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1.
黑龙江绥滨地区晚侏罗世Buchia带   总被引:11,自引:2,他引:9  
绥滨地区晚侏罗世东荣组的双壳类Buchia,划分为4个带:(1)晚牛津至早启莫利期的B.concentrica带;(2)晚启莫利期的B.tenuistriata带;(3)早-中伏尔加期的B.mosquensis-B.rugosa带;及(4)晚伏尔加期的B.fischeriana带。文内共描述3属9种。  相似文献   

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描述产自辽宁北票上园地区黄半吉沟上侏罗统义县组下部膜翅目昆虫化石1新属新种Trematothoracoides liaoningensis gen.et sp.nov.,归入薤式产(Sepulcidae)中的陷胸茎蜂亚科(Trematothoracinae)。这是首次在我国发现可行的陷胸茎蜂化石,也是该亚科在侏罗纪的产次报道,分支分析结果表明Trematothoracinae为一单系类群。Thoracotrema与Prosyntexis进化程度较高,构成一对姊妹群,同时又是Trematothorax的姊妹群,Trematothoracoides最为原始,为Thoracotrema Prosymtexis Trematothorax的姊妹群。  相似文献   

4.
Today, the genus Sutneria comprises 14 species, 12 of which have been found in the Submediterranean Upper Jurassic of southern Germany, representing in some cases important stratigraphic marker fossils. In southern Germany, Sutneria appears from the Upper Oxfordian to the Middle Tithonian. It is also represented in the Epicontinental and Sub-mediterranean Upper Jurassic of the Ardèche (southeastern France) and in the Celtiberic (northeastern Spain). But in the typical Mediterranean as well as in the typical Boreal ammonite faunas Sutneria has been unknown up until now. New findings show Sutneria platynota (Lowermost Kimeridgian) in an Ammonitico rosso facies of the Betic Jurassic in southeastern Spain and Sutneria cf. subeumela (Uppermost Lower Kimeridgian) in the stratotype section of the Volgian near Gorodishche, north of Ulyanovsk, USSR. The value of the species of Sutneria as index fossils has been established for areas outside Central Europe as well as for different facies. Como mínimo, doce de las catorce especies actualmente encuadradas en el género Sutneria han sido identificadas en el Jurásico superior de Alemania meridional; los fósiles característicos suministrados por esta formación permiten puntualizar que las especies de Sutneria se localizan en los pisos comprendidos entre el Oxfordiense superior y el Titoniense medio. Las facies epicontinentales y submediterráneas de estos pisos son identicas a las presentadas por el Jurásico superior del SE de Francia (Ardèche) y del NE de España (Cordillera Ibérica) donde tambien ha sido identificada la presencia de Sutneria. Sin embargo, venia siendo desconocida la asociación de este género con la fauna amonítica típicamente mediterránea y boreal hasta que nuevos y afortunados hallazgos han permitido descubrir Sutneria platynota en una facies de Ammonitico rosso correspondiente a la base del Kimeridgiense inferior de la Cordillera Bética (SE. de España) y Sutneria cf. subeumela hacia el techo de Kimeridgiense inferior en el perfil estratotípico del Volgiense cerca de Gorodishche, N. Ulyanovsk (U.R.S.S.); estos hallazgos en facies distintas y alejadas de las de Europa Central parecen evidenciar la significación cronoestratigráfica atribuible a las especies del género Sutneria  相似文献   

5.
辽西义县组长节锯蜂科(昆虫纲,膜翅目)昆虫化石   总被引:4,自引:0,他引:4  
描述产自辽宁西部北票上园地区和凌源大王杖子义县组长节锯蜂科(Xyelidae)巨长节锯蜂亚科(Macroxyelinae)昆虫化石12种,归于4族8属,其中6新属12新种,包括Angaridyela robusta sp.nov.,Angaridyela exculpta sp.nov.,Angaridyela suspecta sp.nov.,Angaridyela endemica sp.no  相似文献   

6.
Abstract: Recent revision of the marine metriorhynchid crocodilians indicates that a partial skull previously assigned to the species Metriorhynchus superciliosus and newly discovered postcranial elements from the Kimmeridge Clay of Westbury, Wiltshire belong to a new species of metriorhynchid. This material is herein described and referred to a new species of the genus Dakosaurus, characterised by four apomorphies: the size and shape of the enlarged supratemporal fossae; relatively large teeth, and half the number in relatives; the robust and unornamented cranium; and the angle that the prefrontal makes with the long axis of the skull. In a new phylogenetic analysis, Dakosaurus carpenteri sp. nov. is the basal member of a clade containing also D. maximus and D. andiniensis: it is not so short‐snouted and its teeth are not so few and large as in the other two species, but the new form illustrates the ecological transition among metriorhynchids from a piscivorous diet to high‐order carnivory.  相似文献   

7.
藏南喜马拉雅地区晚侏罗世地层中雏蛤化石丰富,其它化石仅有少量箭石和菊石,而且属种单一,多为地方种,无法进一步划分和对比,因此,雏蛤属(Buchia)的组合特征具有重要的地质意义。结合菊石Uhligites和Substeuraces,作者在藏南喜马拉雅地区上侏罗统中识别出:1)Buchia concentrica-Buchia spitiensis;2)Buchiamosquensis- Buchia rugosa;3)Buchia blanfordiana- Buchia piochii等3个雏蛤动物组合;在下白垩统中识别出Buchiasubokensis雏蛤动物组合,其中,Buchia mosquensis-Buchia rugosa组合为证明拉弄拉地区存在晚侏罗世晚基末利期至早提塘期地层提供了新的证据,并与斯匹提地区、北美等地区进行了动物群和地层的对比,初步探讨了本区雏蛤动物群在生物地层方面的研究价值。  相似文献   

8.
Abstract:  Vertebrae of Suuwassea demonstrate an interesting combination of plesiomorphies and autapomorphies among known members of the Flagellicaudata. The cranial cervical vertebrae have proportions close to Diplodocus but resemble those of Apatosaurus except by having greatly reduced cranial and caudal spinozygapophyseal laminae. As a result, they have craniocaudally compressed, caudally positioned spinous processes excavated on all sides by fossae. The cranial thoracic vertebrae are again similarly proportioned as those of Diplodocus but are morphologically similar to those of Apatosaurus . The most distinguishing feature of Suuwassea caudal vertebrae are the short, amphiplatyan, distalmost 'whiplash' caudal vertebrae. These may be either a retention of or a reversal to the plesiomorphic sauropod condition because classic flagellicaudatan, biconvex distalmost caudals occur in the Middle Jurassic of England.  相似文献   

9.
Abstract: The quality of the Triassic–Jurassic bivalve fossil record in northwest Europe has been measured using the Simple Completeness Metric (SCM). The SCM has been applied to the fossil record of total bivalve diversity and to the records of different ecological guilds. The Westbury and Lilstock Formations record high SCM values for most ecological groups. The ‘Pre‐Planorbis Beds’ of the lower Lias Group, however, witness a precipitous decline in the completeness of most guilds and emigration of taxa due to localized marine anoxia is a likely cause. Neither variation in lithofacies, shell mineralogy, sedimentary rock outcrop area, nor sequence architecture can convincingly explain the observed patterns of completeness. Our SCM data reveal that the Early Jurassic fossil record of infaunal suspension‐feeding bivalves is significantly poorer than that of epifaunal bivalves. Any differences in the apparent Rhaetian extinction rates between these two guilds should therefore be viewed with caution. Analyses of selectivity during the Late Triassic mass extinction based on studies of global databases appear robust in light of our SCM data. Nevertheless, future investigations of the Triassic–Jurassic benthic marine ecosystem undertaken at a finer‐resolution, may need to account for the poor quality of the Early Jurassic fossil records of certain ecological guilds, such as the infaunal suspension‐feeding taxa.  相似文献   

10.
Cohen , Lila M., and Theodore Delevoryas . (Yale U., New Haven, Conn.) An occurrence of Cordaites in the upper Pennsylvanian of Illinois. Amer. Jour. Bot. 46(7): 545–549. Illus. 1959.—Cordaites validus a new cordaitean species from Calhoun, Illinois, is described. It is characterized by one or more vertical series of large, barrel-shaped parenchyma cells in association with the primary xylem, a short transition zone of primary xylem elements, extremely shallow uniseriate rays and generally uniseriate pitting. This species represents the first North American Cordaites shown to be endarch throughout.  相似文献   

11.
Abstract:  A new semionotiform fish, Isanichthys palustris gen. et sp. nov., is described from the Late Jurassic – Early Cretaceous Phu Kradung Formation, north-east Thailand. I. palustris is known from a single, nearly complete specimen found alongside abundant Lepidotes specimens at the Phu Nam Jun locality. I. palustris shows a mixture of semionotid-like characters, such as the pattern of cheek ossifications, and lepisosteid-like characters, such as the body shape and a dorsal fin opposed by an anal fin. I. palustris possesses only some of the characters currently used to define the Semionotidae. Cladistic analyses including various semionotid and gar taxa, together with Amia calva and Leptolepis coryphaenoides , suggest that the Semionotiformes (Lepisosteidae and 'Semionotidae') form a monophyletic clade, but the 'Semionotidae' taxa form an unresolved polytomy. The relationships between Semionotiformes, Halecomorphi and Teleostei are unresolved. When restricted to the best-known taxa, however, the analysis shows the monophyly of the Semionotidae sensu stricto ( Semionotus + Lepidotes ) and a sister-group relationship between halecomorphs and teleosts. These last two results are regarded as the preferred hypothesis for further studies. I. palustris is the only known example of a predaceous, probably piscivorous, 'semionotid'. It illustrates the great diversity and ecological adaptation of the semionotiforms during the Late Jurassic – Early Cretaceous. We question the phylogenetic relationships of 'ancient fishes' founded on molecular-based trees because we suspect that the use of very few Recent taxa as representatives of previously diverse lineages is an inevitable, but important, bias in the construction of such trees.  相似文献   

12.
A NEW PADDLEFISH FROM THE UPPER JURASSIC OF NORTHEAST CHINA   总被引:2,自引:0,他引:2  
orderAdpenseriformesBerg,l94oFaedyPolyodontidaeBonaparte,l838Genu8Protopsephuru8gen.nov.TyPespede8P.liuigen.etsp.nov.Protopsephuru8liuigen.etsp.nov.(Fig.1Ipl.1)HolotypeAnearlycompletefishanditscounterpart,lackingpartofitscau-dalfin.GMV2032-la,b.Horizonandl0ealityUpperJurassicYixianF0rmation,S0ngzhangzivillage,LingyuanCounty,LiaoningProvince.Diagn0chPadd1efishofmiddlesizewithtotallengthreachinglm0rmore.Rostralpartisaboutl/40fthefishlengthwithmanyr0stralsandrareste1latebones.Derm0sphe…  相似文献   

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14.
滇西晚石炭世一早二叠世苔藓虫   总被引:2,自引:0,他引:2  
简述了4个双壳类化石组合特征及沉积环境,描述了双壳类2新属(Sichuatrigonia, Pseudoburmesia)和11新种(包括新亚种).  相似文献   

15.
The oxygen consumption of the protobranch bivalve Nucula turgidawas measured in relation to size and to variation in temperatureand ambient oxygen tension. The slope of the line relating logsize and log oxygen uptake varied from 0.539 to 0.884 over therange 5°C to 40°C in summer – conditioned (S)animals but for winter – conditioned (W) animals the slopevaried from 0.561 to 0.762 over the range 5°C to 15°Conly; from 20°C to 35°C the values for the slope fellfrom 0.298 to 0.092. There was evidence of reverse acclimation,since the absolute rate of oxygen consumption was greater inS animals than in W over the temperature range studied. Thelethal limit for both groups appeared to be between 30°Cand 35°C. At all temperatures (5°C–25°C) N. turgida wasfound to be a near complete oxyconformer with b2 x 103 valuesranging from +0.0754 to –0.0234. The responses to temperature differ little from those of eulamellibranchbivalves, but the lack of ability to oxyregulate does demonstratea difference which may be linked to the different gill structure. (Received 13 January 1983;  相似文献   

16.
Three species of Antithamnion Naegeli were previously known from Natal, all reported since 1984. A more thorough collection of the flora in recent months has revealed that there are nine species in Natal, four of which are newly described. Vegetative characteristics are emphasized in this study of the taxonomy of Antithamnion, the most important being (1) size of axial cells, (2) form of whorl-branchlets, (3) size of whorl-branchlet basal cells, (4) size and shape of whorl-branchlet terminal cells, (5) size and position of gland cells, (6) primary or secondary derivation of indeterminate lateral branches, and (7) the relationship of primary indeterminate branches, if present, to normal arrangement of whorl-branchlets. Two closely related species, A. diminuatum Wollaston and A. eliseae sp. nov. have been grown in laboratory culture allowing for testing of stability and reliability of vegetative characteristics for use in taxonomic studies. Conclusions are that these criteria can be effectively used for these purposes. In addition to A. eliseae, A. nematocladellum, A. pterocladellum and A. adenocladellum also are described as new species. A tropical species previously known from the Caribbean and Red Seas, A. Iherminieri Nasr, a species previously recorded from Japan, A. secundum Itono, a species previously known from California and Japan, A hubbsii Dawson, and two species from Australia, A. diminuatum Wollaston and A. divergens (J. Agardh) J. Agardh, are also described from Natal.  相似文献   

17.
Three species of Antithamnion Naegeli were previously known from Natal, all reported since 1984. A more thorough collection of the flora in recent months has revealed that there are nine species in Natal, four of which are newly described. Vegetative characteristics are emphasized in this study of the taxonomy of Antithamnion, the most important being (1) size of axial cells, (2) form of whorl-branchlets, (3) size of whorl-branchlet basal cells, (4) size and shape of whorl-branchlet terminal cells, (5) size and position of gland cells, (6) primary or secondary derivation of indeterminate lateral branches, and (7) the relationship of primary indeterminate branches, if present, to normal arrangement of whorl-branchlets. Two closely related species, A. diminuatum Wollaston and A. eliseae sp. nov. have been grown in laboratory culture allowing for testing of stability and reliability of vegetative characteristics for use in taxonomic studies. Conclusions are that these criteria can be effectively used for these purposes. In addition to A. eliseae, A. nematocladellum, A. pterocladellum and A. adenocladellum also are described as new species. A tropical species previously known from the Caribbean and Red Seas, A. lherminieri Nasr, a species previously recorded from Japan, A. secundum Itono, a species previously known from California and Japan, A hubbsii Dawson, and two species from Australia, A. diminuatum Wollaston and A. divergens (J. Agardh) J. Agardh, are also described from Natal.  相似文献   

18.
Abstract:  Abundant well-preserved jellyfish impressions are described from the Cerin Lagerstätte (Ain, eastern France). The enclosing sediments are lithographic limestones deposited in a Late Kimmeridgian lagoon lying on an emergent reef complex. Two new taxa of Scyphozoa are proposed: Paraurelia cerinensis gen. et sp. nov. (abundant) and Paraurelia sp. A (rare), and two new taxa of Cubozoa: Bipedalia cerinensis gen. et sp. nov. (rare) and Paracarybdea lithographica gen. et sp. nov. (very rare). Rapid covering by a microbial mat helped the preservation of the animals. Many specimens of Paraurelia cerinensis are deformed by slippage down the palaeoslope, which characterizes the margin of the lagoon. Their resultant morphology and their orientation clearly indicate the downslope direction. Tentacles of Bipedalia cerinensis and Paracarybdea lithographica are also orientated according to the palaeoslope. The jellyfish were probably dead individuals occasionally introduced into the Cerin lagoon. However, another hypothesis may be considered with reference to the model of the present-day jellyfish lakes in Palau (Caroline Islands, Western Pacific). Jellyfish could have lived in the more oxygenated upper layer of water of the Cerin lagoon that allowed pelagic life. This situation could have corresponded to short periods of easier communication between the open sea and the lagoon. Jellyfish are only found in the lower beds of the lithographic limestones and their distribution illustrates the supposed evolution of the Cerin lagoon. Initially, it was deep, mainly flooded, with possibly autochthonous jellyfish and allochthonous animals indicating clear marine influence. Later, the lagoon shallowed and its sediments often emerged with marginal marine burrows and plants indicating increasing terrestrial influence.  相似文献   

19.
我国上侏罗统牛津阶-基末利阶(163-150Ma)保存有完好的最原始的蠼螋昆虫化石,首次描述,分析和讨论了原始蠼螋后翅脉序特征,认为与现代生存的蠼螋后翅基本相同。因此,提出了与西方某些蠼螋昆虫分类学者不同的意见,认为始螋亚目(Aechidermaptera)应归入于革翅目(Dermaptera)之中,且视其为一个最原始的类群较为合理,内蒙古自治区这个原始类群的下列重要特征皆为首次发现;胸骨具有特殊的形态结构;革翅锁具(Tegmina locking device)和刺脊突(spiny crest)发育;前,中,后足跗节皆为5节;后足基节显著伸长;颈部被划分为前,后两个颈片;革翅后缘收缩变尖,上述5项被视为厚原始蠼螋特有的祖征,下列特征应为早期蠼螋共有的原始性状;虫体扁平,通常具毛;腹部侧缘彼此近平行;触角显长,丝状,多节(通常多于11节);两只单眼发育;上颚具齿;中胸小盾片显大;革翅较长,通常具有明显的翅脉;股节具隆脊;爪和爪垫通常发育;腹部各节背板与腹板不重叠(两者位置非简单的上,下关系);尾须柔软,多节,雌性产卵器鞘显著外伸,本文建立了始螋亚目1新科Sinopalaeo-dermatidae和2新属2新种Sinopalaeodermata neimonggolensis gen.et sp.nov,Jurassimedeola orientalis gen,et sp.nov。同时,对蠼螋昆虫的起源和演化重新进行了讨论,做出了与西方某些蠼螋昆虫研究者结论不同的推断。  相似文献   

20.
侏罗纪双壳类动物群的分布与古气候和古地理因素   总被引:1,自引:0,他引:1  
刘春莲 《古生物学报》1999,38(4):544-550
生物群的地理分布受各种生物和环境因素的影响,对于不同地史晚期以及不同的生物类型,控制生物群分布的主导因素也不同的。就侏罗纪古大西洋双壳类动物群而言古地理和古气候条件是影响其分布的主要环境因素。  相似文献   

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