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1.
Study of Recent abyssal benthic foraminifera from core-top samples in the eastern equatorial Indian Ocean has identified distinctive faunas whose distribution patterns reflect the major hydrographic features of the region. Above 3800 m, Indian Deep Water (IDW) is characterized by a diverse and evenly-distributed biofacies to whichGlobocassidulina subglobosa, Pyrgo spp.,Uvigerina peregrina, andEggerella bradyi are the major contributors.Nuttalides umbonifera andEpistominella exigua are associated with Indian Bottom Water (IBW) below 3800 m. Within the IBW fauna,N. umbonifera andE. exigua are characteristic of two biofacies with independent distribution patterns.Nuttalides umbonifera systematically increases in abundance with increasing water depth. TheE. exigua biofacies reaches its greatest abundance in sediments on the eastern flank of the Ninetyeast Ridge and in the Wharton-Cocos Basin. The hydrographic transition between IDW and IBW coincides with the level of transition from waters supersaturated to waters undersaturated with respect to calcite and with the depth of the lysocline. Carbonate saturation levels, possibly combined with the effects of selective dissolution on the benthic foraminiferal populations, best explain the change in faunas across the IDW/IBW boundary and the bathymetric distribution pattern ofN. umbonifera. The distribution of theE. exigua fauna cannot be explained with this model.Epistominella exigua is associated with the colder, more oxygenated IBW of the Wharton-Cocos Basin. The distribution of this biofacies on the eastern flank of the Ninetyeast Ridge agrees well with the calculated bathymetric position of the northward flowing deep boundary current which aerates the eastern basins of the Indian Ocean.  相似文献   

2.
在黔西水城地区的K576井长兴组共鉴定钙藻3属3种,包括Gymnocodium bellerophontis、Permocalculus sp.和Tauridiumkurdistanensis;有孔虫8属10种,其中(虫筳)类2属2种,有孔虫动物群主要由Reichelinasp.indet.、Nankinella sp.、Pachyphloia schwageri、Pachyphloia sp.、Geinitzina sp.、Nestellorella sp. indet.、Howchinella sp.、Hemigordius aff. saranensis、Hemigordius sp.和Midiella sp. indet.组成。将本井按照生物特征分为有孔虫-钙藻-介形虫组合、有孔虫-腕足类-介形虫组合、介形虫-双壳类-腹足类组合、有孔虫-钙藻-双壳类组合、有孔虫-腕足类-介形虫组合、有孔虫-钙藻-双壳类组合和介形虫组合等7个组合。按照层序地层划分、垂向沉积序列特征和测井资料的分析,有孔虫-钙藻-介形虫组合(SQ3-3)和有孔虫-腕足类-介形虫组合(SQ3-4)时期地层为三角洲前...  相似文献   

3.
Three hundred and sixty-nine macroalgal and non-algal samples were collected from six coastal sites around the island of Hawai‘i on a biweekly basis over a 1-year period to ascertain (1) the presence of potentially toxigenic benthic dinoflagellates, and (2) substrate and environmental preferences of the dinoflagellates. Twenty-six genera/species of dinoflagellates were encountered including the (potentially) toxigenic species Amphidinium sp., Coolia monotis, Gambierdiscus sp., Ostreopsis ovata, Prorocentrum concavum, Prorocentrum hoffmannianum, Prorocentrum lima, and Prorocentrum mexicanum. Twenty of the species are being reported for the first time as present in Hawaiian coastal waters. There was some evidence of macroalgal host preference (e.g., C. monotis on Tolypiocladia glomerulata), although host morphology preferences was greater (e.g., Gambierdiscus sp., and P. lima on filamentous turfs; O. sp. 1 on sheet-like macroblades). While some dinoflagellate groups were significantly correlated with nutrient concentrations (e.g., total dinoflagellates with nitrate + nitrite and phosphate concentrations), others were not (e.g., Gambierdiscus sp., Prorocentrum emarginatum, P. lima, and Sinophysis microcephalus). The presence of several potentially toxigenic dinoflagellate species in Hawai‘i merits future study on possible impacts of these dinoflagellates on coastal food webs and human health.  相似文献   

4.
Summary An assemblage of microfossils, including calcareous green algae (dasycladaleans:Deloffrella quercifoliipora, Bakalovaella elitzae, Salpingoporella cf.muehlbergii, Terquemella sp.,Neomeris sp., andCylindroporella? sp.; Halimedaceans/Gymnocodiaceans:Boueina sp.Permocalculus aff.minutus), red algae (Solenoporaceans?:Marinella lugeoni), cysts of dinoflagellates? (Cadosina fusca fusca, Colomisphaera aff.conferta) and foraminifers (Torinosuella peneropliformis, Charentia cuvillieri, Commaliama sp.) is described from the carbonate beds within the terrigenous-carbonate Sangestan Formation (Upper Jurassic—Neocomian) exposed near the small village of Zereshk, approximately 63 km SW of Yard, central Iran. The micropaleontological assemblage indicates a late Neocomian (Hauterivian) age of the carbonate beds.  相似文献   

5.
High-resolution foraminiferal analysis was conducted on a short sediment core from the inner part of Osaka Bay, Japan. Changes in foraminiferal assemblages were associated with eutrophication, bottom water hypoxia, and changes in red tide-causing algae. Before the 1920s, the calcareous species Ammonia beccarii, and the agglutinated species Eggerella advena and Trochammina hadai were rare, but calcareous foraminifers in general were abundant. Between the 1920s and 1940s, calcareous foraminifers decreased abruptly in abundance, while A. beccarii, E. advena and T. hadai increased in abundance. This faunal change corresponded in time to an increase in nutrients flowing in through the Yodo River, and bottom water hypoxia related to eutrophication. In the 1960s and 1970s, A. beccarii, E. advena and T. hadai further increased in abundance to become dominant, and many calcareous foraminifers nearly disappeared, corresponding to increasing bottom water hypoxia related to the rapid increase in discharged nutrients during the high economic growth period from 1953 to 1971. After the 1990s, A. beccarii decreased rapidly in abundance and E. advena and Uvigerinella glabra increased in abundance. The main components of red tide-causing algae changed from dinoflagellates to diatoms in the 1980s through 1990s, thus there was a change in the food supply to the benthos, which may have caused the increase in abundance of E. advena and U. glabra.  相似文献   

6.
A new genus and two new species of water scavenger beetles, Hydrophilopsia bontsaganica, sp. nov. and Prospercheus cristatus, gen. et sp. nov., are described from the Upper Jurassic and Lower Cretaceous of Mongolia. The systematic position of the new genus is discussed.  相似文献   

7.
Thirty-five species belonging to 21 genera of foraminifers are distinguished from allochthonous limestone blocks contained within the autochthonous mudstones and sandstones of the Carnian Tanoura Formation, Kurosegawa Terrane of West Kyushu (SW Japan). These blocks are considered to be Anisian in age, based on the occurrence of two foraminifers widely distributed in the Anisian of the Tethyan Realm, Pilammina densa and Meandrospira dinarica; they are associated with Involutinid-like forms, such as Triadodiscus and Aulotortus, and with other foraminifers. The allochthonous limestones are mostly composed of oolites, abundant bioclasts and detrital quartz grains. They are thought to have been redeposited during the Carnian on the shelf slope of the South Kitakami-Kurosegawa Old Land. Palaeogeographically, this terrane was part of the North Gondwana margin, then isolated eastwards before its Early Cretaceous amalgamation with South China. Three foraminiferal species, Triadodiscus eomesozoicus (Oberhauser), Triadodiscus? tanourensis, n. sp., and Triadodiscus? sp. are described from the Anisian allochthonous blocks.  相似文献   

8.
Three new species of mayfly nymphs, Clavineta excavata sp. nov., Clavineta brevinodia sp. nov., and Siberiogenites branchicillus sp. nov., from the Yixian Formation (Late Jurassic-Early Cretaceous) in western Liaoning Province, China, are described. These mature nymphs are small-sized, with the body less than 16.0 mm long. The systematic position of the genera Clavineta and Siberiogenites, which are recorded for the first time in the Yixian Formation, is briefly discussed.  相似文献   

9.
The position of the Iberian Peninsula during the Early Cretaceous, sandwiched between Laurasia and Gondwana, makes it an important area for the biogeography study of terrestrial ecosystems. Relevant data are, however, scarce. The discovery of silicified wood in the west of the Cameros Basin, in the village Hacinas (Spain), is the first record of the genus Protopodocarpoxylon in Spain and the seventh of Agathoxylon. A new species, Protopodocarpoxylon haciniensis sp. nov., is described. The anatomy of the samples studied shows that paleoclimatic conditions during the Early Cretaceous in the western part of the Cameros Basin were favorable to tree growth, with good water supply during the growth season. Although much impoverished in comparison with Western Europe, the Iberian Early Cretaceous wood floras are clearly Laurasian in affinity.  相似文献   

10.
In the framework of the palaeogeographical reconstruction of the Western Taurus during Jurassic, the study of northern and eastern boundary of the Taurids started. Detailed facies analysis evidenced the position of the Barla Dag ramp between two elevated areas: the southern rimmed shelf extension of the platform system and the northern neritic-beach-land plain. In the basal biostratigraphical and ecological characteristics of the Balcikhisar volcano-sedimentary sequence, correlated with the Fele outcrop, one genus and three new species of foraminifers have been found: Sievoides kocyigiti n. gen., n. sp. and Mesoendothyra altineriana n. sp. from neritic environment, and Kurnubia feleensis n. sp. from rimmed shelf lagoon. Both carbonate sedimentary deposits are intercalated with spilitic-basalt pillow lava flows. The age of the new three species is Kimmeridgian, controlled by some foraminifer golden hooks.  相似文献   

11.
Ostracodes Healdianella splendida Belousova, Paraparchites ganelini sp. nov., Paraparchites? hivachensis sp. nov. and Arcibairdia vodopadniensis sp. nov. are described from the Upper Permian deposits of the Khivach Formation (Kolyma-Omolon Basin, Eastern Siberia). Paraparchites species most closely resemble ancient Paleozoic ostracodes of the Boreal province. Valve morphology of Healdianella and Acribairdia points to their similarity to ostracodes from the upper levels of the Upper Permian of the Tethyan realm.  相似文献   

12.
Investigations on calcareous dinoflagellates from surface sediments from the Mediterranean Sea revealed 14 species, including one new genus and four previously undescribed species: Calciodinellum levantinum sp. nov., Calciodinellum elongatum nov. comb., Lebessphaera urania gen. nov. et sp. nov., and Scripp‐ siella triquetracapitata sp. nov. Furthermore, Fuettererella cf. tesserula, so far only known from the fossil record, was found. The cyst–theca relationships of C. levantinum and C. elongatum are given, based on strains established from water samples of the Mediterranean Sea and the Atlantic Ocean. This study gives an insight into the importance of the modern Mediterranean Sea as an unique region concerning calcareous cyst producing dinoflagellates.  相似文献   

13.
New bryozoans characterized by a bilateral vertical colonies colonies—Cardioecia refuga sp. nov. (Tubuliporida), Elea lyapini sp. nov., E. troshkovensis sp. nov., and E. taylori sp. nov. (Melicerititida) from Middle Jurassic (Middle Callovian) of the Moscow region (Russia), and Biforicula legitima sp. nov. (Melicerititida) from the Upper Cretaceous (Lower Campanian) of the Southern Donets Basin (Ukraine)—are described. All species described in this paper belong to genera that have been recorded for the first time in the East European Platform. Some morphological structures in the colonies of these bryozoans and some distinctive features of the order Melicerititida that emphasize the difference of this order from bryozoans of other orders of the class Stenolaemata are examined.  相似文献   

14.
Maastrichtian cephalopods and a brachiopod were dredged from the Butakov, Fedorov, Kotsebu, Il’ichev, Govorov, Gelendzhik, and Ita-Mai-Tai guyots in the Magellan Seamounts. The ammonoids Hypophylloceras sp., Phyllopachiceras sp., Anagaudryceras? sp. A, Anagaudryceras? sp. B, Gaudryceras aff. propemite Marshall, Gaudryceras sp., and Pseudophyllites cf. indra (Forbes), and the single brachiopod Basiliolidae gen. and sp. indet. are a first discovery in this oceanic region, following earlier finds of belemnites (Dimitobelus? sp., Dimitobelidae gen. and sp. nov., and Belemnitella? sp.), and two ammonoid species (Zelandites aff. japonicus Matsumoto and Tetragonitidae gen. and sp. indet.). The Late Cretaceous Magellan Seamounts dimitobelid belemnite fauna shows affinities with southern high latitude forms (New Zealand) and the ammonoid fauna with northern, middle and high latitude ones (Hokkaido-Sakhalin and/or Kamchatka). This suggests by the end of the Cretaceous major surface palaeo-currents from S and N sides in direction of the central Palaeo-Pacific, a position coinciding with the plate tectonic reconstruction of the Magellan Seamounts.  相似文献   

15.
Three new species of the fossil Lower Cretaceous family Praeichneumonidae are described from the Lower Cretaceous of Transbaikalia (Russia, Buryatia, Khasurty locality): Praeichneumon dzhidensis sp. nov., P. khamardabanicus sp. nov., and P. zakhaaminicus sp. nov. One poorly preserved specimen, Praeichneumon sp., is described. Rudiments of the second anal vein A2 and internal vein a1–a2 and bullae in crossveins of the fore- and hindwing are described in Praeichneumonidae for the first time.  相似文献   

16.
More than 100 species of gastropods from vent and seep localities around the world are reviewed, based on literature information and new material. The following new taxa are described (localities with parentheses, systematic position within brackets): Cantrainea macleani sp.n. (Louisiana Slope) [Turbinidae]; Fucaria striata gen. et sp.n. (Juan de Fuca Ridge area), Vetuloniaphalcata sp.n. (North Fiji Basin) [both Trochidae]; Protolira valvatoides gen. et sp.n. (Mid-Atlantic Ridge) [Skeneidae]; Ventsia tricarinata gen. et sp.n. (Lau Basin), Bruceiella globulus gen. et sp.n. (Lau Basin) [both tentatively in Skeneidae]; Melanodrymia brightae sp.n. (Juan de Fuca Ridge area), Pachydermia sculpta sp.n. (Lau Basin), Planorbidella gen.n., P. depressa sp.n. (Lau Basin), Ctenopelta porifera gen. et sp.n. (EPR 13°N)[Peltospiridae]; Helicrenion reticulatum gen. et sp.n. (Lau Basin), Lepfogyra inflata sp.n. (Lau Basin) [families unknown]; Desbruyeresia spinosa gen. et sp.n. (Lau Basin), D. cancellata sp.n.(Lau Basin), D. melanioides sp.n. (Lau Basin), Provanna buccinoides sp.n. (Lau Basin) [Provannidae]; Hyalogyra vitrinelloides sp.n. (Lau Basin), Hyalogyrina grasslei s p a (Guaymas Basin)[Hyalogyrinidae fam. n.], Xylodiscula major sp.n. (North Fiji Basin) [Xylodisculidae]. The external morphology of the soft parts [for Ifremeria and Alviniconcha (Provannidae) also the anatomy] is described for most of the taxa involved. Some features in the biology and distribution of the gastropod fauna are discussed. About half the fauna consists of species belonging to families or superfamilies endemic to this environment. One-fifth of the remaining species belong to taxa normally associated with biogenic substrates in the deep sea. Alviniconcha hessleri has previously been shown to harbour chemosynthetic bacteria in the gill; Ifremeria nautilei is here confirmed to do the same. Ctenopelta porifera, and Hirtopelta hirta are suspected to have such bacteria because of reduction of the alimentary system.  相似文献   

17.
A new species, Tanychora loki, sp. nov., and a new genus and species, Megachora sibirica gen. et sp. nov., are described from the Lower Cretaceous of Transbaikalia and Mongolia. The genus Tanychora Townes, 1973 is divided into two genera: Tanychora s. str., composed of T. petiolata Townes, 1973 (type species), T. sinensis Zhang, 1991, and T. loki sp. nov., and Amplicella, gen. nov., composed of A. sessilis (Townes, 1973) (type species), A. exquisite (Zhang et Rasnitsyn, 2003), A. beipiaoensis (Zhang et Rasnitsyn, 2003), and A. spinata (Zhang et Rasnitsyn, 2003). The frequency of occurrence of ichneumonids in the principal Cretaceous localities of central and northern Asia is calculated.  相似文献   

18.
The fatty acid and sterol compositions of five species of marine dinoflagellates (Scrippsiella sp. Symbiodinium microadriaticum Freud, Gymnodinium sp., Gymnodinium sanguineum Hirasaki, and Fragilidium sp.) are reported. All contained the major fatty acids that are considered common in dinoflagellates, but the proportions were quite variable, and some species contained low contents of some polyunsaturated fatty acids. Concentration ranges for the major fatty acids were: 16:0 (9.0%–24.8%), 18:4(n-3) (2.5%–11.5%), 18:5(n-3) (7.0%–43.1%), 20:5(n-3) (EPA) (1.8%–20.9%), and 22:6(n-3) (DHA) (9.9%– 26.3%). Small amounts of novel very-long-chain highly unsaturated C28 fatty acids occurred in all species. Each dinoflagellate contained a complex mixture of 4-methyl sterols and 4-desmethyl sterols. Four species contained cholesterol, although the amounts were highly variable (from 0.2% of total sterols in Scrippsiella sp. to 45.6% in Fragilidium sp.). All but G. sanguineum contained the 4-methyl sterol dinosterol, and all species contained sterols lacking a double bond in the ring system (i.e. stanols); in Scrippsiella sp. cholestanol composed 24.3% of the total sterols. Other common features of the 4-methylsterol profiles were the presence of 23,24-dimethyl alkylation and unsaturation at Δ22 in the side chain. In Scrippsiella sp., four steroidal ketones were identified: cholestanone, dinosterone, 4α,23,24-trimethyl-5α-cholest-8(14)-en-3-one, and dinostanone. The structures of these corresponded to the major sterols in this species, suggesting that the sterols and steroidal ketones are biosynthetically linked. Steroidal ketones were not detected in the other species. Although fatty acid profiles can be used to distinguish among algal classes, they were not useful for differentiating among dinoflagellate species. In contrast, whereas some taxonomic groupings of dinoflagellates display similar sterol patterns, others, such as the gymnodinoids studied here, clearly do not. The combination of fatty acid, sterol, and steroidal ketone profiles may be useful complementary chemotaxonomic tools for distinguishing morphologically similar species. The identification of steroidal ketones supports earlier suggestions that certain dinoflagellates might be a significant source of such components in marine environments.  相似文献   

19.
Abstract: Bulk sampling of upper Campanian to lower–middle Maastrichtian coastal and lagoonal deposits in five sections of the Tremp Formation in the south‐central Pyrenees yielded numerous neoselachian teeth. The fauna comprises nine taxa of which three species and one genus are new: Hemiscyllium sp., Lamniformes indet., Paratrygonorrhina amblysoda gen. et sp. nov., Coupatezia trempina sp. nov., Coupatezia sp., Coupatezia? sp., Rhombodus ibericus sp. nov. and Igdabatis indicus. The neoselachian fauna is dominated by small nectobenthic rays. This composition resembles assemblages known from the marine Upper Cretaceous, but differs from nearby localities of the Basque‐Cantabrian region and continental selachian associations of the French Pyrenees. The results indicate that Rhombodus might not be a reliable biostratigraphic marker for the Maastrichtian. The faunal composition suggests a shallow trans‐Tethyan connection between Eurasia and India at the end of the Cretaceous Period.  相似文献   

20.
Diverse radiolarians from the Upper Cretaceous Perapedhi and Moni formations (southern Cyprus) are studied. Many representatives of the genus Afens Riedel et Sanfilippo, 1974 are recognized. The diagnosis of the genus Afens is emended and three new species of this genus, Afens perapediensis sp. nov., Afens moniensis sp. nov., and Afens concinnus sp. nov., are described. In addition, the species Afens liriodes Riedel et Sanfilippo, 1974 is redescribed.  相似文献   

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