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1.
The spinicaudatan Neodiestheria Chen is an important component of the diverse Early Cretaceous Yanjiestheria fauna in eastern Asia. Examination under a scanning electron microscope of newly collected and well-preserved specimens of Neodiestheria dalaziensis Chen from the Albian Dalazi Formation of Zhixin, Jilin Province, north-eastern China, has revealed morphological features of the carapace not recognized previously, namely that puncta are not only evenly distributed on growth bands near the umbo and gradually merge into a punctate fine reticulation and dense radial lirae on each growth band in the upper-middle part of the carapace, but also occur on growth lines and within the lumina of a fine reticulum, and between radial lirae on growth bands in the middle and lower parts of the carapace. Growth bands in anteroventral, ventral and posteroventral parts of the carapace are also ornamented with transversely elongate large pits (depressions) surrounded by swellings, appearing as a large reticulum superimposed over fine reticulation and radial lirae. These ontogenetically developing morphological patterns on the growth bands of the juvenile stage of the carapace indicate that Neodiestheria is closely related phylogenetically to Triglypta Wang. 相似文献
2.
The diagnoses of the conchostracan genera Cratostracus and Porostracus are revised following a re-examination of their type species under a scanning electron microscope. In Cratostracus each growth line has a serrated lower margin. Radial lirae branch into smaller ridges that merge with each other to give the upper part of each growth band in the ventral region of the carapace a slightly undulating surface. Cross-bars are present between these lirae. In Porostracus the radial lirae on the growth bands near the umbo are long and relatively widely spaced. There is a fine reticulum between them in the umbonal part of the carapace and cross-bars on the ventral surface. The ornament of Porostracus indicates that it can be assigned to the family Halysestheriidae rather than to the Afrograptidae, in which it has been placed previously. Morphological analysis of most of the species of the two genera and closely related Orthestheria (Migransia) under the scanning electron microscope is required before their stratigraphic potential can be fully realized. 相似文献
3.
LI Gang SHEN Yanbin LIU Yongqing Peter BENGTSON Helmut WILLEMS Hiramichi HIRANO 《《地质学报》英文版》2009,83(1):46-51
The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China. Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin, northern Hebei, China, is revised on the basis of a scanning electron microscope (SEM) examination of the type species M. jingshangensis Wang, 1984, which revealed morphological features not recognized previously. These include coarse reticulation on the umbo and prominent growth lines ornamented with densely spaced, small tubercles and fine lirae. 相似文献
4.
The fossil snakefly family Baissopteridae from the Lower Cretaceous (upper Barremian) of the Yixian Formation of Liaoning Province, China is reviewed. Two genera and five species of Baissopteridae are recorded, including a new genus, namely Microbaissoptera gen. nov., and three new species, i.e., Baissoptera bicolor sp. nov., Baissoptera sinica sp. nov., and Microbaissoptera monosticha sp. nov. Moreover, Baissoptera euneura Ren, 1997 is herein treated as a new junior synonymy of Baissoptera grandis Ren in Ren et al., 1995. Baissoptera minima Ponomarenko, 1993 is transferred to the presently described new genus Microbaissoptera gen. nov. based on the small body-size and the presence of a single gradate series of crossveins in radial and medial areas of posterior part of both fore- and hind wings. A key to genera of Baissopteridae is provided. 相似文献
5.
New Middle Turonian mosasauroid remains were discovered in the same large-sized nodule that yielded a specimen referred to Tethysaurus nopcsai Bardet et al., 2003, from the Goulmima region (southern Morocco). They comprise isolated, fragmentary cranial elements (skull and mandible) and some vertebrae. Their very small size suggests a juvenile condition, an observation supported also by anatomical (spongious nature of numerous bone parts), micro-anatomical (loose inner spongiosa) and histological (numerous remains of calcified cartilage deep into the centrum; radial vascular canals) data. These bones belonged to a basal mosasauroid that cannot be distinguished from Tethysaurus nopcsai to which taxon we tentatively assign the material. 相似文献
6.
We describe two new species of extinct biting midges in the fossil genus Protoculicoides: Protoculicoides hispanicus Szadziewski and Arillo, sp. nov. and Protoculicodes sanjusti Szadziewski and Arillo, sp. nov., from Albian (101–113 Ma) amber of San Just, Spain. Atriculicoides Remm, 1976 is recognized as a new junior synonym of Protoculicoides Boesel, 1937 (NEW SYNONYM). Devalquia Choufani et al., 2013 is regarded here as a new junior synonym of the extant genus Culicoides Latreille, 1809 (NEW SYNONYM). Metahelea roggeroi Choufani et al., 2013 from Upper Cretaceous French amber, is excluded from the tribe Heteromyiini and placed in the extant genus Stilobezzia Kieffer, 1911, tribe Ceratopogonini: Stilobezzia roggeroi (Choufani et al., 2013), comb. nov. The extinct tribe Atriculicoidini Szadziewski, 1996 is regarded as a new subfamily, Atriculicoidinae, stat. nov., that includes the fossil genus Protoculicoides, with 13 species reported from Albian, Turonian, Cenomanian, Coniacian, Santonian and Campanian ambers (78–113 Ma). Protoculicoides skalskii Szadziewski & Arillo, 1998 from Lower Cretaceous amber of Álava, Spain, Protoculicoides succineus Szadziewski, 1966 from Lower Cretaceous Lebanese amber and Protoculicoides burmiticus Szadziewski & Poinar, 2005 from Upper Cretaceous Burmese amber are transferred to the extinct genus Archiculicoides Szadziewski, 1996, comb. nov. Protoculicoides krzeminskii Choufani et al., 2014 from Lower Cretaceous Lebanese amber is transferred to the extinct genus Archiaustroconops Szadziewski, 1996, comb. nov. The Cretaceous subfamily Atriculicoidinae forms an unresolved trichotomy with the extant subfamilies Forcipomyiinae and Dasyheleinae, both of which date to the Eocene. The fossil record indicates that wings with macrotrichia in biting midges evolved during the mid-Cretaceous greenhouse climate. We suggest that this was an evolutionary adaptation to new atmospheric conditions with higher levels of CO2 in order for the antennal Johnston's organs of males to receive the vibrational sex signals produced by females during flight. 相似文献
7.
Micromantispa cristata Shi et al., 2014 from Burmese amber does not belong to Paraberothinae (Berothidae), but most likely to Mantispidae. 相似文献
8.
Micromantispa cristata Shi et al., 2014 from Burmese amber belongs to Paraberothinae (Berothidae), not to Mantispidae. 相似文献
9.
Terry et al. (2001) proposed that the Fox Hills Formation in the area of Badlands National Park, southwestern South Dakota, USA, contains the Cretaceous/Paleogene (K/Pg) boundary, marked by a thick layer of contorted bedding called the Disturbed or Disrupted Zone (DZ). Examination of the ammonites from just below this layer yields Hoploscaphites nicolletii (Morton, 1842), H. spedeni (Landman and Waage, 1993), Discoscaphites gulosus (Morton, 1834), D. conradi (Morton, 1834), and Sphenodiscus lobatus (Tuomey, 1856). The abundance of Discoscaphites and the presence of a coarsely ornamented specimen of H. spedeni suggest that this assemblage corresponds to the upper part of the H. nicolletii Zone in the type area of the Fox Hills Formation. No ammonites are present above the DZ, but previous analyses of the dinoflagellates from just below, within, and above the DZ by Palamarczuk et al. (2004) are consistent with the ammonite results. Together, these fossils indicate that the interval just below and above the DZ represents the upper part of the lower upper Maastrichtian (≈ middle upper Maastichtian). Belemnites are present in the strata just below the DZ and occur as guards either isolated in the matrix or associated with fragmentary ammonites in concretions composed of soft sandy marl. The belemnites are assigned to Belemnitella bulbosa Meek and Hayden, 1857a, and B. badlandsensis n. sp., which is characterized by an unusually large fissure angle. The distribution of ammonites and lithofacies at this time reveals that the western shoreline of the Western Interior Seaway trended northeast–southwest across western South Dakota and adjacent parts of North Dakota. Based on an examination of the oxygen isotopes of the belemnites and scaphites in this area, the seawater temperature was nearly constant along the coast, approximately 17–20 °C. A comparison of the contact between the Pierre Shale and Fox Hills Formation at various localities in the Western Interior Basin indicates that this contact rises in the section toward the east, reflecting the final retreat of the Seaway during the late Maastrichtian. 相似文献
10.
The Late Cretaceous (Turonian–Campanian) turritellid gastropod Roemerella Akopyan in Akopyan et al., 1990, is a junior homonym of the Devonian inarticulate brachiopod Roemerella Hall and Clarke, 1890. The generic name Roamerella nom. nov. is proposed for the homonymous gastropod. 相似文献
11.
A microfossil assemblage has been found in the widely spaced (300 km apart) Baikit and Katanga areas (inner Siberian Platform) in stratigraphically coeval strata in the lower part of the petroliferous Kamo Group (Riphean). It comprises complex protists Tappania plana Yin; acritarchs Valeria lophostriata Jank., Satka sp., Lophosphaeridium sp., Pulvinosphaeridium sp., and Miroedichia sp.; porous vesicles of Tasmanites sp. and Osculosphaera sp.; vesicles with anastomosing processes, and spiral filaments of Obruchevella and Glomovertella. Siberian fossil microbiota is considerably more diverse than biota with Tappania protists known in Australia and China. A taxonomically similar fossil biota found 1500 km northeast of the well-studied Riphean section in the Olenek uplift suggests that the host rocks, too, are stratigraphically coeval. This permits refining the age of remains of the first complex eukaryotes from the inner platform and is an additional correlation criterion for the lower Kamo Group. 相似文献
12.
Several analogue modeling studies have been conducted during the past fifteen years with the aim to discuss the effects of sedimentation and erosion on Foreland Fold and Thrust Belt, among which a few have analyzed these processes at kilometric scale (Malavieille et al., 1993; Nalpas et al., 1999; Barrier et al., 2002; Pichot and Nalpas, 2009). The influence of syn-deformation sedimentation and erosion on the structural evolution of FFTB has been clearly demonstrated. Here, we propose to go further in this approach by the study of a more complex system with a double decollement level. The natural study case is the Bolivian sub-Andean thrust and fold belt, which present all the required criteria, such as the double decollement level. A set of analogue models performed under a CT-scan have been used to test the influence of several parameters on a fold and thrust belt system, among which: (i) the spatial variation of the sediment input, (ii) the spatial variation of the erosion rate, (iii) the relative distribution of sedimentation between foreland and hinterland. These experiments led to the following observations:
- 1. The upper decollement level acts as a decoupling level in case of increased sedimentation rate: it results in the verticalization of the shallower part (above the upper decollement level), while the deeper parts are not impacted.
- 2. Similarly, the increase of the erosion rate involves the uplift of the deeper part (below the upper decollement level), whereas the shallower parts are not impacted.
- 3. A high sedimentation rate in the foreland involves a fault and fold vergence reversal, followed by a back-thrusting of the shallower part.
- 4. A high sedimentation rate in the hinterland favours thrust development toward the foreland in the shallower parts.
13.
Schistose high-grade hematite orebodies (>64 wt % Fe) in the Iron Quadrangle, Minas Gerais, were formed in shear zones by hydrothermal alteration of the Paleoproterozoic Cauê BIF during the Transamazonian orogenesis. The ore is comprised of platy hematite (specularite) grains that define the foliation and overprint a relict banded martite-hematite fabric resembling, at first sight, a mylonite. The EBSD analyses of a m-scale schistose orebody from the Pau Branco mine show that specularite grew as elongated plates with the (00.1) plane parallel to the foliation. The population of the measured grain aspect ratio (GAR) is homogenous in different scales, and the longest axes of the crystals align with the stretching lineation (L//X) building continuous domains, or anastomose around stretched iron oxide aggregates and rootless fold hinges. The pole figure of the (00.1) plane shows usually a maximum centered on the pole of the foliation Z often elongated on a girdle perpendicular to the lineation L. The {10.4} pole figure has the configuration of a symmetric cleft girdle and the corresponding {11.0} and {10.0} pole figures present well developed girdles parallel to the foliation with an elongated maximum centered on X. Microstructures associated with crystal-plastic behavior and dynamic recrystallization are missing and the fabric of the orebody probably results from precipitation of strain-controlled oriented hematite plates and anisotropic syntaxial growth of favorably oriented grains with the intervention of hydrothermal fluids during Fe enrichment. The shear zone provided pathways for the percolation of mineralizing fluids under temperatures that varied from 140 to 350 °C or higher, under ductile or ductile–brittle conditions. The orthorhombic fabric and CPO (crystallographic preferred orientation) of the ore nevertheless contrast with the asymmetry of simple shear as observed in the torsion experiments by Siemes et al., 2010, Siemes et al., 2011, probably due to volume loss and possibly a flattening component of deformation in the ore zone. 相似文献
14.
Émile Temgoua Dieudonné Bitom Paul Bilong Yves Lucas Hans-Rudolf Pfeifer 《Comptes Rendus Geoscience》2002,334(8):537-543
Present downslope iron accumulations were investigated in the rainforest zone in southern Cameroon. Six clay and Fe-hydroxide dominated patterns have been identified and occur on the lower part of hill slopes. They can be subdivided in three different sequences, related to gentle, moderate or steep slopes. They are discontinuous with respect to the dismantling zone of the old ferricrete cap formed at Cretaceous period. They show a gradual development from a soft Fe-crust (carapace) to a vesicular facies that will, with time, cover the whole landscape again. To cite this article: É. Temgoua et al., C. R. Geoscience 334 (2002) 537–543. 相似文献
15.
A new genus and species of Mesozoic alderfly is described as Haplosialodes liui gen. et sp. nov., and from an adult male preserved in Cretaceous Burmese amber. The new genus is closely related to the genera Haplosialis Navás (Recent fauna of Madagascar), Indosialis Lestage (Recent fauna of Southeast Asia), and Eosialis Nel et al. (Eocene of France), suggesting a possible Early Cretaceous age for the clade that comprises these groups. 相似文献
16.
Recent work on the weathering of high standing islands (HSI’s) of New Zealand (Goldsmith et al., 2008), Dominica (Goldsmith et al., 2010) Martinique and Guadeloupe (Rad et al., 2006) and portions of the Philippines (Schopka et al., 2011) shows weathering rates based on stream water chemistry for areas draining andesitic terrains are comparable to weathering rates determined for basaltic terrains, indicating that andesite weathering might be much more important in drawing down atmospheric CO2 than previously recognized. While an easily erodible parent material has been largely attributed to sustaining rates at these locations, little is known to known regarding its associated reaction kinetics. We conducted a series of batch dissolution experiments on andesitic material collected from ∼10,000 year old tephra deposits from Dominica to determine the dissolution rate of major and trace mineral phases to better understand geochemical processes controlling weathering flux from these areas. Dissolution experiments were conducted over a range of pH (4 and 7) on bulk samples and mineral separates.The dissolution rates based on Si release from the Dominica tephra bulk samples were similar, and ranged from 0.04 to 0.13 μmole Si/g-day in water, and ∼0.14 to 0.27 μmole Si/g-day in dilute acid (initial pH ∼4). Although the bulk of the ash is predominately composed of vesicular felsic (Na–Al–Si) volcanic glass, reaction rates and stoichiometry indicate ash dissolution is dominated by the reactivity of trace Mg or Ca-bearing silicate phases (olivine, pyroxene or amphiboles) and Ca–phosphate phases (apatite), especially under slightly acidic conditions. Analysis of reacted phases by SEM shows little evidence of alteration of glassy material, whereas surfaces of Ca–Mg inosilicates, olivine and apatite show etched features indicative of dissolution. Results of the dissolution experiments suggest that, although these phases are relatively minor components of the ash, they contribute disproportionately to the overall weathering flux, and their reactivity may be particularly important in areas where physical weathering and erosion are constantly exposing new fresh surfaces available for chemical reaction. 相似文献
17.
A total of 24 tephra-bearing volcanic layers have been recognized between 550 and 987 m depth in the Siple Dome A (SDM-A) ice core, in addition to a number already recognized tephra in the upper 550 m (Dunbar et al., 2003, Kurbatov et al., 2006). The uniform composition and distinctive morphological of the particles composing these tephra layers suggest deposition as a result of explosive volcanic eruptions and that the layers therefore represent time-stratigraphic markers in the ice core. Despite the very fine grain size of these tephra (mostly less than 20 microns), robust geochemical compositions were determined by electron microprobe analysis. The source volcanoes for these tephra layers are largely found within the Antarctic plate. Statistical geochemical correlations tie nine of the tephra layers to known eruptions from Mt. Berlin, a West Antarctic volcano that has been very active for the past 100,000 years. Previous correlations were made to an eruption of Mt. Takahe, another West Antarctic volcano, and one to Mt. Hudson, located in South America (Kurbatov et al., 2006). The lowest tephra layer in the ice core, located at 986.21 m depth, is correlated to a source eruption with an age of 118.1 ± 1.3 ka, suggesting a chronological pinning point for the lower ice. An episode of anomalously high volcanic activity in the ice in the SDM-A core between 18 and 35 ka (Gow and Meese, 2007) appears to be related to eruptive activity of Mt. Berlin volcano. At least some of the tephra layers found in the SDM-A core appear to be the result of very explosive eruptions that spread ash across large parts of West Antarctica, off the West Antarctic coast, as well as also being recognized in East Antarctica (Basile et al., 2001, Narcisi et al., 2005, Narcisi et al., 2006). Some of these layers would be expected to should be found in other deep Antarctic ice cores, particularly ones drilled in West Antarctica, providing correlative markers between different cores. The analysis of the tephra layers in the Siple Dome core, along with other Antarctic cores, provides a timing framework for the relatively proximal Antarctic and South American volcanic eruptive events, allowing these to be distinguished from the tropical eruptions that may play a greater role in climate forcing. 相似文献
18.
The Family Afrograptidae is a ‘conchostracan’ group with multiple radial costae reaching to the umbo on their carapaces. It comprises four described genera: Afrograpta, Camerunograpta, Congestheriella and Graptoestheriella with a total of thirteen described species which are occasionally reported from the Jurassic and the Cretaceous in Africa, Europe and South America (i.e. Afrograpta from the Upper Cretaceous of Cameroon; Camerunograpta from the Jurassic to Cretaceous of Cameroon; Congestheriella from the Jurassic to Upper Cretaceous of the Congo Basin, Brazil, Bulgaria, Venezuela and Argentina; and Graptoestheriella from the Upper Jurassic to Lower Cretaceous of Brazil). A new genus and a new species, Surreyestheria ockleyensis gen. et sp. nov., belonging to the Family Afrograptidae from the Lower Cretaceous (lower Barremian) Upper Weald Clay Formation of Ockley Village, Surrey County, southern England is described in this paper. The new genus mainly differs from the other four genera by the special reticulate ornamentation on its carapace. It indicates that the Family Afrograptidae was more diverse and more widely distributed in the late Mesozoic than previously supposed. Afrograptidae is a special branch of Estheriellina the latter originating in the late Palaeozoic and the former in the early Mesozoic. Afrograptids, as a whole had been widespread across Pangea in the Early Jurassic. 相似文献
19.
A jaw bone attributed to the mid-Cretaceous azhdarchid pterosaur Alanqa saharica Ibrahim et al., 2010 is described. The new specimen from the Kem Kem beds of south eastern Morocco is unusual for the presence of expanded rostral bones that protrude above the occlusal surface of the jaws. The function of this unusual osteological modification is uncertain, but it is considered likely that it served a role in food processing, or perhaps jaw stability. 相似文献
20.
A second Mesozoic twisted-wing parasite (Strepsiptera) is described and figured based on an exceptionally well-preserved male in mid-Cretaceous (Cenomanian) amber from northern Myanmar. Phthanoxenos nervosus Engel and Huang, gen. et sp. nov., is distinguished from other strepsipteran lineages, particularly the contemporaneous Cretostylops engeli Grimaldi and Kathirithamby, also in Burmese amber, and Protoxenos janzeni Pohl et al. in mid-Eocene Baltic amber, and assigned to a new family, Phthanoxenidae Engel and Huang, fam. nov. Phthanoxenos exhibit features indicative of a more primitive phylogenetic position than Cretostylopidae but still more derived than Protoxenidae. Brief remarks are made on the geological history of the Strepsiptera. 相似文献