résumé Stethorus exspectatus n.sp. etS. exsultabilis n.sp. sont décrits de Papouasie Nouvelle-Guinée. Leurs proies connues sont citées, et quelques informations nouvelles sur la répartition du genreStethorus dans le Pacifique sont données.
Summary Stethorus exspectatus n.sp. andS. exsultabilis n.sp. are described from Papua New Guinea, with records of their prey and new data on the distribution ofStethorus in the Pacific area.
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Rossmania ukurunduensis gen. and sp. nov. collected in the reverve Bolshekhekhtsirsky (Khabarovsk Territory, Russian Far East) is described and illustrated.Rossmania aculeata comb. Nov. is indicated as the second species of the genus.  相似文献   

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大家知道,鳞翅目通常是取食高等植物,但其中也有取食低等植物的——真菌(食菌性,MeToa);植物的碎屑(食残性,eTpToA);甚至有的取食动物躯体附属物——毛皮、毛、皮革等(食角性,kepaToa);此外,还应指出,有食动物的情况,即捕食性(XHecTBo)。 对鳞翅目来说,肉食性(OTOHocTb)及捕食性的现象是很稀少的,目前共有几十种  相似文献   

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In Opiliones, male genital morphology plays a key role in systematics and understanding the evolution of the group because functional modifications often outline higher taxonomic levels. In Nemastomatidae, different lateral stabilizing structures on the penial truncus cane developed independently. These wing-like protuberances serve as anchor points for two muscular tendons and are interpreted traditionally as generic characters. A newly discovered species from Monte Saccarello in the Ligurian Alps of North-western Italy is unique in providing anchor points as stabilizing parts of the distal truncus cane below the glans by short and narrow lateral folds. To place this unusual species within the Nemastomatidae one must re-evaluate the usefulness of male genital morphological and other characters used in the systematics of the family. The resulting phylogenetic framework is supplemented with available molecular genetic data. Based on both datasets, the creation of a new genus seems justified. Saccarella schilleri gen. n. sp. n. is subsequently described and further defined. The endemism and biogeography of the harvestmen fauna in the South-western Alps are discussed with respect to this enigmatic genus.  相似文献   

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The fore wing of the new genus and speciesMoltenia rieki of the order Hymenoptera, tentatively belonging to the family Xyelidae, is described from the Molteno Formation (Upper Triassic) of South Africa. This fossil is a representative from the early evolutionary history of this order and the oldest Hymenoptera from central Gondwanaland. However, the plesiomorphic characters in its wing venation do not allow a clear assignment to a recent subgroup of the Hymenoptera, although generally it can be assumed that the Xyelidae had a much higher diversity during the Triassic than today.  相似文献   

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A mass occurrence of peculiar centric diatoms was found in a freshwater diatomite included in Miocene deposits of the Rhoen mountains in Central Germany. Similar forms were determined asMelosira jouseana in the literature. However, detailed observations in the LM and SEM exhibit morphologic characteristics which are completely unknown inMelosira and inAulacoseira. Regular triangulate and trilobate outlines of the valve faces occur and dominate besides circular ones. Variable support partitions and pillars are inserted between discus and Ringleiste. Such stabilizing elements are lacking in all comparable recent and known fossil genera. Instead of the extensive cingulum inAulacoseira the cells possess only a single copula which encloses the very short collum. A structure (l“fringe-curtain“) starting from the distal margin of this copula covers like a grid the mantle of the associated valve. Sulcus and pseudosulcus do not occur and rimoportulae or fultoportulae were not observed. Therefore a new genus is introduced with a new species,Miosira rhoenana. Miosira jouseana in the new combination is based onMelosira jouseana Moiseeva 1971.  相似文献   

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The laminated sediments of the Lower Oligocene ‘Sieblos-Schichten’ (dysodile and kieselgur-sediments) contain many individuals of a naviculoid diatom species. Formerly this group of diatoms would have been classified without doubt as Navicula (section ‘Minusculae’). After splitting this extremely heterogeneous genus in Navicula sensu stricto and some other homogeneous genera, the pattern of structures of this fossil species does not correspond to any established genus. For that reason this form will be described as the generotype of a new genus Eolimna. Furthermore it became evident that some Recent species (assigned to Navicula) show the same pattern of structures as the new genus Eolimna (generotype: E. martinii) which represents one of the first naviculoid diatoms of limnic origin. The essential criteria of this genus are: comparatively small cells with narrow girdle; simple alveolated rib system; areolae with a hymen in approximately medium position between relatively large sized foramina outside and inside of the valve; a single row of more or less irregular arranged areolae in close position to each other, on one or several of the copulae. The differences to supposed related genera are discussed.  相似文献   

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The authors describe and illustrate two trematodes from Belize (Central America): Paramaritremopsis solielangi n. sp. from the small intestine of Arenaria interpres is characterised by a body length of 478 m, two short and pre-acetabular caeca, part of the uterus in close association with the cirrus-sac and left caecum, vitelline glands in the shape of a horseshoe, a short pre-ovarian cirrus-sac containing a long, cylindrical, voluminous and unarmed cirrus (size when evaginated: 150×20–30 m) and Microphallus kinsellai n. sp. from the caeca of Actitis macularia characterised by a body length of 370 m and a phallus which is 30 m in diameter and asymmetrical (basically a pad with a moderately developed accessory lobe) and a straight ejaculatory canal. Levinseniella carteretensis is another microphallid recovered from Arenaria interpres. The term of ``phallus' is proposed to name the male copulatory organ which characterizes the Microphallinae.  相似文献   

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依据一近完整的相关节的骨骼化石,记述了辽宁建昌早白垩世九佛堂组原始今鸟类一新属种:小齿建昌鸟(Jianchangornis microdonta gen.et sp.nov.)。新鸟个体较大,但从骨化程度分析,正型标本可能属于一亚成年个体。具有一些进步特征,如胸骨及龙骨突加长,乌喙骨具有发育的前乌喙突以及和肩胛骨关联的关节窝,叉骨"U"字型,愈合荐椎包括9-10枚荐椎,尾综骨短小,第二、三掌骨远端愈合,跗跖骨完全愈合等,表明新属无疑属于今鸟类。在以下特征组合上很容易和已知的早白垩世今鸟类化石相区别:齿骨上至少有16枚细小牙齿,从齿骨前端向后沿齿骨大部密集排列;肩胛骨强烈弯曲;第一掌骨粗壮,较其他掌骨宽;第一指长并且远端延伸明显超过第二掌骨;肱骨+尺骨+第二掌骨与股骨+胫跗骨+跗跖骨的长度比例约为1.1。系统发育分析表明新属属于基干的今鸟类。新发现的材料第二、三掌骨远端愈合很好,但近端却未完全愈合,这一特征尚未见于其他已知鸟类,或许表明今鸟类腕掌骨的愈合和现生鸟类的跗跖骨一样是从远端开始的,不同于反鸟类和其他基干鸟类。建昌鸟的下颌还保存了一个前齿骨,这是继早白垩世红山鸟之后的另一例报道,可能进一步表明这一结构在今鸟类中曾普遍出现。新鸟肩带、胸骨和前肢的特征显示了和现代鸟类相近的飞行能力,其后肢、脚趾的比例以及趾爪的形态等显示和燕鸟、义县鸟等相似的地栖特征。保存于标本上的鱼类残骸可能显示了建昌鸟食鱼类的习性。今鸟类新属种的发现进一步表明,早白垩世这一进步鸟类类群的分化已不亚于反鸟类,湖滨环境在今鸟类的早期演化中确实扮演了重要的角色。  相似文献   

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1957年,苏联科学院动物研究所的考察队在黄海工作时,我们曾经对寄生於海产鱼类的单殖亚綱动物区系作了研究。在所发现的大量种类之中,有一种按其形态学的特徵是如此的特殊,不仅足以划分为单独的一属,而且无疑地还是一个新科的代表。在考虑到这一个种的重要意义时,我们认为提出其初步的描述是适当的。关於这一种的较详细的报导,要在作者把所收集的,不仅包括成体的,而且还有它们胚胎期后各发育阶段的全部资料加以详细的研究后,才能完成。  相似文献   

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