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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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Eine nèue foliikole Flechte (Pleurotrema epiphylla sp. n.) aus Zaïre (Zentral-Afrika) wird beschrieben. Die systematischen Beziehungen der neuen Art zu den anderenPleurotrema-Arten und die Stellung der GattungPleurotrema innerhalb der FamilieParatheliaceae wird kurz diskutiert.  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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A completely perichondrally ossified endocranium of a generalized reprsentative of the Eubrachythoraci,Beyrichosteus radiatus n. g., n. sp., is described. The specimen shows a typical platybasie skull with widely separated nasal capsules like that of the mainly Early Devonian Dolichothoraci. This is contrary to the spezialized generaTapinosteus andPholidosteus from Wildungen, being previously often regarded as model for the endocranium of coccosteomorph arthrodires. However, characters of the orbit and the nasal capsule are more similar to other Eubrachythoraci than to those of Dolichothoraci and primitive Brachythoraci. Until now, there are not enough other examples of sufficiently preserved endocrania of brachythoracid arthrodires known for a phylogenetic analysis. Nevertheless, the observations made onBeyrichosteus are questioning the assignment of the Pholidosteidae to the Coccosteomorphi.  相似文献   

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Arthopyrenia endobrya from Southern Brazil is illustrated and described as a new species of lichens. The thallus is composed of filamentous green algae loosely surrounded by fungal hyphae. Both symbionts grow endophytically within the leaf cells of two species ofLejeuneaceae (Hepaticae). The algae and hyphae penetrate the cell walls of the host by means of fine perforations. The ascocarps develop between the leaves and perforate them with their apical region. The classification as a member of the genusArthopyrenia is preliminary.
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A pseudomonotide pelecypod-Pachypteria sinaitica n. sp. - is described from Abu Durba Formation (Visé) of southwest Sinai. The new species forms a link with rather similar populations in the Lower Carboniferous of Marocco. Like the oysters, but byssate and cemented with its right valve,P. sinaitica n. sp. built up small limestone beds within a marginal marine environment of sedimentation. As regards the isotopie composition, the carbonates of the shell were secreted in a water of approximately 25° C.It follows, that the littoral waters of the southern Tethys were warmer during the Lower Carboniferous than those of present Red Sea.  相似文献   

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Résumé Sonderia labiata n. sp., se distingue de Pespèce voisine S. vorax Kahl par ses caractères écologiques de Cilié marin psammobie et facultativement sédentaire; par une asymétrie moins marquée que chez les autres espèces du genre; par la presence de corps de réserve polysaccharidiques de forme lamellaire.  相似文献   

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Rotasaccus dentifer n. g. n. sp., a Devonian ophiocistioid (Echinodermata) from the eastern Rheinisches Schiefergebirge differs from other ophiocistioids in some extraordinary features: there is no plated theca but a body wall containing a continuous layer of wheellike micro-sclerites; instead of perradial plates there are 7 fragile swallow-like elements with oral furrow in each perradial row; the relatively small tube feet are not covered by scale plates but by microscopic sieve plates. The formerly unknown masticatory apparatus of ophiocistioids is shown inRotasaccus to be built in principle like an echinoid lantern. In the systematical part, some revision for the class ophiocistioidea is realized from these results and a new family, Rotasacciidae, is introduced.  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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Zusammenfassung Die neu beschriebene Algen-SyncynoseCyanoptyche dispersa n. sp. unterscheidet sich vonCyanoptyche gloeocystis durch bestimmte, charakteristische Merkmale. Im zentralen Teil ihrer Cyanellen findet sich ein auffallender, eigentümlicher Körper, der bisher nur bei dem Flagellaten-EndocyanomCyanophora paradoxa beobachtet wurde.Über die Natur der Cyanellen läßt sich noch kein abschließendes Urteil fällen. Doch bestehen Bedenken, sie einfach freilebenden Cyanophyceen gleichzusetzen.  相似文献   

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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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